| Message ID | 1431336382-13167-3-git-send-email-yh.huang@mediatek.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Hi YH, 2015-05-11 11:26 GMT+02:00 YH Huang <yh.huang@mediatek.com>: > Add display PWM driver support to modify backlight for MT8173/MT6595. > > Signed-off-by: YH Huang <yh.huang@mediatek.com> > --- > drivers/pwm/Kconfig | 9 ++ > drivers/pwm/Makefile | 1 + > drivers/pwm/pwm-disp-mediatek.c | 225 ++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 235 insertions(+) > create mode 100644 drivers/pwm/pwm-disp-mediatek.c > > diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig > index b1541f4..9edbb5a 100644 > --- a/drivers/pwm/Kconfig > +++ b/drivers/pwm/Kconfig > @@ -111,6 +111,15 @@ config PWM_CLPS711X > To compile this driver as a module, choose M here: the module > will be called pwm-clps711x. > > +config PWM_DISP_MEDIATEK > + tristate "MEDIATEK display PWM driver" > + depends on OF > + help > + Generic PWM framework driver for mediatek disp-pwm device. > + > + To compile this driver as a module, choose M here: the module > + will be called pwm-disp-mediatek. > + > config PWM_EP93XX > tristate "Cirrus Logic EP93xx PWM support" > depends on ARCH_EP93XX > diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile > index ec50eb5..c5ff72a 100644 > --- a/drivers/pwm/Makefile > +++ b/drivers/pwm/Makefile > @@ -8,6 +8,7 @@ obj-$(CONFIG_PWM_BCM_KONA) += pwm-bcm-kona.o > obj-$(CONFIG_PWM_BCM2835) += pwm-bcm2835.o > obj-$(CONFIG_PWM_BFIN) += pwm-bfin.o > obj-$(CONFIG_PWM_CLPS711X) += pwm-clps711x.o > +obj-$(CONFIG_PWM_DISP_MEDIATEK) += pwm-disp-mediatek.o > obj-$(CONFIG_PWM_EP93XX) += pwm-ep93xx.o > obj-$(CONFIG_PWM_FSL_FTM) += pwm-fsl-ftm.o > obj-$(CONFIG_PWM_IMG) += pwm-img.o > diff --git a/drivers/pwm/pwm-disp-mediatek.c b/drivers/pwm/pwm-disp-mediatek.c > new file mode 100644 > index 0000000..38293af > --- /dev/null > +++ b/drivers/pwm/pwm-disp-mediatek.c > @@ -0,0 +1,225 @@ > +/* > + * Mediatek display pulse-width-modulation controller driver. > + * Copyright (c) 2015 MediaTek Inc. > + * Author: YH Huang <yh.huang@mediatek.com> > + * > + * This program is free software; you can redistribute it and/or modify > + * it under the terms of the GNU General Public License version 2 as > + * published by the Free Software Foundation. > + * > + * This program is distributed in the hope that it will be useful, > + * but WITHOUT ANY WARRANTY; without even the implied warranty of > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the > + * GNU General Public License for more details. > + */ > + > +#include <linux/clk.h> > +#include <linux/err.h> > +#include <linux/io.h> > +#include <linux/module.h> > +#include <linux/of.h> > +#include <linux/pwm.h> > +#include <linux/platform_device.h> > +#include <linux/slab.h> > + > +#define DISP_PWM_EN_OFF (0x0) > +#define PWM_ENABLE_SHIFT (0x0) > +#define PWM_ENABLE_MASK (0x1 << PWM_ENABLE_SHIFT) Get rid of the _SHIFT which are actually zero, it will make the code more readable. > + > +#define DISP_PWM_COMMIT_OFF (0x08) > +#define PWM_COMMIT_SHIFT (0x0) > +#define PWM_COMMIT_MASK (0x1 << PWM_COMMIT_SHIFT) > + > +#define DISP_PWM_CON_0_OFF (0x10) > +#define PWM_CLKDIV_SHIFT (0x10) > +#define PWM_CLKDIV_MASK (0x3ff << PWM_CLKDIV_SHIFT) > +#define PWM_CLKDIV_MAX (0x000003ff) > + > +#define DISP_PWM_CON_1_OFF (0x14) > +#define PWM_PERIOD_SHIFT (0x0) > +#define PWM_PERIOD_MASK (0xfff << PWM_PERIOD_SHIFT) > +#define PWM_PERIOD_MAX (0x00000fff) > +/* Shift log2(PWM_PERIOD_MAX + 1) as divisor */ > +#define PWM_PERIOD_BIT_SHIFT 12 > + > +#define PWM_HIGH_WIDTH_SHIFT (0x10) > +#define PWM_HIGH_WIDTH_MASK (0x1fff << PWM_HIGH_WIDTH_SHIFT) > + > +#define NUM_PWM 1 > + > +struct mtk_disp_pwm_chip { > + struct pwm_chip chip; > + struct device *dev; > + struct clk *clk_main; > + struct clk *clk_mm; > + void __iomem *mmio_base; > +}; > + > +static void mtk_disp_pwm_setting(void __iomem *address, u32 value, u32 mask) > +{ > + u32 val; > + > + val = readl(address); > + val &= ~mask; > + val |= value; > + writel(val, address); > +} > + > +static int mtk_disp_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, > + int duty_ns, int period_ns) > +{ > + struct mtk_disp_pwm_chip *mpc; > + u64 div, rate; > + u32 clk_div, period, high_width, rem; > + > + /* > + * Find period, high_width and clk_div to suit duty_ns and period_ns. > + * Calculate proper div value to keep period value in the bound. > + * > + * period_ns = 10^9 * (clk_div + 1) * (period +1) / PWM_CLK_RATE > + * duty_ns = 10^9 * (clk_div + 1) * (high_width + 1) / PWM_CLK_RATE > + * > + * period = (PWM_CLK_RATE * period_ns) / (10^9 * (clk_div + 1)) - 1 > + * high_width = (PWM_CLK_RATE * duty_ns) / (10^9 * (clk_div + 1)) - 1 > + */ > + mpc = container_of(chip, struct mtk_disp_pwm_chip, chip); > + rate = clk_get_rate(mpc->clk_main); > + clk_div = div_u64_rem(rate * period_ns, NSEC_PER_SEC, &rem) >> > + PWM_PERIOD_BIT_SHIFT; You never use the remainder, so better use div_u64 to make the code cleaner. > + if (clk_div > PWM_CLKDIV_MAX) > + return -EINVAL; > + > + div = clk_div + 1; > + period = div64_u64(rate * period_ns, NSEC_PER_SEC * div); > + if (period > 0) > + period--; > + high_width = div64_u64(rate * duty_ns, NSEC_PER_SEC * div); > + if (high_width > 0) > + high_width--; > + > + mtk_disp_pwm_setting(mpc->mmio_base + DISP_PWM_CON_0_OFF, > + clk_div << PWM_CLKDIV_SHIFT, PWM_CLKDIV_MASK); > + mtk_disp_pwm_setting(mpc->mmio_base + DISP_PWM_CON_1_OFF, > + (period << PWM_PERIOD_SHIFT) | > + (high_width << PWM_HIGH_WIDTH_SHIFT), > + PWM_PERIOD_MASK | PWM_HIGH_WIDTH_MASK); > + > + mtk_disp_pwm_setting(mpc->mmio_base + DISP_PWM_COMMIT_OFF, > + 1 << PWM_COMMIT_SHIFT, PWM_COMMIT_MASK); > + mtk_disp_pwm_setting(mpc->mmio_base + DISP_PWM_COMMIT_OFF, > + 0 << PWM_COMMIT_SHIFT, PWM_COMMIT_MASK); > + > + return 0; > +} > + > +static int mtk_disp_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm) > +{ > + struct mtk_disp_pwm_chip *mpc; > + > + mpc = container_of(chip, struct mtk_disp_pwm_chip, chip); > + mtk_disp_pwm_setting(mpc->mmio_base + DISP_PWM_EN_OFF, > + 1 << PWM_ENABLE_SHIFT, PWM_ENABLE_MASK); > + > + return 0; > +} > + > +static void mtk_disp_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm) > +{ > + struct mtk_disp_pwm_chip *mpc; > + > + mpc = container_of(chip, struct mtk_disp_pwm_chip, chip); > + mtk_disp_pwm_setting(mpc->mmio_base + DISP_PWM_EN_OFF, > + 0 << PWM_ENABLE_SHIFT, PWM_ENABLE_MASK); > +} > + > +static const struct pwm_ops mtk_disp_pwm_ops = { > + .config = mtk_disp_pwm_config, > + .enable = mtk_disp_pwm_enable, > + .disable = mtk_disp_pwm_disable, > + .owner = THIS_MODULE, > +}; > + > +static int mtk_disp_pwm_probe(struct platform_device *pdev) > +{ > + struct mtk_disp_pwm_chip *pwm; > + struct resource *r; > + int ret; > + > + pwm = devm_kzalloc(&pdev->dev, sizeof(*pwm), GFP_KERNEL); > + if (!pwm) > + return -ENOMEM; > + > + pwm->dev = &pdev->dev; > + > + r = platform_get_resource(pdev, IORESOURCE_MEM, 0); > + pwm->mmio_base = devm_ioremap_resource(&pdev->dev, r); > + if (IS_ERR(pwm->mmio_base)) > + return PTR_ERR(pwm->mmio_base); > + > + pwm->clk_main = devm_clk_get(&pdev->dev, "main"); > + if (IS_ERR(pwm->clk_main)) > + return PTR_ERR(pwm->clk_main); I prefer to have a newline after the if-then-ese block, which makes it (at least for me) easier to read the code. Thanks, Matthias
2015-05-12 14:37 GMT+02:00 Matthias Brugger <matthias.bgg@gmail.com>: > Hi YH, > > 2015-05-11 11:26 GMT+02:00 YH Huang <yh.huang@mediatek.com>: >> Add display PWM driver support to modify backlight for MT8173/MT6595. >> >> Signed-off-by: YH Huang <yh.huang@mediatek.com> >> --- >> drivers/pwm/Kconfig | 9 ++ >> drivers/pwm/Makefile | 1 + >> drivers/pwm/pwm-disp-mediatek.c | 225 ++++++++++++++++++++++++++++++++++++++++ >> 3 files changed, 235 insertions(+) >> create mode 100644 drivers/pwm/pwm-disp-mediatek.c >> >> diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig >> index b1541f4..9edbb5a 100644 >> --- a/drivers/pwm/Kconfig >> +++ b/drivers/pwm/Kconfig >> @@ -111,6 +111,15 @@ config PWM_CLPS711X >> To compile this driver as a module, choose M here: the module >> will be called pwm-clps711x. >> >> +config PWM_DISP_MEDIATEK >> + tristate "MEDIATEK display PWM driver" >> + depends on OF >> + help >> + Generic PWM framework driver for mediatek disp-pwm device. >> + >> + To compile this driver as a module, choose M here: the module >> + will be called pwm-disp-mediatek. >> + >> config PWM_EP93XX >> tristate "Cirrus Logic EP93xx PWM support" >> depends on ARCH_EP93XX >> diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile >> index ec50eb5..c5ff72a 100644 >> --- a/drivers/pwm/Makefile >> +++ b/drivers/pwm/Makefile >> @@ -8,6 +8,7 @@ obj-$(CONFIG_PWM_BCM_KONA) += pwm-bcm-kona.o >> obj-$(CONFIG_PWM_BCM2835) += pwm-bcm2835.o >> obj-$(CONFIG_PWM_BFIN) += pwm-bfin.o >> obj-$(CONFIG_PWM_CLPS711X) += pwm-clps711x.o >> +obj-$(CONFIG_PWM_DISP_MEDIATEK) += pwm-disp-mediatek.o >> obj-$(CONFIG_PWM_EP93XX) += pwm-ep93xx.o >> obj-$(CONFIG_PWM_FSL_FTM) += pwm-fsl-ftm.o >> obj-$(CONFIG_PWM_IMG) += pwm-img.o >> diff --git a/drivers/pwm/pwm-disp-mediatek.c b/drivers/pwm/pwm-disp-mediatek.c >> new file mode 100644 >> index 0000000..38293af >> --- /dev/null >> +++ b/drivers/pwm/pwm-disp-mediatek.c >> @@ -0,0 +1,225 @@ >> +/* >> + * Mediatek display pulse-width-modulation controller driver. >> + * Copyright (c) 2015 MediaTek Inc. >> + * Author: YH Huang <yh.huang@mediatek.com> >> + * >> + * This program is free software; you can redistribute it and/or modify >> + * it under the terms of the GNU General Public License version 2 as >> + * published by the Free Software Foundation. >> + * >> + * This program is distributed in the hope that it will be useful, >> + * but WITHOUT ANY WARRANTY; without even the implied warranty of >> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the >> + * GNU General Public License for more details. >> + */ >> + >> +#include <linux/clk.h> >> +#include <linux/err.h> >> +#include <linux/io.h> >> +#include <linux/module.h> >> +#include <linux/of.h> >> +#include <linux/pwm.h> >> +#include <linux/platform_device.h> >> +#include <linux/slab.h> >> + >> +#define DISP_PWM_EN_OFF (0x0) >> +#define PWM_ENABLE_SHIFT (0x0) >> +#define PWM_ENABLE_MASK (0x1 << PWM_ENABLE_SHIFT) > > Get rid of the _SHIFT which are actually zero, it will make the code > more readable. > >> + >> +#define DISP_PWM_COMMIT_OFF (0x08) >> +#define PWM_COMMIT_SHIFT (0x0) >> +#define PWM_COMMIT_MASK (0x1 << PWM_COMMIT_SHIFT) >> + >> +#define DISP_PWM_CON_0_OFF (0x10) >> +#define PWM_CLKDIV_SHIFT (0x10) I prefer to have the shift values in decimal instead of hex, as it makes it easier to see which bits in the registers are the relevant ones. Sorry forgot that one. Cheers, Matthias
On Mon, May 11, 2015 at 05:26:22PM +0800, YH Huang wrote: > + > +static int mtk_disp_pwm_probe(struct platform_device *pdev) > +{ > + struct mtk_disp_pwm_chip *pwm; The struct mtk_disp_pwm_chip * is named 'mpc' in the other functions. For consistency reasons you should do that here aswell. > + struct resource *r; > + int ret; > + > + pwm = devm_kzalloc(&pdev->dev, sizeof(*pwm), GFP_KERNEL); > + if (!pwm) > + return -ENOMEM; > + > + pwm->dev = &pdev->dev; > + > + r = platform_get_resource(pdev, IORESOURCE_MEM, 0); > + pwm->mmio_base = devm_ioremap_resource(&pdev->dev, r); > + if (IS_ERR(pwm->mmio_base)) > + return PTR_ERR(pwm->mmio_base); > + > + pwm->clk_main = devm_clk_get(&pdev->dev, "main"); > + if (IS_ERR(pwm->clk_main)) > + return PTR_ERR(pwm->clk_main); > + pwm->clk_mm = devm_clk_get(&pdev->dev, "mm"); > + if (IS_ERR(pwm->clk_mm)) > + return PTR_ERR(pwm->clk_mm); > + > + ret = clk_prepare_enable(pwm->clk_main); > + if (ret < 0) > + return ret; > + ret = clk_prepare_enable(pwm->clk_mm); > + if (ret < 0) { > + clk_disable_unprepare(pwm->clk_main); > + return ret; > + } > + > + platform_set_drvdata(pdev, pwm); > + > + pwm->chip.dev = &pdev->dev; > + pwm->chip.ops = &mtk_disp_pwm_ops; > + pwm->chip.base = -1; > + pwm->chip.npwm = NUM_PWM; > + > + ret = pwmchip_add(&pwm->chip); > + if (ret < 0) { > + dev_err(&pdev->dev, "pwmchip_add() failed: %d\n", ret); > + return ret; This error path leaves the clocks enabled. > + } > + > + return 0; > +} > + > +static int mtk_disp_pwm_remove(struct platform_device *pdev) > +{ > + struct mtk_disp_pwm_chip *pc = platform_get_drvdata(pdev); > + > + if (WARN_ON(!pc)) > + return -ENODEV; > + > + clk_disable_unprepare(pc->clk_main); > + clk_disable_unprepare(pc->clk_mm); > + > + return pwmchip_remove(&pc->chip); You should first remove the pwmchip and disable the clocks afterwards. Also note that this function can fail. Sascha
On Mon, May 11, 2015 at 05:26:22PM +0800, YH Huang wrote: > Add display PWM driver support to modify backlight for MT8173/MT6595. > > Signed-off-by: YH Huang <yh.huang@mediatek.com> > --- > drivers/pwm/Kconfig | 9 ++ > drivers/pwm/Makefile | 1 + > drivers/pwm/pwm-disp-mediatek.c | 225 ++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 235 insertions(+) > create mode 100644 drivers/pwm/pwm-disp-mediatek.c > > diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig > index b1541f4..9edbb5a 100644 > --- a/drivers/pwm/Kconfig > +++ b/drivers/pwm/Kconfig > @@ -111,6 +111,15 @@ config PWM_CLPS711X > To compile this driver as a module, choose M here: the module > will be called pwm-clps711x. > > +config PWM_DISP_MEDIATEK Please make this "PWM_MEDIATEK_DISP" so we can keep everything sorted by vendor. > + tristate "MEDIATEK display PWM driver" "MediaTek"? > + depends on OF Technically I think you need depends on HAS_IOMEM here to avoid breakage on randconfig builds. > + help > + Generic PWM framework driver for mediatek disp-pwm device. "MediaTek"? Also perhaps this should describe what this PWM is instead of just the "disp-pwm" which leaves everyone guessing what it is. From the name I'd expect it to be the PWM that is used to control the backlight brightness for display, but I think this description should say that explicitly. > + > + To compile this driver as a module, choose M here: the module > + will be called pwm-disp-mediatek. pwm-mediatek-disp > + > config PWM_EP93XX > tristate "Cirrus Logic EP93xx PWM support" > depends on ARCH_EP93XX > diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile > index ec50eb5..c5ff72a 100644 > --- a/drivers/pwm/Makefile > +++ b/drivers/pwm/Makefile > @@ -8,6 +8,7 @@ obj-$(CONFIG_PWM_BCM_KONA) += pwm-bcm-kona.o > obj-$(CONFIG_PWM_BCM2835) += pwm-bcm2835.o > obj-$(CONFIG_PWM_BFIN) += pwm-bfin.o > obj-$(CONFIG_PWM_CLPS711X) += pwm-clps711x.o > +obj-$(CONFIG_PWM_DISP_MEDIATEK) += pwm-disp-mediatek.o Also name this "pwm-mediatek-disp.o" to reflect the Kconfig name. > obj-$(CONFIG_PWM_EP93XX) += pwm-ep93xx.o > obj-$(CONFIG_PWM_FSL_FTM) += pwm-fsl-ftm.o > obj-$(CONFIG_PWM_IMG) += pwm-img.o > diff --git a/drivers/pwm/pwm-disp-mediatek.c b/drivers/pwm/pwm-disp-mediatek.c > new file mode 100644 > index 0000000..38293af > --- /dev/null > +++ b/drivers/pwm/pwm-disp-mediatek.c > @@ -0,0 +1,225 @@ > +/* > + * Mediatek display pulse-width-modulation controller driver. > + * Copyright (c) 2015 MediaTek Inc. > + * Author: YH Huang <yh.huang@mediatek.com> > + * > + * This program is free software; you can redistribute it and/or modify > + * it under the terms of the GNU General Public License version 2 as > + * published by the Free Software Foundation. > + * > + * This program is distributed in the hope that it will be useful, > + * but WITHOUT ANY WARRANTY; without even the implied warranty of > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the > + * GNU General Public License for more details. > + */ > + > +#include <linux/clk.h> > +#include <linux/err.h> > +#include <linux/io.h> > +#include <linux/module.h> > +#include <linux/of.h> > +#include <linux/pwm.h> > +#include <linux/platform_device.h> > +#include <linux/slab.h> > + > +#define DISP_PWM_EN_OFF (0x0) The _OFF suffix here is unfortunate because I'm reading this as being the "OFF" value for a field named "DISP_PWM_EN". I think it'd be better to name this one DISP_PWM_EN. The same goes for any of the following registers. Also, drop the parentheses if the expression is simple. > +#define PWM_ENABLE_SHIFT (0x0) > +#define PWM_ENABLE_MASK (0x1 << PWM_ENABLE_SHIFT) > + > +#define DISP_PWM_COMMIT_OFF (0x08) > +#define PWM_COMMIT_SHIFT (0x0) > +#define PWM_COMMIT_MASK (0x1 << PWM_COMMIT_SHIFT) > + > +#define DISP_PWM_CON_0_OFF (0x10) > +#define PWM_CLKDIV_SHIFT (0x10) > +#define PWM_CLKDIV_MASK (0x3ff << PWM_CLKDIV_SHIFT) > +#define PWM_CLKDIV_MAX (0x000003ff) > + > +#define DISP_PWM_CON_1_OFF (0x14) > +#define PWM_PERIOD_SHIFT (0x0) > +#define PWM_PERIOD_MASK (0xfff << PWM_PERIOD_SHIFT) > +#define PWM_PERIOD_MAX (0x00000fff) > +/* Shift log2(PWM_PERIOD_MAX + 1) as divisor */ > +#define PWM_PERIOD_BIT_SHIFT 12 This is confusing, see below. > + > +#define PWM_HIGH_WIDTH_SHIFT (0x10) > +#define PWM_HIGH_WIDTH_MASK (0x1fff << PWM_HIGH_WIDTH_SHIFT) > + > +#define NUM_PWM 1 You can drop this, it's only used once. > + > +struct mtk_disp_pwm_chip { > + struct pwm_chip chip; > + struct device *dev; > + struct clk *clk_main; > + struct clk *clk_mm; > + void __iomem *mmio_base; > +}; Please don't add this artificial padding, a single space is enough as a separator. Also, I think you can drop the _chip suffix on the structure name. > + > +static void mtk_disp_pwm_setting(void __iomem *address, u32 value, u32 mask) This is a bad name. I think you should adopt the naming of regmap, which this effectively copies, so this should be: static void mtk_disp_pwm_update_bits(void __iomem *address, u32 mask, u32 value) > +static int mtk_disp_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, > + int duty_ns, int period_ns) > +{ > + struct mtk_disp_pwm_chip *mpc; > + u64 div, rate; > + u32 clk_div, period, high_width, rem; > + > + /* > + * Find period, high_width and clk_div to suit duty_ns and period_ns. > + * Calculate proper div value to keep period value in the bound. > + * > + * period_ns = 10^9 * (clk_div + 1) * (period +1) / PWM_CLK_RATE > + * duty_ns = 10^9 * (clk_div + 1) * (high_width + 1) / PWM_CLK_RATE > + * > + * period = (PWM_CLK_RATE * period_ns) / (10^9 * (clk_div + 1)) - 1 > + * high_width = (PWM_CLK_RATE * duty_ns) / (10^9 * (clk_div + 1)) - 1 > + */ > + mpc = container_of(chip, struct mtk_disp_pwm_chip, chip); Can you add a static inline function to wrap the container_of() invocation? You need to do this quite often and the wrapper will shorten the code significantly: static inline struct mtk_disp_pwm *to_mtk_disp_pwm(struct pwm_chip *chip) { return container_of(chip, struct mtk_disp_pwm, chip); } Also it's slightly more canonical to initialize the mpc variable as part of the declaration. > + rate = clk_get_rate(mpc->clk_main); > + clk_div = div_u64_rem(rate * period_ns, NSEC_PER_SEC, &rem) >> > + PWM_PERIOD_BIT_SHIFT; > + if (clk_div > PWM_CLKDIV_MAX) > + return -EINVAL; > + > + div = clk_div + 1; > + period = div64_u64(rate * period_ns, NSEC_PER_SEC * div); > + if (period > 0) > + period--; > + high_width = div64_u64(rate * duty_ns, NSEC_PER_SEC * div); > + if (high_width > 0) > + high_width--; > + > + mtk_disp_pwm_setting(mpc->mmio_base + DISP_PWM_CON_0_OFF, > + clk_div << PWM_CLKDIV_SHIFT, PWM_CLKDIV_MASK); > + mtk_disp_pwm_setting(mpc->mmio_base + DISP_PWM_CON_1_OFF, > + (period << PWM_PERIOD_SHIFT) | > + (high_width << PWM_HIGH_WIDTH_SHIFT), > + PWM_PERIOD_MASK | PWM_HIGH_WIDTH_MASK); Can you align these differently to make it more readable? mtk_display_pwm_update_bits(mpc->mmio_base + DISP_PWM_CON_1, PWM_PERIOD_MASK | PWM_HIGH_WIDTH_MASK, (period << PWM_PERIOD_SHIFT) | (high_width << PWM_HIGH_WIDTH_SHIFT)); Or perhaps split it into multiple steps to make it even more readable: value = (high_width << PWM_HIGH_WIDTH_SHIFT) | (period << PWM_PERIOD_SHIFT); mtk_display_pwm_update_bits(mpc->mmio_base + DISP_PWM_CON_1, PWM_HIGH_WIDTH_MASK | PWM_PERIOD_MASK, value); > +static int mtk_disp_pwm_probe(struct platform_device *pdev) > +{ > + struct mtk_disp_pwm_chip *pwm; > + struct resource *r; > + int ret; > + > + pwm = devm_kzalloc(&pdev->dev, sizeof(*pwm), GFP_KERNEL); > + if (!pwm) > + return -ENOMEM; > + > + pwm->dev = &pdev->dev; > + > + r = platform_get_resource(pdev, IORESOURCE_MEM, 0); > + pwm->mmio_base = devm_ioremap_resource(&pdev->dev, r); > + if (IS_ERR(pwm->mmio_base)) > + return PTR_ERR(pwm->mmio_base); > + > + pwm->clk_main = devm_clk_get(&pdev->dev, "main"); > + if (IS_ERR(pwm->clk_main)) > + return PTR_ERR(pwm->clk_main); > + pwm->clk_mm = devm_clk_get(&pdev->dev, "mm"); I think it's more readable if a blank line separates the above two lines. > + if (IS_ERR(pwm->clk_mm)) > + return PTR_ERR(pwm->clk_mm); > + > + ret = clk_prepare_enable(pwm->clk_main); > + if (ret < 0) > + return ret; > + ret = clk_prepare_enable(pwm->clk_mm); Same here. > + if (ret < 0) { > + clk_disable_unprepare(pwm->clk_main); > + return ret; > + } > + > + platform_set_drvdata(pdev, pwm); > + > + pwm->chip.dev = &pdev->dev; > + pwm->chip.ops = &mtk_disp_pwm_ops; > + pwm->chip.base = -1; > + pwm->chip.npwm = NUM_PWM; > + > + ret = pwmchip_add(&pwm->chip); > + if (ret < 0) { > + dev_err(&pdev->dev, "pwmchip_add() failed: %d\n", ret); Shouldn't you disable the clocks here? > + return ret; > + } > + > + return 0; > +} > + > +static int mtk_disp_pwm_remove(struct platform_device *pdev) > +{ > + struct mtk_disp_pwm_chip *pc = platform_get_drvdata(pdev); > + > + if (WARN_ON(!pc)) > + return -ENODEV; You can drop this. Better to let it crash so that you have to fix it if you ever encounter it. > + > + clk_disable_unprepare(pc->clk_main); > + clk_disable_unprepare(pc->clk_mm); > + > + return pwmchip_remove(&pc->chip); > +} > + > +static const struct of_device_id mtk_disp_pwm_of_match[] = { > + { .compatible = "mediatek,mt6595-disp-pwm" }, > + { } > +}; > + > +MODULE_DEVICE_TABLE(of, mtk_disp_pwm_of_match); No blank line between the above two lines. > + > +static struct platform_driver mtk_disp_pwm_driver = { > + .driver = { > + .name = "mediatek-disp-pwm", > + .owner = THIS_MODULE, > + .of_match_table = mtk_disp_pwm_of_match, > + }, > + .probe = mtk_disp_pwm_probe, > + .remove = mtk_disp_pwm_remove, > +}; > + > +module_platform_driver(mtk_disp_pwm_driver); Same here. Also, no need to initialize .driver.owner, module_platform_driver() does that for you. Thierry
2015-05-12 15:32 GMT+02:00 Thierry Reding <thierry.reding@gmail.com>: > On Mon, May 11, 2015 at 05:26:22PM +0800, YH Huang wrote: >> Add display PWM driver support to modify backlight for MT8173/MT6595. >> >> Signed-off-by: YH Huang <yh.huang@mediatek.com> >> --- >> drivers/pwm/Kconfig | 9 ++ >> drivers/pwm/Makefile | 1 + >> drivers/pwm/pwm-disp-mediatek.c | 225 ++++++++++++++++++++++++++++++++++++++++ >> 3 files changed, 235 insertions(+) >> create mode 100644 drivers/pwm/pwm-disp-mediatek.c >> >> diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig >> index b1541f4..9edbb5a 100644 >> --- a/drivers/pwm/Kconfig >> +++ b/drivers/pwm/Kconfig >> @@ -111,6 +111,15 @@ config PWM_CLPS711X >> To compile this driver as a module, choose M here: the module >> will be called pwm-clps711x. >> >> +config PWM_DISP_MEDIATEK > > Please make this "PWM_MEDIATEK_DISP" so we can keep everything sorted by > vendor. > >> + tristate "MEDIATEK display PWM driver" > > "MediaTek"? > >> + depends on OF > > Technically I think you need depends on HAS_IOMEM here to avoid breakage > on randconfig builds. > >> + help >> + Generic PWM framework driver for mediatek disp-pwm device. > > "MediaTek"? Also perhaps this should describe what this PWM is instead > of just the "disp-pwm" which leaves everyone guessing what it is. From > the name I'd expect it to be the PWM that is used to control the > backlight brightness for display, but I think this description should > say that explicitly. > >> + >> + To compile this driver as a module, choose M here: the module >> + will be called pwm-disp-mediatek. > > pwm-mediatek-disp I would prefert pwm-mtk-disp which is in line with the other drivers. Also I have to admit that unfortunately the naming is not uniformly throughout the kernel. Thanks, Matthias
On Tue, 2015-05-12 at 14:37 +0200, Matthias Brugger wrote: > Hi YH, > > 2015-05-11 11:26 GMT+02:00 YH Huang <yh.huang@mediatek.com>: > > Add display PWM driver support to modify backlight for MT8173/MT6595. > > > > Signed-off-by: YH Huang <yh.huang@mediatek.com> > > --- > > drivers/pwm/Kconfig | 9 ++ > > drivers/pwm/Makefile | 1 + > > drivers/pwm/pwm-disp-mediatek.c | 225 ++++++++++++++++++++++++++++++++++++++++ > > 3 files changed, 235 insertions(+) > > create mode 100644 drivers/pwm/pwm-disp-mediatek.c > > > > diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig > > index b1541f4..9edbb5a 100644 > > --- a/drivers/pwm/Kconfig > > +++ b/drivers/pwm/Kconfig > > @@ -111,6 +111,15 @@ config PWM_CLPS711X > > To compile this driver as a module, choose M here: the module > > will be called pwm-clps711x. > > > > +config PWM_DISP_MEDIATEK > > + tristate "MEDIATEK display PWM driver" > > + depends on OF > > + help > > + Generic PWM framework driver for mediatek disp-pwm device. > > + > > + To compile this driver as a module, choose M here: the module > > + will be called pwm-disp-mediatek. > > + > > config PWM_EP93XX > > tristate "Cirrus Logic EP93xx PWM support" > > depends on ARCH_EP93XX > > diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile > > index ec50eb5..c5ff72a 100644 > > --- a/drivers/pwm/Makefile > > +++ b/drivers/pwm/Makefile > > @@ -8,6 +8,7 @@ obj-$(CONFIG_PWM_BCM_KONA) += pwm-bcm-kona.o > > obj-$(CONFIG_PWM_BCM2835) += pwm-bcm2835.o > > obj-$(CONFIG_PWM_BFIN) += pwm-bfin.o > > obj-$(CONFIG_PWM_CLPS711X) += pwm-clps711x.o > > +obj-$(CONFIG_PWM_DISP_MEDIATEK) += pwm-disp-mediatek.o > > obj-$(CONFIG_PWM_EP93XX) += pwm-ep93xx.o > > obj-$(CONFIG_PWM_FSL_FTM) += pwm-fsl-ftm.o > > obj-$(CONFIG_PWM_IMG) += pwm-img.o > > diff --git a/drivers/pwm/pwm-disp-mediatek.c b/drivers/pwm/pwm-disp-mediatek.c > > new file mode 100644 > > index 0000000..38293af > > --- /dev/null > > +++ b/drivers/pwm/pwm-disp-mediatek.c > > @@ -0,0 +1,225 @@ > > +/* > > + * Mediatek display pulse-width-modulation controller driver. > > + * Copyright (c) 2015 MediaTek Inc. > > + * Author: YH Huang <yh.huang@mediatek.com> > > + * > > + * This program is free software; you can redistribute it and/or modify > > + * it under the terms of the GNU General Public License version 2 as > > + * published by the Free Software Foundation. > > + * > > + * This program is distributed in the hope that it will be useful, > > + * but WITHOUT ANY WARRANTY; without even the implied warranty of > > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the > > + * GNU General Public License for more details. > > + */ > > + > > +#include <linux/clk.h> > > +#include <linux/err.h> > > +#include <linux/io.h> > > +#include <linux/module.h> > > +#include <linux/of.h> > > +#include <linux/pwm.h> > > +#include <linux/platform_device.h> > > +#include <linux/slab.h> > > + > > +#define DISP_PWM_EN_OFF (0x0) > > +#define PWM_ENABLE_SHIFT (0x0) > > +#define PWM_ENABLE_MASK (0x1 << PWM_ENABLE_SHIFT) > > Get rid of the _SHIFT which are actually zero, it will make the code > more readable. > It seems unnecessary to add it and I will fix it. > > + > > +#define DISP_PWM_COMMIT_OFF (0x08) > > +#define PWM_COMMIT_SHIFT (0x0) > > +#define PWM_COMMIT_MASK (0x1 << PWM_COMMIT_SHIFT) > > + > > +#define DISP_PWM_CON_0_OFF (0x10) > > +#define PWM_CLKDIV_SHIFT (0x10) > > +#define PWM_CLKDIV_MASK (0x3ff << PWM_CLKDIV_SHIFT) > > +#define PWM_CLKDIV_MAX (0x000003ff) > > + > > +#define DISP_PWM_CON_1_OFF (0x14) > > +#define PWM_PERIOD_SHIFT (0x0) > > +#define PWM_PERIOD_MASK (0xfff << PWM_PERIOD_SHIFT) > > +#define PWM_PERIOD_MAX (0x00000fff) > > +/* Shift log2(PWM_PERIOD_MAX + 1) as divisor */ > > +#define PWM_PERIOD_BIT_SHIFT 12 > > + > > +#define PWM_HIGH_WIDTH_SHIFT (0x10) > > +#define PWM_HIGH_WIDTH_MASK (0x1fff << PWM_HIGH_WIDTH_SHIFT) > > + > > +#define NUM_PWM 1 > > + > > +struct mtk_disp_pwm_chip { > > + struct pwm_chip chip; > > + struct device *dev; > > + struct clk *clk_main; > > + struct clk *clk_mm; > > + void __iomem *mmio_base; > > +}; > > + > > +static void mtk_disp_pwm_setting(void __iomem *address, u32 value, u32 mask) > > +{ > > + u32 val; > > + > > + val = readl(address); > > + val &= ~mask; > > + val |= value; > > + writel(val, address); > > +} > > + > > +static int mtk_disp_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, > > + int duty_ns, int period_ns) > > +{ > > + struct mtk_disp_pwm_chip *mpc; > > + u64 div, rate; > > + u32 clk_div, period, high_width, rem; > > + > > + /* > > + * Find period, high_width and clk_div to suit duty_ns and period_ns. > > + * Calculate proper div value to keep period value in the bound. > > + * > > + * period_ns = 10^9 * (clk_div + 1) * (period +1) / PWM_CLK_RATE > > + * duty_ns = 10^9 * (clk_div + 1) * (high_width + 1) / PWM_CLK_RATE > > + * > > + * period = (PWM_CLK_RATE * period_ns) / (10^9 * (clk_div + 1)) - 1 > > + * high_width = (PWM_CLK_RATE * duty_ns) / (10^9 * (clk_div + 1)) - 1 > > + */ > > + mpc = container_of(chip, struct mtk_disp_pwm_chip, chip); > > + rate = clk_get_rate(mpc->clk_main); > > + clk_div = div_u64_rem(rate * period_ns, NSEC_PER_SEC, &rem) >> > > + PWM_PERIOD_BIT_SHIFT; > > You never use the remainder, so better use div_u64 to make the code cleaner. > OK. > > + if (clk_div > PWM_CLKDIV_MAX) > > + return -EINVAL; > > + > > + div = clk_div + 1; > > + period = div64_u64(rate * period_ns, NSEC_PER_SEC * div); > > + if (period > 0) > > + period--; > > + high_width = div64_u64(rate * duty_ns, NSEC_PER_SEC * div); > > + if (high_width > 0) > > + high_width--; > > + > > + mtk_disp_pwm_setting(mpc->mmio_base + DISP_PWM_CON_0_OFF, > > + clk_div << PWM_CLKDIV_SHIFT, PWM_CLKDIV_MASK); > > + mtk_disp_pwm_setting(mpc->mmio_base + DISP_PWM_CON_1_OFF, > > + (period << PWM_PERIOD_SHIFT) | > > + (high_width << PWM_HIGH_WIDTH_SHIFT), > > + PWM_PERIOD_MASK | PWM_HIGH_WIDTH_MASK); > > + > > + mtk_disp_pwm_setting(mpc->mmio_base + DISP_PWM_COMMIT_OFF, > > + 1 << PWM_COMMIT_SHIFT, PWM_COMMIT_MASK); > > + mtk_disp_pwm_setting(mpc->mmio_base + DISP_PWM_COMMIT_OFF, > > + 0 << PWM_COMMIT_SHIFT, PWM_COMMIT_MASK); > > + > > + return 0; > > +} > > + > > +static int mtk_disp_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm) > > +{ > > + struct mtk_disp_pwm_chip *mpc; > > + > > + mpc = container_of(chip, struct mtk_disp_pwm_chip, chip); > > + mtk_disp_pwm_setting(mpc->mmio_base + DISP_PWM_EN_OFF, > > + 1 << PWM_ENABLE_SHIFT, PWM_ENABLE_MASK); > > + > > + return 0; > > +} > > + > > +static void mtk_disp_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm) > > +{ > > + struct mtk_disp_pwm_chip *mpc; > > + > > + mpc = container_of(chip, struct mtk_disp_pwm_chip, chip); > > + mtk_disp_pwm_setting(mpc->mmio_base + DISP_PWM_EN_OFF, > > + 0 << PWM_ENABLE_SHIFT, PWM_ENABLE_MASK); > > +} > > + > > +static const struct pwm_ops mtk_disp_pwm_ops = { > > + .config = mtk_disp_pwm_config, > > + .enable = mtk_disp_pwm_enable, > > + .disable = mtk_disp_pwm_disable, > > + .owner = THIS_MODULE, > > +}; > > + > > +static int mtk_disp_pwm_probe(struct platform_device *pdev) > > +{ > > + struct mtk_disp_pwm_chip *pwm; > > + struct resource *r; > > + int ret; > > + > > + pwm = devm_kzalloc(&pdev->dev, sizeof(*pwm), GFP_KERNEL); > > + if (!pwm) > > + return -ENOMEM; > > + > > + pwm->dev = &pdev->dev; > > + > > + r = platform_get_resource(pdev, IORESOURCE_MEM, 0); > > + pwm->mmio_base = devm_ioremap_resource(&pdev->dev, r); > > + if (IS_ERR(pwm->mmio_base)) > > + return PTR_ERR(pwm->mmio_base); > > + > > + pwm->clk_main = devm_clk_get(&pdev->dev, "main"); > > + if (IS_ERR(pwm->clk_main)) > > + return PTR_ERR(pwm->clk_main); > > I prefer to have a newline after the if-then-ese block, which makes it > (at least for me) easier to read the code. > OK. > Thanks, > Matthias Thank for your suggestion. Regards, YH Huang
On Tue, 2015-05-12 at 14:44 +0200, Matthias Brugger wrote: > 2015-05-12 14:37 GMT+02:00 Matthias Brugger <matthias.bgg@gmail.com>: > > Hi YH, > > > > 2015-05-11 11:26 GMT+02:00 YH Huang <yh.huang@mediatek.com>: > >> Add display PWM driver support to modify backlight for MT8173/MT6595. > >> > >> Signed-off-by: YH Huang <yh.huang@mediatek.com> > >> --- > >> drivers/pwm/Kconfig | 9 ++ > >> drivers/pwm/Makefile | 1 + > >> drivers/pwm/pwm-disp-mediatek.c | 225 ++++++++++++++++++++++++++++++++++++++++ > >> 3 files changed, 235 insertions(+) > >> create mode 100644 drivers/pwm/pwm-disp-mediatek.c > >> > >> diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig > >> index b1541f4..9edbb5a 100644 > >> --- a/drivers/pwm/Kconfig > >> +++ b/drivers/pwm/Kconfig > >> @@ -111,6 +111,15 @@ config PWM_CLPS711X > >> To compile this driver as a module, choose M here: the module > >> will be called pwm-clps711x. > >> > >> +config PWM_DISP_MEDIATEK > >> + tristate "MEDIATEK display PWM driver" > >> + depends on OF > >> + help > >> + Generic PWM framework driver for mediatek disp-pwm device. > >> + > >> + To compile this driver as a module, choose M here: the module > >> + will be called pwm-disp-mediatek. > >> + > >> config PWM_EP93XX > >> tristate "Cirrus Logic EP93xx PWM support" > >> depends on ARCH_EP93XX > >> diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile > >> index ec50eb5..c5ff72a 100644 > >> --- a/drivers/pwm/Makefile > >> +++ b/drivers/pwm/Makefile > >> @@ -8,6 +8,7 @@ obj-$(CONFIG_PWM_BCM_KONA) += pwm-bcm-kona.o > >> obj-$(CONFIG_PWM_BCM2835) += pwm-bcm2835.o > >> obj-$(CONFIG_PWM_BFIN) += pwm-bfin.o > >> obj-$(CONFIG_PWM_CLPS711X) += pwm-clps711x.o > >> +obj-$(CONFIG_PWM_DISP_MEDIATEK) += pwm-disp-mediatek.o > >> obj-$(CONFIG_PWM_EP93XX) += pwm-ep93xx.o > >> obj-$(CONFIG_PWM_FSL_FTM) += pwm-fsl-ftm.o > >> obj-$(CONFIG_PWM_IMG) += pwm-img.o > >> diff --git a/drivers/pwm/pwm-disp-mediatek.c b/drivers/pwm/pwm-disp-mediatek.c > >> new file mode 100644 > >> index 0000000..38293af > >> --- /dev/null > >> +++ b/drivers/pwm/pwm-disp-mediatek.c > >> @@ -0,0 +1,225 @@ > >> +/* > >> + * Mediatek display pulse-width-modulation controller driver. > >> + * Copyright (c) 2015 MediaTek Inc. > >> + * Author: YH Huang <yh.huang@mediatek.com> > >> + * > >> + * This program is free software; you can redistribute it and/or modify > >> + * it under the terms of the GNU General Public License version 2 as > >> + * published by the Free Software Foundation. > >> + * > >> + * This program is distributed in the hope that it will be useful, > >> + * but WITHOUT ANY WARRANTY; without even the implied warranty of > >> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the > >> + * GNU General Public License for more details. > >> + */ > >> + > >> +#include <linux/clk.h> > >> +#include <linux/err.h> > >> +#include <linux/io.h> > >> +#include <linux/module.h> > >> +#include <linux/of.h> > >> +#include <linux/pwm.h> > >> +#include <linux/platform_device.h> > >> +#include <linux/slab.h> > >> + > >> +#define DISP_PWM_EN_OFF (0x0) > >> +#define PWM_ENABLE_SHIFT (0x0) > >> +#define PWM_ENABLE_MASK (0x1 << PWM_ENABLE_SHIFT) > > > > Get rid of the _SHIFT which are actually zero, it will make the code > > more readable. > > > >> + > >> +#define DISP_PWM_COMMIT_OFF (0x08) > >> +#define PWM_COMMIT_SHIFT (0x0) > >> +#define PWM_COMMIT_MASK (0x1 << PWM_COMMIT_SHIFT) > >> + > >> +#define DISP_PWM_CON_0_OFF (0x10) > >> +#define PWM_CLKDIV_SHIFT (0x10) > > I prefer to have the shift values in decimal instead of hex, as it > makes it easier to see which bits in the registers are the relevant > ones. > Sorry forgot that one. > I think you are right. > Cheers, > Matthias Thank for your suggestion. Regards, YH Huang
On Tue, 2015-05-12 at 15:00 +0200, Sascha Hauer wrote: > On Mon, May 11, 2015 at 05:26:22PM +0800, YH Huang wrote: > > + > > +static int mtk_disp_pwm_probe(struct platform_device *pdev) > > +{ > > + struct mtk_disp_pwm_chip *pwm; > > The struct mtk_disp_pwm_chip * is named 'mpc' in the other functions. > For consistency reasons you should do that here aswell. > I miss it! Maybe 'mdpc' is a better name for mtk_disp_pwm_chip. > > + struct resource *r; > > + int ret; > > + > > + pwm = devm_kzalloc(&pdev->dev, sizeof(*pwm), GFP_KERNEL); > > + if (!pwm) > > + return -ENOMEM; > > + > > + pwm->dev = &pdev->dev; > > + > > + r = platform_get_resource(pdev, IORESOURCE_MEM, 0); > > + pwm->mmio_base = devm_ioremap_resource(&pdev->dev, r); > > + if (IS_ERR(pwm->mmio_base)) > > + return PTR_ERR(pwm->mmio_base); > > + > > + pwm->clk_main = devm_clk_get(&pdev->dev, "main"); > > + if (IS_ERR(pwm->clk_main)) > > + return PTR_ERR(pwm->clk_main); > > + pwm->clk_mm = devm_clk_get(&pdev->dev, "mm"); > > + if (IS_ERR(pwm->clk_mm)) > > + return PTR_ERR(pwm->clk_mm); > > + > > + ret = clk_prepare_enable(pwm->clk_main); > > + if (ret < 0) > > + return ret; > > + ret = clk_prepare_enable(pwm->clk_mm); > > + if (ret < 0) { > > + clk_disable_unprepare(pwm->clk_main); > > + return ret; > > + } > > + > > + platform_set_drvdata(pdev, pwm); > > + > > + pwm->chip.dev = &pdev->dev; > > + pwm->chip.ops = &mtk_disp_pwm_ops; > > + pwm->chip.base = -1; > > + pwm->chip.npwm = NUM_PWM; > > + > > + ret = pwmchip_add(&pwm->chip); > > + if (ret < 0) { > > + dev_err(&pdev->dev, "pwmchip_add() failed: %d\n", ret); > > + return ret; > > This error path leaves the clocks enabled. > I forgot this one. I will fix it. > > + } > > + > > + return 0; > > +} > > + > > +static int mtk_disp_pwm_remove(struct platform_device *pdev) > > +{ > > + struct mtk_disp_pwm_chip *pc = platform_get_drvdata(pdev); > > + > > + if (WARN_ON(!pc)) > > + return -ENODEV; > > + > > + clk_disable_unprepare(pc->clk_main); > > + clk_disable_unprepare(pc->clk_mm); > > + > > + return pwmchip_remove(&pc->chip); > > You should first remove the pwmchip and disable the clocks afterwards. > Also note that this function can fail. > OK. > Sascha > Thank for your suggestion. Regards, YH Huang
On Tue, 2015-05-12 at 15:32 +0200, Thierry Reding wrote: > On Mon, May 11, 2015 at 05:26:22PM +0800, YH Huang wrote: > > Add display PWM driver support to modify backlight for MT8173/MT6595. > > > > Signed-off-by: YH Huang <yh.huang@mediatek.com> > > --- > > drivers/pwm/Kconfig | 9 ++ > > drivers/pwm/Makefile | 1 + > > drivers/pwm/pwm-disp-mediatek.c | 225 ++++++++++++++++++++++++++++++++++++++++ > > 3 files changed, 235 insertions(+) > > create mode 100644 drivers/pwm/pwm-disp-mediatek.c > > > > diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig > > index b1541f4..9edbb5a 100644 > > --- a/drivers/pwm/Kconfig > > +++ b/drivers/pwm/Kconfig > > @@ -111,6 +111,15 @@ config PWM_CLPS711X > > To compile this driver as a module, choose M here: the module > > will be called pwm-clps711x. > > > > +config PWM_DISP_MEDIATEK > > Please make this "PWM_MEDIATEK_DISP" so we can keep everything sorted by > vendor. > Probably "PWM_MTK_DSIP" for Matthias opinion? > > + tristate "MEDIATEK display PWM driver" > > "MediaTek"? > OK. > > + depends on OF > > Technically I think you need depends on HAS_IOMEM here to avoid breakage > on randconfig builds. > OK. > > + help > > + Generic PWM framework driver for mediatek disp-pwm device. > > "MediaTek"? Also perhaps this should describe what this PWM is instead > of just the "disp-pwm" which leaves everyone guessing what it is. From > the name I'd expect it to be the PWM that is used to control the > backlight brightness for display, but I think this description should > say that explicitly. > > > + > > + To compile this driver as a module, choose M here: the module > > + will be called pwm-disp-mediatek. > > pwm-mediatek-disp pwm-mtk-disp? > > > + > > config PWM_EP93XX > > tristate "Cirrus Logic EP93xx PWM support" > > depends on ARCH_EP93XX > > diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile > > index ec50eb5..c5ff72a 100644 > > --- a/drivers/pwm/Makefile > > +++ b/drivers/pwm/Makefile > > @@ -8,6 +8,7 @@ obj-$(CONFIG_PWM_BCM_KONA) += pwm-bcm-kona.o > > obj-$(CONFIG_PWM_BCM2835) += pwm-bcm2835.o > > obj-$(CONFIG_PWM_BFIN) += pwm-bfin.o > > obj-$(CONFIG_PWM_CLPS711X) += pwm-clps711x.o > > +obj-$(CONFIG_PWM_DISP_MEDIATEK) += pwm-disp-mediatek.o > > Also name this "pwm-mediatek-disp.o" to reflect the Kconfig name. pwm-mtk-disp.o? > > > obj-$(CONFIG_PWM_EP93XX) += pwm-ep93xx.o > > obj-$(CONFIG_PWM_FSL_FTM) += pwm-fsl-ftm.o > > obj-$(CONFIG_PWM_IMG) += pwm-img.o > > diff --git a/drivers/pwm/pwm-disp-mediatek.c b/drivers/pwm/pwm-disp-mediatek.c > > new file mode 100644 > > index 0000000..38293af > > --- /dev/null > > +++ b/drivers/pwm/pwm-disp-mediatek.c > > @@ -0,0 +1,225 @@ > > +/* > > + * Mediatek display pulse-width-modulation controller driver. > > + * Copyright (c) 2015 MediaTek Inc. > > + * Author: YH Huang <yh.huang@mediatek.com> > > + * > > + * This program is free software; you can redistribute it and/or modify > > + * it under the terms of the GNU General Public License version 2 as > > + * published by the Free Software Foundation. > > + * > > + * This program is distributed in the hope that it will be useful, > > + * but WITHOUT ANY WARRANTY; without even the implied warranty of > > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the > > + * GNU General Public License for more details. > > + */ > > + > > +#include <linux/clk.h> > > +#include <linux/err.h> > > +#include <linux/io.h> > > +#include <linux/module.h> > > +#include <linux/of.h> > > +#include <linux/pwm.h> > > +#include <linux/platform_device.h> > > +#include <linux/slab.h> > > + > > +#define DISP_PWM_EN_OFF (0x0) > > The _OFF suffix here is unfortunate because I'm reading this as being > the "OFF" value for a field named "DISP_PWM_EN". I think it'd be better > to name this one DISP_PWM_EN. The same goes for any of the following > registers. > > Also, drop the parentheses if the expression is simple. OK. It is really confusing. > > > +#define PWM_ENABLE_SHIFT (0x0) > > +#define PWM_ENABLE_MASK (0x1 << PWM_ENABLE_SHIFT) > > + > > +#define DISP_PWM_COMMIT_OFF (0x08) > > +#define PWM_COMMIT_SHIFT (0x0) > > +#define PWM_COMMIT_MASK (0x1 << PWM_COMMIT_SHIFT) > > + > > +#define DISP_PWM_CON_0_OFF (0x10) > > +#define PWM_CLKDIV_SHIFT (0x10) > > +#define PWM_CLKDIV_MASK (0x3ff << PWM_CLKDIV_SHIFT) > > +#define PWM_CLKDIV_MAX (0x000003ff) > > + > > +#define DISP_PWM_CON_1_OFF (0x14) > > +#define PWM_PERIOD_SHIFT (0x0) > > +#define PWM_PERIOD_MASK (0xfff << PWM_PERIOD_SHIFT) > > +#define PWM_PERIOD_MAX (0x00000fff) > > +/* Shift log2(PWM_PERIOD_MAX + 1) as divisor */ > > +#define PWM_PERIOD_BIT_SHIFT 12 > > This is confusing, see below. I don't really understand what does this mean. Please help me. > > > + > > +#define PWM_HIGH_WIDTH_SHIFT (0x10) > > +#define PWM_HIGH_WIDTH_MASK (0x1fff << PWM_HIGH_WIDTH_SHIFT) > > + > > +#define NUM_PWM 1 > > You can drop this, it's only used once. > OK. > > + > > +struct mtk_disp_pwm_chip { > > + struct pwm_chip chip; > > + struct device *dev; > > + struct clk *clk_main; > > + struct clk *clk_mm; > > + void __iomem *mmio_base; > > +}; > > Please don't add this artificial padding, a single space is enough as a > separator. Also, I think you can drop the _chip suffix on the structure > name. > OK. > > + > > +static void mtk_disp_pwm_setting(void __iomem *address, u32 value, u32 mask) > > This is a bad name. I think you should adopt the naming of regmap, which > this effectively copies, so this should be: > > static void mtk_disp_pwm_update_bits(void __iomem *address, u32 mask, u32 value) > It is much readable. > > +static int mtk_disp_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, > > + int duty_ns, int period_ns) > > +{ > > + struct mtk_disp_pwm_chip *mpc; > > + u64 div, rate; > > + u32 clk_div, period, high_width, rem; > > + > > + /* > > + * Find period, high_width and clk_div to suit duty_ns and period_ns. > > + * Calculate proper div value to keep period value in the bound. > > + * > > + * period_ns = 10^9 * (clk_div + 1) * (period +1) / PWM_CLK_RATE > > + * duty_ns = 10^9 * (clk_div + 1) * (high_width + 1) / PWM_CLK_RATE > > + * > > + * period = (PWM_CLK_RATE * period_ns) / (10^9 * (clk_div + 1)) - 1 > > + * high_width = (PWM_CLK_RATE * duty_ns) / (10^9 * (clk_div + 1)) - 1 > > + */ > > + mpc = container_of(chip, struct mtk_disp_pwm_chip, chip); > > Can you add a static inline function to wrap the container_of() > invocation? You need to do this quite often and the wrapper will shorten > the code significantly: > > static inline struct mtk_disp_pwm *to_mtk_disp_pwm(struct pwm_chip *chip) > { > return container_of(chip, struct mtk_disp_pwm, chip); > } > > Also it's slightly more canonical to initialize the mpc variable as part > of the declaration. > This is a good way to shorten the code. > > + rate = clk_get_rate(mpc->clk_main); > > + clk_div = div_u64_rem(rate * period_ns, NSEC_PER_SEC, &rem) >> > > + PWM_PERIOD_BIT_SHIFT; > > + if (clk_div > PWM_CLKDIV_MAX) > > + return -EINVAL; > > + > > + div = clk_div + 1; > > + period = div64_u64(rate * period_ns, NSEC_PER_SEC * div); > > + if (period > 0) > > + period--; > > + high_width = div64_u64(rate * duty_ns, NSEC_PER_SEC * div); > > + if (high_width > 0) > > + high_width--; > > + > > + mtk_disp_pwm_setting(mpc->mmio_base + DISP_PWM_CON_0_OFF, > > + clk_div << PWM_CLKDIV_SHIFT, PWM_CLKDIV_MASK); > > + mtk_disp_pwm_setting(mpc->mmio_base + DISP_PWM_CON_1_OFF, > > + (period << PWM_PERIOD_SHIFT) | > > + (high_width << PWM_HIGH_WIDTH_SHIFT), > > + PWM_PERIOD_MASK | PWM_HIGH_WIDTH_MASK); > > Can you align these differently to make it more readable? > > mtk_display_pwm_update_bits(mpc->mmio_base + DISP_PWM_CON_1, > PWM_PERIOD_MASK | PWM_HIGH_WIDTH_MASK, > (period << PWM_PERIOD_SHIFT) | > (high_width << PWM_HIGH_WIDTH_SHIFT)); > > Or perhaps split it into multiple steps to make it even more readable: > > value = (high_width << PWM_HIGH_WIDTH_SHIFT) | > (period << PWM_PERIOD_SHIFT); > mtk_display_pwm_update_bits(mpc->mmio_base + DISP_PWM_CON_1, > PWM_HIGH_WIDTH_MASK | PWM_PERIOD_MASK, > value); > OK, it is really hard to read. > > +static int mtk_disp_pwm_probe(struct platform_device *pdev) > > +{ > > + struct mtk_disp_pwm_chip *pwm; > > + struct resource *r; > > + int ret; > > + > > + pwm = devm_kzalloc(&pdev->dev, sizeof(*pwm), GFP_KERNEL); > > + if (!pwm) > > + return -ENOMEM; > > + > > + pwm->dev = &pdev->dev; > > + > > + r = platform_get_resource(pdev, IORESOURCE_MEM, 0); > > + pwm->mmio_base = devm_ioremap_resource(&pdev->dev, r); > > + if (IS_ERR(pwm->mmio_base)) > > + return PTR_ERR(pwm->mmio_base); > > + > > + pwm->clk_main = devm_clk_get(&pdev->dev, "main"); > > + if (IS_ERR(pwm->clk_main)) > > + return PTR_ERR(pwm->clk_main); > > + pwm->clk_mm = devm_clk_get(&pdev->dev, "mm"); > > I think it's more readable if a blank line separates the above two > lines. OK. > > > + if (IS_ERR(pwm->clk_mm)) > > + return PTR_ERR(pwm->clk_mm); > > + > > + ret = clk_prepare_enable(pwm->clk_main); > > + if (ret < 0) > > + return ret; > > + ret = clk_prepare_enable(pwm->clk_mm); > > Same here. OK. > > > + if (ret < 0) { > > + clk_disable_unprepare(pwm->clk_main); > > + return ret; > > + } > > + > > + platform_set_drvdata(pdev, pwm); > > + > > + pwm->chip.dev = &pdev->dev; > > + pwm->chip.ops = &mtk_disp_pwm_ops; > > + pwm->chip.base = -1; > > + pwm->chip.npwm = NUM_PWM; > > + > > + ret = pwmchip_add(&pwm->chip); > > + if (ret < 0) { > > + dev_err(&pdev->dev, "pwmchip_add() failed: %d\n", ret); > > Shouldn't you disable the clocks here? I will fix it. > > > + return ret; > > + } > > + > > + return 0; > > +} > > + > > +static int mtk_disp_pwm_remove(struct platform_device *pdev) > > +{ > > + struct mtk_disp_pwm_chip *pc = platform_get_drvdata(pdev); > > + > > + if (WARN_ON(!pc)) > > + return -ENODEV; > > You can drop this. Better to let it crash so that you have to fix it if > you ever encounter it. I will think about it. > > > + > > + clk_disable_unprepare(pc->clk_main); > > + clk_disable_unprepare(pc->clk_mm); > > + > > + return pwmchip_remove(&pc->chip); > > +} > > + > > +static const struct of_device_id mtk_disp_pwm_of_match[] = { > > + { .compatible = "mediatek,mt6595-disp-pwm" }, > > + { } > > +}; > > + > > +MODULE_DEVICE_TABLE(of, mtk_disp_pwm_of_match); > > No blank line between the above two lines. OK. > > > + > > +static struct platform_driver mtk_disp_pwm_driver = { > > + .driver = { > > + .name = "mediatek-disp-pwm", > > + .owner = THIS_MODULE, > > + .of_match_table = mtk_disp_pwm_of_match, > > + }, > > + .probe = mtk_disp_pwm_probe, > > + .remove = mtk_disp_pwm_remove, > > +}; > > + > > +module_platform_driver(mtk_disp_pwm_driver); > > Same here. Also, no need to initialize .driver.owner, > module_platform_driver() does that for you. Got it. > > Thierry Thank for your suggestion. Regards, YH Huang
On Tue, 2015-05-12 at 16:34 +0200, Matthias Brugger wrote: > 2015-05-12 15:32 GMT+02:00 Thierry Reding <thierry.reding@gmail.com>: > > On Mon, May 11, 2015 at 05:26:22PM +0800, YH Huang wrote: > >> Add display PWM driver support to modify backlight for MT8173/MT6595. > >> > >> Signed-off-by: YH Huang <yh.huang@mediatek.com> > >> --- > >> drivers/pwm/Kconfig | 9 ++ > >> drivers/pwm/Makefile | 1 + > >> drivers/pwm/pwm-disp-mediatek.c | 225 ++++++++++++++++++++++++++++++++++++++++ > >> 3 files changed, 235 insertions(+) > >> create mode 100644 drivers/pwm/pwm-disp-mediatek.c > >> > >> diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig > >> index b1541f4..9edbb5a 100644 > >> --- a/drivers/pwm/Kconfig > >> +++ b/drivers/pwm/Kconfig > >> @@ -111,6 +111,15 @@ config PWM_CLPS711X > >> To compile this driver as a module, choose M here: the module > >> will be called pwm-clps711x. > >> > >> +config PWM_DISP_MEDIATEK > > > > Please make this "PWM_MEDIATEK_DISP" so we can keep everything sorted by > > vendor. > > > >> + tristate "MEDIATEK display PWM driver" > > > > "MediaTek"? > > > >> + depends on OF > > > > Technically I think you need depends on HAS_IOMEM here to avoid breakage > > on randconfig builds. > > > >> + help > >> + Generic PWM framework driver for mediatek disp-pwm device. > > > > "MediaTek"? Also perhaps this should describe what this PWM is instead > > of just the "disp-pwm" which leaves everyone guessing what it is. From > > the name I'd expect it to be the PWM that is used to control the > > backlight brightness for display, but I think this description should > > say that explicitly. > > > >> + > >> + To compile this driver as a module, choose M here: the module > >> + will be called pwm-disp-mediatek. > > > > pwm-mediatek-disp > > I would prefert pwm-mtk-disp which is in line with the other drivers. > Also I have to admit that unfortunately the naming is not uniformly > throughout the kernel. > OK. I will take it. > Thanks, > Matthias Thank for your suggestion. Regards, YH Huang
On Mon, May 11, 2015 at 5:26 PM, YH Huang <yh.huang@mediatek.com> wrote: > Add display PWM driver support to modify backlight for MT8173/MT6595. > > Signed-off-by: YH Huang <yh.huang@mediatek.com> > --- > drivers/pwm/Kconfig | 9 ++ > drivers/pwm/Makefile | 1 + > drivers/pwm/pwm-disp-mediatek.c | 225 ++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 235 insertions(+) > create mode 100644 drivers/pwm/pwm-disp-mediatek.c > > diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig > index b1541f4..9edbb5a 100644 > --- a/drivers/pwm/Kconfig > +++ b/drivers/pwm/Kconfig > @@ -111,6 +111,15 @@ config PWM_CLPS711X > To compile this driver as a module, choose M here: the module > will be called pwm-clps711x. > > +config PWM_DISP_MEDIATEK > + tristate "MEDIATEK display PWM driver" > + depends on OF > + help > + Generic PWM framework driver for mediatek disp-pwm device. > + > + To compile this driver as a module, choose M here: the module > + will be called pwm-disp-mediatek. > + > config PWM_EP93XX > tristate "Cirrus Logic EP93xx PWM support" > depends on ARCH_EP93XX > diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile > index ec50eb5..c5ff72a 100644 > --- a/drivers/pwm/Makefile > +++ b/drivers/pwm/Makefile > @@ -8,6 +8,7 @@ obj-$(CONFIG_PWM_BCM_KONA) += pwm-bcm-kona.o > obj-$(CONFIG_PWM_BCM2835) += pwm-bcm2835.o > obj-$(CONFIG_PWM_BFIN) += pwm-bfin.o > obj-$(CONFIG_PWM_CLPS711X) += pwm-clps711x.o > +obj-$(CONFIG_PWM_DISP_MEDIATEK) += pwm-disp-mediatek.o > obj-$(CONFIG_PWM_EP93XX) += pwm-ep93xx.o > obj-$(CONFIG_PWM_FSL_FTM) += pwm-fsl-ftm.o > obj-$(CONFIG_PWM_IMG) += pwm-img.o > diff --git a/drivers/pwm/pwm-disp-mediatek.c b/drivers/pwm/pwm-disp-mediatek.c > new file mode 100644 > index 0000000..38293af > --- /dev/null > +++ b/drivers/pwm/pwm-disp-mediatek.c > @@ -0,0 +1,225 @@ > +/* > + * Mediatek display pulse-width-modulation controller driver. > + * Copyright (c) 2015 MediaTek Inc. > + * Author: YH Huang <yh.huang@mediatek.com> > + * > + * This program is free software; you can redistribute it and/or modify > + * it under the terms of the GNU General Public License version 2 as > + * published by the Free Software Foundation. > + * > + * This program is distributed in the hope that it will be useful, > + * but WITHOUT ANY WARRANTY; without even the implied warranty of > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the > + * GNU General Public License for more details. > + */ > + > +#include <linux/clk.h> > +#include <linux/err.h> > +#include <linux/io.h> > +#include <linux/module.h> > +#include <linux/of.h> > +#include <linux/pwm.h> > +#include <linux/platform_device.h> > +#include <linux/slab.h> > + > +#define DISP_PWM_EN_OFF (0x0) > +#define PWM_ENABLE_SHIFT (0x0) > +#define PWM_ENABLE_MASK (0x1 << PWM_ENABLE_SHIFT) > + > +#define DISP_PWM_COMMIT_OFF (0x08) > +#define PWM_COMMIT_SHIFT (0x0) > +#define PWM_COMMIT_MASK (0x1 << PWM_COMMIT_SHIFT) > + > +#define DISP_PWM_CON_0_OFF (0x10) > +#define PWM_CLKDIV_SHIFT (0x10) > +#define PWM_CLKDIV_MASK (0x3ff << PWM_CLKDIV_SHIFT) > +#define PWM_CLKDIV_MAX (0x000003ff) > + > +#define DISP_PWM_CON_1_OFF (0x14) > +#define PWM_PERIOD_SHIFT (0x0) > +#define PWM_PERIOD_MASK (0xfff << PWM_PERIOD_SHIFT) > +#define PWM_PERIOD_MAX (0x00000fff) > +/* Shift log2(PWM_PERIOD_MAX + 1) as divisor */ > +#define PWM_PERIOD_BIT_SHIFT 12 > + > +#define PWM_HIGH_WIDTH_SHIFT (0x10) > +#define PWM_HIGH_WIDTH_MASK (0x1fff << PWM_HIGH_WIDTH_SHIFT) > + > +#define NUM_PWM 1 > + > +struct mtk_disp_pwm_chip { > + struct pwm_chip chip; > + struct device *dev; > + struct clk *clk_main; > + struct clk *clk_mm; > + void __iomem *mmio_base; > +}; > + > +static void mtk_disp_pwm_setting(void __iomem *address, u32 value, u32 mask) > +{ > + u32 val; > + > + val = readl(address); > + val &= ~mask; > + val |= value; > + writel(val, address); > +} > + > +static int mtk_disp_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, > + int duty_ns, int period_ns) > +{ > + struct mtk_disp_pwm_chip *mpc; > + u64 div, rate; > + u32 clk_div, period, high_width, rem; > + > + /* > + * Find period, high_width and clk_div to suit duty_ns and period_ns. > + * Calculate proper div value to keep period value in the bound. > + * > + * period_ns = 10^9 * (clk_div + 1) * (period +1) / PWM_CLK_RATE > + * duty_ns = 10^9 * (clk_div + 1) * (high_width + 1) / PWM_CLK_RATE > + * > + * period = (PWM_CLK_RATE * period_ns) / (10^9 * (clk_div + 1)) - 1 > + * high_width = (PWM_CLK_RATE * duty_ns) / (10^9 * (clk_div + 1)) - 1 > + */ > + mpc = container_of(chip, struct mtk_disp_pwm_chip, chip); > + rate = clk_get_rate(mpc->clk_main); > + clk_div = div_u64_rem(rate * period_ns, NSEC_PER_SEC, &rem) >> > + PWM_PERIOD_BIT_SHIFT; > + if (clk_div > PWM_CLKDIV_MAX) > + return -EINVAL; > + > + div = clk_div + 1; > + period = div64_u64(rate * period_ns, NSEC_PER_SEC * div); > + if (period > 0) > + period--; > + high_width = div64_u64(rate * duty_ns, NSEC_PER_SEC * div); > + if (high_width > 0) > + high_width--; > + > + mtk_disp_pwm_setting(mpc->mmio_base + DISP_PWM_CON_0_OFF, > + clk_div << PWM_CLKDIV_SHIFT, PWM_CLKDIV_MASK); > + mtk_disp_pwm_setting(mpc->mmio_base + DISP_PWM_CON_1_OFF, > + (period << PWM_PERIOD_SHIFT) | > + (high_width << PWM_HIGH_WIDTH_SHIFT), > + PWM_PERIOD_MASK | PWM_HIGH_WIDTH_MASK); > + > + mtk_disp_pwm_setting(mpc->mmio_base + DISP_PWM_COMMIT_OFF, > + 1 << PWM_COMMIT_SHIFT, PWM_COMMIT_MASK); > + mtk_disp_pwm_setting(mpc->mmio_base + DISP_PWM_COMMIT_OFF, > + 0 << PWM_COMMIT_SHIFT, PWM_COMMIT_MASK); > + > + return 0; > +} > + > +static int mtk_disp_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm) > +{ > + struct mtk_disp_pwm_chip *mpc; > + > + mpc = container_of(chip, struct mtk_disp_pwm_chip, chip); > + mtk_disp_pwm_setting(mpc->mmio_base + DISP_PWM_EN_OFF, > + 1 << PWM_ENABLE_SHIFT, PWM_ENABLE_MASK); > + > + return 0; > +} > + > +static void mtk_disp_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm) > +{ > + struct mtk_disp_pwm_chip *mpc; > + > + mpc = container_of(chip, struct mtk_disp_pwm_chip, chip); > + mtk_disp_pwm_setting(mpc->mmio_base + DISP_PWM_EN_OFF, > + 0 << PWM_ENABLE_SHIFT, PWM_ENABLE_MASK); > +} > + > +static const struct pwm_ops mtk_disp_pwm_ops = { > + .config = mtk_disp_pwm_config, > + .enable = mtk_disp_pwm_enable, > + .disable = mtk_disp_pwm_disable, > + .owner = THIS_MODULE, > +}; > + > +static int mtk_disp_pwm_probe(struct platform_device *pdev) > +{ > + struct mtk_disp_pwm_chip *pwm; > + struct resource *r; > + int ret; > + > + pwm = devm_kzalloc(&pdev->dev, sizeof(*pwm), GFP_KERNEL); > + if (!pwm) > + return -ENOMEM; > + > + pwm->dev = &pdev->dev; > + > + r = platform_get_resource(pdev, IORESOURCE_MEM, 0); > + pwm->mmio_base = devm_ioremap_resource(&pdev->dev, r); > + if (IS_ERR(pwm->mmio_base)) > + return PTR_ERR(pwm->mmio_base); > + > + pwm->clk_main = devm_clk_get(&pdev->dev, "main"); > + if (IS_ERR(pwm->clk_main)) > + return PTR_ERR(pwm->clk_main); > + pwm->clk_mm = devm_clk_get(&pdev->dev, "mm"); > + if (IS_ERR(pwm->clk_mm)) > + return PTR_ERR(pwm->clk_mm); > + > + ret = clk_prepare_enable(pwm->clk_main); > + if (ret < 0) > + return ret; > + ret = clk_prepare_enable(pwm->clk_mm); > + if (ret < 0) { > + clk_disable_unprepare(pwm->clk_main); > + return ret; > + } > + > + platform_set_drvdata(pdev, pwm); > + > + pwm->chip.dev = &pdev->dev; > + pwm->chip.ops = &mtk_disp_pwm_ops; > + pwm->chip.base = -1; > + pwm->chip.npwm = NUM_PWM; > + > + ret = pwmchip_add(&pwm->chip); > + if (ret < 0) { > + dev_err(&pdev->dev, "pwmchip_add() failed: %d\n", ret); > + return ret; > + } > + > + return 0; > +} > + > +static int mtk_disp_pwm_remove(struct platform_device *pdev) > +{ > + struct mtk_disp_pwm_chip *pc = platform_get_drvdata(pdev); > + > + if (WARN_ON(!pc)) > + return -ENODEV; > + > + clk_disable_unprepare(pc->clk_main); > + clk_disable_unprepare(pc->clk_mm); > + > + return pwmchip_remove(&pc->chip); > +} > + > +static const struct of_device_id mtk_disp_pwm_of_match[] = { > + { .compatible = "mediatek,mt6595-disp-pwm" }, Does this driver support the PWM in mt8173? If so, don't you need this, too: { .compatible = "mediatek,mt8173-disp-pwm" }, > + { } > +}; > + > +MODULE_DEVICE_TABLE(of, mtk_disp_pwm_of_match); > + > +static struct platform_driver mtk_disp_pwm_driver = { > + .driver = { > + .name = "mediatek-disp-pwm", > + .owner = THIS_MODULE, > + .of_match_table = mtk_disp_pwm_of_match, > + }, > + .probe = mtk_disp_pwm_probe, > + .remove = mtk_disp_pwm_remove, > +}; > + > +module_platform_driver(mtk_disp_pwm_driver); > + > +MODULE_AUTHOR("YH Huang <yh.huang@mediatek.com>"); > +MODULE_DESCRIPTION("MediaTek SoC display PWM driver"); > +MODULE_LICENSE("GPL v2"); > -- > 1.8.1.1.dirty > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/
On Mon, 2015-05-18 at 11:42 +0800, Daniel Kurtz wrote: > On Mon, May 11, 2015 at 5:26 PM, YH Huang <yh.huang@mediatek.com> wrote: > > Add display PWM driver support to modify backlight for MT8173/MT6595. > > > > Signed-off-by: YH Huang <yh.huang@mediatek.com> > > --- > > drivers/pwm/Kconfig | 9 ++ > > drivers/pwm/Makefile | 1 + > > drivers/pwm/pwm-disp-mediatek.c | 225 ++++++++++++++++++++++++++++++++++++++++ > > 3 files changed, 235 insertions(+) > > create mode 100644 drivers/pwm/pwm-disp-mediatek.c > > > > diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig > > index b1541f4..9edbb5a 100644 > > --- a/drivers/pwm/Kconfig > > +++ b/drivers/pwm/Kconfig > > @@ -111,6 +111,15 @@ config PWM_CLPS711X > > To compile this driver as a module, choose M here: the module > > will be called pwm-clps711x. > > > > +config PWM_DISP_MEDIATEK > > + tristate "MEDIATEK display PWM driver" > > + depends on OF > > + help > > + Generic PWM framework driver for mediatek disp-pwm device. > > + > > + To compile this driver as a module, choose M here: the module > > + will be called pwm-disp-mediatek. > > + > > config PWM_EP93XX > > tristate "Cirrus Logic EP93xx PWM support" > > depends on ARCH_EP93XX > > diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile > > index ec50eb5..c5ff72a 100644 > > --- a/drivers/pwm/Makefile > > +++ b/drivers/pwm/Makefile > > @@ -8,6 +8,7 @@ obj-$(CONFIG_PWM_BCM_KONA) += pwm-bcm-kona.o > > obj-$(CONFIG_PWM_BCM2835) += pwm-bcm2835.o > > obj-$(CONFIG_PWM_BFIN) += pwm-bfin.o > > obj-$(CONFIG_PWM_CLPS711X) += pwm-clps711x.o > > +obj-$(CONFIG_PWM_DISP_MEDIATEK) += pwm-disp-mediatek.o > > obj-$(CONFIG_PWM_EP93XX) += pwm-ep93xx.o > > obj-$(CONFIG_PWM_FSL_FTM) += pwm-fsl-ftm.o > > obj-$(CONFIG_PWM_IMG) += pwm-img.o > > diff --git a/drivers/pwm/pwm-disp-mediatek.c b/drivers/pwm/pwm-disp-mediatek.c > > new file mode 100644 > > index 0000000..38293af > > --- /dev/null > > +++ b/drivers/pwm/pwm-disp-mediatek.c > > @@ -0,0 +1,225 @@ > > +/* > > + * Mediatek display pulse-width-modulation controller driver. > > + * Copyright (c) 2015 MediaTek Inc. > > + * Author: YH Huang <yh.huang@mediatek.com> > > + * > > + * This program is free software; you can redistribute it and/or modify > > + * it under the terms of the GNU General Public License version 2 as > > + * published by the Free Software Foundation. > > + * > > + * This program is distributed in the hope that it will be useful, > > + * but WITHOUT ANY WARRANTY; without even the implied warranty of > > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the > > + * GNU General Public License for more details. > > + */ > > + > > +#include <linux/clk.h> > > +#include <linux/err.h> > > +#include <linux/io.h> > > +#include <linux/module.h> > > +#include <linux/of.h> > > +#include <linux/pwm.h> > > +#include <linux/platform_device.h> > > +#include <linux/slab.h> > > + > > +#define DISP_PWM_EN_OFF (0x0) > > +#define PWM_ENABLE_SHIFT (0x0) > > +#define PWM_ENABLE_MASK (0x1 << PWM_ENABLE_SHIFT) > > + > > +#define DISP_PWM_COMMIT_OFF (0x08) > > +#define PWM_COMMIT_SHIFT (0x0) > > +#define PWM_COMMIT_MASK (0x1 << PWM_COMMIT_SHIFT) > > + > > +#define DISP_PWM_CON_0_OFF (0x10) > > +#define PWM_CLKDIV_SHIFT (0x10) > > +#define PWM_CLKDIV_MASK (0x3ff << PWM_CLKDIV_SHIFT) > > +#define PWM_CLKDIV_MAX (0x000003ff) > > + > > +#define DISP_PWM_CON_1_OFF (0x14) > > +#define PWM_PERIOD_SHIFT (0x0) > > +#define PWM_PERIOD_MASK (0xfff << PWM_PERIOD_SHIFT) > > +#define PWM_PERIOD_MAX (0x00000fff) > > +/* Shift log2(PWM_PERIOD_MAX + 1) as divisor */ > > +#define PWM_PERIOD_BIT_SHIFT 12 > > + > > +#define PWM_HIGH_WIDTH_SHIFT (0x10) > > +#define PWM_HIGH_WIDTH_MASK (0x1fff << PWM_HIGH_WIDTH_SHIFT) > > + > > +#define NUM_PWM 1 > > + > > +struct mtk_disp_pwm_chip { > > + struct pwm_chip chip; > > + struct device *dev; > > + struct clk *clk_main; > > + struct clk *clk_mm; > > + void __iomem *mmio_base; > > +}; > > + > > +static void mtk_disp_pwm_setting(void __iomem *address, u32 value, u32 mask) > > +{ > > + u32 val; > > + > > + val = readl(address); > > + val &= ~mask; > > + val |= value; > > + writel(val, address); > > +} > > + > > +static int mtk_disp_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, > > + int duty_ns, int period_ns) > > +{ > > + struct mtk_disp_pwm_chip *mpc; > > + u64 div, rate; > > + u32 clk_div, period, high_width, rem; > > + > > + /* > > + * Find period, high_width and clk_div to suit duty_ns and period_ns. > > + * Calculate proper div value to keep period value in the bound. > > + * > > + * period_ns = 10^9 * (clk_div + 1) * (period +1) / PWM_CLK_RATE > > + * duty_ns = 10^9 * (clk_div + 1) * (high_width + 1) / PWM_CLK_RATE > > + * > > + * period = (PWM_CLK_RATE * period_ns) / (10^9 * (clk_div + 1)) - 1 > > + * high_width = (PWM_CLK_RATE * duty_ns) / (10^9 * (clk_div + 1)) - 1 > > + */ > > + mpc = container_of(chip, struct mtk_disp_pwm_chip, chip); > > + rate = clk_get_rate(mpc->clk_main); > > + clk_div = div_u64_rem(rate * period_ns, NSEC_PER_SEC, &rem) >> > > + PWM_PERIOD_BIT_SHIFT; > > + if (clk_div > PWM_CLKDIV_MAX) > > + return -EINVAL; > > + > > + div = clk_div + 1; > > + period = div64_u64(rate * period_ns, NSEC_PER_SEC * div); > > + if (period > 0) > > + period--; > > + high_width = div64_u64(rate * duty_ns, NSEC_PER_SEC * div); > > + if (high_width > 0) > > + high_width--; > > + > > + mtk_disp_pwm_setting(mpc->mmio_base + DISP_PWM_CON_0_OFF, > > + clk_div << PWM_CLKDIV_SHIFT, PWM_CLKDIV_MASK); > > + mtk_disp_pwm_setting(mpc->mmio_base + DISP_PWM_CON_1_OFF, > > + (period << PWM_PERIOD_SHIFT) | > > + (high_width << PWM_HIGH_WIDTH_SHIFT), > > + PWM_PERIOD_MASK | PWM_HIGH_WIDTH_MASK); > > + > > + mtk_disp_pwm_setting(mpc->mmio_base + DISP_PWM_COMMIT_OFF, > > + 1 << PWM_COMMIT_SHIFT, PWM_COMMIT_MASK); > > + mtk_disp_pwm_setting(mpc->mmio_base + DISP_PWM_COMMIT_OFF, > > + 0 << PWM_COMMIT_SHIFT, PWM_COMMIT_MASK); > > + > > + return 0; > > +} > > + > > +static int mtk_disp_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm) > > +{ > > + struct mtk_disp_pwm_chip *mpc; > > + > > + mpc = container_of(chip, struct mtk_disp_pwm_chip, chip); > > + mtk_disp_pwm_setting(mpc->mmio_base + DISP_PWM_EN_OFF, > > + 1 << PWM_ENABLE_SHIFT, PWM_ENABLE_MASK); > > + > > + return 0; > > +} > > + > > +static void mtk_disp_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm) > > +{ > > + struct mtk_disp_pwm_chip *mpc; > > + > > + mpc = container_of(chip, struct mtk_disp_pwm_chip, chip); > > + mtk_disp_pwm_setting(mpc->mmio_base + DISP_PWM_EN_OFF, > > + 0 << PWM_ENABLE_SHIFT, PWM_ENABLE_MASK); > > +} > > + > > +static const struct pwm_ops mtk_disp_pwm_ops = { > > + .config = mtk_disp_pwm_config, > > + .enable = mtk_disp_pwm_enable, > > + .disable = mtk_disp_pwm_disable, > > + .owner = THIS_MODULE, > > +}; > > + > > +static int mtk_disp_pwm_probe(struct platform_device *pdev) > > +{ > > + struct mtk_disp_pwm_chip *pwm; > > + struct resource *r; > > + int ret; > > + > > + pwm = devm_kzalloc(&pdev->dev, sizeof(*pwm), GFP_KERNEL); > > + if (!pwm) > > + return -ENOMEM; > > + > > + pwm->dev = &pdev->dev; > > + > > + r = platform_get_resource(pdev, IORESOURCE_MEM, 0); > > + pwm->mmio_base = devm_ioremap_resource(&pdev->dev, r); > > + if (IS_ERR(pwm->mmio_base)) > > + return PTR_ERR(pwm->mmio_base); > > + > > + pwm->clk_main = devm_clk_get(&pdev->dev, "main"); > > + if (IS_ERR(pwm->clk_main)) > > + return PTR_ERR(pwm->clk_main); > > + pwm->clk_mm = devm_clk_get(&pdev->dev, "mm"); > > + if (IS_ERR(pwm->clk_mm)) > > + return PTR_ERR(pwm->clk_mm); > > + > > + ret = clk_prepare_enable(pwm->clk_main); > > + if (ret < 0) > > + return ret; > > + ret = clk_prepare_enable(pwm->clk_mm); > > + if (ret < 0) { > > + clk_disable_unprepare(pwm->clk_main); > > + return ret; > > + } > > + > > + platform_set_drvdata(pdev, pwm); > > + > > + pwm->chip.dev = &pdev->dev; > > + pwm->chip.ops = &mtk_disp_pwm_ops; > > + pwm->chip.base = -1; > > + pwm->chip.npwm = NUM_PWM; > > + > > + ret = pwmchip_add(&pwm->chip); > > + if (ret < 0) { > > + dev_err(&pdev->dev, "pwmchip_add() failed: %d\n", ret); > > + return ret; > > + } > > + > > + return 0; > > +} > > + > > +static int mtk_disp_pwm_remove(struct platform_device *pdev) > > +{ > > + struct mtk_disp_pwm_chip *pc = platform_get_drvdata(pdev); > > + > > + if (WARN_ON(!pc)) > > + return -ENODEV; > > + > > + clk_disable_unprepare(pc->clk_main); > > + clk_disable_unprepare(pc->clk_mm); > > + > > + return pwmchip_remove(&pc->chip); > > +} > > + > > +static const struct of_device_id mtk_disp_pwm_of_match[] = { > > + { .compatible = "mediatek,mt6595-disp-pwm" }, > > Does this driver support the PWM in mt8173? > If so, don't you need this, too: > > { .compatible = "mediatek,mt8173-disp-pwm" }, Yes, it supports mt8173. I will add it. > > > + { } > > +}; > > + > > +MODULE_DEVICE_TABLE(of, mtk_disp_pwm_of_match); > > + > > +static struct platform_driver mtk_disp_pwm_driver = { > > + .driver = { > > + .name = "mediatek-disp-pwm", > > + .owner = THIS_MODULE, > > + .of_match_table = mtk_disp_pwm_of_match, > > + }, > > + .probe = mtk_disp_pwm_probe, > > + .remove = mtk_disp_pwm_remove, > > +}; > > + > > +module_platform_driver(mtk_disp_pwm_driver); > > + > > +MODULE_AUTHOR("YH Huang <yh.huang@mediatek.com>"); > > +MODULE_DESCRIPTION("MediaTek SoC display PWM driver"); > > +MODULE_LICENSE("GPL v2"); > > -- > > 1.8.1.1.dirty > > > > -- > > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > > the body of a message to majordomo@vger.kernel.org > > More majordomo info at http://vger.kernel.org/majordomo-info.html > > Please read the FAQ at http://www.tux.org/lkml/ Thank for your suggestion. Regards, YH Huang
On Thu, May 21, 2015 at 04:22:31PM +0800, YH Huang wrote: > On Mon, 2015-05-18 at 11:42 +0800, Daniel Kurtz wrote: > > On Mon, May 11, 2015 at 5:26 PM, YH Huang <yh.huang@mediatek.com> wrote: > > > Add display PWM driver support to modify backlight for MT8173/MT6595. > > > > > > Signed-off-by: YH Huang <yh.huang@mediatek.com> > > > --- > > > drivers/pwm/Kconfig | 9 ++ > > > drivers/pwm/Makefile | 1 + > > > drivers/pwm/pwm-disp-mediatek.c | 225 ++++++++++++++++++++++++++++++++++++++++ > > > 3 files changed, 235 insertions(+) > > > create mode 100644 drivers/pwm/pwm-disp-mediatek.c > > > > > > diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig > > > index b1541f4..9edbb5a 100644 > > > --- a/drivers/pwm/Kconfig > > > +++ b/drivers/pwm/Kconfig > > > @@ -111,6 +111,15 @@ config PWM_CLPS711X > > > To compile this driver as a module, choose M here: the module > > > will be called pwm-clps711x. > > > > > > +config PWM_DISP_MEDIATEK > > > + tristate "MEDIATEK display PWM driver" > > > + depends on OF > > > + help > > > + Generic PWM framework driver for mediatek disp-pwm device. > > > + > > > + To compile this driver as a module, choose M here: the module > > > + will be called pwm-disp-mediatek. > > > + > > > config PWM_EP93XX > > > tristate "Cirrus Logic EP93xx PWM support" > > > depends on ARCH_EP93XX > > > diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile > > > index ec50eb5..c5ff72a 100644 > > > --- a/drivers/pwm/Makefile > > > +++ b/drivers/pwm/Makefile > > > @@ -8,6 +8,7 @@ obj-$(CONFIG_PWM_BCM_KONA) += pwm-bcm-kona.o > > > obj-$(CONFIG_PWM_BCM2835) += pwm-bcm2835.o > > > obj-$(CONFIG_PWM_BFIN) += pwm-bfin.o > > > obj-$(CONFIG_PWM_CLPS711X) += pwm-clps711x.o > > > +obj-$(CONFIG_PWM_DISP_MEDIATEK) += pwm-disp-mediatek.o > > > obj-$(CONFIG_PWM_EP93XX) += pwm-ep93xx.o > > > obj-$(CONFIG_PWM_FSL_FTM) += pwm-fsl-ftm.o > > > obj-$(CONFIG_PWM_IMG) += pwm-img.o > > > diff --git a/drivers/pwm/pwm-disp-mediatek.c b/drivers/pwm/pwm-disp-mediatek.c > > > new file mode 100644 > > > index 0000000..38293af > > > --- /dev/null > > > +++ b/drivers/pwm/pwm-disp-mediatek.c > > > @@ -0,0 +1,225 @@ > > > +/* > > > + * Mediatek display pulse-width-modulation controller driver. > > > + * Copyright (c) 2015 MediaTek Inc. > > > + * Author: YH Huang <yh.huang@mediatek.com> > > > + * > > > + * This program is free software; you can redistribute it and/or modify > > > + * it under the terms of the GNU General Public License version 2 as > > > + * published by the Free Software Foundation. > > > + * > > > + * This program is distributed in the hope that it will be useful, > > > + * but WITHOUT ANY WARRANTY; without even the implied warranty of > > > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the > > > + * GNU General Public License for more details. > > > + */ > > > + > > > +#include <linux/clk.h> > > > +#include <linux/err.h> > > > +#include <linux/io.h> > > > +#include <linux/module.h> > > > +#include <linux/of.h> > > > +#include <linux/pwm.h> > > > +#include <linux/platform_device.h> > > > +#include <linux/slab.h> > > > + > > > +#define DISP_PWM_EN_OFF (0x0) > > > +#define PWM_ENABLE_SHIFT (0x0) > > > +#define PWM_ENABLE_MASK (0x1 << PWM_ENABLE_SHIFT) > > > + > > > +#define DISP_PWM_COMMIT_OFF (0x08) > > > +#define PWM_COMMIT_SHIFT (0x0) > > > +#define PWM_COMMIT_MASK (0x1 << PWM_COMMIT_SHIFT) > > > + > > > +#define DISP_PWM_CON_0_OFF (0x10) > > > +#define PWM_CLKDIV_SHIFT (0x10) > > > +#define PWM_CLKDIV_MASK (0x3ff << PWM_CLKDIV_SHIFT) > > > +#define PWM_CLKDIV_MAX (0x000003ff) > > > + > > > +#define DISP_PWM_CON_1_OFF (0x14) > > > +#define PWM_PERIOD_SHIFT (0x0) > > > +#define PWM_PERIOD_MASK (0xfff << PWM_PERIOD_SHIFT) > > > +#define PWM_PERIOD_MAX (0x00000fff) > > > +/* Shift log2(PWM_PERIOD_MAX + 1) as divisor */ > > > +#define PWM_PERIOD_BIT_SHIFT 12 > > > + > > > +#define PWM_HIGH_WIDTH_SHIFT (0x10) > > > +#define PWM_HIGH_WIDTH_MASK (0x1fff << PWM_HIGH_WIDTH_SHIFT) > > > + > > > +#define NUM_PWM 1 > > > + > > > +struct mtk_disp_pwm_chip { > > > + struct pwm_chip chip; > > > + struct device *dev; > > > + struct clk *clk_main; > > > + struct clk *clk_mm; > > > + void __iomem *mmio_base; > > > +}; > > > + > > > +static void mtk_disp_pwm_setting(void __iomem *address, u32 value, u32 mask) > > > +{ > > > + u32 val; > > > + > > > + val = readl(address); > > > + val &= ~mask; > > > + val |= value; > > > + writel(val, address); > > > +} > > > + > > > +static int mtk_disp_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, > > > + int duty_ns, int period_ns) > > > +{ > > > + struct mtk_disp_pwm_chip *mpc; > > > + u64 div, rate; > > > + u32 clk_div, period, high_width, rem; > > > + > > > + /* > > > + * Find period, high_width and clk_div to suit duty_ns and period_ns. > > > + * Calculate proper div value to keep period value in the bound. > > > + * > > > + * period_ns = 10^9 * (clk_div + 1) * (period +1) / PWM_CLK_RATE > > > + * duty_ns = 10^9 * (clk_div + 1) * (high_width + 1) / PWM_CLK_RATE > > > + * > > > + * period = (PWM_CLK_RATE * period_ns) / (10^9 * (clk_div + 1)) - 1 > > > + * high_width = (PWM_CLK_RATE * duty_ns) / (10^9 * (clk_div + 1)) - 1 > > > + */ > > > + mpc = container_of(chip, struct mtk_disp_pwm_chip, chip); > > > + rate = clk_get_rate(mpc->clk_main); > > > + clk_div = div_u64_rem(rate * period_ns, NSEC_PER_SEC, &rem) >> > > > + PWM_PERIOD_BIT_SHIFT; > > > + if (clk_div > PWM_CLKDIV_MAX) > > > + return -EINVAL; > > > + > > > + div = clk_div + 1; > > > + period = div64_u64(rate * period_ns, NSEC_PER_SEC * div); > > > + if (period > 0) > > > + period--; > > > + high_width = div64_u64(rate * duty_ns, NSEC_PER_SEC * div); > > > + if (high_width > 0) > > > + high_width--; > > > + > > > + mtk_disp_pwm_setting(mpc->mmio_base + DISP_PWM_CON_0_OFF, > > > + clk_div << PWM_CLKDIV_SHIFT, PWM_CLKDIV_MASK); > > > + mtk_disp_pwm_setting(mpc->mmio_base + DISP_PWM_CON_1_OFF, > > > + (period << PWM_PERIOD_SHIFT) | > > > + (high_width << PWM_HIGH_WIDTH_SHIFT), > > > + PWM_PERIOD_MASK | PWM_HIGH_WIDTH_MASK); > > > + > > > + mtk_disp_pwm_setting(mpc->mmio_base + DISP_PWM_COMMIT_OFF, > > > + 1 << PWM_COMMIT_SHIFT, PWM_COMMIT_MASK); > > > + mtk_disp_pwm_setting(mpc->mmio_base + DISP_PWM_COMMIT_OFF, > > > + 0 << PWM_COMMIT_SHIFT, PWM_COMMIT_MASK); > > > + > > > + return 0; > > > +} > > > + > > > +static int mtk_disp_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm) > > > +{ > > > + struct mtk_disp_pwm_chip *mpc; > > > + > > > + mpc = container_of(chip, struct mtk_disp_pwm_chip, chip); > > > + mtk_disp_pwm_setting(mpc->mmio_base + DISP_PWM_EN_OFF, > > > + 1 << PWM_ENABLE_SHIFT, PWM_ENABLE_MASK); > > > + > > > + return 0; > > > +} > > > + > > > +static void mtk_disp_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm) > > > +{ > > > + struct mtk_disp_pwm_chip *mpc; > > > + > > > + mpc = container_of(chip, struct mtk_disp_pwm_chip, chip); > > > + mtk_disp_pwm_setting(mpc->mmio_base + DISP_PWM_EN_OFF, > > > + 0 << PWM_ENABLE_SHIFT, PWM_ENABLE_MASK); > > > +} > > > + > > > +static const struct pwm_ops mtk_disp_pwm_ops = { > > > + .config = mtk_disp_pwm_config, > > > + .enable = mtk_disp_pwm_enable, > > > + .disable = mtk_disp_pwm_disable, > > > + .owner = THIS_MODULE, > > > +}; > > > + > > > +static int mtk_disp_pwm_probe(struct platform_device *pdev) > > > +{ > > > + struct mtk_disp_pwm_chip *pwm; > > > + struct resource *r; > > > + int ret; > > > + > > > + pwm = devm_kzalloc(&pdev->dev, sizeof(*pwm), GFP_KERNEL); > > > + if (!pwm) > > > + return -ENOMEM; > > > + > > > + pwm->dev = &pdev->dev; > > > + > > > + r = platform_get_resource(pdev, IORESOURCE_MEM, 0); > > > + pwm->mmio_base = devm_ioremap_resource(&pdev->dev, r); > > > + if (IS_ERR(pwm->mmio_base)) > > > + return PTR_ERR(pwm->mmio_base); > > > + > > > + pwm->clk_main = devm_clk_get(&pdev->dev, "main"); > > > + if (IS_ERR(pwm->clk_main)) > > > + return PTR_ERR(pwm->clk_main); > > > + pwm->clk_mm = devm_clk_get(&pdev->dev, "mm"); > > > + if (IS_ERR(pwm->clk_mm)) > > > + return PTR_ERR(pwm->clk_mm); > > > + > > > + ret = clk_prepare_enable(pwm->clk_main); > > > + if (ret < 0) > > > + return ret; > > > + ret = clk_prepare_enable(pwm->clk_mm); > > > + if (ret < 0) { > > > + clk_disable_unprepare(pwm->clk_main); > > > + return ret; > > > + } > > > + > > > + platform_set_drvdata(pdev, pwm); > > > + > > > + pwm->chip.dev = &pdev->dev; > > > + pwm->chip.ops = &mtk_disp_pwm_ops; > > > + pwm->chip.base = -1; > > > + pwm->chip.npwm = NUM_PWM; > > > + > > > + ret = pwmchip_add(&pwm->chip); > > > + if (ret < 0) { > > > + dev_err(&pdev->dev, "pwmchip_add() failed: %d\n", ret); > > > + return ret; > > > + } > > > + > > > + return 0; > > > +} > > > + > > > +static int mtk_disp_pwm_remove(struct platform_device *pdev) > > > +{ > > > + struct mtk_disp_pwm_chip *pc = platform_get_drvdata(pdev); > > > + > > > + if (WARN_ON(!pc)) > > > + return -ENODEV; > > > + > > > + clk_disable_unprepare(pc->clk_main); > > > + clk_disable_unprepare(pc->clk_mm); > > > + > > > + return pwmchip_remove(&pc->chip); > > > +} > > > + > > > +static const struct of_device_id mtk_disp_pwm_of_match[] = { > > > + { .compatible = "mediatek,mt6595-disp-pwm" }, > > > > Does this driver support the PWM in mt8173? > > If so, don't you need this, too: > > > > { .compatible = "mediatek,mt8173-disp-pwm" }, > > Yes, it supports mt8173. > I will add it. If both yre compatible you don't need to add it since you have a "mediatek,mt6595-disp-pwm" in the mt8173 device tree. Sascha
On Tue, 2015-05-26 at 08:05 +0200, Sascha Hauer wrote: > On Thu, May 21, 2015 at 04:22:31PM +0800, YH Huang wrote: > > On Mon, 2015-05-18 at 11:42 +0800, Daniel Kurtz wrote: <...> > > > On Mon, May 11, 2015 at 5:26 PM, YH Huang <yh.huang@mediatek.com> wrote: > > > > + > > > > +static const struct of_device_id mtk_disp_pwm_of_match[] = { > > > > + { .compatible = "mediatek,mt6595-disp-pwm" }, > > > > > > Does this driver support the PWM in mt8173? > > > If so, don't you need this, too: > > > > > > { .compatible = "mediatek,mt8173-disp-pwm" }, > > > > Yes, it supports mt8173. > > I will add it. > > If both yre compatible you don't need to add it since you have a > "mediatek,mt6595-disp-pwm" in the mt8173 device tree. Hi Sascha, We got a similar discussion about this with Mark Brown for spi driver, please see: http://lists.infradead.org/pipermail/linux-mediatek/2015-May/000673.html Joe.C
diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig index b1541f4..9edbb5a 100644 --- a/drivers/pwm/Kconfig +++ b/drivers/pwm/Kconfig @@ -111,6 +111,15 @@ config PWM_CLPS711X To compile this driver as a module, choose M here: the module will be called pwm-clps711x. +config PWM_DISP_MEDIATEK + tristate "MEDIATEK display PWM driver" + depends on OF + help + Generic PWM framework driver for mediatek disp-pwm device. + + To compile this driver as a module, choose M here: the module + will be called pwm-disp-mediatek. + config PWM_EP93XX tristate "Cirrus Logic EP93xx PWM support" depends on ARCH_EP93XX diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile index ec50eb5..c5ff72a 100644 --- a/drivers/pwm/Makefile +++ b/drivers/pwm/Makefile @@ -8,6 +8,7 @@ obj-$(CONFIG_PWM_BCM_KONA) += pwm-bcm-kona.o obj-$(CONFIG_PWM_BCM2835) += pwm-bcm2835.o obj-$(CONFIG_PWM_BFIN) += pwm-bfin.o obj-$(CONFIG_PWM_CLPS711X) += pwm-clps711x.o +obj-$(CONFIG_PWM_DISP_MEDIATEK) += pwm-disp-mediatek.o obj-$(CONFIG_PWM_EP93XX) += pwm-ep93xx.o obj-$(CONFIG_PWM_FSL_FTM) += pwm-fsl-ftm.o obj-$(CONFIG_PWM_IMG) += pwm-img.o diff --git a/drivers/pwm/pwm-disp-mediatek.c b/drivers/pwm/pwm-disp-mediatek.c new file mode 100644 index 0000000..38293af --- /dev/null +++ b/drivers/pwm/pwm-disp-mediatek.c @@ -0,0 +1,225 @@ +/* + * Mediatek display pulse-width-modulation controller driver. + * Copyright (c) 2015 MediaTek Inc. + * Author: YH Huang <yh.huang@mediatek.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + */ + +#include <linux/clk.h> +#include <linux/err.h> +#include <linux/io.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/pwm.h> +#include <linux/platform_device.h> +#include <linux/slab.h> + +#define DISP_PWM_EN_OFF (0x0) +#define PWM_ENABLE_SHIFT (0x0) +#define PWM_ENABLE_MASK (0x1 << PWM_ENABLE_SHIFT) + +#define DISP_PWM_COMMIT_OFF (0x08) +#define PWM_COMMIT_SHIFT (0x0) +#define PWM_COMMIT_MASK (0x1 << PWM_COMMIT_SHIFT) + +#define DISP_PWM_CON_0_OFF (0x10) +#define PWM_CLKDIV_SHIFT (0x10) +#define PWM_CLKDIV_MASK (0x3ff << PWM_CLKDIV_SHIFT) +#define PWM_CLKDIV_MAX (0x000003ff) + +#define DISP_PWM_CON_1_OFF (0x14) +#define PWM_PERIOD_SHIFT (0x0) +#define PWM_PERIOD_MASK (0xfff << PWM_PERIOD_SHIFT) +#define PWM_PERIOD_MAX (0x00000fff) +/* Shift log2(PWM_PERIOD_MAX + 1) as divisor */ +#define PWM_PERIOD_BIT_SHIFT 12 + +#define PWM_HIGH_WIDTH_SHIFT (0x10) +#define PWM_HIGH_WIDTH_MASK (0x1fff << PWM_HIGH_WIDTH_SHIFT) + +#define NUM_PWM 1 + +struct mtk_disp_pwm_chip { + struct pwm_chip chip; + struct device *dev; + struct clk *clk_main; + struct clk *clk_mm; + void __iomem *mmio_base; +}; + +static void mtk_disp_pwm_setting(void __iomem *address, u32 value, u32 mask) +{ + u32 val; + + val = readl(address); + val &= ~mask; + val |= value; + writel(val, address); +} + +static int mtk_disp_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, + int duty_ns, int period_ns) +{ + struct mtk_disp_pwm_chip *mpc; + u64 div, rate; + u32 clk_div, period, high_width, rem; + + /* + * Find period, high_width and clk_div to suit duty_ns and period_ns. + * Calculate proper div value to keep period value in the bound. + * + * period_ns = 10^9 * (clk_div + 1) * (period +1) / PWM_CLK_RATE + * duty_ns = 10^9 * (clk_div + 1) * (high_width + 1) / PWM_CLK_RATE + * + * period = (PWM_CLK_RATE * period_ns) / (10^9 * (clk_div + 1)) - 1 + * high_width = (PWM_CLK_RATE * duty_ns) / (10^9 * (clk_div + 1)) - 1 + */ + mpc = container_of(chip, struct mtk_disp_pwm_chip, chip); + rate = clk_get_rate(mpc->clk_main); + clk_div = div_u64_rem(rate * period_ns, NSEC_PER_SEC, &rem) >> + PWM_PERIOD_BIT_SHIFT; + if (clk_div > PWM_CLKDIV_MAX) + return -EINVAL; + + div = clk_div + 1; + period = div64_u64(rate * period_ns, NSEC_PER_SEC * div); + if (period > 0) + period--; + high_width = div64_u64(rate * duty_ns, NSEC_PER_SEC * div); + if (high_width > 0) + high_width--; + + mtk_disp_pwm_setting(mpc->mmio_base + DISP_PWM_CON_0_OFF, + clk_div << PWM_CLKDIV_SHIFT, PWM_CLKDIV_MASK); + mtk_disp_pwm_setting(mpc->mmio_base + DISP_PWM_CON_1_OFF, + (period << PWM_PERIOD_SHIFT) | + (high_width << PWM_HIGH_WIDTH_SHIFT), + PWM_PERIOD_MASK | PWM_HIGH_WIDTH_MASK); + + mtk_disp_pwm_setting(mpc->mmio_base + DISP_PWM_COMMIT_OFF, + 1 << PWM_COMMIT_SHIFT, PWM_COMMIT_MASK); + mtk_disp_pwm_setting(mpc->mmio_base + DISP_PWM_COMMIT_OFF, + 0 << PWM_COMMIT_SHIFT, PWM_COMMIT_MASK); + + return 0; +} + +static int mtk_disp_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm) +{ + struct mtk_disp_pwm_chip *mpc; + + mpc = container_of(chip, struct mtk_disp_pwm_chip, chip); + mtk_disp_pwm_setting(mpc->mmio_base + DISP_PWM_EN_OFF, + 1 << PWM_ENABLE_SHIFT, PWM_ENABLE_MASK); + + return 0; +} + +static void mtk_disp_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm) +{ + struct mtk_disp_pwm_chip *mpc; + + mpc = container_of(chip, struct mtk_disp_pwm_chip, chip); + mtk_disp_pwm_setting(mpc->mmio_base + DISP_PWM_EN_OFF, + 0 << PWM_ENABLE_SHIFT, PWM_ENABLE_MASK); +} + +static const struct pwm_ops mtk_disp_pwm_ops = { + .config = mtk_disp_pwm_config, + .enable = mtk_disp_pwm_enable, + .disable = mtk_disp_pwm_disable, + .owner = THIS_MODULE, +}; + +static int mtk_disp_pwm_probe(struct platform_device *pdev) +{ + struct mtk_disp_pwm_chip *pwm; + struct resource *r; + int ret; + + pwm = devm_kzalloc(&pdev->dev, sizeof(*pwm), GFP_KERNEL); + if (!pwm) + return -ENOMEM; + + pwm->dev = &pdev->dev; + + r = platform_get_resource(pdev, IORESOURCE_MEM, 0); + pwm->mmio_base = devm_ioremap_resource(&pdev->dev, r); + if (IS_ERR(pwm->mmio_base)) + return PTR_ERR(pwm->mmio_base); + + pwm->clk_main = devm_clk_get(&pdev->dev, "main"); + if (IS_ERR(pwm->clk_main)) + return PTR_ERR(pwm->clk_main); + pwm->clk_mm = devm_clk_get(&pdev->dev, "mm"); + if (IS_ERR(pwm->clk_mm)) + return PTR_ERR(pwm->clk_mm); + + ret = clk_prepare_enable(pwm->clk_main); + if (ret < 0) + return ret; + ret = clk_prepare_enable(pwm->clk_mm); + if (ret < 0) { + clk_disable_unprepare(pwm->clk_main); + return ret; + } + + platform_set_drvdata(pdev, pwm); + + pwm->chip.dev = &pdev->dev; + pwm->chip.ops = &mtk_disp_pwm_ops; + pwm->chip.base = -1; + pwm->chip.npwm = NUM_PWM; + + ret = pwmchip_add(&pwm->chip); + if (ret < 0) { + dev_err(&pdev->dev, "pwmchip_add() failed: %d\n", ret); + return ret; + } + + return 0; +} + +static int mtk_disp_pwm_remove(struct platform_device *pdev) +{ + struct mtk_disp_pwm_chip *pc = platform_get_drvdata(pdev); + + if (WARN_ON(!pc)) + return -ENODEV; + + clk_disable_unprepare(pc->clk_main); + clk_disable_unprepare(pc->clk_mm); + + return pwmchip_remove(&pc->chip); +} + +static const struct of_device_id mtk_disp_pwm_of_match[] = { + { .compatible = "mediatek,mt6595-disp-pwm" }, + { } +}; + +MODULE_DEVICE_TABLE(of, mtk_disp_pwm_of_match); + +static struct platform_driver mtk_disp_pwm_driver = { + .driver = { + .name = "mediatek-disp-pwm", + .owner = THIS_MODULE, + .of_match_table = mtk_disp_pwm_of_match, + }, + .probe = mtk_disp_pwm_probe, + .remove = mtk_disp_pwm_remove, +}; + +module_platform_driver(mtk_disp_pwm_driver); + +MODULE_AUTHOR("YH Huang <yh.huang@mediatek.com>"); +MODULE_DESCRIPTION("MediaTek SoC display PWM driver"); +MODULE_LICENSE("GPL v2");
Add display PWM driver support to modify backlight for MT8173/MT6595. Signed-off-by: YH Huang <yh.huang@mediatek.com> --- drivers/pwm/Kconfig | 9 ++ drivers/pwm/Makefile | 1 + drivers/pwm/pwm-disp-mediatek.c | 225 ++++++++++++++++++++++++++++++++++++++++ 3 files changed, 235 insertions(+) create mode 100644 drivers/pwm/pwm-disp-mediatek.c