| Message ID | 1437380237-28961-3-git-send-email-yh.huang@mediatek.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Mon, Jul 20, 2015 at 04:17:16PM +0800, YH Huang wrote: > Add display PWM driver support to modify backlight for MT8173 and MT6595. > The PWM has one channel to control the brightness of the display. > When the (high_width / period) is closer to 1, the screen is brighter; > otherwise, it is darker. > > Signed-off-by: YH Huang <yh.huang@mediatek.com> > --- > drivers/pwm/Kconfig | 10 ++ > drivers/pwm/Makefile | 1 + > drivers/pwm/pwm-mtk-disp.c | 232 +++++++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 243 insertions(+) > create mode 100644 drivers/pwm/pwm-mtk-disp.c > > diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig > index b1541f4..f5b03a4 100644 > --- a/drivers/pwm/Kconfig > +++ b/drivers/pwm/Kconfig > @@ -211,6 +211,16 @@ config PWM_LPSS_PLATFORM > To compile this driver as a module, choose M here: the module > will be called pwm-lpss-platform. > > +config PWM_MTK_DISP > + tristate "MediaTek display PWM driver" > + depends on ARCH_MEDIATEK || COMPILE_TEST This is going to break randconfig builds. From a quick look your driver will fail to build at least on architectures that don't set HAVE_IOMEM. I know that's quite exotic, but I've had to deal with fallout from things like this in the past. If you want || COMPILE_TEST you should at least add a "depends on HAVE_IOMEM". linux/clk.h seems to have stubs for all of the functions that you use, so those shouldn't be a problem. > + help > + Generic PWM framework driver for MediaTek disp-pwm device. > + The PWM is used to control the backlight brightness for display. > + > + To compile this driver as a module, choose M here: the module > + will be called pwm-mtk-disp. > + > config PWM_MXS > tristate "Freescale MXS PWM support" > depends on ARCH_MXS && OF [...] > diff --git a/drivers/pwm/pwm-mtk-disp.c b/drivers/pwm/pwm-mtk-disp.c > new file mode 100644 > index 0000000..69682a0 > --- /dev/null > +++ b/drivers/pwm/pwm-mtk-disp.c > @@ -0,0 +1,232 @@ > +/* > + * 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> The above two aren't correctly sorted. > +#include <linux/slab.h> > + > +#define DISP_PWM_EN 0x00 > +#define PWM_ENABLE_MASK BIT(0) > + > +#define DISP_PWM_COMMIT 0x08 > +#define PWM_COMMIT_MASK BIT(0) > + > +#define DISP_PWM_CON_0 0x10 > +#define PWM_CLKDIV_SHIFT 16 > +#define PWM_CLKDIV_MAX 0x3ff > +#define PWM_CLKDIV_MASK (PWM_CLKDIV_MAX << PWM_CLKDIV_SHIFT) > + > +#define DISP_PWM_CON_1 0x14 > +#define PWM_PERIOD_MASK 0xfff > +/* Shift log2(PWM_PERIOD_MASK + 1) as divisor */ > +#define PWM_PERIOD_BIT_SHIFT 12 There are still two names for the same value here. I thought we had agreed on this becoming something like the below? #define PWM_PERIOD_BIT_SHIFT 12 #define PWM_PERIOD_MASK ((1 << PWM_PERIOD_BIT_SHIFT) - 1) Although PWM_PERIOD_BIT_WIDTH would probably be a better name. Or PWM_PERIOD_BITS or similar. > +static int mtk_disp_pwm_remove(struct platform_device *pdev) > +{ > + struct mtk_disp_pwm *mdp = platform_get_drvdata(pdev); > + int ret = pwmchip_remove(&mdp->chip); I'd prefer this to be separate lines: int ret; ret = pwmchip_remove(&mdp->chip); Thierry
On Mon, 2015-08-17 at 15:23 +0200, Thierry Reding wrote: > On Mon, Jul 20, 2015 at 04:17:16PM +0800, YH Huang wrote: > > Add display PWM driver support to modify backlight for MT8173 and MT6595. > > The PWM has one channel to control the brightness of the display. > > When the (high_width / period) is closer to 1, the screen is brighter; > > otherwise, it is darker. > > > > Signed-off-by: YH Huang <yh.huang@mediatek.com> > > --- > > drivers/pwm/Kconfig | 10 ++ > > drivers/pwm/Makefile | 1 + > > drivers/pwm/pwm-mtk-disp.c | 232 +++++++++++++++++++++++++++++++++++++++++++++ > > 3 files changed, 243 insertions(+) > > create mode 100644 drivers/pwm/pwm-mtk-disp.c > > > > diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig > > index b1541f4..f5b03a4 100644 > > --- a/drivers/pwm/Kconfig > > +++ b/drivers/pwm/Kconfig > > @@ -211,6 +211,16 @@ config PWM_LPSS_PLATFORM > > To compile this driver as a module, choose M here: the module > > will be called pwm-lpss-platform. > > > > +config PWM_MTK_DISP > > + tristate "MediaTek display PWM driver" > > + depends on ARCH_MEDIATEK || COMPILE_TEST > > This is going to break randconfig builds. From a quick look your driver > will fail to build at least on architectures that don't set HAVE_IOMEM. > I know that's quite exotic, but I've had to deal with fallout from > things like this in the past. If you want || COMPILE_TEST you should at > least add a "depends on HAVE_IOMEM". > > linux/clk.h seems to have stubs for all of the functions that you use, > so those shouldn't be a problem. > I will add it and this will be like: depends on ARCH_MEDIATEK || COMPILE_TEST depends on HAS_IOMEM > > + help > > + Generic PWM framework driver for MediaTek disp-pwm device. > > + The PWM is used to control the backlight brightness for display. > > + > > + To compile this driver as a module, choose M here: the module > > + will be called pwm-mtk-disp. > > + > > config PWM_MXS > > tristate "Freescale MXS PWM support" > > depends on ARCH_MXS && OF > [...] > > diff --git a/drivers/pwm/pwm-mtk-disp.c b/drivers/pwm/pwm-mtk-disp.c > > new file mode 100644 > > index 0000000..69682a0 > > --- /dev/null > > +++ b/drivers/pwm/pwm-mtk-disp.c > > @@ -0,0 +1,232 @@ > > +/* > > + * 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> > > The above two aren't correctly sorted. > Arrange like this: #include <linux/platform_device.h> #include <linux/pwm.h> > > +#include <linux/slab.h> > > + > > +#define DISP_PWM_EN 0x00 > > +#define PWM_ENABLE_MASK BIT(0) > > + > > +#define DISP_PWM_COMMIT 0x08 > > +#define PWM_COMMIT_MASK BIT(0) > > + > > +#define DISP_PWM_CON_0 0x10 > > +#define PWM_CLKDIV_SHIFT 16 > > +#define PWM_CLKDIV_MAX 0x3ff > > +#define PWM_CLKDIV_MASK (PWM_CLKDIV_MAX << PWM_CLKDIV_SHIFT) > > + > > +#define DISP_PWM_CON_1 0x14 > > +#define PWM_PERIOD_MASK 0xfff > > +/* Shift log2(PWM_PERIOD_MASK + 1) as divisor */ > > +#define PWM_PERIOD_BIT_SHIFT 12 > > There are still two names for the same value here. I thought we had > agreed on this becoming something like the below? > > #define PWM_PERIOD_BIT_SHIFT 12 > #define PWM_PERIOD_MASK ((1 << PWM_PERIOD_BIT_SHIFT) - 1) > > Although PWM_PERIOD_BIT_WIDTH would probably be a better name. Or > PWM_PERIOD_BITS or similar. > I will revise to #define PWM_PERIOD_BIT_WIDTH 12 #define PWM_PERIOD_MASK ((1 << PWM_PERIOD_BIT_WIDTH) - 1) > > +static int mtk_disp_pwm_remove(struct platform_device *pdev) > > +{ > > + struct mtk_disp_pwm *mdp = platform_get_drvdata(pdev); > > + int ret = pwmchip_remove(&mdp->chip); > > I'd prefer this to be separate lines: > > int ret; > > ret = pwmchip_remove(&mdp->chip); OK. Thanks for your suggestions. Regards, YH Huang
diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig index b1541f4..f5b03a4 100644 --- a/drivers/pwm/Kconfig +++ b/drivers/pwm/Kconfig @@ -211,6 +211,16 @@ config PWM_LPSS_PLATFORM To compile this driver as a module, choose M here: the module will be called pwm-lpss-platform. +config PWM_MTK_DISP + tristate "MediaTek display PWM driver" + depends on ARCH_MEDIATEK || COMPILE_TEST + help + Generic PWM framework driver for MediaTek disp-pwm device. + The PWM is used to control the backlight brightness for display. + + To compile this driver as a module, choose M here: the module + will be called pwm-mtk-disp. + config PWM_MXS tristate "Freescale MXS PWM support" depends on ARCH_MXS && OF diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile index ec50eb5..99c9e75 100644 --- a/drivers/pwm/Makefile +++ b/drivers/pwm/Makefile @@ -18,6 +18,7 @@ obj-$(CONFIG_PWM_LPC32XX) += pwm-lpc32xx.o obj-$(CONFIG_PWM_LPSS) += pwm-lpss.o obj-$(CONFIG_PWM_LPSS_PCI) += pwm-lpss-pci.o obj-$(CONFIG_PWM_LPSS_PLATFORM) += pwm-lpss-platform.o +obj-$(CONFIG_PWM_MTK_DISP) += pwm-mtk-disp.o obj-$(CONFIG_PWM_MXS) += pwm-mxs.o obj-$(CONFIG_PWM_PCA9685) += pwm-pca9685.o obj-$(CONFIG_PWM_PUV3) += pwm-puv3.o diff --git a/drivers/pwm/pwm-mtk-disp.c b/drivers/pwm/pwm-mtk-disp.c new file mode 100644 index 0000000..69682a0 --- /dev/null +++ b/drivers/pwm/pwm-mtk-disp.c @@ -0,0 +1,232 @@ +/* + * 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 0x00 +#define PWM_ENABLE_MASK BIT(0) + +#define DISP_PWM_COMMIT 0x08 +#define PWM_COMMIT_MASK BIT(0) + +#define DISP_PWM_CON_0 0x10 +#define PWM_CLKDIV_SHIFT 16 +#define PWM_CLKDIV_MAX 0x3ff +#define PWM_CLKDIV_MASK (PWM_CLKDIV_MAX << PWM_CLKDIV_SHIFT) + +#define DISP_PWM_CON_1 0x14 +#define PWM_PERIOD_MASK 0xfff +/* Shift log2(PWM_PERIOD_MASK + 1) as divisor */ +#define PWM_PERIOD_BIT_SHIFT 12 + +#define PWM_HIGH_WIDTH_SHIFT 16 +#define PWM_HIGH_WIDTH_MASK (0x1fff << PWM_HIGH_WIDTH_SHIFT) + +struct mtk_disp_pwm { + struct pwm_chip chip; + struct clk *clk_main; + struct clk *clk_mm; + void __iomem *base; +}; + +static inline struct mtk_disp_pwm *to_mtk_disp_pwm(struct pwm_chip *chip) +{ + return container_of(chip, struct mtk_disp_pwm, chip); +} + +static void mtk_disp_pwm_update_bits(struct mtk_disp_pwm *mdp, u32 offset, + u32 mask, u32 value) +{ + void __iomem *address; + u32 val; + + address = mdp->base + offset; + 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 *mdp = to_mtk_disp_pwm(chip); + u64 div, rate; + u32 clk_div, period, high_width, value; + + /* + * 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 / 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)) + */ + rate = clk_get_rate(mdp->clk_main); + clk_div = div_u64(rate * period_ns, NSEC_PER_SEC) >> + PWM_PERIOD_BIT_SHIFT; + if (clk_div > PWM_CLKDIV_MAX) + return -EINVAL; + + div = NSEC_PER_SEC * (clk_div + 1); + period = div64_u64(rate * period_ns, div); + if (period > 0) + period--; + + high_width = div64_u64(rate * duty_ns, div); + value = period | (high_width << PWM_HIGH_WIDTH_SHIFT); + + clk_enable(mdp->clk_main); + clk_enable(mdp->clk_mm); + + mtk_disp_pwm_update_bits(mdp, DISP_PWM_CON_0, + PWM_CLKDIV_MASK, clk_div << PWM_CLKDIV_SHIFT); + mtk_disp_pwm_update_bits(mdp, DISP_PWM_CON_1, + PWM_PERIOD_MASK | PWM_HIGH_WIDTH_MASK, value); + mtk_disp_pwm_update_bits(mdp, DISP_PWM_COMMIT, + PWM_COMMIT_MASK, 1); + mtk_disp_pwm_update_bits(mdp, DISP_PWM_COMMIT, + PWM_COMMIT_MASK, 0); + + clk_disable(mdp->clk_mm); + clk_disable(mdp->clk_main); + + return 0; +} + +static int mtk_disp_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm) +{ + struct mtk_disp_pwm *mdp = to_mtk_disp_pwm(chip); + + clk_enable(mdp->clk_main); + clk_enable(mdp->clk_mm); + + mtk_disp_pwm_update_bits(mdp, DISP_PWM_EN, + PWM_ENABLE_MASK, 1); + + return 0; +} + +static void mtk_disp_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm) +{ + struct mtk_disp_pwm *mdp = to_mtk_disp_pwm(chip); + + mtk_disp_pwm_update_bits(mdp, DISP_PWM_EN, + PWM_ENABLE_MASK, 0); + + clk_disable(mdp->clk_mm); + clk_disable(mdp->clk_main); +} + +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 *mdp; + struct resource *r; + int ret; + + mdp = devm_kzalloc(&pdev->dev, sizeof(*mdp), GFP_KERNEL); + if (!mdp) + return -ENOMEM; + + r = platform_get_resource(pdev, IORESOURCE_MEM, 0); + mdp->base = devm_ioremap_resource(&pdev->dev, r); + if (IS_ERR(mdp->base)) + return PTR_ERR(mdp->base); + + mdp->clk_main = devm_clk_get(&pdev->dev, "main"); + if (IS_ERR(mdp->clk_main)) + return PTR_ERR(mdp->clk_main); + + mdp->clk_mm = devm_clk_get(&pdev->dev, "mm"); + if (IS_ERR(mdp->clk_mm)) + return PTR_ERR(mdp->clk_mm); + + ret = clk_prepare(mdp->clk_main); + if (ret < 0) + return ret; + + ret = clk_prepare(mdp->clk_mm); + if (ret < 0) + goto disable_clk_main; + + mdp->chip.dev = &pdev->dev; + mdp->chip.ops = &mtk_disp_pwm_ops; + mdp->chip.base = -1; + mdp->chip.npwm = 1; + + ret = pwmchip_add(&mdp->chip); + if (ret < 0) { + dev_err(&pdev->dev, "pwmchip_add() failed: %d\n", ret); + goto disable_clk_mm; + } + + platform_set_drvdata(pdev, mdp); + + return 0; + +disable_clk_mm: + clk_unprepare(mdp->clk_mm); +disable_clk_main: + clk_unprepare(mdp->clk_main); + return ret; +} + +static int mtk_disp_pwm_remove(struct platform_device *pdev) +{ + struct mtk_disp_pwm *mdp = platform_get_drvdata(pdev); + int ret = pwmchip_remove(&mdp->chip); + + clk_unprepare(mdp->clk_mm); + clk_unprepare(mdp->clk_main); + + return ret; +} + +static const struct of_device_id mtk_disp_pwm_of_match[] = { + { .compatible = "mediatek,mt8173-disp-pwm" }, + { .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", + .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 and MT6595. The PWM has one channel to control the brightness of the display. When the (high_width / period) is closer to 1, the screen is brighter; otherwise, it is darker. Signed-off-by: YH Huang <yh.huang@mediatek.com> --- drivers/pwm/Kconfig | 10 ++ drivers/pwm/Makefile | 1 + drivers/pwm/pwm-mtk-disp.c | 232 +++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 243 insertions(+) create mode 100644 drivers/pwm/pwm-mtk-disp.c