| Message ID | 20231005160550.2423075-2-quic_devipriy@quicinc.com (mailing list archive) |
|---|---|
| State | Not Applicable |
| Headers | show |
| Series | Add PWM support for IPQ chipsets | expand |
On Thu, Oct 05, 2023 at 09:35:47PM +0530, Devi Priya wrote: > diff --git a/drivers/pwm/pwm-ipq.c b/drivers/pwm/pwm-ipq.c > new file mode 100644 > index 000000000000..5dbe46bb56d6 > --- /dev/null > +++ b/drivers/pwm/pwm-ipq.c > @@ -0,0 +1,282 @@ > +// SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0 > +/* > + * Copyright (c) 2016-2017, 2020 The Linux Foundation. All rights reserved. > + */ > + > +#include <linux/module.h> > +#include <linux/platform_device.h> > +#include <linux/pwm.h> > +#include <linux/clk.h> > +#include <linux/io.h> > +#include <linux/of.h> > +#include <linux/math64.h> > +#include <linux/of_device.h> > +#include <linux/bitfield.h> > +#include <linux/units.h> > + > +/* The frequency range supported is 1 Hz to clock rate */ > +#define IPQ_PWM_MAX_PERIOD_NS ((u64)NSEC_PER_SEC) > + > +/* > + * The max value specified for each field is based on the number of bits > + * in the pwm control register for that field > + */ > +#define IPQ_PWM_MAX_DIV 0xFFFF > + > +/* > + * Two 32-bit registers for each PWM: REG0, and REG1. > + * Base offset for PWM #i is at 8 * #i. > + */ > +#define IPQ_PWM_REG0 0 > +#define IPQ_PWM_REG0_PWM_DIV GENMASK(15, 0) > +#define IPQ_PWM_REG0_HI_DURATION GENMASK(31, 16) > + > +#define IPQ_PWM_REG1 4 > +#define IPQ_PWM_REG1_PRE_DIV GENMASK(15, 0) > +/* > + * Enable bit is set to enable output toggling in pwm device. > + * Update bit is set to reflect the changed divider and high duration > + * values in register. > + */ > +#define IPQ_PWM_REG1_UPDATE BIT(30) > +#define IPQ_PWM_REG1_ENABLE BIT(31) > + > +struct ipq_pwm_chip { > + struct pwm_chip chip; > + struct clk *clk; > + void __iomem *mem; > +}; > + > +static struct ipq_pwm_chip *ipq_pwm_from_chip(struct pwm_chip *chip) > +{ > + return container_of(chip, struct ipq_pwm_chip, chip); > +} > + > +static unsigned int ipq_pwm_reg_read(struct pwm_device *pwm, unsigned int reg) > +{ > + struct ipq_pwm_chip *ipq_chip = ipq_pwm_from_chip(pwm->chip); > + unsigned int off = 8 * pwm->hwpwm + reg; > + > + return readl(ipq_chip->mem + off); > +} > + > +static void ipq_pwm_reg_write(struct pwm_device *pwm, unsigned int reg, > + unsigned int val) > +{ > + struct ipq_pwm_chip *ipq_chip = ipq_pwm_from_chip(pwm->chip); > + unsigned int off = 8 * pwm->hwpwm + reg; > + > + writel(val, ipq_chip->mem + off); > +} > + > +static void config_div_and_duty(struct pwm_device *pwm, unsigned int pre_div, > + unsigned int pwm_div, unsigned long rate, u64 duty_ns, > + bool enable) > +{ > + unsigned long hi_dur; > + unsigned long val = 0; > + > + /* > + * high duration = pwm duty * (pwm div + 1) > + * pwm duty = duty_ns / period_ns > + */ > + hi_dur = div64_u64(duty_ns * rate, (pre_div + 1) * NSEC_PER_SEC); > + > + val = FIELD_PREP(IPQ_PWM_REG0_HI_DURATION, hi_dur) | > + FIELD_PREP(IPQ_PWM_REG0_PWM_DIV, pwm_div); > + ipq_pwm_reg_write(pwm, IPQ_PWM_REG0, val); > + > + val = FIELD_PREP(IPQ_PWM_REG1_PRE_DIV, pre_div); > + ipq_pwm_reg_write(pwm, IPQ_PWM_REG1, val); > + > + /* PWM enable toggle needs a separate write to REG1 */ > + val |= IPQ_PWM_REG1_UPDATE; > + if (enable) > + val |= IPQ_PWM_REG1_ENABLE; > + ipq_pwm_reg_write(pwm, IPQ_PWM_REG1, val); > +} > + > +static int ipq_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, > + const struct pwm_state *state) > +{ > + struct ipq_pwm_chip *ipq_chip = ipq_pwm_from_chip(chip); > + unsigned int pre_div, pwm_div, best_pre_div, best_pwm_div; > + unsigned long rate = clk_get_rate(ipq_chip->clk); > + u64 period_ns, duty_ns, period_rate; > + u64 min_diff; > + > + if (state->polarity != PWM_POLARITY_NORMAL) > + return -EINVAL; > + > + if (state->period < DIV64_U64_ROUND_UP(NSEC_PER_SEC, rate)) > + return -ERANGE; > + > + period_ns = min(state->period, IPQ_PWM_MAX_PERIOD_NS); > + duty_ns = min(state->duty_cycle, period_ns); > + > + /* > + * period_ns is 1G or less. As long as rate is less than 16 GHz, > + * period_rate does not overflow. Make that explicit. > + */ > + if ((unsigned long long)rate > 16ULL * GIGA) > + return -EINVAL; > + period_rate = period_ns * rate; > + best_pre_div = IPQ_PWM_MAX_DIV; > + best_pwm_div = IPQ_PWM_MAX_DIV; > + /* > + * We don't need to consider pre_div values smaller than > + * > + * period_rate > + * pre_div_min := ------------------------------------ > + * NSEC_PER_SEC * (IPQ_PWM_MAX_DIV + 1) > + * > + * because pre_div = pre_div_min results in a better > + * approximation. > + */ > + pre_div = div64_u64(period_rate, > + (u64)NSEC_PER_SEC * (IPQ_PWM_MAX_DIV + 1)); Consider period_ns = 0x10000 and rate = NSEC_PER_SEC. Then we get pre_div = 1 ... > + min_diff = period_rate; > + > + for (; pre_div <= IPQ_PWM_MAX_DIV; pre_div++) { > + u64 remainder; > + > + pwm_div = div64_u64_rem(period_rate, > + (u64)NSEC_PER_SEC * (pre_div + 1), &remainder); > + /* pwm_div is unsigned; the check below catches underflow */ > + pwm_div--; ... pwm_div then will be 0x7fff and remainder is 0. This is wrong, isn't it? I think you lack a -1 in the assignment of pre_div above. And/or you need to round up the division? Having said that the loop here is quite heavy. I'd opt for restricing pwm_div to 0xfffe (to get a finegrained domain for HI_DURATION) and then the appropriate value for pre_div can be computed in a single division. While being more coarse for the domain of periods, a simple algorithm is worth quite a lot (for reviewers of your code and also for consumers that benefit from a small runtime of .apply()) and you get a fine-grained domain for duty_cycle. In my experience outweighs the increased precision for the period. > + /* > + * Swapping values for pre_div and pwm_div produces the same > + * period length. So we can skip all settings with pre_div > > + * pwm_div which results in bigger constraints for selecting > + * the duty_cycle than with the two values swapped. > + */ > + if (pre_div > pwm_div) > + break; > + > + /* > + * Make sure we can do 100% duty cycle where > + * hi_dur == pwm_div + 1 > + */ > + if (pwm_div > IPQ_PWM_MAX_DIV - 1) > + continue; > + > + if (remainder < min_diff) { > + best_pre_div = pre_div; > + best_pwm_div = pwm_div; > + min_diff = remainder; > + > + if (min_diff == 0) /* bingo */ > + break; > + } > + } > + > + /* config divider values for the closest possible frequency */ > + config_div_and_duty(pwm, best_pre_div, best_pwm_div, > + rate, duty_ns, state->enabled); > + > + return 0; > +} > + > +static int ipq_pwm_get_state(struct pwm_chip *chip, struct pwm_device *pwm, > + struct pwm_state *state) > +{ > + struct ipq_pwm_chip *ipq_chip = ipq_pwm_from_chip(chip); > + unsigned long rate = clk_get_rate(ipq_chip->clk); > + unsigned int pre_div, pwm_div, hi_dur; > + u64 effective_div, hi_div; > + u32 reg0, reg1; > + > + reg0 = ipq_pwm_reg_read(pwm, IPQ_PWM_REG0); > + reg1 = ipq_pwm_reg_read(pwm, IPQ_PWM_REG1); > + > + state->polarity = PWM_POLARITY_NORMAL; > + state->enabled = reg1 & IPQ_PWM_REG1_ENABLE; > + > + pwm_div = FIELD_GET(IPQ_PWM_REG0_PWM_DIV, reg0); > + hi_dur = FIELD_GET(IPQ_PWM_REG0_HI_DURATION, reg0); > + pre_div = FIELD_GET(IPQ_PWM_REG1_PRE_DIV, reg1); > + > + /* No overflow here, both pre_div and pwm_div <= 0xffff */ > + effective_div = (u64)(pre_div + 1) * (pwm_div + 1); This cast is not needed. > + state->period = DIV64_U64_ROUND_UP(effective_div * NSEC_PER_SEC, rate); > + > + hi_div = hi_dur * (pre_div + 1); > + state->duty_cycle = DIV64_U64_ROUND_UP(hi_div * NSEC_PER_SEC, rate); > + > + return 0; > +} > + > +static const struct pwm_ops ipq_pwm_ops = { > + .apply = ipq_pwm_apply, > + .get_state = ipq_pwm_get_state, > + .owner = THIS_MODULE, With 384461abcab6 in next (https://git.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm.git/log/?h=for-next, currently for-next~30), the .owner line should be dropped. ..ooOO(You claimed to have dropped that for v5 already in the changelog above. Hmm?!) > +}; > + > +static int ipq_pwm_probe(struct platform_device *pdev) > +{ > + struct ipq_pwm_chip *pwm; > + struct device *dev = &pdev->dev; > + int ret; > + > + pwm = devm_kzalloc(dev, sizeof(*pwm), GFP_KERNEL); > + if (!pwm) > + return -ENOMEM; > + > + platform_set_drvdata(pdev, pwm); > + > + pwm->mem = devm_platform_ioremap_resource(pdev, 0); > + if (IS_ERR(pwm->mem)) > + return dev_err_probe(dev, PTR_ERR(pwm->mem), > + "regs map failed"); > + > + pwm->clk = devm_clk_get(dev, NULL); > + if (IS_ERR(pwm->clk)) > + return dev_err_probe(dev, PTR_ERR(pwm->clk), > + "failed to get clock"); > + > + ret = clk_prepare_enable(pwm->clk); devm_clk_get_enabled() > + if (ret) > + return dev_err_probe(dev, ret, "clock enable failed"); > + > + pwm->chip.dev = dev; > + pwm->chip.ops = &ipq_pwm_ops; > + pwm->chip.npwm = 4; > + > + ret = pwmchip_add(&pwm->chip); devm_pwmchip_add() > + if (ret < 0) { > + dev_err_probe(dev, ret, "pwmchip_add() failed\n"); > + clk_disable_unprepare(pwm->clk); > + } > + > + return ret; > +} > + > +static int ipq_pwm_remove(struct platform_device *pdev) > +{ > + struct ipq_pwm_chip *pwm = platform_get_drvdata(pdev); > + > + pwmchip_remove(&pwm->chip); > + clk_disable_unprepare(pwm->clk); > + > + return 0; > +} With the above suggestions .remove can be dropped. If there is still a reason to keep it in the next revision, please switch to .remove_new(). > +static const struct of_device_id pwm_ipq_dt_match[] = { > + { .compatible = "qcom,ipq6018-pwm", }, > + {} > +}; > +MODULE_DEVICE_TABLE(of, pwm_ipq_dt_match); > + > +static struct platform_driver ipq_pwm_driver = { > + .driver = { > + .name = "ipq-pwm", > + .of_match_table = pwm_ipq_dt_match, > + }, > + .probe = ipq_pwm_probe, > + .remove = ipq_pwm_remove, > +}; > + > +module_platform_driver(ipq_pwm_driver); > + > +MODULE_LICENSE("Dual BSD/GPL"); I don't oppose to this dual licensing, but I wonder what the motivation is. Seeing that the copyright is assigned to the Linux Foundation, is this related to Zephyr? (Which however uses an Apache license.) Best regards Uwe
diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig index 8ebcddf91f7b..c2d51680823a 100644 --- a/drivers/pwm/Kconfig +++ b/drivers/pwm/Kconfig @@ -282,6 +282,18 @@ config PWM_INTEL_LGM To compile this driver as a module, choose M here: the module will be called pwm-intel-lgm. +config PWM_IPQ + tristate "IPQ PWM support" + depends on ARCH_QCOM || COMPILE_TEST + depends on HAVE_CLK && HAS_IOMEM + help + Generic PWM framework driver for IPQ PWM block which supports + 4 pwm channels. Each of the these channels can be configured + independent of each other. + + To compile this driver as a module, choose M here: the module + will be called pwm-ipq. + config PWM_IQS620A tristate "Azoteq IQS620A PWM support" depends on MFD_IQS62X || COMPILE_TEST diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile index c822389c2a24..1b69e8cb2b91 100644 --- a/drivers/pwm/Makefile +++ b/drivers/pwm/Makefile @@ -24,6 +24,7 @@ obj-$(CONFIG_PWM_IMX1) += pwm-imx1.o obj-$(CONFIG_PWM_IMX27) += pwm-imx27.o obj-$(CONFIG_PWM_IMX_TPM) += pwm-imx-tpm.o obj-$(CONFIG_PWM_INTEL_LGM) += pwm-intel-lgm.o +obj-$(CONFIG_PWM_IPQ) += pwm-ipq.o obj-$(CONFIG_PWM_IQS620A) += pwm-iqs620a.o obj-$(CONFIG_PWM_JZ4740) += pwm-jz4740.o obj-$(CONFIG_PWM_KEEMBAY) += pwm-keembay.o diff --git a/drivers/pwm/pwm-ipq.c b/drivers/pwm/pwm-ipq.c new file mode 100644 index 000000000000..5dbe46bb56d6 --- /dev/null +++ b/drivers/pwm/pwm-ipq.c @@ -0,0 +1,282 @@ +// SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0 +/* + * Copyright (c) 2016-2017, 2020 The Linux Foundation. All rights reserved. + */ + +#include <linux/module.h> +#include <linux/platform_device.h> +#include <linux/pwm.h> +#include <linux/clk.h> +#include <linux/io.h> +#include <linux/of.h> +#include <linux/math64.h> +#include <linux/of_device.h> +#include <linux/bitfield.h> +#include <linux/units.h> + +/* The frequency range supported is 1 Hz to clock rate */ +#define IPQ_PWM_MAX_PERIOD_NS ((u64)NSEC_PER_SEC) + +/* + * The max value specified for each field is based on the number of bits + * in the pwm control register for that field + */ +#define IPQ_PWM_MAX_DIV 0xFFFF + +/* + * Two 32-bit registers for each PWM: REG0, and REG1. + * Base offset for PWM #i is at 8 * #i. + */ +#define IPQ_PWM_REG0 0 +#define IPQ_PWM_REG0_PWM_DIV GENMASK(15, 0) +#define IPQ_PWM_REG0_HI_DURATION GENMASK(31, 16) + +#define IPQ_PWM_REG1 4 +#define IPQ_PWM_REG1_PRE_DIV GENMASK(15, 0) +/* + * Enable bit is set to enable output toggling in pwm device. + * Update bit is set to reflect the changed divider and high duration + * values in register. + */ +#define IPQ_PWM_REG1_UPDATE BIT(30) +#define IPQ_PWM_REG1_ENABLE BIT(31) + +struct ipq_pwm_chip { + struct pwm_chip chip; + struct clk *clk; + void __iomem *mem; +}; + +static struct ipq_pwm_chip *ipq_pwm_from_chip(struct pwm_chip *chip) +{ + return container_of(chip, struct ipq_pwm_chip, chip); +} + +static unsigned int ipq_pwm_reg_read(struct pwm_device *pwm, unsigned int reg) +{ + struct ipq_pwm_chip *ipq_chip = ipq_pwm_from_chip(pwm->chip); + unsigned int off = 8 * pwm->hwpwm + reg; + + return readl(ipq_chip->mem + off); +} + +static void ipq_pwm_reg_write(struct pwm_device *pwm, unsigned int reg, + unsigned int val) +{ + struct ipq_pwm_chip *ipq_chip = ipq_pwm_from_chip(pwm->chip); + unsigned int off = 8 * pwm->hwpwm + reg; + + writel(val, ipq_chip->mem + off); +} + +static void config_div_and_duty(struct pwm_device *pwm, unsigned int pre_div, + unsigned int pwm_div, unsigned long rate, u64 duty_ns, + bool enable) +{ + unsigned long hi_dur; + unsigned long val = 0; + + /* + * high duration = pwm duty * (pwm div + 1) + * pwm duty = duty_ns / period_ns + */ + hi_dur = div64_u64(duty_ns * rate, (pre_div + 1) * NSEC_PER_SEC); + + val = FIELD_PREP(IPQ_PWM_REG0_HI_DURATION, hi_dur) | + FIELD_PREP(IPQ_PWM_REG0_PWM_DIV, pwm_div); + ipq_pwm_reg_write(pwm, IPQ_PWM_REG0, val); + + val = FIELD_PREP(IPQ_PWM_REG1_PRE_DIV, pre_div); + ipq_pwm_reg_write(pwm, IPQ_PWM_REG1, val); + + /* PWM enable toggle needs a separate write to REG1 */ + val |= IPQ_PWM_REG1_UPDATE; + if (enable) + val |= IPQ_PWM_REG1_ENABLE; + ipq_pwm_reg_write(pwm, IPQ_PWM_REG1, val); +} + +static int ipq_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, + const struct pwm_state *state) +{ + struct ipq_pwm_chip *ipq_chip = ipq_pwm_from_chip(chip); + unsigned int pre_div, pwm_div, best_pre_div, best_pwm_div; + unsigned long rate = clk_get_rate(ipq_chip->clk); + u64 period_ns, duty_ns, period_rate; + u64 min_diff; + + if (state->polarity != PWM_POLARITY_NORMAL) + return -EINVAL; + + if (state->period < DIV64_U64_ROUND_UP(NSEC_PER_SEC, rate)) + return -ERANGE; + + period_ns = min(state->period, IPQ_PWM_MAX_PERIOD_NS); + duty_ns = min(state->duty_cycle, period_ns); + + /* + * period_ns is 1G or less. As long as rate is less than 16 GHz, + * period_rate does not overflow. Make that explicit. + */ + if ((unsigned long long)rate > 16ULL * GIGA) + return -EINVAL; + period_rate = period_ns * rate; + best_pre_div = IPQ_PWM_MAX_DIV; + best_pwm_div = IPQ_PWM_MAX_DIV; + /* + * We don't need to consider pre_div values smaller than + * + * period_rate + * pre_div_min := ------------------------------------ + * NSEC_PER_SEC * (IPQ_PWM_MAX_DIV + 1) + * + * because pre_div = pre_div_min results in a better + * approximation. + */ + pre_div = div64_u64(period_rate, + (u64)NSEC_PER_SEC * (IPQ_PWM_MAX_DIV + 1)); + min_diff = period_rate; + + for (; pre_div <= IPQ_PWM_MAX_DIV; pre_div++) { + u64 remainder; + + pwm_div = div64_u64_rem(period_rate, + (u64)NSEC_PER_SEC * (pre_div + 1), &remainder); + /* pwm_div is unsigned; the check below catches underflow */ + pwm_div--; + + /* + * Swapping values for pre_div and pwm_div produces the same + * period length. So we can skip all settings with pre_div > + * pwm_div which results in bigger constraints for selecting + * the duty_cycle than with the two values swapped. + */ + if (pre_div > pwm_div) + break; + + /* + * Make sure we can do 100% duty cycle where + * hi_dur == pwm_div + 1 + */ + if (pwm_div > IPQ_PWM_MAX_DIV - 1) + continue; + + if (remainder < min_diff) { + best_pre_div = pre_div; + best_pwm_div = pwm_div; + min_diff = remainder; + + if (min_diff == 0) /* bingo */ + break; + } + } + + /* config divider values for the closest possible frequency */ + config_div_and_duty(pwm, best_pre_div, best_pwm_div, + rate, duty_ns, state->enabled); + + return 0; +} + +static int ipq_pwm_get_state(struct pwm_chip *chip, struct pwm_device *pwm, + struct pwm_state *state) +{ + struct ipq_pwm_chip *ipq_chip = ipq_pwm_from_chip(chip); + unsigned long rate = clk_get_rate(ipq_chip->clk); + unsigned int pre_div, pwm_div, hi_dur; + u64 effective_div, hi_div; + u32 reg0, reg1; + + reg0 = ipq_pwm_reg_read(pwm, IPQ_PWM_REG0); + reg1 = ipq_pwm_reg_read(pwm, IPQ_PWM_REG1); + + state->polarity = PWM_POLARITY_NORMAL; + state->enabled = reg1 & IPQ_PWM_REG1_ENABLE; + + pwm_div = FIELD_GET(IPQ_PWM_REG0_PWM_DIV, reg0); + hi_dur = FIELD_GET(IPQ_PWM_REG0_HI_DURATION, reg0); + pre_div = FIELD_GET(IPQ_PWM_REG1_PRE_DIV, reg1); + + /* No overflow here, both pre_div and pwm_div <= 0xffff */ + effective_div = (u64)(pre_div + 1) * (pwm_div + 1); + state->period = DIV64_U64_ROUND_UP(effective_div * NSEC_PER_SEC, rate); + + hi_div = hi_dur * (pre_div + 1); + state->duty_cycle = DIV64_U64_ROUND_UP(hi_div * NSEC_PER_SEC, rate); + + return 0; +} + +static const struct pwm_ops ipq_pwm_ops = { + .apply = ipq_pwm_apply, + .get_state = ipq_pwm_get_state, + .owner = THIS_MODULE, +}; + +static int ipq_pwm_probe(struct platform_device *pdev) +{ + struct ipq_pwm_chip *pwm; + struct device *dev = &pdev->dev; + int ret; + + pwm = devm_kzalloc(dev, sizeof(*pwm), GFP_KERNEL); + if (!pwm) + return -ENOMEM; + + platform_set_drvdata(pdev, pwm); + + pwm->mem = devm_platform_ioremap_resource(pdev, 0); + if (IS_ERR(pwm->mem)) + return dev_err_probe(dev, PTR_ERR(pwm->mem), + "regs map failed"); + + pwm->clk = devm_clk_get(dev, NULL); + if (IS_ERR(pwm->clk)) + return dev_err_probe(dev, PTR_ERR(pwm->clk), + "failed to get clock"); + + ret = clk_prepare_enable(pwm->clk); + if (ret) + return dev_err_probe(dev, ret, "clock enable failed"); + + pwm->chip.dev = dev; + pwm->chip.ops = &ipq_pwm_ops; + pwm->chip.npwm = 4; + + ret = pwmchip_add(&pwm->chip); + if (ret < 0) { + dev_err_probe(dev, ret, "pwmchip_add() failed\n"); + clk_disable_unprepare(pwm->clk); + } + + return ret; +} + +static int ipq_pwm_remove(struct platform_device *pdev) +{ + struct ipq_pwm_chip *pwm = platform_get_drvdata(pdev); + + pwmchip_remove(&pwm->chip); + clk_disable_unprepare(pwm->clk); + + return 0; +} + +static const struct of_device_id pwm_ipq_dt_match[] = { + { .compatible = "qcom,ipq6018-pwm", }, + {} +}; +MODULE_DEVICE_TABLE(of, pwm_ipq_dt_match); + +static struct platform_driver ipq_pwm_driver = { + .driver = { + .name = "ipq-pwm", + .of_match_table = pwm_ipq_dt_match, + }, + .probe = ipq_pwm_probe, + .remove = ipq_pwm_remove, +}; + +module_platform_driver(ipq_pwm_driver); + +MODULE_LICENSE("Dual BSD/GPL");