| Message ID | 20221102141513.49289-3-fnkl.kernel@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | PWM and keyboard backlight driver for ARM Macs | expand |
Hi Sasha Finkelstein, Thanks for the patch. > Subject: [PATCH v2 2/4] pwm: Add Apple PWM controller > > Adds the Apple PWM controller driver. > > Signed-off-by: Sasha Finkelstein <fnkl.kernel@gmail.com> > --- > drivers/pwm/Kconfig | 12 ++++ > drivers/pwm/Makefile | 1 + > drivers/pwm/pwm-apple.c | 127 > ++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 140 insertions(+) > create mode 100644 drivers/pwm/pwm-apple.c > > diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig index > 60d13a949bc5..c3be11468414 100644 > --- a/drivers/pwm/Kconfig > +++ b/drivers/pwm/Kconfig > @@ -51,6 +51,18 @@ config PWM_AB8500 > To compile this driver as a module, choose M here: the module > will be called pwm-ab8500. > > +config PWM_APPLE > + tristate "Apple SoC PWM support" > + depends on ARCH_APPLE || COMPILE_TEST > + help > + Generic PWM framework driver for PWM controller present on > + Apple SoCs > + > + Say Y here if you have an ARM Apple laptop, otherwise say N > + > + To compile this driver as a module, choose M here: the module > + will be called pwm-apple. > + > config PWM_ATMEL > tristate "Atmel PWM support" > depends on ARCH_AT91 || COMPILE_TEST > diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile index > 7bf1a29f02b8..19899b912e00 100644 > --- a/drivers/pwm/Makefile > +++ b/drivers/pwm/Makefile > @@ -2,6 +2,7 @@ > obj-$(CONFIG_PWM) += core.o > obj-$(CONFIG_PWM_SYSFS) += sysfs.o > obj-$(CONFIG_PWM_AB8500) += pwm-ab8500.o > +obj-$(CONFIG_PWM_APPLE) += pwm-apple.o > obj-$(CONFIG_PWM_ATMEL) += pwm-atmel.o > obj-$(CONFIG_PWM_ATMEL_HLCDC_PWM) += pwm-atmel-hlcdc.o > obj-$(CONFIG_PWM_ATMEL_TCB) += pwm-atmel-tcb.o > diff --git a/drivers/pwm/pwm-apple.c b/drivers/pwm/pwm-apple.c new > file mode 100644 index 000000000000..7b2936346f4e > --- /dev/null > +++ b/drivers/pwm/pwm-apple.c > @@ -0,0 +1,127 @@ > +// SPDX-License-Identifier: GPL-2.0 OR MIT > +/* > + * Driver for the Apple SoC PWM controller > + * > + * Copyright The Asahi Linux Contributors */ > + > +#include <linux/module.h> > +#include <linux/of.h> > +#include <linux/of_device.h> > +#include <linux/platform_device.h> > +#include <linux/pwm.h> > +#include <linux/io.h> > +#include <linux/clk.h> > +#include <linux/pm_runtime.h> > +#include <linux/math64.h> May be sort header alphabetically?? > + > +#define PWM_CONTROL 0x00 > +#define PWM_ON_CYCLES 0x1c > +#define PWM_OFF_CYCLES 0x18 > + > +#define CTRL_ENABLE BIT(0) > +#define CTRL_MODE BIT(2) > +#define CTRL_UPDATE BIT(5) > +#define CTRL_TRIGGER BIT(9) > +#define CTRL_INVERT BIT(10) > +#define CTRL_OUTPUT_ENABLE BIT(14) > + > +struct apple_pwm { > + struct pwm_chip chip; > + void __iomem *base; > + u64 clkrate; > +}; > + > +static int apple_pwm_apply(struct pwm_chip *chip, struct pwm_device > *pwm, > + const struct pwm_state *state) > +{ > + struct apple_pwm *fpwm; > + u64 on_cycles, off_cycles; > + > + fpwm = container_of(chip, struct apple_pwm, chip); > + if (state->enabled) { > + on_cycles = mul_u64_u64_div_u64(fpwm->clkrate, > + state->duty_cycle, NSEC_PER_SEC); > + off_cycles = mul_u64_u64_div_u64(fpwm->clkrate, > + state->period, NSEC_PER_SEC) - > on_cycles; > + writel(on_cycles, fpwm->base + PWM_ON_CYCLES); > + writel(off_cycles, fpwm->base + PWM_OFF_CYCLES); > + writel(CTRL_ENABLE | CTRL_OUTPUT_ENABLE | CTRL_UPDATE, > + fpwm->base + PWM_CONTROL); > + } else { > + writel(0, fpwm->base + PWM_CONTROL); > + } > + return 0; > +} > + > +static void apple_pwm_get_state(struct pwm_chip *chip, struct > pwm_device *pwm, > + struct pwm_state *state) > +{ > + struct apple_pwm *fpwm; > + u32 on_cycles, off_cycles, ctrl; > + > + fpwm = container_of(chip, struct apple_pwm, chip); > + > + ctrl = readl(fpwm->base + PWM_CONTROL); > + on_cycles = readl(fpwm->base + PWM_ON_CYCLES); > + off_cycles = readl(fpwm->base + PWM_OFF_CYCLES); > + > + state->enabled = (ctrl & CTRL_ENABLE) && (ctrl & > CTRL_OUTPUT_ENABLE); > + state->polarity = PWM_POLARITY_NORMAL; > + state->duty_cycle = div_u64(on_cycles, fpwm->clkrate) * > NSEC_PER_SEC; > + state->period = div_u64(off_cycles + on_cycles, fpwm->clkrate) * > +NSEC_PER_SEC; } > + > +static const struct pwm_ops apple_pwm_ops = { > + .apply = apple_pwm_apply, > + .get_state = apple_pwm_get_state, > + .owner = THIS_MODULE, > +}; > + > +static int apple_pwm_probe(struct platform_device *pdev) { > + struct apple_pwm *pwm; > + struct clk *clk; > + int ret; > + > + pwm = devm_kzalloc(&pdev->dev, sizeof(*pwm), GFP_KERNEL); > + if (!pwm) > + return -ENOMEM; > + > + pwm->base = devm_platform_ioremap_resource(pdev, 0); > + if (IS_ERR(pwm->base)) > + return PTR_ERR(pwm->base); > + > + platform_set_drvdata(pdev, pwm); > + > + clk = devm_clk_get_enabled(&pdev->dev, NULL); > + if (IS_ERR(clk)) > + return PTR_ERR(clk); What is your use case? PWM is configured by bootloader intially?? Or PWM is configured by Linux not by the bootloader? Or Driver needs to support both ?? Cheers, Biju > + > + pwm->clkrate = clk_get_rate(clk); > + pwm->chip.dev = &pdev->dev; > + pwm->chip.npwm = 1; > + pwm->chip.ops = &apple_pwm_ops; > + > + ret = devm_pwmchip_add(&pdev->dev, &pwm->chip); > + return ret; > +} > + > +static const struct of_device_id apple_pwm_of_match[] = { > + { .compatible = "apple,s5l-fpwm" }, > + {} > +}; > +MODULE_DEVICE_TABLE(of, apple_pwm_of_match); > + > +static struct platform_driver apple_pwm_driver = { > + .probe = apple_pwm_probe, > + .driver = { > + .name = "apple-pwm", > + .owner = THIS_MODULE, > + .of_match_table = apple_pwm_of_match, > + }, > +}; > +module_platform_driver(apple_pwm_driver); > + > +MODULE_DESCRIPTION("Apple SoC PWM driver"); MODULE_LICENSE("Dual > +MIT/GPL"); > -- > 2.37.3 > > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > https://jpn01.safelinks.protection.outlook.com/?url=http%3A%2F%2Flists > .infradead.org%2Fmailman%2Flistinfo%2Flinux-arm- > kernel&data=05%7C01%7Cbiju.das.jz%40bp.renesas.com%7C0ff5a9275b954 > eff39ae08dabcde3c28%7C53d82571da1947e49cb4625a166a4a2a%7C0%7C0%7C63802 > 9959918512569%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2lu > MzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=zdoRENBcN > FUDLdqC8wOspyvoOzRsTkBkS01Q8ff9okk%3D&reserved=0
On Wed, 2 Nov 2022 at 18:33, Biju Das <biju.das.jz@bp.renesas.com> wrote: > > + clk = devm_clk_get_enabled(&pdev->dev, NULL); > > + if (IS_ERR(clk)) > > + return PTR_ERR(clk); > > What is your use case? > > PWM is configured by bootloader intially?? > > Or > > PWM is configured by Linux not by the bootloader? > > Or > > Driver needs to support both ?? The PWM device itself is configured by linux, but the clock it uses is the systemwide 24 MHz clock, and that is configured by platform firmware.
> Subject: Re: [PATCH v2 2/4] pwm: Add Apple PWM controller > > On Wed, 2 Nov 2022 at 18:33, Biju Das <biju.das.jz@bp.renesas.com> > wrote: > > > + clk = devm_clk_get_enabled(&pdev->dev, NULL); > > > + if (IS_ERR(clk)) > > > + return PTR_ERR(clk); > > > > What is your use case? > > > > PWM is configured by bootloader intially?? > > > > Or > > > > PWM is configured by Linux not by the bootloader? > > > > Or > > > > Driver needs to support both ?? > > The PWM device itself is configured by linux, but the clock it uses is > the systemwide 24 MHz clock, and that is configured by platform > firmware. I just asked, because you are unnecessarily turning on the clock or increasing the usage Count, even if it is not used by anyone during probe. Cheers, Biju
On Wed, 2 Nov 2022 at 19:02, Biju Das <biju.das.jz@bp.renesas.com> wrote: > I just asked, because you are unnecessarily turning on the clock or increasing the usage > Count, even if it is not used by anyone during probe. It is used to get the clock rate so it can be used to convert between seconds and pwm ticks, and the pwm uses that clock, so it is kept enabled while the pwm is active.
> Subject: Re: [PATCH v2 2/4] pwm: Add Apple PWM controller > > On Wed, 2 Nov 2022 at 19:02, Biju Das <biju.das.jz@bp.renesas.com> > wrote: > > > I just asked, because you are unnecessarily turning on the clock or > > increasing the usage Count, even if it is not used by anyone during > probe. > > It is used to get the clock rate so it can be used to convert between > seconds and pwm ticks, and the pwm uses that clock, so it is kept > enabled while the pwm is active. You don't need to enable the pwm clock for getting the clock rate. devm_clk_get() and then get the rate. Then enable the clk whenever pwm is enabled And disable the clk whenever pwm is disabled. Cheers, Biju
On Wed, 2 Nov 2022 at 19:29, Biju Das <biju.das.jz@bp.renesas.com> wrote: > > Then enable the clk whenever pwm is enabled > And disable the clk whenever pwm is disabled. I can do that, but I do not see the point in doing that. This clock is active whenever the system is turned on, all this will result in is some unnecessary clock refcount increments/decrements.
> Subject: Re: [PATCH v2 2/4] pwm: Add Apple PWM controller > > On Wed, 2 Nov 2022 at 19:29, Biju Das <biju.das.jz@bp.renesas.com> > wrote: > > > > Then enable the clk whenever pwm is enabled And disable the clk > > whenever pwm is disabled. > I can do that, but I do not see the point in doing that. This clock is > active whenever the system is turned on, all this will result in is > some unnecessary clock refcount increments/decrements. OK for me, as I do not know about your system. I just pointed out you are unnecessarily turning on the clock during probe even if the pwm is not used. Cheers, Biju
diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig index 60d13a949bc5..c3be11468414 100644 --- a/drivers/pwm/Kconfig +++ b/drivers/pwm/Kconfig @@ -51,6 +51,18 @@ config PWM_AB8500 To compile this driver as a module, choose M here: the module will be called pwm-ab8500. +config PWM_APPLE + tristate "Apple SoC PWM support" + depends on ARCH_APPLE || COMPILE_TEST + help + Generic PWM framework driver for PWM controller present on + Apple SoCs + + Say Y here if you have an ARM Apple laptop, otherwise say N + + To compile this driver as a module, choose M here: the module + will be called pwm-apple. + config PWM_ATMEL tristate "Atmel PWM support" depends on ARCH_AT91 || COMPILE_TEST diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile index 7bf1a29f02b8..19899b912e00 100644 --- a/drivers/pwm/Makefile +++ b/drivers/pwm/Makefile @@ -2,6 +2,7 @@ obj-$(CONFIG_PWM) += core.o obj-$(CONFIG_PWM_SYSFS) += sysfs.o obj-$(CONFIG_PWM_AB8500) += pwm-ab8500.o +obj-$(CONFIG_PWM_APPLE) += pwm-apple.o obj-$(CONFIG_PWM_ATMEL) += pwm-atmel.o obj-$(CONFIG_PWM_ATMEL_HLCDC_PWM) += pwm-atmel-hlcdc.o obj-$(CONFIG_PWM_ATMEL_TCB) += pwm-atmel-tcb.o diff --git a/drivers/pwm/pwm-apple.c b/drivers/pwm/pwm-apple.c new file mode 100644 index 000000000000..7b2936346f4e --- /dev/null +++ b/drivers/pwm/pwm-apple.c @@ -0,0 +1,127 @@ +// SPDX-License-Identifier: GPL-2.0 OR MIT +/* + * Driver for the Apple SoC PWM controller + * + * Copyright The Asahi Linux Contributors + */ + +#include <linux/module.h> +#include <linux/of.h> +#include <linux/of_device.h> +#include <linux/platform_device.h> +#include <linux/pwm.h> +#include <linux/io.h> +#include <linux/clk.h> +#include <linux/pm_runtime.h> +#include <linux/math64.h> + +#define PWM_CONTROL 0x00 +#define PWM_ON_CYCLES 0x1c +#define PWM_OFF_CYCLES 0x18 + +#define CTRL_ENABLE BIT(0) +#define CTRL_MODE BIT(2) +#define CTRL_UPDATE BIT(5) +#define CTRL_TRIGGER BIT(9) +#define CTRL_INVERT BIT(10) +#define CTRL_OUTPUT_ENABLE BIT(14) + +struct apple_pwm { + struct pwm_chip chip; + void __iomem *base; + u64 clkrate; +}; + +static int apple_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, + const struct pwm_state *state) +{ + struct apple_pwm *fpwm; + u64 on_cycles, off_cycles; + + fpwm = container_of(chip, struct apple_pwm, chip); + if (state->enabled) { + on_cycles = mul_u64_u64_div_u64(fpwm->clkrate, + state->duty_cycle, NSEC_PER_SEC); + off_cycles = mul_u64_u64_div_u64(fpwm->clkrate, + state->period, NSEC_PER_SEC) - on_cycles; + writel(on_cycles, fpwm->base + PWM_ON_CYCLES); + writel(off_cycles, fpwm->base + PWM_OFF_CYCLES); + writel(CTRL_ENABLE | CTRL_OUTPUT_ENABLE | CTRL_UPDATE, + fpwm->base + PWM_CONTROL); + } else { + writel(0, fpwm->base + PWM_CONTROL); + } + return 0; +} + +static void apple_pwm_get_state(struct pwm_chip *chip, struct pwm_device *pwm, + struct pwm_state *state) +{ + struct apple_pwm *fpwm; + u32 on_cycles, off_cycles, ctrl; + + fpwm = container_of(chip, struct apple_pwm, chip); + + ctrl = readl(fpwm->base + PWM_CONTROL); + on_cycles = readl(fpwm->base + PWM_ON_CYCLES); + off_cycles = readl(fpwm->base + PWM_OFF_CYCLES); + + state->enabled = (ctrl & CTRL_ENABLE) && (ctrl & CTRL_OUTPUT_ENABLE); + state->polarity = PWM_POLARITY_NORMAL; + state->duty_cycle = div_u64(on_cycles, fpwm->clkrate) * NSEC_PER_SEC; + state->period = div_u64(off_cycles + on_cycles, fpwm->clkrate) * NSEC_PER_SEC; +} + +static const struct pwm_ops apple_pwm_ops = { + .apply = apple_pwm_apply, + .get_state = apple_pwm_get_state, + .owner = THIS_MODULE, +}; + +static int apple_pwm_probe(struct platform_device *pdev) +{ + struct apple_pwm *pwm; + struct clk *clk; + int ret; + + pwm = devm_kzalloc(&pdev->dev, sizeof(*pwm), GFP_KERNEL); + if (!pwm) + return -ENOMEM; + + pwm->base = devm_platform_ioremap_resource(pdev, 0); + if (IS_ERR(pwm->base)) + return PTR_ERR(pwm->base); + + platform_set_drvdata(pdev, pwm); + + clk = devm_clk_get_enabled(&pdev->dev, NULL); + if (IS_ERR(clk)) + return PTR_ERR(clk); + + pwm->clkrate = clk_get_rate(clk); + pwm->chip.dev = &pdev->dev; + pwm->chip.npwm = 1; + pwm->chip.ops = &apple_pwm_ops; + + ret = devm_pwmchip_add(&pdev->dev, &pwm->chip); + return ret; +} + +static const struct of_device_id apple_pwm_of_match[] = { + { .compatible = "apple,s5l-fpwm" }, + {} +}; +MODULE_DEVICE_TABLE(of, apple_pwm_of_match); + +static struct platform_driver apple_pwm_driver = { + .probe = apple_pwm_probe, + .driver = { + .name = "apple-pwm", + .owner = THIS_MODULE, + .of_match_table = apple_pwm_of_match, + }, +}; +module_platform_driver(apple_pwm_driver); + +MODULE_DESCRIPTION("Apple SoC PWM driver"); +MODULE_LICENSE("Dual MIT/GPL");
Adds the Apple PWM controller driver. Signed-off-by: Sasha Finkelstein <fnkl.kernel@gmail.com> --- drivers/pwm/Kconfig | 12 ++++ drivers/pwm/Makefile | 1 + drivers/pwm/pwm-apple.c | 127 ++++++++++++++++++++++++++++++++++++++++ 3 files changed, 140 insertions(+) create mode 100644 drivers/pwm/pwm-apple.c