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SubjectRe: [PATCH v4 2/4] pwm: Add Apple PWM controller
On Fri, Dec 09, 2022 at 02:13:11PM +0300, Sasha Finkelstein wrote:
> Adds the Apple PWM controller driver.
>
> Signed-off-by: Sasha Finkelstein <fnkl.kernel@gmail.com>
> Acked-by: Sven Peter <sven@svenpeter.dev>
> ---
> drivers/pwm/Kconfig | 12 ++++
> drivers/pwm/Makefile | 1 +
> drivers/pwm/pwm-apple.c | 150 ++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 163 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..a85fecb20105
> --- /dev/null
> +++ b/drivers/pwm/pwm-apple.c
> @@ -0,0 +1,150 @@
> +// SPDX-License-Identifier: GPL-2.0 OR MIT
> +/*
> + * Driver for the Apple SoC PWM controller
> + *
> + * Copyright The Asahi Linux Contributors
> + *
> + * Limitations:
> + * - The writes to cycle registers are shadowed until a write to
> + * the control register.
> + */
> +
> +#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 APPLE_PWM_CONTROL 0x00
> +#define APPLE_PWM_ON_CYCLES 0x1c
> +#define APPLE_PWM_OFF_CYCLES 0x18
> +
> +#define APPLE_CTRL_ENABLE BIT(0)
> +#define APPLE_CTRL_MODE BIT(2)
> +#define APPLE_CTRL_UPDATE BIT(5)
> +#define APPLE_CTRL_TRIGGER BIT(9)
> +#define APPLE_CTRL_INVERT BIT(10)
> +#define APPLE_CTRL_OUTPUT_ENABLE BIT(14)
> +
> +struct apple_pwm {
> + struct pwm_chip chip;
> + void __iomem *base;
> + u64 clkrate;
> +};
> +
> +static inline struct apple_pwm *to_apple_pwm(struct pwm_chip *chip)
> +{
> + return container_of(chip, struct apple_pwm, chip);
> +}
> +
> +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;
> +

polarity handling is missing here and in .get_state(). I assume you
want:

if (state->polarity == PWM_POLARITY_INVERSED)
return -EINVAL;

here and

state->polarity = PWM_POLARITY_NORMAL;

in .get_state().

> + fpwm = to_apple_pwm(chip);
> + if (state->enabled) {
> + on_cycles = mul_u64_u64_div_u64(fpwm->clkrate,
> + state->duty_cycle, NSEC_PER_SEC);
> + if (on_cycles > 0xFFFFFFFF)
> + return -ERANGE;
> +
> + off_cycles = mul_u64_u64_div_u64(fpwm->clkrate,
> + state->period, NSEC_PER_SEC) - on_cycles;
> + if (off_cycles > 0xFFFFFFFF)
> + return -ERANGE;
> +
> + writel(on_cycles, fpwm->base + APPLE_PWM_ON_CYCLES);
> + writel(off_cycles, fpwm->base + APPLE_PWM_OFF_CYCLES);
> + writel(APPLE_CTRL_ENABLE | APPLE_CTRL_OUTPUT_ENABLE | APPLE_CTRL_UPDATE,
> + fpwm->base + APPLE_PWM_CONTROL);
> + } else {
> + writel(0, fpwm->base + APPLE_PWM_CONTROL);
> + }
> + return 0;
> +}

Best regards
Uwe

--
Pengutronix e.K. | Uwe Kleine-König |
Industrial Linux Solutions | https://www.pengutronix.de/ |
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