pwm: jz4740: Let the pinctrl driver configure the pins (47096d70) · Commits · 戴 / test

Now that the JZ4740 and similar SoCs have a pinctrl driver, we rely on the pins being properly configured before the driver probes. One inherent problem of this new approach is that the pinctrl framework does not allow us to configure each pin on demand, when the various PWM channels are requested or released. For instance, the PWM channels can be configured from sysfs, which would require all PWM pins to be configured properly beforehand for the PWM function, eventually causing conflicts with other platform or board drivers. The proper solution here would be to modify the pwm-jz4740 driver to handle only one PWM channel, and create an instance of this driver for each one of the 8 PWM channels. Then, it could use the pinctrl framework to dynamically configure the PWM pin it controls. Until this can be done, the only jz4740 board supported upstream (Qi lb60) can configure all of its connected PWM pins in PWM function mode, since those are not used by other drivers nor by GPIOs on the board. Signed-off-by:

Paul Cercueil <paul@crapouillou.net> Acked-by:

Thierry Reding <thierry.reding@gmail.com> Signed-off-by:

Linus Walleij <linus.walleij@linaro.org>

drivers/pwm/pwm-jz4740.c

+0 −29

Original line number	Diff line number	Diff line
		@@ -21,22 +21,10 @@
		#include <linux/platform_device.h>
		#include <linux/pwm.h>

		#include <asm/mach-jz4740/gpio.h>
		#include <asm/mach-jz4740/timer.h>

		#define NUM_PWM 8

		static const unsigned int jz4740_pwm_gpio_list[NUM_PWM] = {
		JZ_GPIO_PWM0,
		JZ_GPIO_PWM1,
		JZ_GPIO_PWM2,
		JZ_GPIO_PWM3,
		JZ_GPIO_PWM4,
		JZ_GPIO_PWM5,
		JZ_GPIO_PWM6,
		JZ_GPIO_PWM7,
		};

		struct jz4740_pwm_chip {
		struct pwm_chip chip;
		struct clk *clk;
		@@ -49,9 +37,6 @@ static inline struct jz4740_pwm_chip to_jz4740(struct pwm_chip chip)

		static int jz4740_pwm_request(struct pwm_chip chip, struct pwm_device pwm)
		{
		unsigned int gpio = jz4740_pwm_gpio_list[pwm->hwpwm];
		int ret;

		/*
		* Timers 0 and 1 are used for system tasks, so they are unavailable
		* for use as PWMs.
		@@ -59,15 +44,6 @@ static int jz4740_pwm_request(struct pwm_chip chip, struct pwm_device pwm)
		if (pwm->hwpwm < 2)
		return -EBUSY;

		ret = gpio_request(gpio, pwm->label);
		if (ret) {
		dev_err(chip->dev, "Failed to request GPIO#%u for PWM: %d\n",
		gpio, ret);
		return ret;
		}

		jz_gpio_set_function(gpio, JZ_GPIO_FUNC_PWM);

		jz4740_timer_start(pwm->hwpwm);

		return 0;
		@@ -75,13 +51,8 @@ static int jz4740_pwm_request(struct pwm_chip chip, struct pwm_device pwm)

		static void jz4740_pwm_free(struct pwm_chip chip, struct pwm_device pwm)
		{
		unsigned int gpio = jz4740_pwm_gpio_list[pwm->hwpwm];

		jz4740_timer_set_ctrl(pwm->hwpwm, 0);

		jz_gpio_set_function(gpio, JZ_GPIO_FUNC_NONE);
		gpio_free(gpio);

		jz4740_timer_stop(pwm->hwpwm);
		}

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