Commit 86585c61 authored by Uwe Kleine-König's avatar Uwe Kleine-König Committed by Guenter Roeck
Browse files

hwmon: (pwm-fan) stop using legacy PWM functions and some cleanups 



pwm_apply_state() does what the legacy functions pwm_config() and
pwm_{en,dis}able() do in a single function call. This simplifies error
handling and is more efficient for new-style PWM hardware drivers.

Instead of repeatedly querying the PWM framework about the initial PWM
configuration, cache the settings in driver data.

Also use __set_pwm() in .probe() to have the algorithm calculating the PWM
state in a single place.

Signed-off-by: default avatarUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Link: https://lore.kernel.org/r/20210112191314.124686-1-u.kleine-koenig@pengutronix.de


[groeck: Added missing empty line after declaration]
Signed-off-by: default avatarGuenter Roeck <linux@roeck-us.net>
parent 8c78f0de

drivers/hwmon/pwm-fan.c

+20 −28
Original line number Diff line number Diff line
@@ -31,6 +31,7 @@ struct pwm_fan_tach { 
struct pwm_fan_ctx {

	struct mutex lock;

	struct pwm_device *pwm;

	struct pwm_state pwm_state;

	struct regulator *reg_en;



	int tach_count;
@@ -95,18 +96,17 @@ static int __set_pwm(struct pwm_fan_ctx *ctx, unsigned long pwm) 
{

	unsigned long period;

	int ret = 0;

	struct pwm_state state = { };

	struct pwm_state *state = &ctx->pwm_state;



	mutex_lock(&ctx->lock);

	if (ctx->pwm_value == pwm)

		goto exit_set_pwm_err;



	pwm_init_state(ctx->pwm, &state);

	period = ctx->pwm->args.period;

	state.duty_cycle = DIV_ROUND_UP(pwm * (period - 1), MAX_PWM);

	state.enabled = pwm ? true : false;

	period = state->period;

	state->duty_cycle = DIV_ROUND_UP(pwm * (period - 1), MAX_PWM);

	state->enabled = pwm ? true : false;



	ret = pwm_apply_state(ctx->pwm, &state);

	ret = pwm_apply_state(ctx->pwm, state);

	if (!ret)

		ctx->pwm_value = pwm;

exit_set_pwm_err:
@@ -288,7 +288,9 @@ static void pwm_fan_regulator_disable(void *data) 
static void pwm_fan_pwm_disable(void *__ctx)

{

	struct pwm_fan_ctx *ctx = __ctx;

	pwm_disable(ctx->pwm);



	ctx->pwm_state.enabled = false;

	pwm_apply_state(ctx->pwm, &ctx->pwm_state);

	del_timer_sync(&ctx->rpm_timer);

}
@@ -299,7 +301,6 @@ static int pwm_fan_probe(struct platform_device *pdev) 
	struct pwm_fan_ctx *ctx;

	struct device *hwmon;

	int ret;

	struct pwm_state state = { };

	const struct hwmon_channel_info **channels;

	u32 *fan_channel_config;

	int channel_count = 1;	/* We always have a PWM channel. */
@@ -337,22 +338,20 @@ static int pwm_fan_probe(struct platform_device *pdev) 


	ctx->pwm_value = MAX_PWM;



	pwm_init_state(ctx->pwm, &state);

	pwm_init_state(ctx->pwm, &ctx->pwm_state);



	/*

	 * __set_pwm assumes that MAX_PWM * (period - 1) fits into an unsigned

	 * long. Check this here to prevent the fan running at a too low

	 * frequency.

	 */

	if (state.period > ULONG_MAX / MAX_PWM + 1) {

	if (ctx->pwm_state.period > ULONG_MAX / MAX_PWM + 1) {

		dev_err(dev, "Configured period too big\n");

		return -EINVAL;

	}



	/* Set duty cycle to maximum allowed and enable PWM output */

	state.duty_cycle = ctx->pwm->args.period - 1;

	state.enabled = true;



	ret = pwm_apply_state(ctx->pwm, &state);

	ret = __set_pwm(ctx, MAX_PWM);

	if (ret) {

		dev_err(dev, "Failed to configure PWM: %d\n", ret);

		return ret;
@@ -468,17 +467,17 @@ static int pwm_fan_probe(struct platform_device *pdev) 
static int pwm_fan_disable(struct device *dev)

{

	struct pwm_fan_ctx *ctx = dev_get_drvdata(dev);

	struct pwm_args args;

	int ret;



	pwm_get_args(ctx->pwm, &args);



	if (ctx->pwm_value) {

		ret = pwm_config(ctx->pwm, 0, args.period);

		/* keep ctx->pwm_state unmodified for pwm_fan_resume() */

		struct pwm_state state = ctx->pwm_state;



		state.duty_cycle = 0;

		state.enabled = false;

		ret = pwm_apply_state(ctx->pwm, &state);

		if (ret < 0)

			return ret;



		pwm_disable(ctx->pwm);

	}



	if (ctx->reg_en) {
@@ -506,8 +505,6 @@ static int pwm_fan_suspend(struct device *dev) 
static int pwm_fan_resume(struct device *dev)

{

	struct pwm_fan_ctx *ctx = dev_get_drvdata(dev);

	struct pwm_args pargs;

	unsigned long duty;

	int ret;



	if (ctx->reg_en) {
@@ -521,12 +518,7 @@ static int pwm_fan_resume(struct device *dev) 
	if (ctx->pwm_value == 0)

		return 0;



	pwm_get_args(ctx->pwm, &pargs);

	duty = DIV_ROUND_UP_ULL(ctx->pwm_value * (pargs.period - 1), MAX_PWM);

	ret = pwm_config(ctx->pwm, duty, pargs.period);

	if (ret)

		return ret;

	return pwm_enable(ctx->pwm);

	return pwm_apply_state(ctx->pwm, &ctx->pwm_state);

}

#endif