On Tue, 15 Dec 2020 at 09:23, Uwe Kleine-König
<u.kleine-koenig@xxxxxxxxxxxxxx> wrote:
>
> 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: Uwe Kleine-König <u.kleine-koenig@xxxxxxxxxxxxxx>
> ---
> drivers/hwmon/pwm-fan.c | 47 +++++++++++++++++------------------------
> 1 file changed, 19 insertions(+), 28 deletions(-)
>
> diff --git a/drivers/hwmon/pwm-fan.c b/drivers/hwmon/pwm-fan.c
> index ec171f2b684a..4ccad5a87019 100644
> --- a/drivers/hwmon/pwm-fan.c
> +++ b/drivers/hwmon/pwm-fan.c
> @@ -25,6 +25,7 @@
> struct pwm_fan_ctx {
> struct mutex lock;
> struct pwm_device *pwm;
> + struct pwm_state pwm_state;
> struct regulator *reg_en;
>
> int irq;
> @@ -73,18 +74,17 @@ 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:
> @@ -274,7 +274,9 @@ 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);
> }
>
> @@ -285,7 +287,6 @@ static int pwm_fan_probe(struct platform_device *pdev)
> struct pwm_fan_ctx *ctx;
> struct device *hwmon;
> int ret;
> - struct pwm_state state = { };
> u32 ppr = 2;
>
> ctx = devm_kzalloc(dev, sizeof(*ctx), GFP_KERNEL);
> @@ -324,22 +325,20 @@ 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;
> @@ -399,17 +398,16 @@ 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) {
> @@ -437,8 +435,6 @@ 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) {
> @@ -452,12 +448,7 @@ 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
>
> --
> 2.29.2
>
All looks good to me at first glance.
This does conflict with the changes I proposed
(https://lore.kernel.org/linux-hwmon/20201212195008.6036-1-pbarker@xxxxxxxxxxxx/T/#t)
so we'll need to figure out that out depending which order they get
applied in (assuming both changes get accepted).
Thanks,
--
Paul Barker
Konsulko Group
