diff options
| author |   Fabrice Gasnier <fabrice.gasnier@st.com> | 2019-10-04 14:53:53 +0200 |
|---|---|---|
| committer |   Thierry Reding <thierry.reding@gmail.com> | 2019-10-21 16:50:01 +0200 |
| commit | 2d3aa06b5de097747d848a9d714987a4aa2303aa (patch) | |
| tree | b7b90299b17a4256a2c2be8e330e41aa64517151 /drivers/pwm | |
| parent | pwm: stm32: Split breakinput apply routine to ease PM support (diff) | |
| download | linux-dev-2d3aa06b5de097747d848a9d714987a4aa2303aa.tar.xz linux-dev-2d3aa06b5de097747d848a9d714987a4aa2303aa.zip | |
pwm: stm32: Add power management support
Add suspend/resume PM sleep ops. When going to low power, enforce the PWM
channel isn't active. Let the PWM consumers disable it during their own
suspend sequence, see [1]. So, perform a check here, and handle the
pinctrl states. Also restore the break inputs upon resume, as registers
content may be lost when going to low power mode.
[1] https://lkml.org/lkml/2019/2/5/770
Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
Diffstat (limited to 'drivers/pwm')
| -rw-r--r-- | drivers/pwm/pwm-stm32.c | 38 |
1 files changed, 38 insertions, 0 deletions
diff --git a/drivers/pwm/pwm-stm32.c b/drivers/pwm/pwm-stm32.c index dd0b27783d02..9430b4cd383f 100644 --- a/drivers/pwm/pwm-stm32.c +++ b/drivers/pwm/pwm-stm32.c @@ -12,6 +12,7 @@ #include <linux/mfd/stm32-timers.h> #include <linux/module.h> #include <linux/of.h> +#include <linux/pinctrl/consumer.h> #include <linux/platform_device.h> #include <linux/pwm.h> @@ -659,6 +660,42 @@ static int stm32_pwm_remove(struct platform_device *pdev) return 0; } +static int __maybe_unused stm32_pwm_suspend(struct device *dev) +{ + struct stm32_pwm *priv = dev_get_drvdata(dev); + unsigned int i; + u32 ccer, mask; + + /* Look for active channels */ + ccer = active_channels(priv); + + for (i = 0; i < priv->chip.npwm; i++) { + mask = TIM_CCER_CC1E << (i * 4); + if (ccer & mask) { + dev_err(dev, "PWM %u still in use by consumer %s\n", + i, priv->chip.pwms[i].label); + return -EBUSY; + } + } + + return pinctrl_pm_select_sleep_state(dev); +} + +static int __maybe_unused stm32_pwm_resume(struct device *dev) +{ + struct stm32_pwm *priv = dev_get_drvdata(dev); + int ret; + + ret = pinctrl_pm_select_default_state(dev); + if (ret) + return ret; + + /* restore breakinput registers that may have been lost in low power */ + return stm32_pwm_apply_breakinputs(priv); +} + +static SIMPLE_DEV_PM_OPS(stm32_pwm_pm_ops, stm32_pwm_suspend, stm32_pwm_resume); + static const struct of_device_id stm32_pwm_of_match[] = { { .compatible = "st,stm32-pwm", }, { /* end node */ }, @@ -671,6 +708,7 @@ static struct platform_driver stm32_pwm_driver = { .driver = { .name = "stm32-pwm", .of_match_table = stm32_pwm_of_match, + .pm = &stm32_pwm_pm_ops, }, }; module_platform_driver(stm32_pwm_driver); |