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pwm: stm32-lp: 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. Only perform a check here, and handle the pinctrl states.
See [1].
[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>
This commit is contained in:
Fabrice Gasnier 2019-04-18 11:37:46 +02:00 committed by Thierry Reding
parent f6c9b59769
commit cce4a833fc
1 changed files with 25 additions and 0 deletions
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25
drivers/pwm/pwm-stm32-lp.c
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@ -13,6 +13,7 @@
#include <linux/mfd/stm32-lptimer.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/pinctrl/consumer.h>
#include <linux/platform_device.h>
#include <linux/pwm.h>
@ -223,6 +224,29 @@ static int stm32_pwm_lp_remove(struct platform_device *pdev)
return pwmchip_remove(&priv->chip);
}
static int __maybe_unused stm32_pwm_lp_suspend(struct device *dev)
{
struct stm32_pwm_lp *priv = dev_get_drvdata(dev);
struct pwm_state state;
pwm_get_state(&priv->chip.pwms[0], &state);
if (state.enabled) {
dev_err(dev, "The consumer didn't stop us (%s)\n",
priv->chip.pwms[0].label);
return -EBUSY;
}
return pinctrl_pm_select_sleep_state(dev);
}
static int __maybe_unused stm32_pwm_lp_resume(struct device *dev)
{
return pinctrl_pm_select_default_state(dev);
}
static SIMPLE_DEV_PM_OPS(stm32_pwm_lp_pm_ops, stm32_pwm_lp_suspend,
stm32_pwm_lp_resume);
static const struct of_device_id stm32_pwm_lp_of_match[] = {
{ .compatible = "st,stm32-pwm-lp", },
{},
@ -235,6 +259,7 @@ static struct platform_driver stm32_pwm_lp_driver = {
.driver = {
.name = "stm32-pwm-lp",
.of_match_table = of_match_ptr(stm32_pwm_lp_of_match),
.pm = &stm32_pwm_lp_pm_ops,
},
};
module_platform_driver(stm32_pwm_lp_driver);