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authorFabrice Gasnier <fabrice.gasnier@st.com>2019-10-04 15:53:53 +0300
committerThierry Reding <thierry.reding@gmail.com>2019-10-21 17:50:01 +0300
commit2d3aa06b5de097747d848a9d714987a4aa2303aa (patch)
treeb7b90299b17a4256a2c2be8e330e41aa64517151 /drivers/pwm
parent0f9d2ecba883d0788a34414a608055479be81ccd (diff)
downloadlinux-2d3aa06b5de097747d848a9d714987a4aa2303aa.tar.xz
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.c38
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);