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Message-ID: <1569857951-20007-3-git-send-email-fabrice.gasnier@st.com>
Date: Mon, 30 Sep 2019 17:39:11 +0200
From: Fabrice Gasnier <fabrice.gasnier@...com>
To: <thierry.reding@...il.com>, <robh+dt@...nel.org>
CC: <alexandre.torgue@...com>, <mark.rutland@....com>,
<mcoquelin.stm32@...il.com>, <fabrice.gasnier@...com>,
<devicetree@...r.kernel.org>,
<linux-arm-kernel@...ts.infradead.org>,
<linux-kernel@...r.kernel.org>, <linux-pwm@...r.kernel.org>,
<benjamin.gaignard@...com>,
<linux-stm32@...md-mailman.stormreply.com>
Subject: [PATCH 2/2] 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@...com>
---
drivers/pwm/pwm-stm32.c | 82 +++++++++++++++++++++++++++++++++++++------------
1 file changed, 62 insertions(+), 20 deletions(-)
diff --git a/drivers/pwm/pwm-stm32.c b/drivers/pwm/pwm-stm32.c
index 740e2de..9bcd73a 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>
@@ -19,6 +20,12 @@
#define CCMR_CHANNEL_MASK 0xFF
#define MAX_BREAKINPUT 2
+struct stm32_breakinput {
+ u32 index;
+ u32 level;
+ u32 filter;
+};
+
struct stm32_pwm {
struct pwm_chip chip;
struct mutex lock; /* protect pwm config/enable */
@@ -26,15 +33,11 @@ struct stm32_pwm {
struct regmap *regmap;
u32 max_arr;
bool have_complementary_output;
+ struct stm32_breakinput breakinput[MAX_BREAKINPUT];
+ unsigned int nbreakinput;
u32 capture[4] ____cacheline_aligned; /* DMA'able buffer */
};
-struct stm32_breakinput {
- u32 index;
- u32 level;
- u32 filter;
-};
-
static inline struct stm32_pwm *to_stm32_pwm_dev(struct pwm_chip *chip)
{
return container_of(chip, struct stm32_pwm, chip);
@@ -512,15 +515,27 @@ static int stm32_pwm_set_breakinput(struct stm32_pwm *priv,
return (bdtr & bke) ? 0 : -EINVAL;
}
-static int stm32_pwm_apply_breakinputs(struct stm32_pwm *priv,
+static int stm32_pwm_apply_breakinputs(struct stm32_pwm *priv)
+{
+ int i, ret = 0;
+
+ for (i = 0; i < priv->nbreakinput && !ret; i++) {
+ ret = stm32_pwm_set_breakinput(priv,
+ priv->breakinput[i].index,
+ priv->breakinput[i].level,
+ priv->breakinput[i].filter);
+ }
+
+ return ret;
+}
+
+static int stm32_pwm_probe_breakinputs(struct stm32_pwm *priv,
struct device_node *np)
{
- struct stm32_breakinput breakinput[MAX_BREAKINPUT];
- int nb, ret, i, array_size;
+ int nb, ret, array_size;
nb = of_property_count_elems_of_size(np, "st,breakinput",
sizeof(struct stm32_breakinput));
-
/*
* Because "st,breakinput" parameter is optional do not make probe
* failed if it doesn't exist.
@@ -531,20 +546,14 @@ static int stm32_pwm_apply_breakinputs(struct stm32_pwm *priv,
if (nb > MAX_BREAKINPUT)
return -EINVAL;
+ priv->nbreakinput = nb;
array_size = nb * sizeof(struct stm32_breakinput) / sizeof(u32);
ret = of_property_read_u32_array(np, "st,breakinput",
- (u32 *)breakinput, array_size);
+ (u32 *)priv->breakinput, array_size);
if (ret)
return ret;
- for (i = 0; i < nb && !ret; i++) {
- ret = stm32_pwm_set_breakinput(priv,
- breakinput[i].index,
- breakinput[i].level,
- breakinput[i].filter);
- }
-
- return ret;
+ return stm32_pwm_apply_breakinputs(priv);
}
static void stm32_pwm_detect_complementary(struct stm32_pwm *priv)
@@ -614,7 +623,7 @@ static int stm32_pwm_probe(struct platform_device *pdev)
if (!priv->regmap || !priv->clk)
return -EINVAL;
- ret = stm32_pwm_apply_breakinputs(priv, np);
+ ret = stm32_pwm_probe_breakinputs(priv, np);
if (ret)
return ret;
@@ -647,6 +656,38 @@ 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);
+ struct pwm_state state;
+ unsigned int i;
+
+ for (i = 0; i < priv->chip.npwm; i++) {
+ pwm_get_state(&priv->chip.pwms[i], &state);
+ if (state.enabled) {
+ dev_err(dev, "The consumer didn't stop us (%s)\n",
+ 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;
+
+ 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 */ },
@@ -659,6 +700,7 @@ 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);
--
2.7.4
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