[PATCH] regulator: stm32-vrefbuf: add power management support

From: Fabrice Gasnier
Date: Thu Feb 28 2019 - 05:45:18 EST


Add support for suspend/resume and runtime PM to stm32-vrefbuf driver.

Signed-off-by: Fabrice Gasnier <fabrice.gasnier@xxxxxx>
Signed-off-by: Mark Brown <broonie@xxxxxxxxxx>
---
drivers/regulator/stm32-vrefbuf.c | 121 ++++++++++++++++++++++++++++--
1 file changed, 114 insertions(+), 7 deletions(-)

diff --git a/drivers/regulator/stm32-vrefbuf.c b/drivers/regulator/stm32-vrefbuf.c
index e0a9c445ed67..ba2f24949dc9 100644
--- a/drivers/regulator/stm32-vrefbuf.c
+++ b/drivers/regulator/stm32-vrefbuf.c
@@ -15,6 +15,7 @@
#include <linux/platform_device.h>
#include <linux/regulator/driver.h>
#include <linux/regulator/of_regulator.h>
+#include <linux/pm_runtime.h>

/* STM32 VREFBUF registers */
#define STM32_VREFBUF_CSR 0x00
@@ -25,9 +26,12 @@
#define STM32_HIZ BIT(1)
#define STM32_ENVR BIT(0)

+#define STM32_VREFBUF_AUTO_SUSPEND_DELAY_MS 10
+
struct stm32_vrefbuf {
void __iomem *base;
struct clk *clk;
+ struct device *dev;
};

static const unsigned int stm32_vrefbuf_voltages[] = {
@@ -38,9 +42,16 @@ static const unsigned int stm32_vrefbuf_voltages[] = {
static int stm32_vrefbuf_enable(struct regulator_dev *rdev)
{
struct stm32_vrefbuf *priv = rdev_get_drvdata(rdev);
- u32 val = readl_relaxed(priv->base + STM32_VREFBUF_CSR);
+ u32 val;
int ret;

+ ret = pm_runtime_get_sync(priv->dev);
+ if (ret < 0) {
+ pm_runtime_put_noidle(priv->dev);
+ return ret;
+ }
+
+ val = readl_relaxed(priv->base + STM32_VREFBUF_CSR);
val = (val & ~STM32_HIZ) | STM32_ENVR;
writel_relaxed(val, priv->base + STM32_VREFBUF_CSR);

@@ -59,45 +70,95 @@ static int stm32_vrefbuf_enable(struct regulator_dev *rdev)
writel_relaxed(val, priv->base + STM32_VREFBUF_CSR);
}

+ pm_runtime_mark_last_busy(priv->dev);
+ pm_runtime_put_autosuspend(priv->dev);
+
return ret;
}

static int stm32_vrefbuf_disable(struct regulator_dev *rdev)
{
struct stm32_vrefbuf *priv = rdev_get_drvdata(rdev);
- u32 val = readl_relaxed(priv->base + STM32_VREFBUF_CSR);
+ u32 val;
+ int ret;

+ ret = pm_runtime_get_sync(priv->dev);
+ if (ret < 0) {
+ pm_runtime_put_noidle(priv->dev);
+ return ret;
+ }
+
+ val = readl_relaxed(priv->base + STM32_VREFBUF_CSR);
val = (val & ~STM32_ENVR) | STM32_HIZ;
writel_relaxed(val, priv->base + STM32_VREFBUF_CSR);

+ pm_runtime_mark_last_busy(priv->dev);
+ pm_runtime_put_autosuspend(priv->dev);
+
return 0;
}

static int stm32_vrefbuf_is_enabled(struct regulator_dev *rdev)
{
struct stm32_vrefbuf *priv = rdev_get_drvdata(rdev);
+ int ret;
+
+ ret = pm_runtime_get_sync(priv->dev);
+ if (ret < 0) {
+ pm_runtime_put_noidle(priv->dev);
+ return ret;
+ }
+
+ ret = readl_relaxed(priv->base + STM32_VREFBUF_CSR) & STM32_ENVR;

- return readl_relaxed(priv->base + STM32_VREFBUF_CSR) & STM32_ENVR;
+ pm_runtime_mark_last_busy(priv->dev);
+ pm_runtime_put_autosuspend(priv->dev);
+
+ return ret;
}

static int stm32_vrefbuf_set_voltage_sel(struct regulator_dev *rdev,
unsigned sel)
{
struct stm32_vrefbuf *priv = rdev_get_drvdata(rdev);
- u32 val = readl_relaxed(priv->base + STM32_VREFBUF_CSR);
+ u32 val;
+ int ret;

+ ret = pm_runtime_get_sync(priv->dev);
+ if (ret < 0) {
+ pm_runtime_put_noidle(priv->dev);
+ return ret;
+ }
+
+ val = readl_relaxed(priv->base + STM32_VREFBUF_CSR);
val = (val & ~STM32_VRS) | FIELD_PREP(STM32_VRS, sel);
writel_relaxed(val, priv->base + STM32_VREFBUF_CSR);

+ pm_runtime_mark_last_busy(priv->dev);
+ pm_runtime_put_autosuspend(priv->dev);
+
return 0;
}

static int stm32_vrefbuf_get_voltage_sel(struct regulator_dev *rdev)
{
struct stm32_vrefbuf *priv = rdev_get_drvdata(rdev);
- u32 val = readl_relaxed(priv->base + STM32_VREFBUF_CSR);
+ u32 val;
+ int ret;

- return FIELD_GET(STM32_VRS, val);
+ ret = pm_runtime_get_sync(priv->dev);
+ if (ret < 0) {
+ pm_runtime_put_noidle(priv->dev);
+ return ret;
+ }
+
+ val = readl_relaxed(priv->base + STM32_VREFBUF_CSR);
+ ret = FIELD_GET(STM32_VRS, val);
+
+ pm_runtime_mark_last_busy(priv->dev);
+ pm_runtime_put_autosuspend(priv->dev);
+
+ return ret;
}

static const struct regulator_ops stm32_vrefbuf_volt_ops = {
@@ -130,6 +191,7 @@ static int stm32_vrefbuf_probe(struct platform_device *pdev)
priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
if (!priv)
return -ENOMEM;
+ priv->dev = &pdev->dev;

res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
priv->base = devm_ioremap_resource(&pdev->dev, res);
@@ -140,10 +202,17 @@ static int stm32_vrefbuf_probe(struct platform_device *pdev)
if (IS_ERR(priv->clk))
return PTR_ERR(priv->clk);

+ pm_runtime_get_noresume(&pdev->dev);
+ pm_runtime_set_active(&pdev->dev);
+ pm_runtime_set_autosuspend_delay(&pdev->dev,
+ STM32_VREFBUF_AUTO_SUSPEND_DELAY_MS);
+ pm_runtime_use_autosuspend(&pdev->dev);
+ pm_runtime_enable(&pdev->dev);
+
ret = clk_prepare_enable(priv->clk);
if (ret) {
dev_err(&pdev->dev, "clk prepare failed with error %d\n", ret);
- return ret;
+ goto err_pm_stop;
}

config.dev = &pdev->dev;
@@ -161,10 +230,17 @@ static int stm32_vrefbuf_probe(struct platform_device *pdev)
}
platform_set_drvdata(pdev, rdev);

+ pm_runtime_mark_last_busy(&pdev->dev);
+ pm_runtime_put_autosuspend(&pdev->dev);
+
return 0;

err_clk_dis:
clk_disable_unprepare(priv->clk);
+err_pm_stop:
+ pm_runtime_disable(&pdev->dev);
+ pm_runtime_set_suspended(&pdev->dev);
+ pm_runtime_put_noidle(&pdev->dev);

return ret;
}
@@ -174,12 +250,42 @@ static int stm32_vrefbuf_remove(struct platform_device *pdev)
struct regulator_dev *rdev = platform_get_drvdata(pdev);
struct stm32_vrefbuf *priv = rdev_get_drvdata(rdev);

+ pm_runtime_get_sync(&pdev->dev);
regulator_unregister(rdev);
clk_disable_unprepare(priv->clk);
+ pm_runtime_disable(&pdev->dev);
+ pm_runtime_set_suspended(&pdev->dev);
+ pm_runtime_put_noidle(&pdev->dev);

return 0;
};

+static int __maybe_unused stm32_vrefbuf_runtime_suspend(struct device *dev)
+{
+ struct regulator_dev *rdev = dev_get_drvdata(dev);
+ struct stm32_vrefbuf *priv = rdev_get_drvdata(rdev);
+
+ clk_disable_unprepare(priv->clk);
+
+ return 0;
+}
+
+static int __maybe_unused stm32_vrefbuf_runtime_resume(struct device *dev)
+{
+ struct regulator_dev *rdev = dev_get_drvdata(dev);
+ struct stm32_vrefbuf *priv = rdev_get_drvdata(rdev);
+
+ return clk_prepare_enable(priv->clk);
+}
+
+static const struct dev_pm_ops stm32_vrefbuf_pm_ops = {
+ SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
+ pm_runtime_force_resume)
+ SET_RUNTIME_PM_OPS(stm32_vrefbuf_runtime_suspend,
+ stm32_vrefbuf_runtime_resume,
+ NULL)
+};
+
static const struct of_device_id stm32_vrefbuf_of_match[] = {
{ .compatible = "st,stm32-vrefbuf", },
{},
@@ -192,6 +298,7 @@ static struct platform_driver stm32_vrefbuf_driver = {
.driver = {
.name = "stm32-vrefbuf",
.of_match_table = of_match_ptr(stm32_vrefbuf_of_match),
+ .pm = &stm32_vrefbuf_pm_ops,
},
};
module_platform_driver(stm32_vrefbuf_driver);
--
2.20.1