iio: adc: stm32-dfsdm: add PM support

Add PM and runtime PM support to STM32 DFSDM drivers:
- stm32-dfsdm-core: manage clocks.
- stm32-dfsdm-adc: restore channels configuration upon resume. Also stop
  restart everything in case of buffer mode.

Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

diff --git a/drivers/iio/adc/stm32-dfsdm-adc.c b/drivers/iio/adc/stm32-dfsdm-adc.c
index 051561c..19adc2b 100644 (file)
--- a/drivers/iio/adc/stm32-dfsdm-adc.c
+++ b/drivers/iio/adc/stm32-dfsdm-adc.c
@@ -868,24 +868,18 @@ static int stm32_dfsdm_update_scan_mode(struct iio_dev *indio_dev,
        return 0;
 }
 
-static int stm32_dfsdm_postenable(struct iio_dev *indio_dev)
+static int __stm32_dfsdm_postenable(struct iio_dev *indio_dev)
 {
        struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
        int ret;
 
-       if (indio_dev->currentmode == INDIO_BUFFER_TRIGGERED) {
-               ret = iio_triggered_buffer_postenable(indio_dev);
-               if (ret < 0)
-                       return ret;
-       }
-
        /* Reset adc buffer index */
        adc->bufi = 0;
 
        if (adc->hwc) {
                ret = iio_hw_consumer_enable(adc->hwc);
                if (ret < 0)
-                       goto err_predisable;
+                       return ret;
        }
 
        ret = stm32_dfsdm_start_dfsdm(adc->dfsdm);
@@ -913,6 +907,26 @@ stop_dfsdm:
 err_stop_hwc:
        if (adc->hwc)
                iio_hw_consumer_disable(adc->hwc);
+
+       return ret;
+}
+
+static int stm32_dfsdm_postenable(struct iio_dev *indio_dev)
+{
+       int ret;
+
+       if (indio_dev->currentmode == INDIO_BUFFER_TRIGGERED) {
+               ret = iio_triggered_buffer_postenable(indio_dev);
+               if (ret < 0)
+                       return ret;
+       }
+
+       ret = __stm32_dfsdm_postenable(indio_dev);
+       if (ret < 0)
+               goto err_predisable;
+
+       return 0;
+
 err_predisable:
        if (indio_dev->currentmode == INDIO_BUFFER_TRIGGERED)
                iio_triggered_buffer_predisable(indio_dev);
@@ -920,7 +934,7 @@ err_predisable:
        return ret;
 }
 
-static int stm32_dfsdm_predisable(struct iio_dev *indio_dev)
+static void __stm32_dfsdm_predisable(struct iio_dev *indio_dev)
 {
        struct stm32_dfsdm_adc *adc = iio_priv(indio_dev);
 
@@ -932,6 +946,11 @@ static int stm32_dfsdm_predisable(struct iio_dev *indio_dev)
 
        if (adc->hwc)
                iio_hw_consumer_disable(adc->hwc);
+}
+
+static int stm32_dfsdm_predisable(struct iio_dev *indio_dev)
+{
+       __stm32_dfsdm_predisable(indio_dev);
 
        if (indio_dev->currentmode == INDIO_BUFFER_TRIGGERED)
                iio_triggered_buffer_predisable(indio_dev);
@@ -1496,10 +1515,48 @@ static int stm32_dfsdm_adc_remove(struct platform_device *pdev)
        return 0;
 }
 
+static int __maybe_unused stm32_dfsdm_adc_suspend(struct device *dev)
+{
+       struct stm32_dfsdm_adc *adc = dev_get_drvdata(dev);
+       struct iio_dev *indio_dev = iio_priv_to_dev(adc);
+
+       if (iio_buffer_enabled(indio_dev))
+               __stm32_dfsdm_predisable(indio_dev);
+
+       return 0;
+}
+
+static int __maybe_unused stm32_dfsdm_adc_resume(struct device *dev)
+{
+       struct stm32_dfsdm_adc *adc = dev_get_drvdata(dev);
+       struct iio_dev *indio_dev = iio_priv_to_dev(adc);
+       const struct iio_chan_spec *chan;
+       struct stm32_dfsdm_channel *ch;
+       int i, ret;
+
+       /* restore channels configuration */
+       for (i = 0; i < indio_dev->num_channels; i++) {
+               chan = indio_dev->channels + i;
+               ch = &adc->dfsdm->ch_list[chan->channel];
+               ret = stm32_dfsdm_chan_configure(adc->dfsdm, ch);
+               if (ret)
+                       return ret;
+       }
+
+       if (iio_buffer_enabled(indio_dev))
+               __stm32_dfsdm_postenable(indio_dev);
+
+       return 0;
+}
+
+static SIMPLE_DEV_PM_OPS(stm32_dfsdm_adc_pm_ops,
+                        stm32_dfsdm_adc_suspend, stm32_dfsdm_adc_resume);
+
 static struct platform_driver stm32_dfsdm_adc_driver = {
        .driver = {
                .name = "stm32-dfsdm-adc",
                .of_match_table = stm32_dfsdm_adc_match,
+               .pm = &stm32_dfsdm_adc_pm_ops,
        },
        .probe = stm32_dfsdm_adc_probe,
        .remove = stm32_dfsdm_adc_remove,

diff --git a/drivers/iio/adc/stm32-dfsdm-core.c b/drivers/iio/adc/stm32-dfsdm-core.c
index 472b809..0a4d374 100644 (file)
--- a/drivers/iio/adc/stm32-dfsdm-core.c
+++ b/drivers/iio/adc/stm32-dfsdm-core.c
@@ -12,6 +12,8 @@
 #include <linux/interrupt.h>
 #include <linux/module.h>
 #include <linux/of_device.h>
+#include <linux/pinctrl/consumer.h>
+#include <linux/pm_runtime.h>
 #include <linux/regmap.h>
 #include <linux/slab.h>
 
@@ -90,6 +92,36 @@ struct dfsdm_priv {
        struct clk *aclk; /* audio clock */
 };
 
+static inline struct dfsdm_priv *to_stm32_dfsdm_priv(struct stm32_dfsdm *dfsdm)
+{
+       return container_of(dfsdm, struct dfsdm_priv, dfsdm);
+}
+
+static int stm32_dfsdm_clk_prepare_enable(struct stm32_dfsdm *dfsdm)
+{
+       struct dfsdm_priv *priv = to_stm32_dfsdm_priv(dfsdm);
+       int ret;
+
+       ret = clk_prepare_enable(priv->clk);
+       if (ret || !priv->aclk)
+               return ret;
+
+       ret = clk_prepare_enable(priv->aclk);
+       if (ret)
+               clk_disable_unprepare(priv->clk);
+
+       return ret;
+}
+
+static void stm32_dfsdm_clk_disable_unprepare(struct stm32_dfsdm *dfsdm)
+{
+       struct dfsdm_priv *priv = to_stm32_dfsdm_priv(dfsdm);
+
+       if (priv->aclk)
+               clk_disable_unprepare(priv->aclk);
+       clk_disable_unprepare(priv->clk);
+}
+
 /**
  * stm32_dfsdm_start_dfsdm - start global dfsdm interface.
  *
@@ -98,24 +130,17 @@ struct dfsdm_priv {
  */
 int stm32_dfsdm_start_dfsdm(struct stm32_dfsdm *dfsdm)
 {
-       struct dfsdm_priv *priv = container_of(dfsdm, struct dfsdm_priv, dfsdm);
+       struct dfsdm_priv *priv = to_stm32_dfsdm_priv(dfsdm);
        struct device *dev = &priv->pdev->dev;
        unsigned int clk_div = priv->spi_clk_out_div, clk_src;
        int ret;
 
        if (atomic_inc_return(&priv->n_active_ch) == 1) {
-               ret = clk_prepare_enable(priv->clk);
+               ret = pm_runtime_get_sync(dev);
                if (ret < 0) {
-                       dev_err(dev, "Failed to start clock\n");
+                       pm_runtime_put_noidle(dev);
                        goto error_ret;
                }
-               if (priv->aclk) {
-                       ret = clk_prepare_enable(priv->aclk);
-                       if (ret < 0) {
-                               dev_err(dev, "Failed to start audio clock\n");
-                               goto disable_clk;
-                       }
-               }
 
                /* select clock source, e.g. 0 for "dfsdm" or 1 for "audio" */
                clk_src = priv->aclk ? 1 : 0;
@@ -123,21 +148,21 @@ int stm32_dfsdm_start_dfsdm(struct stm32_dfsdm *dfsdm)
                                         DFSDM_CHCFGR1_CKOUTSRC_MASK,
                                         DFSDM_CHCFGR1_CKOUTSRC(clk_src));
                if (ret < 0)
-                       goto disable_aclk;
+                       goto pm_put;
 
                /* Output the SPI CLKOUT (if clk_div == 0 clock if OFF) */
                ret = regmap_update_bits(dfsdm->regmap, DFSDM_CHCFGR1(0),
                                         DFSDM_CHCFGR1_CKOUTDIV_MASK,
                                         DFSDM_CHCFGR1_CKOUTDIV(clk_div));
                if (ret < 0)
-                       goto disable_aclk;
+                       goto pm_put;
 
                /* Global enable of DFSDM interface */
                ret = regmap_update_bits(dfsdm->regmap, DFSDM_CHCFGR1(0),
                                         DFSDM_CHCFGR1_DFSDMEN_MASK,
                                         DFSDM_CHCFGR1_DFSDMEN(1));
                if (ret < 0)
-                       goto disable_aclk;
+                       goto pm_put;
        }
 
        dev_dbg(dev, "%s: n_active_ch %d\n", __func__,
@@ -145,11 +170,8 @@ int stm32_dfsdm_start_dfsdm(struct stm32_dfsdm *dfsdm)
 
        return 0;
 
-disable_aclk:
-       clk_disable_unprepare(priv->aclk);
-disable_clk:
-       clk_disable_unprepare(priv->clk);
-
+pm_put:
+       pm_runtime_put_sync(dev);
 error_ret:
        atomic_dec(&priv->n_active_ch);
 
@@ -165,7 +187,7 @@ EXPORT_SYMBOL_GPL(stm32_dfsdm_start_dfsdm);
  */
 int stm32_dfsdm_stop_dfsdm(struct stm32_dfsdm *dfsdm)
 {
-       struct dfsdm_priv *priv = container_of(dfsdm, struct dfsdm_priv, dfsdm);
+       struct dfsdm_priv *priv = to_stm32_dfsdm_priv(dfsdm);
        int ret;
 
        if (atomic_dec_and_test(&priv->n_active_ch)) {
@@ -183,9 +205,7 @@ int stm32_dfsdm_stop_dfsdm(struct stm32_dfsdm *dfsdm)
                if (ret < 0)
                        return ret;
 
-               clk_disable_unprepare(priv->clk);
-               if (priv->aclk)
-                       clk_disable_unprepare(priv->aclk);
+               pm_runtime_put_sync(&priv->pdev->dev);
        }
        dev_dbg(&priv->pdev->dev, "%s: n_active_ch %d\n", __func__,
                atomic_read(&priv->n_active_ch));
@@ -325,14 +345,111 @@ static int stm32_dfsdm_probe(struct platform_device *pdev)
 
        platform_set_drvdata(pdev, dfsdm);
 
-       return devm_of_platform_populate(&pdev->dev);
+       ret = stm32_dfsdm_clk_prepare_enable(dfsdm);
+       if (ret) {
+               dev_err(&pdev->dev, "Failed to start clock\n");
+               return ret;
+       }
+
+       pm_runtime_get_noresume(&pdev->dev);
+       pm_runtime_set_active(&pdev->dev);
+       pm_runtime_enable(&pdev->dev);
+
+       ret = of_platform_populate(pdev->dev.of_node, NULL, NULL, &pdev->dev);
+       if (ret)
+               goto pm_put;
+
+       pm_runtime_put(&pdev->dev);
+
+       return 0;
+
+pm_put:
+       pm_runtime_disable(&pdev->dev);
+       pm_runtime_set_suspended(&pdev->dev);
+       pm_runtime_put_noidle(&pdev->dev);
+       stm32_dfsdm_clk_disable_unprepare(dfsdm);
+
+       return ret;
+}
+
+static int stm32_dfsdm_core_remove(struct platform_device *pdev)
+{
+       struct stm32_dfsdm *dfsdm = platform_get_drvdata(pdev);
+
+       pm_runtime_get_sync(&pdev->dev);
+       of_platform_depopulate(&pdev->dev);
+       pm_runtime_disable(&pdev->dev);
+       pm_runtime_set_suspended(&pdev->dev);
+       pm_runtime_put_noidle(&pdev->dev);
+       stm32_dfsdm_clk_disable_unprepare(dfsdm);
+
+       return 0;
+}
+
+static int __maybe_unused stm32_dfsdm_core_suspend(struct device *dev)
+{
+       struct stm32_dfsdm *dfsdm = dev_get_drvdata(dev);
+       struct dfsdm_priv *priv = to_stm32_dfsdm_priv(dfsdm);
+       int ret;
+
+       ret = pm_runtime_force_suspend(dev);
+       if (ret)
+               return ret;
+
+       /* Balance devm_regmap_init_mmio_clk() clk_prepare() */
+       clk_unprepare(priv->clk);
+
+       return pinctrl_pm_select_sleep_state(dev);
+}
+
+static int __maybe_unused stm32_dfsdm_core_resume(struct device *dev)
+{
+       struct stm32_dfsdm *dfsdm = dev_get_drvdata(dev);
+       struct dfsdm_priv *priv = to_stm32_dfsdm_priv(dfsdm);
+       int ret;
+
+       ret = pinctrl_pm_select_default_state(dev);
+       if (ret)
+               return ret;
+
+       ret = clk_prepare(priv->clk);
+       if (ret)
+               return ret;
+
+       return pm_runtime_force_resume(dev);
 }
 
+static int __maybe_unused stm32_dfsdm_core_runtime_suspend(struct device *dev)
+{
+       struct stm32_dfsdm *dfsdm = dev_get_drvdata(dev);
+
+       stm32_dfsdm_clk_disable_unprepare(dfsdm);
+
+       return 0;
+}
+
+static int __maybe_unused stm32_dfsdm_core_runtime_resume(struct device *dev)
+{
+       struct stm32_dfsdm *dfsdm = dev_get_drvdata(dev);
+
+       return stm32_dfsdm_clk_prepare_enable(dfsdm);
+}
+
+static const struct dev_pm_ops stm32_dfsdm_core_pm_ops = {
+       SET_SYSTEM_SLEEP_PM_OPS(stm32_dfsdm_core_suspend,
+                               stm32_dfsdm_core_resume)
+       SET_RUNTIME_PM_OPS(stm32_dfsdm_core_runtime_suspend,
+                          stm32_dfsdm_core_runtime_resume,
+                          NULL)
+};
+
 static struct platform_driver stm32_dfsdm_driver = {
        .probe = stm32_dfsdm_probe,
+       .remove = stm32_dfsdm_core_remove,
        .driver = {
                .name = "stm32-dfsdm",
                .of_match_table = stm32_dfsdm_of_match,
+               .pm = &stm32_dfsdm_core_pm_ops,
        },
 };