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iio: adc: stm32-dfsdm: add PM support
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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 <[email protected]>
Signed-off-by: Jonathan Cameron <[email protected]>
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@jic23
Fabrice Gasnier authored and jic23 committed Apr 4, 2019
1 parent 9f57110 commit 6ec417d
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Showing 2 changed files with 206 additions and 32 deletions.
75 changes: 66 additions & 9 deletions drivers/iio/adc/stm32-dfsdm-adc.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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);
Expand Down Expand Up @@ -913,14 +907,34 @@ static int stm32_dfsdm_postenable(struct iio_dev *indio_dev)
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);

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);

Expand All @@ -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);
Expand Down Expand Up @@ -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,
Expand Down
163 changes: 140 additions & 23 deletions drivers/iio/adc/stm32-dfsdm-core.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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>

Expand Down Expand Up @@ -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.
*
Expand All @@ -98,58 +130,48 @@ 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;
ret = regmap_update_bits(dfsdm->regmap, DFSDM_CHCFGR1(0),
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__,
atomic_read(&priv->n_active_ch));

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);

Expand All @@ -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)) {
Expand All @@ -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));
Expand Down Expand Up @@ -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,
},
};

Expand Down

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