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iio: adc: stm32-adc: add power management support
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Add support for runtime PM & sleep. Move all regulator and clock management
to dedicated HW start/stop routines. Then rely on (runtime) PM OPS to
call them.

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 Nov 25, 2018
1 parent 0da98c7 commit 9bdbb11
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Showing 2 changed files with 258 additions and 93 deletions.
182 changes: 126 additions & 56 deletions drivers/iio/adc/stm32-adc-core.c
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Original file line number Diff line number Diff line change
Expand Up @@ -16,6 +16,7 @@
#include <linux/irqdomain.h>
#include <linux/module.h>
#include <linux/of_device.h>
#include <linux/pm_runtime.h>
#include <linux/regulator/consumer.h>
#include <linux/slab.h>

Expand Down Expand Up @@ -48,15 +49,19 @@
#define STM32H7_CKMODE_SHIFT 16
#define STM32H7_CKMODE_MASK GENMASK(17, 16)

#define STM32_ADC_CORE_SLEEP_DELAY_MS 2000

/**
* stm32_adc_common_regs - stm32 common registers, compatible dependent data
* @csr: common status register offset
* @ccr: common control register offset
* @eoc1: adc1 end of conversion flag in @csr
* @eoc2: adc2 end of conversion flag in @csr
* @eoc3: adc3 end of conversion flag in @csr
*/
struct stm32_adc_common_regs {
u32 csr;
u32 ccr;
u32 eoc1_msk;
u32 eoc2_msk;
u32 eoc3_msk;
Expand Down Expand Up @@ -85,6 +90,7 @@ struct stm32_adc_priv_cfg {
* @vref: regulator reference
* @cfg: compatible configuration data
* @common: common data for all ADC instances
* @ccr_bak: backup CCR in low power mode
*/
struct stm32_adc_priv {
int irq[STM32_ADC_MAX_ADCS];
Expand All @@ -94,6 +100,7 @@ struct stm32_adc_priv {
struct regulator *vref;
const struct stm32_adc_priv_cfg *cfg;
struct stm32_adc_common common;
u32 ccr_bak;
};

static struct stm32_adc_priv *to_stm32_adc_priv(struct stm32_adc_common *com)
Expand Down Expand Up @@ -265,6 +272,7 @@ static int stm32h7_adc_clk_sel(struct platform_device *pdev,
/* STM32F4 common registers definitions */
static const struct stm32_adc_common_regs stm32f4_adc_common_regs = {
.csr = STM32F4_ADC_CSR,
.ccr = STM32F4_ADC_CCR,
.eoc1_msk = STM32F4_EOC1,
.eoc2_msk = STM32F4_EOC2,
.eoc3_msk = STM32F4_EOC3,
Expand All @@ -273,6 +281,7 @@ static const struct stm32_adc_common_regs stm32f4_adc_common_regs = {
/* STM32H7 common registers definitions */
static const struct stm32_adc_common_regs stm32h7_adc_common_regs = {
.csr = STM32H7_ADC_CSR,
.ccr = STM32H7_ADC_CCR,
.eoc1_msk = STM32H7_EOC_MST,
.eoc2_msk = STM32H7_EOC_SLV,
};
Expand Down Expand Up @@ -379,6 +388,61 @@ static void stm32_adc_irq_remove(struct platform_device *pdev,
}
}

static int stm32_adc_core_hw_start(struct device *dev)
{
struct stm32_adc_common *common = dev_get_drvdata(dev);
struct stm32_adc_priv *priv = to_stm32_adc_priv(common);
int ret;

ret = regulator_enable(priv->vref);
if (ret < 0) {
dev_err(dev, "vref enable failed\n");
return ret;
}

if (priv->bclk) {
ret = clk_prepare_enable(priv->bclk);
if (ret < 0) {
dev_err(dev, "bus clk enable failed\n");
goto err_regulator_disable;
}
}

if (priv->aclk) {
ret = clk_prepare_enable(priv->aclk);
if (ret < 0) {
dev_err(dev, "adc clk enable failed\n");
goto err_bclk_disable;
}
}

writel_relaxed(priv->ccr_bak, priv->common.base + priv->cfg->regs->ccr);

return 0;

err_bclk_disable:
if (priv->bclk)
clk_disable_unprepare(priv->bclk);
err_regulator_disable:
regulator_disable(priv->vref);

return ret;
}

static void stm32_adc_core_hw_stop(struct device *dev)
{
struct stm32_adc_common *common = dev_get_drvdata(dev);
struct stm32_adc_priv *priv = to_stm32_adc_priv(common);

/* Backup CCR that may be lost (depends on power state to achieve) */
priv->ccr_bak = readl_relaxed(priv->common.base + priv->cfg->regs->ccr);
if (priv->aclk)
clk_disable_unprepare(priv->aclk);
if (priv->bclk)
clk_disable_unprepare(priv->bclk);
regulator_disable(priv->vref);
}

static int stm32_adc_probe(struct platform_device *pdev)
{
struct stm32_adc_priv *priv;
Expand All @@ -393,6 +457,7 @@ static int stm32_adc_probe(struct platform_device *pdev)
priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
if (!priv)
return -ENOMEM;
platform_set_drvdata(pdev, &priv->common);

priv->cfg = (const struct stm32_adc_priv_cfg *)
of_match_device(dev->driver->of_match_table, dev)->data;
Expand All @@ -410,89 +475,71 @@ static int stm32_adc_probe(struct platform_device *pdev)
return ret;
}

ret = regulator_enable(priv->vref);
if (ret < 0) {
dev_err(&pdev->dev, "vref enable failed\n");
return ret;
}

ret = regulator_get_voltage(priv->vref);
if (ret < 0) {
dev_err(&pdev->dev, "vref get voltage failed, %d\n", ret);
goto err_regulator_disable;
}
priv->common.vref_mv = ret / 1000;
dev_dbg(&pdev->dev, "vref+=%dmV\n", priv->common.vref_mv);

priv->aclk = devm_clk_get(&pdev->dev, "adc");
if (IS_ERR(priv->aclk)) {
ret = PTR_ERR(priv->aclk);
if (ret == -ENOENT) {
priv->aclk = NULL;
} else {
if (ret != -ENOENT) {
dev_err(&pdev->dev, "Can't get 'adc' clock\n");
goto err_regulator_disable;
}
}

if (priv->aclk) {
ret = clk_prepare_enable(priv->aclk);
if (ret < 0) {
dev_err(&pdev->dev, "adc clk enable failed\n");
goto err_regulator_disable;
return ret;
}
priv->aclk = NULL;
}

priv->bclk = devm_clk_get(&pdev->dev, "bus");
if (IS_ERR(priv->bclk)) {
ret = PTR_ERR(priv->bclk);
if (ret == -ENOENT) {
priv->bclk = NULL;
} else {
if (ret != -ENOENT) {
dev_err(&pdev->dev, "Can't get 'bus' clock\n");
goto err_aclk_disable;
return ret;
}
priv->bclk = NULL;
}

if (priv->bclk) {
ret = clk_prepare_enable(priv->bclk);
if (ret < 0) {
dev_err(&pdev->dev, "adc clk enable failed\n");
goto err_aclk_disable;
}
pm_runtime_get_noresume(dev);
pm_runtime_set_active(dev);
pm_runtime_set_autosuspend_delay(dev, STM32_ADC_CORE_SLEEP_DELAY_MS);
pm_runtime_use_autosuspend(dev);
pm_runtime_enable(dev);

ret = stm32_adc_core_hw_start(dev);
if (ret)
goto err_pm_stop;

ret = regulator_get_voltage(priv->vref);
if (ret < 0) {
dev_err(&pdev->dev, "vref get voltage failed, %d\n", ret);
goto err_hw_stop;
}
priv->common.vref_mv = ret / 1000;
dev_dbg(&pdev->dev, "vref+=%dmV\n", priv->common.vref_mv);

ret = priv->cfg->clk_sel(pdev, priv);
if (ret < 0)
goto err_bclk_disable;
goto err_hw_stop;

ret = stm32_adc_irq_probe(pdev, priv);
if (ret < 0)
goto err_bclk_disable;

platform_set_drvdata(pdev, &priv->common);
goto err_hw_stop;

ret = of_platform_populate(np, NULL, NULL, &pdev->dev);
if (ret < 0) {
dev_err(&pdev->dev, "failed to populate DT children\n");
goto err_irq_remove;
}

pm_runtime_mark_last_busy(dev);
pm_runtime_put_autosuspend(dev);

return 0;

err_irq_remove:
stm32_adc_irq_remove(pdev, priv);

err_bclk_disable:
if (priv->bclk)
clk_disable_unprepare(priv->bclk);

err_aclk_disable:
if (priv->aclk)
clk_disable_unprepare(priv->aclk);

err_regulator_disable:
regulator_disable(priv->vref);
err_hw_stop:
stm32_adc_core_hw_stop(dev);
err_pm_stop:
pm_runtime_disable(dev);
pm_runtime_set_suspended(dev);
pm_runtime_put_noidle(dev);

return ret;
}
Expand All @@ -502,17 +549,39 @@ static int stm32_adc_remove(struct platform_device *pdev)
struct stm32_adc_common *common = platform_get_drvdata(pdev);
struct stm32_adc_priv *priv = to_stm32_adc_priv(common);

pm_runtime_get_sync(&pdev->dev);
of_platform_depopulate(&pdev->dev);
stm32_adc_irq_remove(pdev, priv);
if (priv->bclk)
clk_disable_unprepare(priv->bclk);
if (priv->aclk)
clk_disable_unprepare(priv->aclk);
regulator_disable(priv->vref);
stm32_adc_core_hw_stop(&pdev->dev);
pm_runtime_disable(&pdev->dev);
pm_runtime_set_suspended(&pdev->dev);
pm_runtime_put_noidle(&pdev->dev);

return 0;
}

#if defined(CONFIG_PM)
static int stm32_adc_core_runtime_suspend(struct device *dev)
{
stm32_adc_core_hw_stop(dev);

return 0;
}

static int stm32_adc_core_runtime_resume(struct device *dev)
{
return stm32_adc_core_hw_start(dev);
}
#endif

static const struct dev_pm_ops stm32_adc_core_pm_ops = {
SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
pm_runtime_force_resume)
SET_RUNTIME_PM_OPS(stm32_adc_core_runtime_suspend,
stm32_adc_core_runtime_resume,
NULL)
};

static const struct stm32_adc_priv_cfg stm32f4_adc_priv_cfg = {
.regs = &stm32f4_adc_common_regs,
.clk_sel = stm32f4_adc_clk_sel,
Expand Down Expand Up @@ -552,6 +621,7 @@ static struct platform_driver stm32_adc_driver = {
.driver = {
.name = "stm32-adc-core",
.of_match_table = stm32_adc_of_match,
.pm = &stm32_adc_core_pm_ops,
},
};
module_platform_driver(stm32_adc_driver);
Expand Down
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