1 files changed, 217 insertions, 86 deletions

diff --git a/drivers/iio/adc/stm32-adc.c b/drivers/iio/adc/stm32-adc.c
index 378411853d75..205e1699f954 100644
--- a/drivers/iio/adc/stm32-adc.c
+++ b/drivers/iio/adc/stm32-adc.c
@@ -22,6 +22,7 @@
 #include <linux/iopoll.h>
 #include <linux/module.h>
 #include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
 #include <linux/of.h>
 #include <linux/of_device.h>
 
@@ -148,6 +149,7 @@ enum stm32h7_adc_dmngt {
 #define STM32_ADC_MAX_SMP		7	/* SMPx range is [0..7] */
 #define STM32_ADC_TIMEOUT_US		100000
 #define STM32_ADC_TIMEOUT	(msecs_to_jiffies(STM32_ADC_TIMEOUT_US / 1000))
+#define STM32_ADC_HW_STOP_DELAY_MS	100
 
 #define STM32_DMA_BUFFER_SIZE		PAGE_SIZE
 
@@ -199,11 +201,13 @@ struct stm32_adc_trig_info {
  * @calfact_s: Calibration offset for single ended channels
  * @calfact_d: Calibration offset in differential
  * @lincalfact: Linearity calibration factor
+ * @calibrated: Indicates calibration status
  */
 struct stm32_adc_calib {
 	u32			calfact_s;
 	u32			calfact_d;
 	u32			lincalfact[STM32H7_LINCALFACT_NUM];
+	bool			calibrated;
 };
 
 /**
@@ -251,7 +255,6 @@ struct stm32_adc;
  * @trigs:		external trigger sources
  * @clk_required:	clock is required
  * @has_vregready:	vregready status flag presence
- * @selfcalib:		optional routine for self-calibration
  * @prepare:		optional prepare routine (power-up, enable)
  * @start_conv:		routine to start conversions
  * @stop_conv:		routine to stop conversions
@@ -264,7 +267,6 @@ struct stm32_adc_cfg {
 	struct stm32_adc_trig_info	*trigs;
 	bool clk_required;
 	bool has_vregready;
-	int (*selfcalib)(struct stm32_adc *);
 	int (*prepare)(struct stm32_adc *);
 	void (*start_conv)(struct stm32_adc *, bool dma);
 	void (*stop_conv)(struct stm32_adc *);
@@ -623,6 +625,47 @@ static void stm32_adc_set_res(struct stm32_adc *adc)
 	stm32_adc_writel(adc, res->reg, val);
 }
 
+static int stm32_adc_hw_stop(struct device *dev)
+{
+	struct stm32_adc *adc = dev_get_drvdata(dev);
+
+	if (adc->cfg->unprepare)
+		adc->cfg->unprepare(adc);
+
+	if (adc->clk)
+		clk_disable_unprepare(adc->clk);
+
+	return 0;
+}
+
+static int stm32_adc_hw_start(struct device *dev)
+{
+	struct stm32_adc *adc = dev_get_drvdata(dev);
+	int ret;
+
+	if (adc->clk) {
+		ret = clk_prepare_enable(adc->clk);
+		if (ret)
+			return ret;
+	}
+
+	stm32_adc_set_res(adc);
+
+	if (adc->cfg->prepare) {
+		ret = adc->cfg->prepare(adc);
+		if (ret)
+			goto err_clk_dis;
+	}
+
+	return 0;
+
+err_clk_dis:
+	if (adc->clk)
+		clk_disable_unprepare(adc->clk);
+
+	return ret;
+}
+
 /**
  * stm32f4_adc_start_conv() - Start conversions for regular channels.
  * @adc: stm32 adc instance
@@ -777,6 +820,7 @@ static void stm32h7_adc_disable(struct stm32_adc *adc)
 /**
  * stm32h7_adc_read_selfcalib() - read calibration shadow regs, save result
  * @adc: stm32 adc instance
+ * Note: Must be called once ADC is enabled, so LINCALRDYW[1..6] are writable
  */
 static int stm32h7_adc_read_selfcalib(struct stm32_adc *adc)
 {
@@ -784,11 +828,6 @@ static int stm32h7_adc_read_selfcalib(struct stm32_adc *adc)
 	int i, ret;
 	u32 lincalrdyw_mask, val;
 
-	/* Enable adc so LINCALRDYW1..6 bits are writable */
-	ret = stm32h7_adc_enable(adc);
-	if (ret)
-		return ret;
-
 	/* Read linearity calibration */
 	lincalrdyw_mask = STM32H7_LINCALRDYW6;
 	for (i = STM32H7_LINCALFACT_NUM - 1; i >= 0; i--) {
@@ -801,7 +840,7 @@ static int stm32h7_adc_read_selfcalib(struct stm32_adc *adc)
 						   100, STM32_ADC_TIMEOUT_US);
 		if (ret) {
 			dev_err(&indio_dev->dev, "Failed to read calfact\n");
-			goto disable;
+			return ret;
 		}
 
 		val = stm32_adc_readl(adc, STM32H7_ADC_CALFACT2);
@@ -817,11 +856,9 @@ static int stm32h7_adc_read_selfcalib(struct stm32_adc *adc)
 	adc->cal.calfact_s >>= STM32H7_CALFACT_S_SHIFT;
 	adc->cal.calfact_d = (val & STM32H7_CALFACT_D_MASK);
 	adc->cal.calfact_d >>= STM32H7_CALFACT_D_SHIFT;
+	adc->cal.calibrated = true;
 
-disable:
-	stm32h7_adc_disable(adc);
-
-	return ret;
+	return 0;
 }
 
 /**
@@ -898,9 +935,9 @@ static int stm32h7_adc_restore_selfcalib(struct stm32_adc *adc)
 #define STM32H7_ADC_CALIB_TIMEOUT_US		100000
 
 /**
- * stm32h7_adc_selfcalib() - Procedure to calibrate ADC (from power down)
+ * stm32h7_adc_selfcalib() - Procedure to calibrate ADC
  * @adc: stm32 adc instance
- * Exit from power down, calibrate ADC, then return to power down.
+ * Note: Must be called once ADC is out of power down.
  */
 static int stm32h7_adc_selfcalib(struct stm32_adc *adc)
 {
@@ -908,9 +945,8 @@ static int stm32h7_adc_selfcalib(struct stm32_adc *adc)
 	int ret;
 	u32 val;
 
-	ret = stm32h7_adc_exit_pwr_down(adc);
-	if (ret)
-		return ret;
+	if (adc->cal.calibrated)
+		return true;
 
 	/*
 	 * Select calibration mode:
@@ -927,7 +963,7 @@ static int stm32h7_adc_selfcalib(struct stm32_adc *adc)
 					   STM32H7_ADC_CALIB_TIMEOUT_US);
 	if (ret) {
 		dev_err(&indio_dev->dev, "calibration failed\n");
-		goto pwr_dwn;
+		goto out;
 	}
 
 	/*
@@ -944,18 +980,13 @@ static int stm32h7_adc_selfcalib(struct stm32_adc *adc)
 					   STM32H7_ADC_CALIB_TIMEOUT_US);
 	if (ret) {
 		dev_err(&indio_dev->dev, "calibration failed\n");
-		goto pwr_dwn;
+		goto out;
 	}
 
+out:
 	stm32_adc_clr_bits(adc, STM32H7_ADC_CR,
 			   STM32H7_ADCALDIF | STM32H7_ADCALLIN);
 
-	/* Read calibration result for future reference */
-	ret = stm32h7_adc_read_selfcalib(adc);
-
-pwr_dwn:
-	stm32h7_adc_enter_pwr_down(adc);
-
 	return ret;
 }
 
@@ -972,19 +1003,28 @@ pwr_dwn:
  */
 static int stm32h7_adc_prepare(struct stm32_adc *adc)
 {
-	int ret;
+	int calib, ret;
 
 	ret = stm32h7_adc_exit_pwr_down(adc);
 	if (ret)
 		return ret;
 
+	ret = stm32h7_adc_selfcalib(adc);
+	if (ret < 0)
+		goto pwr_dwn;
+	calib = ret;
+
 	stm32_adc_writel(adc, STM32H7_ADC_DIFSEL, adc->difsel);
 
 	ret = stm32h7_adc_enable(adc);
 	if (ret)
 		goto pwr_dwn;
 
-	ret = stm32h7_adc_restore_selfcalib(adc);
+	/* Either restore or read calibration result for future reference */
+	if (calib)
+		ret = stm32h7_adc_restore_selfcalib(adc);
+	else
+		ret = stm32h7_adc_read_selfcalib(adc);
 	if (ret)
 		goto disable;
 
@@ -1174,6 +1214,7 @@ static int stm32_adc_single_conv(struct iio_dev *indio_dev,
 				 int *res)
 {
 	struct stm32_adc *adc = iio_priv(indio_dev);
+	struct device *dev = indio_dev->dev.parent;
 	const struct stm32_adc_regspec *regs = adc->cfg->regs;
 	long timeout;
 	u32 val;
@@ -1183,10 +1224,10 @@ static int stm32_adc_single_conv(struct iio_dev *indio_dev,
 
 	adc->bufi = 0;
 
-	if (adc->cfg->prepare) {
-		ret = adc->cfg->prepare(adc);
-		if (ret)
-			return ret;
+	ret = pm_runtime_get_sync(dev);
+	if (ret < 0) {
+		pm_runtime_put_noidle(dev);
+		return ret;
 	}
 
 	/* Apply sampling time settings */
@@ -1224,8 +1265,8 @@ static int stm32_adc_single_conv(struct iio_dev *indio_dev,
 
 	stm32_adc_conv_irq_disable(adc);
 
-	if (adc->cfg->unprepare)
-		adc->cfg->unprepare(adc);
+	pm_runtime_mark_last_busy(dev);
+	pm_runtime_put_autosuspend(dev);
 
 	return ret;
 }
@@ -1333,15 +1374,22 @@ static int stm32_adc_update_scan_mode(struct iio_dev *indio_dev,
 				      const unsigned long *scan_mask)
 {
 	struct stm32_adc *adc = iio_priv(indio_dev);
+	struct device *dev = indio_dev->dev.parent;
 	int ret;
 
+	ret = pm_runtime_get_sync(dev);
+	if (ret < 0) {
+		pm_runtime_put_noidle(dev);
+		return ret;
+	}
+
 	adc->num_conv = bitmap_weight(scan_mask, indio_dev->masklength);
 
 	ret = stm32_adc_conf_scan_seq(indio_dev, scan_mask);
-	if (ret)
-		return ret;
+	pm_runtime_mark_last_busy(dev);
+	pm_runtime_put_autosuspend(dev);
 
-	return 0;
+	return ret;
 }
 
 static int stm32_adc_of_xlate(struct iio_dev *indio_dev,
@@ -1371,12 +1419,23 @@ static int stm32_adc_debugfs_reg_access(struct iio_dev *indio_dev,
 					unsigned *readval)
 {
 	struct stm32_adc *adc = iio_priv(indio_dev);
+	struct device *dev = indio_dev->dev.parent;
+	int ret;
+
+	ret = pm_runtime_get_sync(dev);
+	if (ret < 0) {
+		pm_runtime_put_noidle(dev);
+		return ret;
+	}
 
 	if (!readval)
 		stm32_adc_writel(adc, reg, writeval);
 	else
 		*readval = stm32_adc_readl(adc, reg);
 
+	pm_runtime_mark_last_busy(dev);
+	pm_runtime_put_autosuspend(dev);
+
 	return 0;
 }
 
@@ -1459,21 +1518,22 @@ static int stm32_adc_dma_start(struct iio_dev *indio_dev)
 	return 0;
 }
 
-static int stm32_adc_buffer_postenable(struct iio_dev *indio_dev)
+static int __stm32_adc_buffer_postenable(struct iio_dev *indio_dev)
 {
 	struct stm32_adc *adc = iio_priv(indio_dev);
+	struct device *dev = indio_dev->dev.parent;
 	int ret;
 
-	if (adc->cfg->prepare) {
-		ret = adc->cfg->prepare(adc);
-		if (ret)
-			return ret;
+	ret = pm_runtime_get_sync(dev);
+	if (ret < 0) {
+		pm_runtime_put_noidle(dev);
+		return ret;
 	}
 
 	ret = stm32_adc_set_trig(indio_dev, indio_dev->trig);
 	if (ret) {
 		dev_err(&indio_dev->dev, "Can't set trigger\n");
-		goto err_unprepare;
+		goto err_pm_put;
 	}
 
 	ret = stm32_adc_dma_start(indio_dev);
@@ -1482,10 +1542,6 @@ static int stm32_adc_buffer_postenable(struct iio_dev *indio_dev)
 		goto err_clr_trig;
 	}
 
-	ret = iio_triggered_buffer_postenable(indio_dev);
-	if (ret < 0)
-		goto err_stop_dma;
-
 	/* Reset adc buffer index */
 	adc->bufi = 0;
 
@@ -1496,39 +1552,58 @@ static int stm32_adc_buffer_postenable(struct iio_dev *indio_dev)
 
 	return 0;
 
-err_stop_dma:
-	if (adc->dma_chan)
-		dmaengine_terminate_all(adc->dma_chan);
 err_clr_trig:
 	stm32_adc_set_trig(indio_dev, NULL);
-err_unprepare:
-	if (adc->cfg->unprepare)
-		adc->cfg->unprepare(adc);
+err_pm_put:
+	pm_runtime_mark_last_busy(dev);
+	pm_runtime_put_autosuspend(dev);
 
 	return ret;
 }
 
-static int stm32_adc_buffer_predisable(struct iio_dev *indio_dev)
+static int stm32_adc_buffer_postenable(struct iio_dev *indio_dev)
 {
-	struct stm32_adc *adc = iio_priv(indio_dev);
 	int ret;
 
+	ret = iio_triggered_buffer_postenable(indio_dev);
+	if (ret < 0)
+		return ret;
+
+	ret = __stm32_adc_buffer_postenable(indio_dev);
+	if (ret < 0)
+		iio_triggered_buffer_predisable(indio_dev);
+
+	return ret;
+}
+
+static void __stm32_adc_buffer_predisable(struct iio_dev *indio_dev)
+{
+	struct stm32_adc *adc = iio_priv(indio_dev);
+	struct device *dev = indio_dev->dev.parent;
+
 	adc->cfg->stop_conv(adc);
 	if (!adc->dma_chan)
 		stm32_adc_conv_irq_disable(adc);
 
-	ret = iio_triggered_buffer_predisable(indio_dev);
-	if (ret < 0)
-		dev_err(&indio_dev->dev, "predisable failed\n");
-
 	if (adc->dma_chan)
 		dmaengine_terminate_all(adc->dma_chan);
 
 	if (stm32_adc_set_trig(indio_dev, NULL))
 		dev_err(&indio_dev->dev, "Can't clear trigger\n");
 
-	if (adc->cfg->unprepare)
-		adc->cfg->unprepare(adc);
+	pm_runtime_mark_last_busy(dev);
+	pm_runtime_put_autosuspend(dev);
+}
+
+static int stm32_adc_buffer_predisable(struct iio_dev *indio_dev)
+{
+	int ret;
+
+	__stm32_adc_buffer_predisable(indio_dev);
+
+	ret = iio_triggered_buffer_predisable(indio_dev);
+	if (ret < 0)
+		dev_err(&indio_dev->dev, "predisable failed\n");
 
 	return ret;
 }
@@ -1867,32 +1942,17 @@ static int stm32_adc_probe(struct platform_device *pdev)
 		}
 	}
 
-	if (adc->clk) {
-		ret = clk_prepare_enable(adc->clk);
-		if (ret < 0) {
-			dev_err(&pdev->dev, "clk enable failed\n");
-			return ret;
-		}
-	}
-
 	ret = stm32_adc_of_get_resolution(indio_dev);
 	if (ret < 0)
-		goto err_clk_disable;
-	stm32_adc_set_res(adc);
-
-	if (adc->cfg->selfcalib) {
-		ret = adc->cfg->selfcalib(adc);
-		if (ret)
-			goto err_clk_disable;
-	}
+		return ret;
 
 	ret = stm32_adc_chan_of_init(indio_dev);
 	if (ret < 0)
-		goto err_clk_disable;
+		return ret;
 
 	ret = stm32_adc_dma_request(indio_dev);
 	if (ret < 0)
-		goto err_clk_disable;
+		return ret;
 
 	ret = iio_triggered_buffer_setup(indio_dev,
 					 &iio_pollfunc_store_time,
@@ -1903,15 +1963,35 @@ static int stm32_adc_probe(struct platform_device *pdev)
 		goto err_dma_disable;
 	}
 
+	/* Get stm32-adc-core PM online */
+	pm_runtime_get_noresume(dev);
+	pm_runtime_set_active(dev);
+	pm_runtime_set_autosuspend_delay(dev, STM32_ADC_HW_STOP_DELAY_MS);
+	pm_runtime_use_autosuspend(dev);
+	pm_runtime_enable(dev);
+
+	ret = stm32_adc_hw_start(dev);
+	if (ret)
+		goto err_buffer_cleanup;
+
 	ret = iio_device_register(indio_dev);
 	if (ret) {
 		dev_err(&pdev->dev, "iio dev register failed\n");
-		goto err_buffer_cleanup;
+		goto err_hw_stop;
 	}
 
+	pm_runtime_mark_last_busy(dev);
+	pm_runtime_put_autosuspend(dev);
+
 	return 0;
 
+err_hw_stop:
+	stm32_adc_hw_stop(dev);
+
 err_buffer_cleanup:
+	pm_runtime_disable(dev);
+	pm_runtime_set_suspended(dev);
+	pm_runtime_put_noidle(dev);
 	iio_triggered_buffer_cleanup(indio_dev);
 
 err_dma_disable:
@@ -1921,9 +2001,6 @@ err_dma_disable:
 				  adc->rx_buf, adc->rx_dma_buf);
 		dma_release_channel(adc->dma_chan);
 	}
-err_clk_disable:
-	if (adc->clk)
-		clk_disable_unprepare(adc->clk);
 
 	return ret;
 }
@@ -1933,7 +2010,12 @@ static int stm32_adc_remove(struct platform_device *pdev)
 	struct stm32_adc *adc = platform_get_drvdata(pdev);
 	struct iio_dev *indio_dev = iio_priv_to_dev(adc);
 
+	pm_runtime_get_sync(&pdev->dev);
 	iio_device_unregister(indio_dev);
+	stm32_adc_hw_stop(&pdev->dev);
+	pm_runtime_disable(&pdev->dev);
+	pm_runtime_set_suspended(&pdev->dev);
+	pm_runtime_put_noidle(&pdev->dev);
 	iio_triggered_buffer_cleanup(indio_dev);
 	if (adc->dma_chan) {
 		dma_free_coherent(adc->dma_chan->device->dev,
@@ -1941,12 +2023,62 @@ static int stm32_adc_remove(struct platform_device *pdev)
 				  adc->rx_buf, adc->rx_dma_buf);
 		dma_release_channel(adc->dma_chan);
 	}
-	if (adc->clk)
-		clk_disable_unprepare(adc->clk);
 
 	return 0;
 }
 
+#if defined(CONFIG_PM_SLEEP)
+static int stm32_adc_suspend(struct device *dev)
+{
+	struct stm32_adc *adc = dev_get_drvdata(dev);
+	struct iio_dev *indio_dev = iio_priv_to_dev(adc);
+
+	if (iio_buffer_enabled(indio_dev))
+		__stm32_adc_buffer_predisable(indio_dev);
+
+	return pm_runtime_force_suspend(dev);
+}
+
+static int stm32_adc_resume(struct device *dev)
+{
+	struct stm32_adc *adc = dev_get_drvdata(dev);
+	struct iio_dev *indio_dev = iio_priv_to_dev(adc);
+	int ret;
+
+	ret = pm_runtime_force_resume(dev);
+	if (ret < 0)
+		return ret;
+
+	if (!iio_buffer_enabled(indio_dev))
+		return 0;
+
+	ret = stm32_adc_update_scan_mode(indio_dev,
+					 indio_dev->active_scan_mask);
+	if (ret < 0)
+		return ret;
+
+	return __stm32_adc_buffer_postenable(indio_dev);
+}
+#endif
+
+#if defined(CONFIG_PM)
+static int stm32_adc_runtime_suspend(struct device *dev)
+{
+	return stm32_adc_hw_stop(dev);
+}
+
+static int stm32_adc_runtime_resume(struct device *dev)
+{
+	return stm32_adc_hw_start(dev);
+}
+#endif
+
+static const struct dev_pm_ops stm32_adc_pm_ops = {
+	SET_SYSTEM_SLEEP_PM_OPS(stm32_adc_suspend, stm32_adc_resume)
+	SET_RUNTIME_PM_OPS(stm32_adc_runtime_suspend, stm32_adc_runtime_resume,
+			   NULL)
+};
+
 static const struct stm32_adc_cfg stm32f4_adc_cfg = {
 	.regs = &stm32f4_adc_regspec,
 	.adc_info = &stm32f4_adc_info,
@@ -1961,7 +2093,6 @@ static const struct stm32_adc_cfg stm32h7_adc_cfg = {
 	.regs = &stm32h7_adc_regspec,
 	.adc_info = &stm32h7_adc_info,
 	.trigs = stm32h7_adc_trigs,
-	.selfcalib = stm32h7_adc_selfcalib,
 	.start_conv = stm32h7_adc_start_conv,
 	.stop_conv = stm32h7_adc_stop_conv,
 	.prepare = stm32h7_adc_prepare,
@@ -1974,7 +2105,6 @@ static const struct stm32_adc_cfg stm32mp1_adc_cfg = {
 	.adc_info = &stm32h7_adc_info,
 	.trigs = stm32h7_adc_trigs,
 	.has_vregready = true,
-	.selfcalib = stm32h7_adc_selfcalib,
 	.start_conv = stm32h7_adc_start_conv,
 	.stop_conv = stm32h7_adc_stop_conv,
 	.prepare = stm32h7_adc_prepare,
@@ -1996,6 +2126,7 @@ static struct platform_driver stm32_adc_driver = {
 	.driver = {
 		.name = "stm32-adc",
 		.of_match_table = stm32_adc_of_match,
+		.pm = &stm32_adc_pm_ops,
 	},
 };
 module_platform_driver(stm32_adc_driver);