[PATCH] spi: lpspi: enable runtime pm for lpspi

[Clark Wang]

	From: Han Xu <han.xu@xxxxxxx>

	Enable the runtime power management for lpspi module.

Signed-off-by: Han Xu <han.xu@xxxxxxx>
Reviewed-by: Frank Li <frank.li@xxxxxxx>
---
 drivers/spi/spi-fsl-lpspi.c | 117 ++++++++++++++++++++++++++++--------
 1 file changed, 92 insertions(+), 25 deletions(-)

diff --git a/drivers/spi/spi-fsl-lpspi.c b/drivers/spi/spi-fsl-lpspi.c
index 5802f188051b..3e935db5ff02 100644
--- a/drivers/spi/spi-fsl-lpspi.c
+++ b/drivers/spi/spi-fsl-lpspi.c
@@ -16,7 +16,9 @@
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_device.h>
+#include <linux/pinctrl/consumer.h>
 #include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
 #include <linux/slab.h>
 #include <linux/spi/spi.h>
 #include <linux/spi/spi_bitbang.h>
@@ -24,6 +26,8 @@
 
 #define DRIVER_NAME "fsl_lpspi"
 
+#define FSL_LPSPI_RPM_TIMEOUT 50 /* 50ms */
+
 /* i.MX7ULP LPSPI registers */
 #define IMX7ULP_VERID	0x0
 #define IMX7ULP_PARAM	0x4
@@ -150,13 +154,9 @@ static int lpspi_prepare_xfer_hardware(struct spi_controller *controller)
 				spi_controller_get_devdata(controller);
 	int ret;
 
-	ret = clk_prepare_enable(fsl_lpspi->clk_ipg);
-	if (ret)
-		return ret;
-
-	ret = clk_prepare_enable(fsl_lpspi->clk_per);
-	if (ret) {
-		clk_disable_unprepare(fsl_lpspi->clk_ipg);
+	ret = pm_runtime_get_sync(fsl_lpspi->dev);
+	if (ret < 0) {
+		dev_err(fsl_lpspi->dev, "failed to enable clock\n");
 		return ret;
 	}
 
@@ -168,8 +168,8 @@ static int lpspi_unprepare_xfer_hardware(struct spi_controller *controller)
 	struct fsl_lpspi_data *fsl_lpspi =
 				spi_controller_get_devdata(controller);
 
-	clk_disable_unprepare(fsl_lpspi->clk_ipg);
-	clk_disable_unprepare(fsl_lpspi->clk_per);
+	pm_runtime_mark_last_busy(fsl_lpspi->dev);
+	pm_runtime_put_autosuspend(fsl_lpspi->dev);
 
 	return 0;
 }
@@ -476,6 +476,45 @@ static irqreturn_t fsl_lpspi_isr(int irq, void *dev_id)
 	return IRQ_NONE;
 }
 
+int fsl_lpspi_runtime_resume(struct device *dev)
+{
+	struct fsl_lpspi_data *fsl_lpspi = dev_get_drvdata(dev);
+	int ret;
+
+	ret = clk_prepare_enable(fsl_lpspi->clk_per);
+	if (ret)
+		return ret;
+
+	ret = clk_prepare_enable(fsl_lpspi->clk_ipg);
+	if (ret) {
+		clk_disable_unprepare(fsl_lpspi->clk_per);
+		return ret;
+	}
+
+	return 0;
+}
+
+int fsl_lpspi_runtime_suspend(struct device *dev)
+{
+	struct fsl_lpspi_data *fsl_lpspi = dev_get_drvdata(dev);
+
+	clk_disable_unprepare(fsl_lpspi->clk_per);
+	clk_disable_unprepare(fsl_lpspi->clk_ipg);
+
+	return 0;
+}
+
+static int fsl_lpspi_init_rpm(struct fsl_lpspi_data *fsl_lpspi)
+{
+	struct device *dev = fsl_lpspi->dev;
+
+	pm_runtime_enable(dev);
+	pm_runtime_set_autosuspend_delay(dev, FSL_LPSPI_RPM_TIMEOUT);
+	pm_runtime_use_autosuspend(dev);
+
+	return 0;
+}
+
 static int fsl_lpspi_probe(struct platform_device *pdev)
 {
 	struct fsl_lpspi_data *fsl_lpspi;
@@ -501,6 +540,7 @@ static int fsl_lpspi_probe(struct platform_device *pdev)
 
 	fsl_lpspi = spi_controller_get_devdata(controller);
 	fsl_lpspi->dev = &pdev->dev;
+	dev_set_drvdata(&pdev->dev, fsl_lpspi);
 	fsl_lpspi->is_slave = of_property_read_bool((&pdev->dev)->of_node,
 						    "spi-slave");
 
@@ -547,28 +587,21 @@ static int fsl_lpspi_probe(struct platform_device *pdev)
 		goto out_controller_put;
 	}
 
-	ret = clk_prepare_enable(fsl_lpspi->clk_ipg);
-	if (ret) {
-		dev_err(&pdev->dev,
-			"can't enable lpspi ipg clock, ret=%d\n", ret);
+	/* enable the clock */
+	ret = fsl_lpspi_init_rpm(fsl_lpspi);
+	if (ret)
 		goto out_controller_put;
-	}
 
-	ret = clk_prepare_enable(fsl_lpspi->clk_per);
-	if (ret) {
-		dev_err(&pdev->dev,
-			"can't enable lpspi per clock, ret=%d\n", ret);
-		clk_disable_unprepare(fsl_lpspi->clk_ipg);
-		goto out_controller_put;
+	ret = pm_runtime_get_sync(fsl_lpspi->dev);
+	if (ret < 0) {
+		dev_err(fsl_lpspi->dev, "failed to enable clock\n");
+		return ret;
 	}
 
 	temp = readl(fsl_lpspi->base + IMX7ULP_PARAM);
 	fsl_lpspi->txfifosize = 1 << (temp & 0x0f);
 	fsl_lpspi->rxfifosize = 1 << ((temp >> 8) & 0x0f);
 
-	clk_disable_unprepare(fsl_lpspi->clk_per);
-	clk_disable_unprepare(fsl_lpspi->clk_ipg);
-
 	ret = devm_spi_register_controller(&pdev->dev, controller);
 	if (ret < 0) {
 		dev_err(&pdev->dev, "spi_register_controller error.\n");
@@ -589,16 +622,50 @@ static int fsl_lpspi_remove(struct platform_device *pdev)
 	struct fsl_lpspi_data *fsl_lpspi =
 				spi_controller_get_devdata(controller);
 
-	clk_disable_unprepare(fsl_lpspi->clk_per);
-	clk_disable_unprepare(fsl_lpspi->clk_ipg);
+	pm_runtime_disable(fsl_lpspi->dev);
+
+	spi_master_put(controller);
+
+	return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int fsl_lpspi_suspend(struct device *dev)
+{
+	int ret;
+
+	pinctrl_pm_select_sleep_state(dev);
+	ret = pm_runtime_force_suspend(dev);
+	return ret;
+}
+
+static int fsl_lpspi_resume(struct device *dev)
+{
+	int ret;
+
+	ret = pm_runtime_force_resume(dev);
+	if (ret) {
+		dev_err(dev, "Error in resume: %d\n", ret);
+		return ret;
+	}
+
+	pinctrl_pm_select_default_state(dev);
 
 	return 0;
 }
+#endif /* CONFIG_PM_SLEEP */
+
+static const struct dev_pm_ops fsl_lpspi_pm_ops = {
+	SET_RUNTIME_PM_OPS(fsl_lpspi_runtime_suspend,
+				fsl_lpspi_runtime_resume, NULL)
+	SET_SYSTEM_SLEEP_PM_OPS(fsl_lpspi_suspend, fsl_lpspi_resume)
+};
 
 static struct platform_driver fsl_lpspi_driver = {
 	.driver = {
 		.name = DRIVER_NAME,
 		.of_match_table = fsl_lpspi_dt_ids,
+		.pm = &fsl_lpspi_pm_ops,
 	},
 	.probe = fsl_lpspi_probe,
 	.remove = fsl_lpspi_remove,
-- 
2.17.1