[PATCH] spi: at91-usart: add power management support

From: Radu Pirea
Date: Wed Nov 21 2018 - 06:27:30 EST


This patch implements power management callback function for USART as
SPI driver.

Signed-off-by: Radu Pirea <radu_nicolae.pirea@xxxxxx>
Signed-off-by: Mark Brown <broonie@xxxxxxxxxx>
---
drivers/spi/spi-at91-usart.c | 61 ++++++++++++++++++++++++++++++++++++
1 file changed, 61 insertions(+)

diff --git a/drivers/spi/spi-at91-usart.c b/drivers/spi/spi-at91-usart.c
index a924657642fa..0b07c746453d 100644
--- a/drivers/spi/spi-at91-usart.c
+++ b/drivers/spi/spi-at91-usart.c
@@ -13,6 +13,7 @@
#include <linux/module.h>
#include <linux/of_gpio.h>
#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>

#include <linux/spi/spi.h>

@@ -399,6 +400,59 @@ static int at91_usart_spi_probe(struct platform_device *pdev)
return ret;
}

+__maybe_unused static int at91_usart_spi_runtime_suspend(struct device *dev)
+{
+ struct spi_controller *ctlr = dev_get_drvdata(dev);
+ struct at91_usart_spi *aus = spi_master_get_devdata(ctlr);
+
+ clk_disable_unprepare(aus->clk);
+ pinctrl_pm_select_sleep_state(dev);
+
+ return 0;
+}
+
+__maybe_unused static int at91_usart_spi_runtime_resume(struct device *dev)
+{
+ struct spi_controller *ctrl = dev_get_drvdata(dev);
+ struct at91_usart_spi *aus = spi_master_get_devdata(ctrl);
+
+ pinctrl_pm_select_default_state(dev);
+
+ return clk_prepare_enable(aus->clk);
+}
+
+__maybe_unused static int at91_usart_spi_suspend(struct device *dev)
+{
+ struct spi_controller *ctrl = dev_get_drvdata(dev);
+ int ret;
+
+ ret = spi_controller_suspend(ctrl);
+ if (ret)
+ return ret;
+
+ if (!pm_runtime_suspended(dev))
+ at91_usart_spi_runtime_suspend(dev);
+
+ return 0;
+}
+
+__maybe_unused static int at91_usart_spi_resume(struct device *dev)
+{
+ struct spi_controller *ctrl = dev_get_drvdata(dev);
+ struct at91_usart_spi *aus = spi_master_get_devdata(ctrl);
+ int ret;
+
+ if (!pm_runtime_suspended(dev)) {
+ ret = at91_usart_spi_runtime_resume(dev);
+ if (ret)
+ return ret;
+ }
+
+ at91_usart_spi_init(aus);
+
+ return spi_controller_resume(ctrl);
+}
+
static int at91_usart_spi_remove(struct platform_device *pdev)
{
struct spi_controller *ctlr = platform_get_drvdata(pdev);
@@ -409,6 +463,12 @@ static int at91_usart_spi_remove(struct platform_device *pdev)
return 0;
}

+static const struct dev_pm_ops at91_usart_spi_pm_ops = {
+ SET_SYSTEM_SLEEP_PM_OPS(at91_usart_spi_suspend, at91_usart_spi_resume)
+ SET_RUNTIME_PM_OPS(at91_usart_spi_runtime_suspend,
+ at91_usart_spi_runtime_resume, NULL)
+};
+
static const struct of_device_id at91_usart_spi_dt_ids[] = {
{ .compatible = "microchip,at91sam9g45-usart-spi"},
{ /* sentinel */}
@@ -419,6 +479,7 @@ MODULE_DEVICE_TABLE(of, at91_usart_spi_dt_ids);
static struct platform_driver at91_usart_spi_driver = {
.driver = {
.name = "at91_usart_spi",
+ .pm = &at91_usart_spi_pm_ops,
},
.probe = at91_usart_spi_probe,
.remove = at91_usart_spi_remove,
--
2.19.0.rc2