[PATCH 8/9] pinctrl: samsung: Add runtime PM support

[Marek Szyprowski <m.szyprowski@samsung.com>]

This patch adds runtime power management support to Samsung pin controller
driver. It uses recently introduced property to mark some pin states as
suitable for power off. When all pins for given controller are set to this
special state, the controller is able to enter runtime suspend state. This
in turn might allow to turn respective power domain off to reduce power
consumption.

This patch moves saving driver state to runtime pm callbacks and implements
system sleep suspend/resume callbacks with pm_runtime_force_suspend/resume
helpers to keep the runtime pm state consistent with the hardware both
during runtime and system sleep transitions.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
---
 drivers/pinctrl/samsung/pinctrl-samsung.c | 24 ++++++++++++++++++++++--
 drivers/pinctrl/samsung/pinctrl-samsung.h |  1 +
 2 files changed, 23 insertions(+), 2 deletions(-)

diff --git a/drivers/pinctrl/samsung/pinctrl-samsung.c b/drivers/pinctrl/samsung/pinctrl-samsung.c
index 301169d2b6e1..c741e93d65b8 100644
--- a/drivers/pinctrl/samsung/pinctrl-samsung.c
+++ b/drivers/pinctrl/samsung/pinctrl-samsung.c
@@ -28,6 +28,7 @@
 #include <linux/gpio.h>
 #include <linux/irqdomain.h>
 #include <linux/of_device.h>
+#include <linux/pm_runtime.h>
 #include <linux/spinlock.h>
 
 #include "../core.h"
@@ -378,6 +379,17 @@ static void samsung_pinmux_setup(struct pinctrl_dev *pctldev, unsigned selector,
 		shift -= 32;
 		reg += 4;
 	}
+	if (func->rpm_active) {
+		if (!(bank->rpm_map & (1 << pin_offset))) {
+			bank->rpm_map |= 1 << pin_offset;
+			pm_runtime_get_sync(drvdata->dev);
+		}
+	} else {
+		if ((bank->rpm_map & (1 << pin_offset))) {
+			bank->rpm_map &= ~(1 << pin_offset);
+			pm_runtime_put(drvdata->dev);
+		}
+	}
 
 	spin_lock_irqsave(&bank->slock, flags);
 
@@ -427,6 +439,8 @@ static int samsung_pinconf_rw(struct pinctrl_dev *pctldev, unsigned int pin,
 	if (cfg_type >= PINCFG_TYPE_NUM || !type->fld_width[cfg_type])
 		return -EINVAL;
 
+	pm_runtime_get_sync(drvdata->dev);
+
 	width = type->fld_width[cfg_type];
 	cfg_reg = type->reg_offset[cfg_type];
 
@@ -449,6 +463,8 @@ static int samsung_pinconf_rw(struct pinctrl_dev *pctldev, unsigned int pin,
 
 	spin_unlock_irqrestore(&bank->slock, flags);
 
+	pm_runtime_put(drvdata->dev);
+
 	return 0;
 }
 
@@ -1096,6 +1112,8 @@ static int samsung_pinctrl_probe(struct platform_device *pdev)
 		ctrl->retention_init(drvdata);
 
 	platform_set_drvdata(pdev, drvdata);
+	pm_runtime_set_active(dev);
+	pm_runtime_enable(dev);
 
 	return 0;
 }
@@ -1242,8 +1260,10 @@ static int samsung_pinctrl_resume(struct device *dev)
 MODULE_DEVICE_TABLE(of, samsung_pinctrl_dt_match);
 
 static const struct dev_pm_ops samsung_pinctrl_pm_ops = {
-	SET_LATE_SYSTEM_SLEEP_PM_OPS(samsung_pinctrl_suspend,
-				     samsung_pinctrl_resume)
+	SET_RUNTIME_PM_OPS(samsung_pinctrl_suspend,
+			   samsung_pinctrl_resume, NULL)
+	SET_LATE_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
+				     pm_runtime_force_resume)
 };
 
 static struct platform_driver samsung_pinctrl_driver = {
diff --git a/drivers/pinctrl/samsung/pinctrl-samsung.h b/drivers/pinctrl/samsung/pinctrl-samsung.h
index edeafa00abd3..ccb24ec46796 100644
--- a/drivers/pinctrl/samsung/pinctrl-samsung.h
+++ b/drivers/pinctrl/samsung/pinctrl-samsung.h
@@ -172,6 +172,7 @@ struct samsung_pin_bank {
 	const char	*name;
 
 	u32		pin_base;
+	u32		rpm_map;
 	void		*soc_priv;
 	struct device_node *of_node;
 	struct samsung_pinctrl_drv_data *drvdata;
-- 
1.9.1