pinctrl: samsung: Add infrastructure for pin-bank retention control

Pad retention control after suspend/resume cycle should be done from pin
controller driver instead of PMU (power management unit) driver to avoid
possible ordering and logical dependencies. Till now it worked fine only
because PMU driver registered its sys_ops after pin controller.

This patch adds infrastructure to handle pad retention during pin control
driver resume.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org>
Acked-by: Tomasz Figa <tomasz.figa@gmail.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/pinctrl/samsung/pinctrl-samsung.c

@@ -1060,6 +1060,13 @@ static int samsung_pinctrl_probe(struct platform_device *pdev)
 	if (res)
 		drvdata->irq = res->start;
 
+	if (ctrl->retention_data) {
+		drvdata->retention_ctrl = ctrl->retention_data->init(drvdata,
+							  ctrl->retention_data);
+		if (IS_ERR(drvdata->retention_ctrl))
+			return PTR_ERR(drvdata->retention_ctrl);
+	}
+
 	ret = samsung_gpiolib_register(pdev, drvdata);
 	if (ret)
 		return ret;
@@ -1126,6 +1133,8 @@ static void samsung_pinctrl_suspend_dev(
 
 	if (drvdata->suspend)
 		drvdata->suspend(drvdata);
+	if (drvdata->retention_ctrl && drvdata->retention_ctrl->enable)
+		drvdata->retention_ctrl->enable(drvdata);
 }
 
 /**
@@ -1173,6 +1182,9 @@ static void samsung_pinctrl_resume_dev(struct samsung_pinctrl_drv_data *drvdata)
 			if (widths[type])
 				writel(bank->pm_save[type], reg + offs[type]);
 	}
+
+	if (drvdata->retention_ctrl && drvdata->retention_ctrl->disable)
+		drvdata->retention_ctrl->disable(drvdata);
 }
 
 /**

drivers/pinctrl/samsung/pinctrl-samsung.h

@@ -184,11 +184,49 @@ struct samsung_pin_bank {
 	u32 pm_save[PINCFG_TYPE_NUM + 1]; /* +1 to handle double CON registers*/
 };
 
+/**
+ * struct samsung_retention_data: runtime pin-bank retention control data.
+ * @regs: array of PMU registers to control pad retention.
+ * @nr_regs: number of registers in @regs array.
+ * @value: value to store to registers to turn off retention.
+ * @refcnt: atomic counter if retention control affects more than one bank.
+ * @priv: retention control code private data
+ * @enable: platform specific callback to enter retention mode.
+ * @disable: platform specific callback to exit retention mode.
+ **/
+struct samsung_retention_ctrl {
+	const u32	*regs;
+	int		nr_regs;
+	u32		value;
+	atomic_t	*refcnt;
+	void		*priv;
+	void		(*enable)(struct samsung_pinctrl_drv_data *);
+	void		(*disable)(struct samsung_pinctrl_drv_data *);
+};
+
+/**
+ * struct samsung_retention_data: represent a pin-bank retention control data.
+ * @regs: array of PMU registers to control pad retention.
+ * @nr_regs: number of registers in @regs array.
+ * @value: value to store to registers to turn off retention.
+ * @refcnt: atomic counter if retention control affects more than one bank.
+ * @init: platform specific callback to initialize retention control.
+ **/
+struct samsung_retention_data {
+	const u32	*regs;
+	int		nr_regs;
+	u32		value;
+	atomic_t	*refcnt;
+	struct samsung_retention_ctrl *(*init)(struct samsung_pinctrl_drv_data *,
+					const struct samsung_retention_data *);
+};
+
 /**
  * struct samsung_pin_ctrl: represent a pin controller.
  * @pin_banks: list of pin banks included in this controller.
  * @nr_banks: number of pin banks.
  * @nr_ext_resources: number of the extra base address for pin banks.
+ * @retention_data: configuration data for retention control.
  * @eint_gpio_init: platform specific callback to setup the external gpio
  *	interrupts for the controller.
  * @eint_wkup_init: platform specific callback to setup the external wakeup
@@ -198,6 +236,7 @@ struct samsung_pin_ctrl {
 	const struct samsung_pin_bank_data *pin_banks;
 	u32		nr_banks;
 	int		nr_ext_resources;
+	const struct samsung_retention_data *retention_data;
 
 	int		(*eint_gpio_init)(struct samsung_pinctrl_drv_data *);
 	int		(*eint_wkup_init)(struct samsung_pinctrl_drv_data *);
@@ -219,6 +258,7 @@ struct samsung_pin_ctrl {
  * @nr_function: number of such pin functions.
  * @pin_base: starting system wide pin number.
  * @nr_pins: number of pins supported by the controller.
+ * @retention_ctrl: retention control runtime data.
  */
 struct samsung_pinctrl_drv_data {
 	struct list_head		node;
@@ -238,6 +278,8 @@ struct samsung_pinctrl_drv_data {
 	unsigned int			pin_base;
 	unsigned int			nr_pins;
 
+	struct samsung_retention_ctrl	*retention_ctrl;
+
 	void (*suspend)(struct samsung_pinctrl_drv_data *);
 	void (*resume)(struct samsung_pinctrl_drv_data *);
 };