2 files changed, 153 insertions, 0 deletions

diff --git a/drivers/pinctrl/pinctrl-samsung.c b/drivers/pinctrl/pinctrl-samsung.c
index 055d0162098b..15db2580c145 100644
--- a/drivers/pinctrl/pinctrl-samsung.c
+++ b/drivers/pinctrl/pinctrl-samsung.c
@@ -28,6 +28,7 @@
 #include <linux/gpio.h>
 #include <linux/irqdomain.h>
 #include <linux/spinlock.h>
+#include <linux/syscore_ops.h>
 
 #include "core.h"
 #include "pinctrl-samsung.h"
@@ -48,6 +49,9 @@ static struct pin_config {
         { "samsung,pin-pud-pdn", PINCFG_TYPE_PUD_PDN },
 };
 
+/* Global list of devices (struct samsung_pinctrl_drv_data) */
+LIST_HEAD(drvdata_list);
+
 static unsigned int pin_base;
 
 static inline struct samsung_pin_bank *gc_to_pin_bank(struct gpio_chip *gc)
@@ -956,9 +960,145 @@ static int samsung_pinctrl_probe(struct platform_device *pdev)
                 ctrl->eint_wkup_init(drvdata);
 
         platform_set_drvdata(pdev, drvdata);
+
+        /* Add to the global list */
+        list_add_tail(&drvdata->node, &drvdata_list);
+
         return 0;
 }
 
+#ifdef CONFIG_PM
+
+/**
+ * samsung_pinctrl_suspend_dev - save pinctrl state for suspend for a device
+ *
+ * Save data for all banks handled by this device.
+ */
+static void samsung_pinctrl_suspend_dev(
+        struct samsung_pinctrl_drv_data *drvdata)
+{
+        struct samsung_pin_ctrl *ctrl = drvdata->ctrl;
+        void __iomem *virt_base = drvdata->virt_base;
+        int i;
+
+        for (i = 0; i < ctrl->nr_banks; i++) {
+                struct samsung_pin_bank *bank = &ctrl->pin_banks[i];
+                void __iomem *reg = virt_base + bank->pctl_offset;
+
+                u8 *offs = bank->type->reg_offset;
+                u8 *widths = bank->type->fld_width;
+                enum pincfg_type type;
+
+                /* Registers without a powerdown config aren't lost */
+                if (!widths[PINCFG_TYPE_CON_PDN])
+                        continue;
+
+                for (type = 0; type < PINCFG_TYPE_NUM; type++)
+                        if (widths[type])
+                                bank->pm_save[type] = readl(reg + offs[type]);
+
+                if (widths[PINCFG_TYPE_FUNC] * bank->nr_pins > 32) {
+                        /* Some banks have two config registers */
+                        bank->pm_save[PINCFG_TYPE_NUM] =
+                                readl(reg + offs[PINCFG_TYPE_FUNC] + 4);
+                        pr_debug("Save %s @ %p (con %#010x %08x)\n",
+                                 bank->name, reg,
+                                 bank->pm_save[PINCFG_TYPE_FUNC],
+                                 bank->pm_save[PINCFG_TYPE_NUM]);
+                } else {
+                        pr_debug("Save %s @ %p (con %#010x)\n", bank->name,
+                                 reg, bank->pm_save[PINCFG_TYPE_FUNC]);
+                }
+        }
+}
+
+/**
+ * samsung_pinctrl_resume_dev - restore pinctrl state from suspend for a device
+ *
+ * Restore one of the banks that was saved during suspend.
+ *
+ * We don't bother doing anything complicated to avoid glitching lines since
+ * we're called before pad retention is turned off.
+ */
+static void samsung_pinctrl_resume_dev(struct samsung_pinctrl_drv_data *drvdata)
+{
+        struct samsung_pin_ctrl *ctrl = drvdata->ctrl;
+        void __iomem *virt_base = drvdata->virt_base;
+        int i;
+
+        for (i = 0; i < ctrl->nr_banks; i++) {
+                struct samsung_pin_bank *bank = &ctrl->pin_banks[i];
+                void __iomem *reg = virt_base + bank->pctl_offset;
+
+                u8 *offs = bank->type->reg_offset;
+                u8 *widths = bank->type->fld_width;
+                enum pincfg_type type;
+
+                /* Registers without a powerdown config aren't lost */
+                if (!widths[PINCFG_TYPE_CON_PDN])
+                        continue;
+
+                if (widths[PINCFG_TYPE_FUNC] * bank->nr_pins > 32) {
+                        /* Some banks have two config registers */
+                        pr_debug("%s @ %p (con %#010x %08x => %#010x %08x)\n",
+                                 bank->name, reg,
+                                 readl(reg + offs[PINCFG_TYPE_FUNC]),
+                                 readl(reg + offs[PINCFG_TYPE_FUNC] + 4),
+                                 bank->pm_save[PINCFG_TYPE_FUNC],
+                                 bank->pm_save[PINCFG_TYPE_NUM]);
+                        writel(bank->pm_save[PINCFG_TYPE_NUM],
+                               reg + offs[PINCFG_TYPE_FUNC] + 4);
+                } else {
+                        pr_debug("%s @ %p (con %#010x => %#010x)\n", bank->name,
+                                 reg, readl(reg + offs[PINCFG_TYPE_FUNC]),
+                                 bank->pm_save[PINCFG_TYPE_FUNC]);
+                }
+                for (type = 0; type < PINCFG_TYPE_NUM; type++)
+                        if (widths[type])
+                                writel(bank->pm_save[type], reg + offs[type]);
+        }
+}
+
+/**
+ * samsung_pinctrl_suspend - save pinctrl state for suspend
+ *
+ * Save data for all banks across all devices.
+ */
+static int samsung_pinctrl_suspend(void)
+{
+        struct samsung_pinctrl_drv_data *drvdata;
+
+        list_for_each_entry(drvdata, &drvdata_list, node) {
+                samsung_pinctrl_suspend_dev(drvdata);
+        }
+
+        return 0;
+}
+
+/**
+ * samsung_pinctrl_resume - restore pinctrl state for suspend
+ *
+ * Restore data for all banks across all devices.
+ */
+static void samsung_pinctrl_resume(void)
+{
+        struct samsung_pinctrl_drv_data *drvdata;
+
+        list_for_each_entry_reverse(drvdata, &drvdata_list, node) {
+                samsung_pinctrl_resume_dev(drvdata);
+        }
+}
+
+#else
+#define samsung_pinctrl_suspend         NULL
+#define samsung_pinctrl_resume          NULL
+#endif
+
+static struct syscore_ops samsung_pinctrl_syscore_ops = {
+        .suspend        = samsung_pinctrl_suspend,
+        .resume         = samsung_pinctrl_resume,
+};
+
 static const struct of_device_id samsung_pinctrl_dt_match[] = {
 #ifdef CONFIG_PINCTRL_EXYNOS
         { .compatible = "samsung,exynos4210-pinctrl",
@@ -987,6 +1127,14 @@ static struct platform_driver samsung_pinctrl_driver = {
 
 static int __init samsung_pinctrl_drv_register(void)
 {
+        /*
+         * Register syscore ops for save/restore of registers across suspend.
+         * It's important to ensure that this driver is running at an earlier
+         * initcall level than any arch-specific init calls that install syscore
+         * ops that turn off pad retention (like exynos_pm_resume).
+         */
+        register_syscore_ops(&samsung_pinctrl_syscore_ops);
+
         return platform_driver_register(&samsung_pinctrl_driver);
 }
 postcore_initcall(samsung_pinctrl_drv_register);
diff --git a/drivers/pinctrl/pinctrl-samsung.h b/drivers/pinctrl/pinctrl-samsung.h
index 7c7f9ebcd05b..9f5cc811b8cf 100644
--- a/drivers/pinctrl/pinctrl-samsung.h
+++ b/drivers/pinctrl/pinctrl-samsung.h
@@ -127,6 +127,7 @@ struct samsung_pin_bank_type {
  * @gpio_chip: GPIO chip of the bank.
  * @grange: linux gpio pin range supported by this bank.
  * @slock: spinlock protecting bank registers
+ * @pm_save: saved register values during suspend
  */
 struct samsung_pin_bank {
         struct samsung_pin_bank_type *type;
@@ -144,6 +145,8 @@ struct samsung_pin_bank {
         struct gpio_chip gpio_chip;
         struct pinctrl_gpio_range grange;
         spinlock_t slock;
+
+        u32 pm_save[PINCFG_TYPE_NUM + 1]; /* +1 to handle double CON registers*/
 };
 
 /**
@@ -189,6 +192,7 @@ struct samsung_pin_ctrl {
 
 /**
  * struct samsung_pinctrl_drv_data: wrapper for holding driver data together.
+ * @node: global list node
  * @virt_base: register base address of the controller.
  * @dev: device instance representing the controller.
  * @irq: interrpt number used by the controller to notify gpio interrupts.
@@ -201,6 +205,7 @@ struct samsung_pin_ctrl {
  * @nr_function: number of such pin functions.
  */
 struct samsung_pinctrl_drv_data {
+        struct list_head                node;
         void __iomem                    *virt_base;
         struct device                   *dev;
         int                             irq;