plat-nomadik: pull-up/down settings for GPIO resume

Suspend/resume didn't take care of pull-up and pull-down
settings and writing back the DAT register at resume can
change pull up/down settings, depending on pin input value.
Output values are now also restored.

Signed-off-by: Jonas Aaberg <jonas.aberg@stericsson.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

2 files changed, 60 insertions, 24 deletions

diff --git a/arch/arm/plat-nomadik/Kconfig b/arch/arm/plat-nomadik/Kconfig
index 187f4e84bb22..ad25c963d437 100644
--- a/arch/arm/plat-nomadik/Kconfig
+++ b/arch/arm/plat-nomadik/Kconfig
@@ -25,4 +25,10 @@ config NOMADIK_GPIO
         help
           Support for the Nomadik GPIO controller.
 
+config NOMADIK_GPIO_PM
+        bool
+        depends on NOMADIK_GPIO && PM
+        help
+          Support PM for the Nomadik GPIO controller.
+
 endif
diff --git a/arch/arm/plat-nomadik/gpio.c b/arch/arm/plat-nomadik/gpio.c
index 971e5d3798e4..71682a87a878 100644
--- a/arch/arm/plat-nomadik/gpio.c
+++ b/arch/arm/plat-nomadik/gpio.c
@@ -30,11 +30,23 @@
 /*
  * The GPIO module in the Nomadik family of Systems-on-Chip is an
  * AMBA device, managing 32 pins and alternate functions.  The logic block
- * is currently only used in the Nomadik.
+ * is currently used in the Nomadik and ux500.
  *
  * Symbols in this file are called "nmk_gpio" for "nomadik gpio"
  */
 
+static const u32 backup_regs[] = {
+        NMK_GPIO_PDIS,
+        NMK_GPIO_DIR,
+        NMK_GPIO_AFSLA,
+        NMK_GPIO_AFSLB,
+        NMK_GPIO_SLPC,
+        NMK_GPIO_RIMSC,
+        NMK_GPIO_FIMSC,
+        NMK_GPIO_RWIMSC,
+        NMK_GPIO_FWIMSC,
+};
+
 struct nmk_gpio_chip {
         struct gpio_chip chip;
         void __iomem *addr;
@@ -47,7 +59,9 @@ struct nmk_gpio_chip {
         /* Keep track of configured edges */
         u32 edge_rising;
         u32 edge_falling;
-        u32 backup[10];
+        u32 backup[ARRAY_SIZE(backup_regs)];
+        /* Bitmap, 1 = pull up, 0 = pull down */
+        u32 pull;
 };
 
 static void __nmk_gpio_set_mode(struct nmk_gpio_chip *nmk_chip,
@@ -93,10 +107,13 @@ static void __nmk_gpio_set_pull(struct nmk_gpio_chip *nmk_chip,
                 pdis &= ~bit;
         writel(pdis, nmk_chip->addr + NMK_GPIO_PDIS);
 
-        if (pull == NMK_GPIO_PULL_UP)
+        if (pull == NMK_GPIO_PULL_UP) {
+                nmk_chip->pull |= bit;
                 writel(bit, nmk_chip->addr + NMK_GPIO_DATS);
-        else if (pull == NMK_GPIO_PULL_DOWN)
+        } else if (pull == NMK_GPIO_PULL_DOWN) {
+                nmk_chip->pull &= ~bit;
                 writel(bit, nmk_chip->addr + NMK_GPIO_DATC);
+        }
 }
 
 static void __nmk_gpio_make_input(struct nmk_gpio_chip *nmk_chip,
@@ -317,6 +334,15 @@ int nmk_gpio_set_pull(int gpio, enum nmk_gpio_pull pull)
 }
 
 /* Mode functions */
+/**
+ * nmk_gpio_set_mode() - set the mux mode of a gpio pin
+ * @gpio: pin number
+ * @gpio_mode: one of NMK_GPIO_ALT_GPIO, NMK_GPIO_ALT_A,
+ *             NMK_GPIO_ALT_B, and NMK_GPIO_ALT_C
+ *
+ * Sets the mode of the specified pin to one of the alternate functions or
+ * plain GPIO.
+ */
 int nmk_gpio_set_mode(int gpio, int gpio_mode)
 {
         struct nmk_gpio_chip *nmk_chip;
@@ -832,35 +858,39 @@ out:
         return ret;
 }
 
-#ifdef CONFIG_PM
+#ifdef CONFIG_NOMADIK_GPIO_PM
 static int nmk_gpio_pm(struct platform_device *dev, bool suspend)
 {
         struct nmk_gpio_chip *nmk_chip = platform_get_drvdata(dev);
         int i;
-        static const unsigned int regs[] = {
-                NMK_GPIO_DAT,
-                NMK_GPIO_PDIS,
-                NMK_GPIO_DIR,
-                NMK_GPIO_AFSLA,
-                NMK_GPIO_AFSLB,
-                NMK_GPIO_SLPC,
-                NMK_GPIO_RIMSC,
-                NMK_GPIO_FIMSC,
-                NMK_GPIO_RWIMSC,
-                NMK_GPIO_FWIMSC,
-        };
+        u32 dir;
+        u32 dat;
 
-        BUILD_BUG_ON(ARRAY_SIZE(nmk_chip->backup) != ARRAY_SIZE(regs));
-
-        /* XXX: is this sufficient? what about pull-up/down configuration? */
-
-        for (i = 0; i < ARRAY_SIZE(regs); i++) {
+        for (i = 0; i < ARRAY_SIZE(backup_regs); i++) {
                 if (suspend)
-                        nmk_chip->backup[i] = readl(nmk_chip->addr + regs[i]);
+                        nmk_chip->backup[i] = readl(nmk_chip->addr +
+                                                    backup_regs[i]);
                 else
-                        writel(nmk_chip->backup[i], nmk_chip->addr + regs[i]);
+                        writel(nmk_chip->backup[i],
+                               nmk_chip->addr + backup_regs[i]);
         }
 
+        if (!suspend) {
+                /*
+                 * Restore pull-up and pull-down on inputs and
+                 * outputs.
+                 */
+                dir = readl(nmk_chip->addr + NMK_GPIO_DIR);
+                dat = readl(nmk_chip->addr + NMK_GPIO_DAT);
+
+                writel((nmk_chip->pull & ~dir) |
+                       (dat & dir),
+                       nmk_chip->addr + NMK_GPIO_DATS);
+
+                writel((~nmk_chip->pull & ~dir) |
+                       (~dat & dir),
+                       nmk_chip->addr + NMK_GPIO_DATC);
+        }
         return 0;
 }