2 files changed, 172 insertions, 40 deletions

diff --git a/arch/arm/plat-nomadik/gpio.c b/arch/arm/plat-nomadik/gpio.c
index bf299cf34594..9f1b72056270 100644
--- a/arch/arm/plat-nomadik/gpio.c
+++ b/arch/arm/plat-nomadik/gpio.c
@@ -47,6 +47,8 @@ static const u32 backup_regs[] = {
 	NMK_GPIO_FWIMSC,
 };
 
+#define NMK_GPIO_PER_CHIP	32
+
 struct nmk_gpio_chip {
 	struct gpio_chip chip;
 	void __iomem *addr;
@@ -55,6 +57,7 @@ struct nmk_gpio_chip {
 	unsigned int parent_irq;
 	int secondary_parent_irq;
 	u32 (*get_secondary_status)(unsigned int bank);
+	void (*set_ioforce)(bool enable);
 	spinlock_t lock;
 	/* Keep track of configured edges */
 	u32 edge_rising;
@@ -64,6 +67,13 @@ struct nmk_gpio_chip {
 	u32 pull;
 };
 
+static struct nmk_gpio_chip *
+nmk_gpio_chips[DIV_ROUND_UP(ARCH_NR_GPIOS, NMK_GPIO_PER_CHIP)];
+
+static DEFINE_SPINLOCK(nmk_gpio_slpm_lock);
+
+#define NUM_BANKS ARRAY_SIZE(nmk_gpio_chips)
+
 static void __nmk_gpio_set_mode(struct nmk_gpio_chip *nmk_chip,
 				unsigned offset, int gpio_mode)
 {
@@ -138,8 +148,38 @@ static void __nmk_gpio_make_output(struct nmk_gpio_chip *nmk_chip,
 	__nmk_gpio_set_output(nmk_chip, offset, val);
 }
 
+static void __nmk_gpio_set_mode_safe(struct nmk_gpio_chip *nmk_chip,
+				     unsigned offset, int gpio_mode,
+				     bool glitch)
+{
+	u32 rwimsc;
+	u32 fwimsc;
+
+	if (glitch && nmk_chip->set_ioforce) {
+		u32 bit = BIT(offset);
+
+		rwimsc = readl(nmk_chip->addr + NMK_GPIO_RWIMSC);
+		fwimsc = readl(nmk_chip->addr + NMK_GPIO_FWIMSC);
+
+		/* Prevent spurious wakeups */
+		writel(rwimsc & ~bit, nmk_chip->addr + NMK_GPIO_RWIMSC);
+		writel(fwimsc & ~bit, nmk_chip->addr + NMK_GPIO_FWIMSC);
+
+		nmk_chip->set_ioforce(true);
+	}
+
+	__nmk_gpio_set_mode(nmk_chip, offset, gpio_mode);
+
+	if (glitch && nmk_chip->set_ioforce) {
+		nmk_chip->set_ioforce(false);
+
+		writel(rwimsc, nmk_chip->addr + NMK_GPIO_RWIMSC);
+		writel(fwimsc, nmk_chip->addr + NMK_GPIO_FWIMSC);
+	}
+}
+
 static void __nmk_config_pin(struct nmk_gpio_chip *nmk_chip, unsigned offset,
-			     pin_cfg_t cfg, bool sleep)
+			     pin_cfg_t cfg, bool sleep, unsigned int *slpmregs)
 {
 	static const char *afnames[] = {
 		[NMK_GPIO_ALT_GPIO]	= "GPIO",
@@ -164,6 +204,7 @@ static void __nmk_config_pin(struct nmk_gpio_chip *nmk_chip, unsigned offset,
 	int slpm = PIN_SLPM(cfg);
 	int output = PIN_DIR(cfg);
 	int val = PIN_VAL(cfg);
+	bool glitch = af == NMK_GPIO_ALT_C;
 
 	dev_dbg(nmk_chip->chip.dev, "pin %d [%#lx]: af %s, pull %s, slpm %s (%s%s)\n",
 		pin, cfg, afnames[af], pullnames[pull], slpmnames[slpm],
@@ -202,8 +243,116 @@ static void __nmk_config_pin(struct nmk_gpio_chip *nmk_chip, unsigned offset,
 		__nmk_gpio_set_pull(nmk_chip, offset, pull);
 	}
 
-	__nmk_gpio_set_slpm(nmk_chip, offset, slpm);
-	__nmk_gpio_set_mode(nmk_chip, offset, af);
+	/*
+	 * If we've backed up the SLPM registers (glitch workaround), modify
+	 * the backups since they will be restored.
+	 */
+	if (slpmregs) {
+		if (slpm == NMK_GPIO_SLPM_NOCHANGE)
+			slpmregs[nmk_chip->bank] |= BIT(offset);
+		else
+			slpmregs[nmk_chip->bank] &= ~BIT(offset);
+	} else
+		__nmk_gpio_set_slpm(nmk_chip, offset, slpm);
+
+	__nmk_gpio_set_mode_safe(nmk_chip, offset, af, glitch);
+}
+
+/*
+ * Safe sequence used to switch IOs between GPIO and Alternate-C mode:
+ *  - Save SLPM registers
+ *  - Set SLPM=0 for the IOs you want to switch and others to 1
+ *  - Configure the GPIO registers for the IOs that are being switched
+ *  - Set IOFORCE=1
+ *  - Modify the AFLSA/B registers for the IOs that are being switched
+ *  - Set IOFORCE=0
+ *  - Restore SLPM registers
+ *  - Any spurious wake up event during switch sequence to be ignored and
+ *    cleared
+ */
+static void nmk_gpio_glitch_slpm_init(unsigned int *slpm)
+{
+	int i;
+
+	for (i = 0; i < NUM_BANKS; i++) {
+		struct nmk_gpio_chip *chip = nmk_gpio_chips[i];
+		unsigned int temp = slpm[i];
+
+		if (!chip)
+			break;
+
+		slpm[i] = readl(chip->addr + NMK_GPIO_SLPC);
+		writel(temp, chip->addr + NMK_GPIO_SLPC);
+	}
+}
+
+static void nmk_gpio_glitch_slpm_restore(unsigned int *slpm)
+{
+	int i;
+
+	for (i = 0; i < NUM_BANKS; i++) {
+		struct nmk_gpio_chip *chip = nmk_gpio_chips[i];
+
+		if (!chip)
+			break;
+
+		writel(slpm[i], chip->addr + NMK_GPIO_SLPC);
+	}
+}
+
+static int __nmk_config_pins(pin_cfg_t *cfgs, int num, bool sleep)
+{
+	static unsigned int slpm[NUM_BANKS];
+	unsigned long flags;
+	bool glitch = false;
+	int ret = 0;
+	int i;
+
+	for (i = 0; i < num; i++) {
+		if (PIN_ALT(cfgs[i]) == NMK_GPIO_ALT_C) {
+			glitch = true;
+			break;
+		}
+	}
+
+	spin_lock_irqsave(&nmk_gpio_slpm_lock, flags);
+
+	if (glitch) {
+		memset(slpm, 0xff, sizeof(slpm));
+
+		for (i = 0; i < num; i++) {
+			int pin = PIN_NUM(cfgs[i]);
+			int offset = pin % NMK_GPIO_PER_CHIP;
+
+			if (PIN_ALT(cfgs[i]) == NMK_GPIO_ALT_C)
+				slpm[pin / NMK_GPIO_PER_CHIP] &= ~BIT(offset);
+		}
+
+		nmk_gpio_glitch_slpm_init(slpm);
+	}
+
+	for (i = 0; i < num; i++) {
+		struct nmk_gpio_chip *nmk_chip;
+		int pin = PIN_NUM(cfgs[i]);
+
+		nmk_chip = get_irq_chip_data(NOMADIK_GPIO_TO_IRQ(pin));
+		if (!nmk_chip) {
+			ret = -EINVAL;
+			break;
+		}
+
+		spin_lock(&nmk_chip->lock);
+		__nmk_config_pin(nmk_chip, pin - nmk_chip->chip.base,
+				 cfgs[i], sleep, glitch ? slpm : NULL);
+		spin_unlock(&nmk_chip->lock);
+	}
+
+	if (glitch)
+		nmk_gpio_glitch_slpm_restore(slpm);
+
+	spin_unlock_irqrestore(&nmk_gpio_slpm_lock, flags);
+
+	return ret;
 }
 
 /**
@@ -222,19 +371,7 @@ static void __nmk_config_pin(struct nmk_gpio_chip *nmk_chip, unsigned offset,
  */
 int nmk_config_pin(pin_cfg_t cfg, bool sleep)
 {
-	struct nmk_gpio_chip *nmk_chip;
-	int gpio = PIN_NUM(cfg);
-	unsigned long flags;
-
-	nmk_chip = get_irq_chip_data(NOMADIK_GPIO_TO_IRQ(gpio));
-	if (!nmk_chip)
-		return -EINVAL;
-
-	spin_lock_irqsave(&nmk_chip->lock, flags);
-	__nmk_config_pin(nmk_chip, gpio - nmk_chip->chip.base, cfg, sleep);
-	spin_unlock_irqrestore(&nmk_chip->lock, flags);
-
-	return 0;
+	return __nmk_config_pins(&cfg, 1, sleep);
 }
 EXPORT_SYMBOL(nmk_config_pin);
 
@@ -248,31 +385,13 @@ EXPORT_SYMBOL(nmk_config_pin);
  */
 int nmk_config_pins(pin_cfg_t *cfgs, int num)
 {
-	int ret = 0;
-	int i;
-
-	for (i = 0; i < num; i++) {
-		ret = nmk_config_pin(cfgs[i], false);
-		if (ret)
-			break;
-	}
-
-	return ret;
+	return __nmk_config_pins(cfgs, num, false);
 }
 EXPORT_SYMBOL(nmk_config_pins);
 
 int nmk_config_pins_sleep(pin_cfg_t *cfgs, int num)
 {
-	int ret = 0;
-	int i;
-
-	for (i = 0; i < num; i++) {
-		ret = nmk_config_pin(cfgs[i], true);
-		if (ret)
-			break;
-	}
-
-	return ret;
+	return __nmk_config_pins(cfgs, num, true);
 }
 EXPORT_SYMBOL(nmk_config_pins_sleep);
 
@@ -299,9 +418,13 @@ int nmk_gpio_set_slpm(int gpio, enum nmk_gpio_slpm mode)
 	if (!nmk_chip)
 		return -EINVAL;
 
-	spin_lock_irqsave(&nmk_chip->lock, flags);
+	spin_lock_irqsave(&nmk_gpio_slpm_lock, flags);
+	spin_lock(&nmk_chip->lock);
+
 	__nmk_gpio_set_slpm(nmk_chip, gpio - nmk_chip->chip.base, mode);
-	spin_unlock_irqrestore(&nmk_chip->lock, flags);
+
+	spin_unlock(&nmk_chip->lock);
+	spin_unlock_irqrestore(&nmk_gpio_slpm_lock, flags);
 
 	return 0;
 }
@@ -474,7 +597,9 @@ static int nmk_gpio_irq_set_wake(struct irq_data *d, unsigned int on)
 	if (!nmk_chip)
 		return -EINVAL;
 
-	spin_lock_irqsave(&nmk_chip->lock, flags);
+	spin_lock_irqsave(&nmk_gpio_slpm_lock, flags);
+	spin_lock(&nmk_chip->lock);
+
 #ifdef CONFIG_ARCH_U8500
 	if (cpu_is_u8500v2()) {
 		__nmk_gpio_set_slpm(nmk_chip, gpio,
@@ -483,7 +608,9 @@ static int nmk_gpio_irq_set_wake(struct irq_data *d, unsigned int on)
 	}
 #endif
 	__nmk_gpio_irq_modify(nmk_chip, gpio, WAKE, on);
-	spin_unlock_irqrestore(&nmk_chip->lock, flags);
+
+	spin_unlock(&nmk_chip->lock);
+	spin_unlock_irqrestore(&nmk_gpio_slpm_lock, flags);
 
 	return 0;
 }
@@ -826,6 +953,7 @@ static int __devinit nmk_gpio_probe(struct platform_device *dev)
 	nmk_chip->parent_irq = irq;
 	nmk_chip->secondary_parent_irq = secondary_irq;
 	nmk_chip->get_secondary_status = pdata->get_secondary_status;
+	nmk_chip->set_ioforce = pdata->set_ioforce;
 	spin_lock_init(&nmk_chip->lock);
 
 	chip = &nmk_chip->chip;
@@ -839,6 +967,9 @@ static int __devinit nmk_gpio_probe(struct platform_device *dev)
 	if (ret)
 		goto out_free;
 
+	BUG_ON(nmk_chip->bank >= ARRAY_SIZE(nmk_gpio_chips));
+
+	nmk_gpio_chips[nmk_chip->bank] = nmk_chip;
 	platform_set_drvdata(dev, nmk_chip);
 
 	nmk_gpio_init_irq(nmk_chip);
diff --git a/arch/arm/plat-nomadik/include/plat/gpio.h b/arch/arm/plat-nomadik/include/plat/gpio.h
index d108a326a0ab..e3a4837e86f4 100644
--- a/arch/arm/plat-nomadik/include/plat/gpio.h
+++ b/arch/arm/plat-nomadik/include/plat/gpio.h
@@ -84,6 +84,7 @@ struct nmk_gpio_platform_data {
 	int first_irq;
 	int num_gpio;
 	u32 (*get_secondary_status)(unsigned int bank);
+	void (*set_ioforce)(bool enable);
 };
 
 #endif /* __ASM_PLAT_GPIO_H */