[U-Boot] [PATCH 09/10] gpio: s3c: Fix the GPIO driver

[Marek Vasut]

The GPIO driver didn't correctly compute the bank offset
from the GPIO number and caused random writes into the
GPIO block address space. Fix the driver so it actually
does the writes correctly. While at it, make use of the
clrsetbits_le32() mechanisms.

Signed-off-by: Marek Vasut <marex at denx.de>
Cc: Kyungmin Park <kyungmin.park at samsung.com>
Cc: Lukasz Majewski <l.majewski at samsung.com>
Cc: Minkyu Kang <mk7.kang at samsung.com>
Cc: Vladimir Zapolskiy <vz at mleia.com>
---
 drivers/gpio/s3c2440_gpio.c | 75 +++++++++++++++++++++++++--------------------
 1 file changed, 42 insertions(+), 33 deletions(-)

diff --git a/drivers/gpio/s3c2440_gpio.c b/drivers/gpio/s3c2440_gpio.c
index e1e2d3f..d6c7eeb 100644
--- a/drivers/gpio/s3c2440_gpio.c
+++ b/drivers/gpio/s3c2440_gpio.c
@@ -8,53 +8,50 @@
 #include <asm/arch/s3c2440.h>
 #include <asm/gpio.h>
 #include <asm/io.h>
+#include <errno.h>
 
 #define GPIO_INPUT  0x0
 #define GPIO_OUTPUT 0x1
 
-/* 0x4 means that we want DAT and not CON register */
-#define GPIO_PORT(x)	((((x) >> 5) & 0x3) + 0x4)
-#define GPIO_BIT(x)		((x) & 0x3f)
+#define S3C_GPIO_CON	0x0
+#define S3C_GPIO_DAT	0x4
 
-/*
- * It's how we calculate the full port address
- * We have to get the number of the port + 1 (Port A is at 0x56000001 ...)
- * We move it at the second digit, and finally we add 0x4 because we want
- * to modify GPIO DAT and not CON
- */
-#define GPIO_FULLPORT(x) (S3C24X0_GPIO_BASE | ((GPIO_PORT(gpio) + 1) << 1))
+static uint32_t s3c_gpio_get_bank_addr(unsigned gpio)
+{
+	/* There is up to 16 pins per bank, one bank is 0x10 big. */
+	uint32_t addr = gpio & ~0xf;
+
+	if (addr >= 0x80 && addr != 0xd0) {	/* Wrong GPIO bank. */
+		printf("Invalid GPIO bank (bank %02x)\n", addr);
+		return 0xffffffff;
+	}
+
+	return addr | S3C24X0_GPIO_BASE;
+}
 
 int gpio_set_value(unsigned gpio, int value)
 {
-	unsigned l = readl(GPIO_FULLPORT(gpio));
-	unsigned bit;
-	unsigned port = GPIO_FULLPORT(gpio);
-
-	/*
-	 * All GPIO Port have a configuration on
-	 * 2 bits excepted the first GPIO (A) which
-	 * have only 1 bit of configuration.
-	 */
-	if (!GPIO_PORT(gpio))
-		bit = (0x1 << GPIO_BIT(gpio));
-	else
-		bit = (0x3 << GPIO_BIT(gpio));
+	uint32_t addr = s3c_gpio_get_bank_addr(gpio);
+
+	if (addr == 0xffffffff)
+		return -EINVAL;
 
 	if (value)
-		l |= bit;
+		setbits_le32(addr | S3C_GPIO_DAT, 1 << (gpio & 0xf));
 	else
-		l &= ~bit;
+		clrbits_le32(addr | S3C_GPIO_DAT, 1 << (gpio & 0xf));
 
-	return writel(l, port);
+	return 0;
 }
 
 int gpio_get_value(unsigned gpio)
 {
-	unsigned l = readl(GPIO_FULLPORT(gpio));
+	uint32_t addr = s3c_gpio_get_bank_addr(gpio);
+
+	if (addr == 0xffffffff)
+		return -EINVAL;
 
-	if (GPIO_PORT(gpio) == 0) /* PORT A */
-		return (l >> GPIO_BIT(gpio)) & 0x1;
-	return (l >> GPIO_BIT(gpio)) & 0x3;
+	return !!(readl(addr | S3C_GPIO_DAT) & (1 << (gpio & 0xf)));
 }
 
 int gpio_request(unsigned gpio, const char *label)
@@ -67,13 +64,25 @@ int gpio_free(unsigned gpio)
 	return 0;
 }
 
+static int s3c_gpio_direction(unsigned gpio, uint8_t dir)
+{
+	uint32_t addr = s3c_gpio_get_bank_addr(gpio);
+	const uint32_t mask = 0x3 << ((gpio & 0xf) << 1);
+	const uint32_t dirm = dir << ((gpio & 0xf) << 1);
+
+	if (addr == 0xffffffff)
+		return -EINVAL;
+
+	clrsetbits_le32(addr | S3C_GPIO_CON, mask, dirm);
+	return 0;
+}
+
 int gpio_direction_input(unsigned gpio)
 {
-	return writel(GPIO_INPUT << GPIO_BIT(gpio), GPIO_FULLPORT(gpio));
+	return s3c_gpio_direction(gpio, GPIO_INPUT);
 }
 
 int gpio_direction_output(unsigned gpio, int value)
 {
-	writel(GPIO_OUTPUT << GPIO_BIT(gpio), GPIO_FULLPORT(gpio));
-	return gpio_set_value(gpio, value);
+	return s3c_gpio_direction(gpio, GPIO_OUTPUT);
 }
-- 
2.1.1