[U-Boot] [PATCH] tegra2: Use new GPIO APIs in gpio_config_uart()

Stephen Warren
2011-10-06T22:52:22Z

... rather than open-coding the register accesses.

However, gpio_request() typically stores the "label" parameter in a global
data structure. This causes problems when called from gpio_config_uart(),
since the code is running before relocation. To solve this, pass a NULL
string to gpio_request(), and modify gpio_request() not to touch the string
if it's NULL.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
---
I tested this on Seaboard. With the code in the patch below, the UART works.
If I comment out the body of gpio_config_uart_seaboard(), the UART does not
work.

This patch should work with ToT U-Boot, but the context relies on the rename
of gpio_config_uart() to gpio_config_uart_seaboard() contained in:
http://patchwork.ozlabs.org/patch/118144/

board/nvidia/seaboard/seaboard.c | 18 ++----------------
drivers/gpio/tegra2_gpio.c | 6 ++++--
2 files changed, 6 insertions(+), 18 deletions(-)

diff --git a/board/nvidia/seaboard/seaboard.c b/board/nvidia/seaboard/seaboard.c
index 260a56d..4492c28 100644
--- a/board/nvidia/seaboard/seaboard.c
+++ b/board/nvidia/seaboard/seaboard.c
@@ -36,23 +36,9 @@
*/
void gpio_config_uart_seaboard(void)
{
- int gp = GPIO_PI3;
- struct gpio_ctlr *gpio = (struct gpio_ctlr *)NV_PA_GPIO_BASE;
- struct gpio_ctlr_bank *bank = &gpio->gpio_bank[GPIO_BANK(gp)];
- u32 val;
-
/* Enable UART via GPIO_PI3 (port 8, bit 3) so serial console works */
- val = readl(&bank->gpio_config[GPIO_PORT(gp)]);
- val |= 1 << GPIO_BIT(gp);
- writel(val, &bank->gpio_config[GPIO_PORT(gp)]);
-
- val = readl(&bank->gpio_out[GPIO_PORT(gp)]);
- val &= ~(1 << GPIO_BIT(gp));
- writel(val, &bank->gpio_out[GPIO_PORT(gp)]);
-
- val = readl(&bank->gpio_dir_out[GPIO_PORT(gp)]);
- val |= 1 << GPIO_BIT(gp);
- writel(val, &bank->gpio_dir_out[GPIO_PORT(gp)]);
+ gpio_request(GPIO_PI3, NULL);
+ gpio_direction_output(GPIO_PI3, 0);
}

void gpio_config_uart(void)
diff --git a/drivers/gpio/tegra2_gpio.c b/drivers/gpio/tegra2_gpio.c
index f686e80..22669b6 100644
--- a/drivers/gpio/tegra2_gpio.c
+++ b/drivers/gpio/tegra2_gpio.c
@@ -146,8 +146,10 @@ int gpio_request(int gp, const char *label)
if (gp >= MAX_NUM_GPIOS)
return -1;

- strncpy(gpio_names[gp].name, label, GPIO_NAME_SIZE);
- gpio_names[gp].name[GPIO_NAME_SIZE - 1] = '\0';
+ if (label != NULL) {
+ strncpy(gpio_names[gp].name, label, GPIO_NAME_SIZE);
+ gpio_names[gp].name[GPIO_NAME_SIZE - 1] = '\0';
+ }

/* Configure as a GPIO */
set_config(gp, 1);
--
1.7.0.4