[U-Boot] [PATCH] mx6sabresd: Allow LVDS backlight to be functional after a kernel reboot

Marco Franchi
2016-06-08T18:05:31Z

Currently the LVDS backlight does not work in U-Boot after a ?reboot? comand
in the kernel.

This problem occurs because the kernel uses this pin in PWM mode and U-Boot
does not configure the backlight pin as GPIO functionality.

So fix the problem by explicitly configuring the backlight pin as GPIO in
U-Boot.

Signed-off-by: Marco Franchi <marco.franchi@nxp.com>
---
board/freescale/mx6sabresd/mx6sabresd.c | 18 ++++++++++++++++--
1 file changed, 16 insertions(+), 2 deletions(-)

diff --git a/board/freescale/mx6sabresd/mx6sabresd.c b/board/freescale/mx6sabresd/mx6sabresd.c
index 54ba36b..28c969d 100644
--- a/board/freescale/mx6sabresd/mx6sabresd.c
+++ b/board/freescale/mx6sabresd/mx6sabresd.c
@@ -177,13 +177,27 @@ static iomux_v3_cfg_t const rgb_pads[] = {
MX6_PAD_DISP0_DAT21__IPU1_DISP0_DATA21 | MUX_PAD_CTRL(NO_PAD_CTRL),
MX6_PAD_DISP0_DAT22__IPU1_DISP0_DATA22 | MUX_PAD_CTRL(NO_PAD_CTRL),
MX6_PAD_DISP0_DAT23__IPU1_DISP0_DATA23 | MUX_PAD_CTRL(NO_PAD_CTRL),
+};
+
+static iomux_v3_cfg_t const bl_pads[] = {
MX6_PAD_SD1_DAT3__GPIO1_IO21 | MUX_PAD_CTRL(NO_PAD_CTRL),
};

+static void enable_backlight(void)
+{
+ imx_iomux_v3_setup_multiple_pads(bl_pads, ARRAY_SIZE(bl_pads));
+ gpio_direction_output(DISP0_PWR_EN, 1);
+}
+
static void enable_rgb(struct display_info_t const *dev)
{
imx_iomux_v3_setup_multiple_pads(rgb_pads, ARRAY_SIZE(rgb_pads));
- gpio_direction_output(DISP0_PWR_EN, 1);
+ enable_backlight();
+}
+
+static void enable_lvds(struct display_info_t const *dev)
+{
+ enable_backlight();
}

static struct i2c_pads_info i2c_pad_info1 = {
@@ -370,7 +384,7 @@ struct display_info_t const displays[] = {{
.addr = 0,
.pixfmt = IPU_PIX_FMT_RGB666,
.detect = NULL,
- .enable = NULL,
+ .enable = enable_lvds,
.mode = {
.name = "Hannstar-XGA",
.refresh = 60,
--
2.7.4