[PATCH 2/2] OMAPDSS: HDMI: Disable HDMI DDC internal pull up

mythripk
2011-10-21T09:35:03Z

From: Mythri P K <mythripk@ti.com>

Disables the internal pull resistor for SDA and SCL enabled by
default as there are expernal pull up's to avoid the EDID read failure.

Signed-off-by: Ricardo Salveti de Araujo <ricardo.salveti@linaro.org>
Signed-off-by: Mythri P K <mythripk@ti.com>
---
arch/arm/mach-omap2/display.c | 18 ++++++++++++++++++
1 files changed, 18 insertions(+), 0 deletions(-)

diff --git a/arch/arm/mach-omap2/display.c b/arch/arm/mach-omap2/display.c
index f6590b9..3e70ef8 100644
--- a/arch/arm/mach-omap2/display.c
+++ b/arch/arm/mach-omap2/display.c
@@ -106,6 +106,9 @@ static const struct omap_dss_hwmod_data omap4_dss_hwmod_data[] __initdata = {

static void omap4_hdmi_mux_pads(void)
{
+ u32 reg;
+ u16 control_i2c_1;
+
/* PAD0_HDMI_HPD_PAD1_HDMI_CEC */
omap_mux_init_signal("hdmi_hpd",
OMAP_PIN_INPUT_PULLUP);
@@ -116,6 +119,21 @@ static void omap4_hdmi_mux_pads(void)
OMAP_PIN_INPUT_PULLUP);
omap_mux_init_signal("hdmi_ddc_sda",
OMAP_PIN_INPUT_PULLUP);
+
+ /*
+ * CONTROL_I2C_1: HDMI_DDC_SDA_PULLUPRESX (bit 28) and
+ * HDMI_DDC_SCL_PULLUPRESX (bit 24) are set to disable
+ * internal pull up resistor - This is a change needed in
+ * OMAP4460 and OMAP4430 ES2.3 as the external pull up
+ * are present. This is needed to avoid EDID read failure.
+ */
+ if (cpu_is_omap446x() || (omap_rev() > OMAP4430_REV_ES2_2)) {
+ control_i2c_1 = OMAP4_CTRL_MODULE_PAD_CORE_CONTROL_I2C_1;
+ reg = omap4_ctrl_pad_readl(control_i2c_1);
+ reg |= (OMAP4_HDMI_DDC_SDA_PULLUPRESX_MASK |
+ OMAP4_HDMI_DDC_SCL_PULLUPRESX_MASK);
+ omap4_ctrl_pad_writel(reg, control_i2c_1);
+ }
}

static int omap4_dsi_mux_pads(int dsi_id, unsigned lanes)
--
1.7.5.4