[U-Boot] [PATCH v2] imx: nitrogen6x: mx6qsabrelite: Add support for DVI monitors

[Robert Winkler]

A little background is probably appropriate for this patch.

Since "the beginning" of usage of the SABRE Lite and Nitrogen6x
boards, DVI detection has been somewhat broken.

Some (most) DVI monitors don't produce the "HPD" bit in
the PHY_STAT0 register, but do show proper toggling of the
RX_SENSE0..3 bits.

Creating a new the bit-mask to include all five bits and
modifying the 'hdmidet' command and internal detection
routines allows these monitors to function properly in U-Boot.

A related patch to our kernels allows things to work under
Linux:
        https://github.com/boundarydevices/linux-imx6/commit/7d8752905c118af9063738a533227de0b2f6ecd4

Signed-off-by: Robert Winkler <robert.winkler at boundarydevices.com>
---
Change from v1:
- Use Eric Nelson's description as commit message

 arch/arm/imx-common/cmd_hdmidet.c             | 3 +--
 arch/arm/include/asm/arch-mx6/mxc_hdmi.h      | 3 +++
 board/boundary/nitrogen6x/nitrogen6x.c        | 2 +-
 board/freescale/mx6qsabrelite/mx6qsabrelite.c | 2 +-
 4 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/arch/arm/imx-common/cmd_hdmidet.c b/arch/arm/imx-common/cmd_hdmidet.c
index 794bf50..ce0b26e 100644
--- a/arch/arm/imx-common/cmd_hdmidet.c
+++ b/arch/arm/imx-common/cmd_hdmidet.c
@@ -27,8 +27,7 @@
 static int do_hdmidet(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 {
 	struct hdmi_regs *hdmi	= (struct hdmi_regs *)HDMI_ARB_BASE_ADDR;
-	u8 reg = readb(&hdmi->phy_stat0) & HDMI_PHY_HPD;
-	return (reg&HDMI_PHY_HPD) ? 0 : 1;
+	return (readb(&hdmi->phy_stat0) & HDMI_DVI_STAT) ? 0 : 1;
 }
 
 U_BOOT_CMD(hdmidet, 1, 1, do_hdmidet,
diff --git a/arch/arm/include/asm/arch-mx6/mxc_hdmi.h b/arch/arm/include/asm/arch-mx6/mxc_hdmi.h
index 9dccb3f..1b55b05 100644
--- a/arch/arm/include/asm/arch-mx6/mxc_hdmi.h
+++ b/arch/arm/include/asm/arch-mx6/mxc_hdmi.h
@@ -896,6 +896,9 @@ enum {
 	HDMI_PHY_HPD = 0x02,
 	HDMI_PHY_TX_PHY_LOCK = 0x01,
 
+/* Convenience macro RX_SENSE | HPD */
+	HDMI_DVI_STAT = 0xF2,
+
 /* PHY_I2CM_SLAVE_ADDR field values */
 	HDMI_PHY_I2CM_SLAVE_ADDR_PHY_GEN2 = 0x69,
 	HDMI_PHY_I2CM_SLAVE_ADDR_HEAC_PHY = 0x49,
diff --git a/board/boundary/nitrogen6x/nitrogen6x.c b/board/boundary/nitrogen6x/nitrogen6x.c
index 8f0f9b8..bb09a6a 100644
--- a/board/boundary/nitrogen6x/nitrogen6x.c
+++ b/board/boundary/nitrogen6x/nitrogen6x.c
@@ -477,7 +477,7 @@ struct display_info_t {
 static int detect_hdmi(struct display_info_t const *dev)
 {
 	struct hdmi_regs *hdmi	= (struct hdmi_regs *)HDMI_ARB_BASE_ADDR;
-	return readb(&hdmi->phy_stat0) & HDMI_PHY_HPD;
+	return readb(&hdmi->phy_stat0) & HDMI_DVI_STAT;
 }
 
 static void enable_hdmi(struct display_info_t const *dev)
diff --git a/board/freescale/mx6qsabrelite/mx6qsabrelite.c b/board/freescale/mx6qsabrelite/mx6qsabrelite.c
index 862bc30..559b082 100644
--- a/board/freescale/mx6qsabrelite/mx6qsabrelite.c
+++ b/board/freescale/mx6qsabrelite/mx6qsabrelite.c
@@ -449,7 +449,7 @@ struct display_info_t {
 static int detect_hdmi(struct display_info_t const *dev)
 {
 	struct hdmi_regs *hdmi	= (struct hdmi_regs *)HDMI_ARB_BASE_ADDR;
-	return readb(&hdmi->phy_stat0) & HDMI_PHY_HPD;
+	return readb(&hdmi->phy_stat0) & HDMI_DVI_STAT;
 }
 
 static void enable_hdmi(struct display_info_t const *dev)
-- 
1.8.3.2