>From 9a6b34dca3ff8ce4a200df4b65037978e4325452 Mon Sep 17 00:00:00 2001
From: Allen Pais <allen.pais@xxxxxx>
Date: Thu, 21 Jan 2010 21:23:41 +0530
Subject: [PATCH 2/2] omap: 3630: Disable internal pull-ups
This patch disables the newly introduced internal pull-up feature in
OMAP3630, to use only the external HW resistor >=470 Ohm for the
assured functionality in HS mode.
While testing the I2C in High Speed mode, it was discovered that
without a proper pull-up resistor, there is data corruption during
multi-byte transfers. RTC(time_set) test case was used for testing.
>From the analysis done, it was concluded that ideally we need a
pull-up of 1.6K Ohm (recomended) or atleast 470 Ohm or greater for
assured performance in HS mode.
Signed-off-by: Moiz Sonasath <m-sonasath@xxxxxx>
Signed-off-by: Allen Pais <allen.pais@xxxxxx>
---
arch/arm/mach-omap2/board-zoom-peripherals.c | 20 ++++++++++++++++++++
arch/arm/plat-omap/include/plat/control.h | 13 +++++++++++++
2 files changed, 33 insertions(+), 0 deletions(-)
diff --git a/arch/arm/mach-omap2/board-zoom-peripherals.c b/arch/arm/mach-omap2/board-zoom-peripherals.c
index 5c8474c..3ddd51a 100755
--- a/arch/arm/mach-omap2/board-zoom-peripherals.c
+++ b/arch/arm/mach-omap2/board-zoom-peripherals.c
@@ -257,6 +257,26 @@ static struct i2c_board_info __initdata zoom_i2c_boardinfo[] = {
static int __init omap_i2c_init(void)
{
+ /* Disable OMAP 3630 internal pull-ups for I2Ci */
+ if (cpu_is_omap3630()) {
+ u32 prog_io;
+ prog_io = omap_ctrl_readl(OMAP343X_CONTROL_PROG_IO1);
+ /* Program (bit 19)=1 to disable internal pull-up on I2C1 */
+ prog_io |= OMAP3630_PRG_I2C1_PULLUPRESX;
+ /* Program (bit 0)=1 to disable internal pull-up on I2C2 */
+ prog_io |= OMAP3630_PRG_I2C2_PULLUPRESX;
+ omap_ctrl_writel(prog_io, OMAP343X_CONTROL_PROG_IO1);
+
+ prog_io = omap_ctrl_readl(OMAP36XX_CONTROL_PROG_IO2);
+ /* Program (bit 7)=1 to disable internal pull-up on I2C3 */
+ prog_io |= OMAP3630_PRG_I2C3_PULLUPRESX;
+ omap_ctrl_writel(prog_io, OMAP36XX_CONTROL_PROG_IO2);
+
+ prog_io = omap_ctrl_readl(OMAP36XX_CONTROL_PROG_IO_WKUP1);
+ /* Program (bit 5)=1 to disable internall pull-up on I2C4(SR) */
+ prog_io |= OMAP_3630_PRG_SR_PULLUPRESX;
+ omap_ctrl_writel(prog_io, OMAP36XX_CONTROL_PROG_IO_WKUP1);
+ }
omap_register_i2c_bus(1, 2400, zoom_i2c_boardinfo,
ARRAY_SIZE(zoom_i2c_boardinfo));
omap_register_i2c_bus(2, 400, NULL, 0);
diff --git a/arch/arm/plat-omap/include/plat/control.h b/arch/arm/plat-omap/include/plat/control.h
index a745d62..2213d4b 100644
--- a/arch/arm/plat-omap/include/plat/control.h
+++ b/arch/arm/plat-omap/include/plat/control.h
@@ -160,6 +160,8 @@
#define OMAP343X_CONTROL_SRAMLDO5 (OMAP2_CONTROL_GENERAL + 0x02C0)
#define OMAP343X_CONTROL_CSI (OMAP2_CONTROL_GENERAL + 0x02C4)
+/* 36xx-only CONTROL_GENERAL registor offsets */
+#define OMAP36XX_CONTROL_PROG_IO2 (OMAP2_CONTROL_GENERAL + 0x0198)
/* 34xx PADCONF register offsets */
#define OMAP343X_PADCONF_ETK(i) (OMAP2_CONTROL_PADCONFS + 0x5a8 + \
@@ -192,6 +194,9 @@
#define OMAP343X_CONTROL_WKUP_DEBOBS3 (OMAP343X_CONTROL_GENERAL_WKUP + 0x014)
#define OMAP343X_CONTROL_WKUP_DEBOBS4 (OMAP343X_CONTROL_GENERAL_WKUP + 0x018)
+/* 36xx-only GENERAL_WKUP register offsets */
+#define OMAP_36XX_CONTROL_PROG_IO_WKUP1 (OMAP343X_CONTROL_GENERAL_WKUP + 0x020)
+
/* 34xx D2D idle-related pins, handled by PM core */
#define OMAP3_PADCONF_SAD2D_MSTANDBY 0x250
#define OMAP3_PADCONF_SAD2D_IDLEACK 0x254
@@ -242,6 +247,8 @@
#define OMAP2_PBIASLITEVMODE0 (1 << 0)
/* CONTROL_PROG_IO1 bits */
+#define OMAP3630_PRG_I2C2_PULLUPRESX (1 << 0)
+#define OMAP3630_PRG_I2C1_PULLUPRESX (1 << 19)
#define OMAP3630_PRG_SDMMC1_SPEEDCTRL (1 << 20)
/* CONTROL_IVA2_BOOTMOD bits */
@@ -249,6 +256,12 @@
#define OMAP3_IVA2_BOOTMOD_MASK (0xf << 0)
#define OMAP3_IVA2_BOOTMOD_IDLE (0x1 << 0)
+/* CONTROL_PROG_IO2 bits on omap3630 */
+#define OMAP3630_PRG_I2C3_PULLUPRESX (1 << 7)
+
+/* CONTROL_PROG_IO_WKUP1 bits on omap3630 */
+#define OMAP3630_PRG_SR_PULLUPRESX (1 << 5)
+
/* CONTROL_PADCONF_X bits */
#define OMAP3_PADCONF_WAKEUPEVENT0 (1 << 15)
#define OMAP3_PADCONF_WAKEUPENABLE0 (1 << 14)
--
1.6.3.3
--
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