[PATCH 2/2 V2] omap: 3630: Disable internal pull-ups

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>From 4aa00e5dd0bdf06b7eb421cef9e066670669691e Mon Sep 17 00:00:00 2001
From: Allen Pais <allen.pais@xxxxxx>
Date: Thu, 21 Jan 2010 21:54:04 +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 |   21 +++++++++++++++++++++
 arch/arm/plat-omap/include/plat/control.h    |   13 +++++++++++++
 2 files changed, 34 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..804e8f5 100755
--- a/arch/arm/mach-omap2/board-zoom-peripherals.c
+++ b/arch/arm/mach-omap2/board-zoom-peripherals.c
@@ -23,6 +23,7 @@
 
 #include <plat/common.h>
 #include <plat/usb.h>
+#include <plat/control.h>
 
 #include "mux.h"
 #include "mmc-twl4030.h"
@@ -257,6 +258,26 @@ 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 |= OMAP3630_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..4fb487a 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 OMAP36XX_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


- Allen --
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