* Pais, Allen <allen.pais@xxxxxx> [100121 02:50]:
> 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);
To me it looks like both of these two patches should be done in a generic
way in the so every board that has this issue can specify it in the
platform data. No point adding the same code to each board-*.c file that
may have this issue. Maybe add it to arch/arm/mach-omap2/i2c.c instead?
Regards,
Tony
> 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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