* Pais, Allen <[email protected]> [100121 02:50]: > From 4aa00e5dd0bdf06b7eb421cef9e066670669691e Mon Sep 17 00:00:00 2001 > From: Allen Pais <[email protected]> > 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 <[email protected]> > Signed-off-by: Allen Pais <[email protected]> > --- > 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 -- > To unsubscribe from this list: send the line "unsubscribe linux-omap" in > the body of a message to [email protected] > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
