* Balaji T K <balajitk@xxxxxx> [110530 07:23]:
> 4 micro seconds is not enough for PBIAS if MMC regulator is
> enabled from MMC regulator OFF.
> Increase the delay for PBIAS to stabilize.
> Wait for PBIAS and timeout if not.
>
> Resolves MMC/SD failure on OMAP4
> "Pbias Voltage is not same as LDO"
>
> Signed-off-by: Balaji T K <balajitk@xxxxxx>
> ---
> arch/arm/mach-omap2/hsmmc.c | 13 ++++++++++---
> 1 files changed, 10 insertions(+), 3 deletions(-)
>
> diff --git a/arch/arm/mach-omap2/hsmmc.c b/arch/arm/mach-omap2/hsmmc.c
> index b2f30be..3f8dc16 100644
> --- a/arch/arm/mach-omap2/hsmmc.c
> +++ b/arch/arm/mach-omap2/hsmmc.c
> @@ -145,6 +145,7 @@ static void omap4_hsmmc1_after_set_reg(struct device *dev, int slot,
> int power_on, int vdd)
> {
> u32 reg;
> + unsigned long timeout;
>
> if (power_on) {
> reg = omap4_ctrl_pad_readl(control_pbias_offset);
> @@ -157,9 +158,15 @@ static void omap4_hsmmc1_after_set_reg(struct device *dev, int slot,
> OMAP4_MMC1_PWRDNZ_MASK |
> OMAP4_USBC1_ICUSB_PWRDNZ_MASK);
> omap4_ctrl_pad_writel(reg, control_pbias_offset);
> - /* 4 microsec delay for comparator to generate an error*/
> - udelay(4);
> - reg = omap4_ctrl_pad_readl(control_pbias_offset);
> +
> + timeout = jiffies + msecs_to_jiffies(5);
> + do {
> + reg = omap4_ctrl_pad_readl(control_pbias_offset);
> + if (!(reg & OMAP4_MMC1_PBIASLITE_VMODE_ERROR_MASK))
> + break;
> + udelay(100);
> + } while (!time_after(jiffies, timeout));
> +
> if (reg & OMAP4_MMC1_PBIASLITE_VMODE_ERROR_MASK) {
> pr_err("Pbias Voltage is not same as LDO\n");
> /* Caution : On VMODE_ERROR Power Down MMC IO */
Actually, can you check if you can use usleep_range here as recommended
by checkpatch.pl?
Tony
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