* Russell King <[email protected]> [060504 00:54]:
> On Thu, May 04, 2006 at 12:26:30AM -0700, Tony Lindgren wrote:
> > MMC spec says that we must not enable clock prior to the power
> > stabilizing. But at least omap16xx needs clock divisor configured
> > during MMC_POWER_UP.
>
> In which case it's probably better to treat MMC_POWER_UP the same as
> MMC_POWER_OFF and just use MMC_POWER_ON and wait for your host to
> complete it's power stabilisation. No need for this additional
> complexity.
Nice, that makes things cleaner. Here's the patch:
Change OMAP MMC to use MMC_POWER_UP to power-up the card,
and set clock divisor with MMC_POWER_ON. Also separate
clock divisor calculation into a separate function.
Signed-off-by: Tony Lindgren <[email protected]>
--- a/drivers/mmc/omap.c
+++ b/drivers/mmc/omap.c
@@ -893,48 +893,56 @@ static void mmc_omap_power(struct mmc_om
}
}
-static void mmc_omap_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
+static inline int mmc_omap_calc_divisor(struct mmc_host *mmc,
+ struct mmc_ios *ios)
{
struct mmc_omap_host *host = mmc_priv(mmc);
+ int func_clk_rate = clk_get_rate(host->fclk);
int dsor;
- int realclock, i;
-
- realclock = ios->clock;
if (ios->clock == 0)
- dsor = 0;
- else {
- int func_clk_rate = clk_get_rate(host->fclk);
-
- dsor = func_clk_rate / realclock;
- if (dsor < 1)
- dsor = 1;
+ return 0;
- if (func_clk_rate / dsor > realclock)
- dsor++;
+ dsor = func_clk_rate / ios->clock;
+ if (dsor < 1)
+ dsor = 1;
- if (dsor > 250)
- dsor = 250;
+ if (func_clk_rate / dsor > ios->clock)
dsor++;
- if (ios->bus_width == MMC_BUS_WIDTH_4)
- dsor |= 1 << 15;
- }
+ if (dsor > 250)
+ dsor = 250;
+ dsor++;
+
+ if (ios->bus_width == MMC_BUS_WIDTH_4)
+ dsor |= 1 << 15;
+
+ return dsor;
+}
+
+static void mmc_omap_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
+{
+ struct mmc_omap_host *host = mmc_priv(mmc);
+ int dsor;
+ int i;
+
+ dsor = mmc_omap_calc_divisor(mmc, ios);
+ host->bus_mode = ios->bus_mode;
+ host->hw_bus_mode = host->bus_mode;
switch (ios->power_mode) {
case MMC_POWER_OFF:
mmc_omap_power(host, 0);
break;
case MMC_POWER_UP:
- case MMC_POWER_ON:
+ /* Cannot touch dsor yet, just power up MMC */
mmc_omap_power(host, 1);
- dsor |= 1<<11;
+ return;
+ case MMC_POWER_ON:
+ dsor |= 1 << 11;
break;
}
- host->bus_mode = ios->bus_mode;
- host->hw_bus_mode = host->bus_mode;
-
clk_enable(host->fclk);
/* On insanely high arm_per frequencies something sometimes
@@ -943,11 +951,12 @@ static void mmc_omap_set_ios(struct mmc_
* Writing to the CON register twice seems to do the trick. */
for (i = 0; i < 2; i++)
OMAP_MMC_WRITE(host->base, CON, dsor);
- if (ios->power_mode == MMC_POWER_UP) {
+
+ if (ios->power_mode == MMC_POWER_ON) {
/* Send clock cycles, poll completion */
OMAP_MMC_WRITE(host->base, IE, 0);
OMAP_MMC_WRITE(host->base, STAT, 0xffff);
- OMAP_MMC_WRITE(host->base, CMD, 1<<7);
+ OMAP_MMC_WRITE(host->base, CMD, 1 << 7);
while (0 == (OMAP_MMC_READ(host->base, STAT) & 1));
OMAP_MMC_WRITE(host->base, STAT, 1);
}
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