Re: MMC: 2/2 Fix MMC_POWER_UP on some OMAP boards

[Tony Lindgren <tony@atomide.com>]

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* Russell King <rmk+lkml@arm.linux.org.uk> [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:


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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 <tony@atomide.com>

--- 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);
 	}