[PATCH] mxs-mmc: fix clock rate setting
From: Koen Beel <hidden>
Date: 2011-06-30 10:13:35
Subsystem:
multimedia card (mmc), secure digital (sd) and sdio subsystem, the rest · Maintainers:
Ulf Hansson, Linus Torvalds
Fix clock rate setting on mxs-mmc driver. Previously, if div2 was zero the value for TIMING_CLOCK_RATE would have been 255 instead of 0. Also the limits for div1 (TIMING_CLOCK_DIVIDE) and div2 (TIMING_CLOCK_RATE + 1) where not correctly defined. Can easily be reproduced on mx23evk: default clock for high speed sdio cards is 50 MHz. With a SSP_CLK of 28.8 MHz (default), this resulted in an actual clock rate of about 56 kHz. Signed-off-by: Koen Beel <koen.beel.barco <at> gmail.com> --- drivers/mmc/host/mxs-mmc.c | 12 ++++++------ 1 files changed, 6 insertions(+), 6 deletions(-)
diff --git a/drivers/mmc/host/mxs-mmc.c b/drivers/mmc/host/mxs-mmc.c
index 99d39a6..3575330 100644
--- a/drivers/mmc/host/mxs-mmc.c
+++ b/drivers/mmc/host/mxs-mmc.c@@ -570,22 +570,22 @@ static void mxs_mmc_set_clk_rate(structmxs_mmc_host *host, unsigned int rate)
ssp_rate = clk_get_rate(host->clk);
- for (div1 = 2; div1 < 254; div1 += 2) {
+ for (div1 = 2; div1 <= 254; div1 += 2) {
div2 = ssp_rate / rate / div1;
- if (div2 < 0x100)
+ if (div2 <= 256)
break;
}
- if (div1 >= 254) {
+ if (div1 > 254) {
dev_err(mmc_dev(host->mmc),
"%s: cannot set clock to %d\n", __func__, rate);
return;
}
if (div2 == 0)
- bit_rate = ssp_rate / div1;
- else
- bit_rate = ssp_rate / div1 / div2;
+ div2 = 1;
+
+ bit_rate = ssp_rate / div1 / div2;
val = readl(host->base + HW_SSP_TIMING);
val &= ~(BM_SSP_TIMING_CLOCK_DIVIDE | BM_SSP_TIMING_CLOCK_RATE);
--
1.7.4.1