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mmc: mtk-sd: increase the minimum bus frequency 

With a 48MHz input clock, the lowest bus frequency can be as low as
48000000 / (4 * 4095) = 2930Hz. Such an extremely low frequency will cause
the mmc framework take seconds to finish the initialization.

Limiting the minimum bus frequency to a slightly higher value can solve the
issue without any side effects.

Reviewed-by: Jaehoon Chung <jh80.chung@samsung.com>
Signed-off-by: Weijie Gao <weijie.gao@mediatek.com>
This commit is contained in:
Weijie Gao 2021-04-20 16:37:10 +08:00 committed by Peng Fan
parent 97c8cb524c
commit 3a3672cc37
1 changed files with 5 additions and 0 deletions
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5
drivers/mmc/mtk-sd.c
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@ -232,6 +232,8 @@
#define SCLK_CYCLES_SHIFT 20
#define MIN_BUS_CLK 200000
#define CMD_INTS_MASK \
(MSDC_INT_CMDRDY | MSDC_INT_RSPCRCERR | MSDC_INT_CMDTMO)
@ -1639,6 +1641,9 @@ static int msdc_drv_probe(struct udevice *dev)
else
cfg->f_min = host->src_clk_freq / (4 * 4095);
if (cfg->f_min < MIN_BUS_CLK)
cfg->f_min = MIN_BUS_CLK;
if (cfg->f_max < cfg->f_min || cfg->f_max > host->src_clk_freq)
cfg->f_max = host->src_clk_freq;