leandrof/linux
1
0
Fork 0
forked from Minki/linux
Code Issues Pull Requests Packages Projects Releases Wiki Activity

mmc: sdhci: fix minimum clock rate for v3 controller

Browse Source 
For SDHCIv3+ with programmable clock mode, minimal clock frequency is
still base clock / max(divider). Minimal programmable clock frequency is
always greater than minimal divided clock frequency. Without this patch,
SDHCI uses out-of-spec initial frequency when multiplier is big enough:

mmc1: mmc_rescan_try_freq: trying to init card at 468750 Hz
[for 480 MHz source clock divided by 1024]

The code in sdhci_calc_clk() already chooses a correct SDCLK clock mode.

Fixes: c3ed387762 ("mmc: sdhci: add support for programmable clock mode")
Cc: <stable@vger.kernel.org> # 4f6aa3264a: mmc: tegra: Only advertise UHS modes if IO regulator is present
Cc: <stable@vger.kernel.org>
Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Link: https://lore.kernel.org/r/ffb489519a446caffe7a0a05c4b9372bd52397bb.1579082031.git.mirq-linux@rere.qmqm.pl
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
This commit is contained in:
Michał Mirosław 2020-01-15 10:54:35 +01:00 committed by Ulf Hansson
parent f571389c0b
commit 2a187d0335
1 changed files with 6 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
drivers/mmc/host/sdhci.c
View File

@ -3913,11 +3913,13 @@ int sdhci_setup_host(struct sdhci_host *host)
if (host->ops->get_min_clock)
mmc->f_min = host->ops->get_min_clock(host);
else if (host->version >= SDHCI_SPEC_300) {
if (host->clk_mul) {
mmc->f_min = (host->max_clk * host->clk_mul) / 1024;
if (host->clk_mul)
max_clk = host->max_clk * host->clk_mul;
} else
mmc->f_min = host->max_clk / SDHCI_MAX_DIV_SPEC_300;
/*
* Divided Clock Mode minimum clock rate is always less than
* Programmable Clock Mode minimum clock rate.
*/
mmc->f_min = host->max_clk / SDHCI_MAX_DIV_SPEC_300;
} else
mmc->f_min = host->max_clk / SDHCI_MAX_DIV_SPEC_200;