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mmc: sdhci: Avoid unnecessary ->set_clock()

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To avoid glitches on the clock line, the card clock is disabled when making
timing changes. Do not do that separately for HISPD and UHS settings.

Tested-by: Haibo Chen <haibo.chen@nxp.com>
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Link: https://lore.kernel.org/r/20221128133259.38305-4-adrian.hunter@intel.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
This commit is contained in:
Adrian Hunter 2022-11-28 15:32:58 +02:00 committed by Ulf Hansson
parent e026a3f917
commit beaba9e46c
1 changed files with 14 additions and 23 deletions
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37
drivers/mmc/host/sdhci.c
View file

@ -2403,8 +2403,21 @@ void sdhci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
if (host->version >= SDHCI_SPEC_300) {
u16 clk, ctrl_2;
/*
* According to SDHCI Spec v3.00, if the Preset Value
* Enable in the Host Control 2 register is set, we
* need to reset SD Clock Enable before changing High
* Speed Enable to avoid generating clock glitches.
*/
clk = sdhci_readw(host, SDHCI_CLOCK_CONTROL);
if (clk & SDHCI_CLOCK_CARD_EN) {
clk &= ~SDHCI_CLOCK_CARD_EN;
sdhci_writew(host, clk, SDHCI_CLOCK_CONTROL);
}
sdhci_writeb(host, ctrl, SDHCI_HOST_CONTROL);
if (!host->preset_enabled) {
sdhci_writeb(host, ctrl, SDHCI_HOST_CONTROL);
/*
* We only need to set Driver Strength if the
* preset value enable is not set.
@ -2427,30 +2440,8 @@ void sdhci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
sdhci_writew(host, ctrl_2, SDHCI_HOST_CONTROL2);
host->drv_type = ios->drv_type;
} else {
/*
* According to SDHC Spec v3.00, if the Preset Value
* Enable in the Host Control 2 register is set, we
* need to reset SD Clock Enable before changing High
* Speed Enable to avoid generating clock gliches.
*/
/* Reset SD Clock Enable */
clk = sdhci_readw(host, SDHCI_CLOCK_CONTROL);
clk &= ~SDHCI_CLOCK_CARD_EN;
sdhci_writew(host, clk, SDHCI_CLOCK_CONTROL);
sdhci_writeb(host, ctrl, SDHCI_HOST_CONTROL);
/* Re-enable SD Clock */
host->ops->set_clock(host, host->clock);
}
/* Reset SD Clock Enable */
clk = sdhci_readw(host, SDHCI_CLOCK_CONTROL);
clk &= ~SDHCI_CLOCK_CARD_EN;
sdhci_writew(host, clk, SDHCI_CLOCK_CONTROL);
host->ops->set_uhs_signaling(host, ios->timing);
host->timing = ios->timing;