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mmc: sdhci_am654: Clear HISPD_ENA in some lower speed modes

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According to the AM654x Data Manual[1], the setup timing in lower speed
modes can only be met if the controller uses a falling edge data launch.

To ensure this, the HIGH_SPEED_ENA (HOST_CONTROL[2]) bit should be
cleared in default speed, SD high speed, MMC high speed, SDR12 and SDR25
speed modes.

Use the sdhci writeb callback to implement this condition.

[1] http://www.ti.com/lit/gpn/am6546 Section 5.10.5.16.1

Signed-off-by: Faiz Abbas <faiz_abbas@ti.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
This commit is contained in:
Faiz Abbas 2019-04-01 18:28:04 +05:30 • committed by Ulf Hansson
parent 3b407b4f3a
commit e374e87538
2 changed files with 23 additions and 0 deletions
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1
drivers/mmc/host/Kconfig
View file

@ -994,6 +994,7 @@ config MMC_SDHCI_OMAP
config MMC_SDHCI_AM654
tristate "Support for the SDHCI Controller in TI's AM654 SOCs"
depends on MMC_SDHCI_PLTFM && OF
select MMC_SDHCI_IO_ACCESSORS
help
This selects the Secure Digital Host Controller Interface (SDHCI)
support present in TI's AM654 SOCs. The controller supports

22
drivers/mmc/host/sdhci_am654.c
View file

@ -158,6 +158,27 @@ static void sdhci_am654_set_power(struct sdhci_host *host, unsigned char mode,
sdhci_set_power_noreg(host, mode, vdd);
}
static void sdhci_am654_write_b(struct sdhci_host *host, u8 val, int reg)
{
unsigned char timing = host->mmc->ios.timing;
if (reg == SDHCI_HOST_CONTROL) {
switch (timing) {
/*
* According to the data manual, HISPD bit
* should not be set in these speed modes.
*/
case MMC_TIMING_SD_HS:
case MMC_TIMING_MMC_HS:
case MMC_TIMING_UHS_SDR12:
case MMC_TIMING_UHS_SDR25:
val &= ~SDHCI_CTRL_HISPD;
}
}
writeb(val, host->ioaddr + reg);
}
static struct sdhci_ops sdhci_am654_ops = {
.get_max_clock = sdhci_pltfm_clk_get_max_clock,
.get_timeout_clock = sdhci_pltfm_clk_get_max_clock,
@ -165,6 +186,7 @@ static struct sdhci_ops sdhci_am654_ops = {
.set_bus_width = sdhci_set_bus_width,
.set_power = sdhci_am654_set_power,
.set_clock = sdhci_am654_set_clock,
.write_b = sdhci_am654_write_b,
.reset = sdhci_reset,
};