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Subject[PATCH v2] mmc: sdhci_am654: Clear HISPD_ENA in some lower speed modes
Date
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>
---

v2: Dropped QUIRK in favour of writeb callback

drivers/mmc/host/Kconfig | 1 +
drivers/mmc/host/sdhci_am654.c | 22 ++++++++++++++++++++++
2 files changed, 23 insertions(+)

diff --git a/drivers/mmc/host/Kconfig b/drivers/mmc/host/Kconfig
index 28fcd8f580a1..6379fba8b122 100644
--- a/drivers/mmc/host/Kconfig
+++ b/drivers/mmc/host/Kconfig
@@ -993,6 +993,7 @@ 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
diff --git a/drivers/mmc/host/sdhci_am654.c b/drivers/mmc/host/sdhci_am654.c
index eea183e90f1b..a91c0b45c48d 100644
--- a/drivers/mmc/host/sdhci_am654.c
+++ b/drivers/mmc/host/sdhci_am654.c
@@ -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,
};

--
2.19.2
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