[PATCH v2 09/21] mmc: am654_sdhci: Fix HISPD bit configuration in some lower speed modes

[Faiz Abbas]

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 at ti.com>
---
 drivers/mmc/Kconfig       |  1 +
 drivers/mmc/am654_sdhci.c | 25 +++++++++++++++++++++++--
 2 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/drivers/mmc/Kconfig b/drivers/mmc/Kconfig
index 0c252e34c7..525445949d 100644
--- a/drivers/mmc/Kconfig
+++ b/drivers/mmc/Kconfig
@@ -521,6 +521,7 @@ config MMC_SDHCI_AM654
 	depends on MMC_SDHCI
 	depends on DM_MMC && OF_CONTROL && BLK
 	depends on REGMAP
+	select MMC_SDHCI_IO_ACCESSORS
 	help
 	  Support for Secure Digital Host Controller Interface (SDHCI)
 	  controllers present on TI's AM654 SOCs.
diff --git a/drivers/mmc/am654_sdhci.c b/drivers/mmc/am654_sdhci.c
index 79b4331c3c..410517398a 100644
--- a/drivers/mmc/am654_sdhci.c
+++ b/drivers/mmc/am654_sdhci.c
@@ -369,6 +369,26 @@ static int am654_sdhci_deferred_probe(struct sdhci_host *host)
 	return sdhci_probe(dev);
 }
 
+static void am654_sdhci_write_b(struct sdhci_host *host, u8 val, int reg)
+{
+	if (reg == SDHCI_HOST_CONTROL) {
+		switch (host->mmc->selected_mode) {
+		/*
+		 * According to the data manual, HISPD bit
+		 * should not be set in these speed modes.
+		 */
+		case SD_HS:
+		case MMC_HS:
+		case UHS_SDR12:
+		case UHS_SDR25:
+			val &= ~SDHCI_CTRL_HISPD;
+		default:
+			break;
+		}
+	}
+
+	writeb(val, host->ioaddr + reg);
+}
 #ifdef MMC_SUPPORTS_TUNING
 #define ITAP_MAX	32
 static int am654_sdhci_execute_tuning(struct mmc *mmc, u8 opcode)
@@ -414,6 +434,7 @@ const struct sdhci_ops am654_sdhci_ops = {
 	.deferred_probe		= am654_sdhci_deferred_probe,
 	.set_ios_post		= &am654_sdhci_set_ios_post,
 	.set_control_reg	= &am654_sdhci_set_control_reg,
+	.write_b		= am654_sdhci_write_b,
 };
 
 const struct am654_driver_data am654_drv_data = {
@@ -455,6 +476,7 @@ const struct sdhci_ops j721e_4bit_sdhci_ops = {
 #endif
 	.deferred_probe		= am654_sdhci_deferred_probe,
 	.set_ios_post		= &j721e_4bit_sdhci_set_ios_post,
+	.write_b		= am654_sdhci_write_b,
 };
 
 const struct am654_driver_data j721e_4bit_drv_data = {
@@ -532,6 +554,7 @@ static int am654_sdhci_probe(struct udevice *dev)
 	host->max_clk = clock;
 	host->mmc = &plat->mmc;
 	host->mmc->dev = dev;
+	host->ops = drv_data->ops;
 	ret = sdhci_setup_cfg(cfg, host, cfg->f_max,
 			      AM654_SDHCI_MIN_FREQ);
 	if (ret)
@@ -541,8 +564,6 @@ static int am654_sdhci_probe(struct udevice *dev)
 	if (ret)
 		return ret;
 
-	host->ops = drv_data->ops;
-
 	/* Update ops based on SoC revision */
 	soc = soc_device_match(am654_sdhci_soc_attr);
 	if (soc && soc->data) {
-- 
2.17.1