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authorStefan Roese <sr@denx.de>2016-12-12 08:34:42 +0100
committerStefan Roese <sr@denx.de>2017-01-25 07:03:39 +0100
commit899fb9e352815ef5a5d9304a097d5abc7c476500 (patch)
tree0bee9781e7ef772dea3981781de8de59f2b7d77a /drivers
parentf2b0c007f84e582b7a101bd49db60cc8d75f5de4 (diff)
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mmc: sdhci: Clear SDHCI_CLOCK_CONTROL before configuring the new value
This patch completely clears the SDHCI_CLOCK_CONTROL register before the new value is configured instead of just clearing the 2 bits SDHCI_CLOCK_CARD_EN and SDHCI_CLOCK_INT_EN. Without this change, some clock configurations will lead to the "Internal clock never stabilised." error message on the Xenon SDHCI controller used on the Marvell Armada 3700 and 7k/8k ARM64 SoCs. The Linux SDHCI core driver also writes 0 to this register before the new value is configured. So this patch simplifies the driver a bit and brings the U-Boot driver more in-line with the Linux one. Signed-off-by: Stefan Roese <sr@denx.de> Cc: Jaehoon Chung <jh80.chung@samsung.com> Cc: Siva Durga Prasad Paladugu <sivadur@xilinx.com> Cc: Michal Simek <michal.simek@xilinx.com> Reviewed-by: Jaehoon Chung <jh80.chung@samsung.com>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/mmc/sdhci.c6
1 files changed, 2 insertions, 4 deletions
diff --git a/drivers/mmc/sdhci.c b/drivers/mmc/sdhci.c
index 84e0581..9902dbd 100644
--- a/drivers/mmc/sdhci.c
+++ b/drivers/mmc/sdhci.c
@@ -295,7 +295,7 @@ static int sdhci_send_command(struct mmc *mmc, struct mmc_cmd *cmd,
static int sdhci_set_clock(struct mmc *mmc, unsigned int clock)
{
struct sdhci_host *host = mmc->priv;
- unsigned int div, clk = 0, timeout, reg;
+ unsigned int div, clk = 0, timeout;
/* Wait max 20 ms */
timeout = 200;
@@ -311,9 +311,7 @@ static int sdhci_set_clock(struct mmc *mmc, unsigned int clock)
udelay(100);
}
- reg = sdhci_readw(host, SDHCI_CLOCK_CONTROL);
- reg &= ~(SDHCI_CLOCK_CARD_EN | SDHCI_CLOCK_INT_EN);
- sdhci_writew(host, reg, SDHCI_CLOCK_CONTROL);
+ sdhci_writew(host, 0, SDHCI_CLOCK_CONTROL);
if (clock == 0)
return 0;