From 899fb9e352815ef5a5d9304a097d5abc7c476500 Mon Sep 17 00:00:00 2001 From: Stefan Roese Date: Mon, 12 Dec 2016 08:34:42 +0100 Subject: [PATCH] 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 Cc: Jaehoon Chung Cc: Siva Durga Prasad Paladugu Cc: Michal Simek Reviewed-by: Jaehoon Chung --- drivers/mmc/sdhci.c | 6 ++---- 1 file 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;