diff options
Diffstat (limited to 'drivers/mmc')
| -rw-r--r-- | drivers/mmc/host/sdhci-of-at91.c | 48 |
1 files changed, 46 insertions, 2 deletions
diff --git a/drivers/mmc/host/sdhci-of-at91.c b/drivers/mmc/host/sdhci-of-at91.c index 2703aa90d018..c1923c094ff6 100644 --- a/drivers/mmc/host/sdhci-of-at91.c +++ b/drivers/mmc/host/sdhci-of-at91.c @@ -15,6 +15,7 @@ */ #include <linux/clk.h> +#include <linux/delay.h> #include <linux/err.h> #include <linux/io.h> #include <linux/mmc/host.h> @@ -37,8 +38,52 @@ struct sdhci_at91_priv { struct clk *mainck; }; +static void sdhci_at91_set_clock(struct sdhci_host *host, unsigned int clock) +{ + u16 clk; + unsigned long timeout; + + host->mmc->actual_clock = 0; + + /* + * There is no requirement to disable the internal clock before + * changing the SD clock configuration. Moreover, disabling the + * internal clock, changing the configuration and re-enabling the + * internal clock causes some bugs. It can prevent to get the internal + * clock stable flag ready and an unexpected switch to the base clock + * when using presets. + */ + clk = sdhci_readw(host, SDHCI_CLOCK_CONTROL); + clk &= SDHCI_CLOCK_INT_EN; + sdhci_writew(host, clk, SDHCI_CLOCK_CONTROL); + + if (clock == 0) + return; + + clk = sdhci_calc_clk(host, clock, &host->mmc->actual_clock); + + clk |= SDHCI_CLOCK_INT_EN; + sdhci_writew(host, clk, SDHCI_CLOCK_CONTROL); + + /* Wait max 20 ms */ + timeout = 20; + while (!((clk = sdhci_readw(host, SDHCI_CLOCK_CONTROL)) + & SDHCI_CLOCK_INT_STABLE)) { + if (timeout == 0) { + pr_err("%s: Internal clock never stabilised.\n", + mmc_hostname(host->mmc)); + return; + } + timeout--; + mdelay(1); + } + + clk |= SDHCI_CLOCK_CARD_EN; + sdhci_writew(host, clk, SDHCI_CLOCK_CONTROL); +} + static const struct sdhci_ops sdhci_at91_sama5d2_ops = { - .set_clock = sdhci_set_clock, + .set_clock = sdhci_at91_set_clock, .set_bus_width = sdhci_set_bus_width, .reset = sdhci_reset, .set_uhs_signaling = sdhci_set_uhs_signaling, @@ -46,7 +91,6 @@ static const struct sdhci_ops sdhci_at91_sama5d2_ops = { static const struct sdhci_pltfm_data soc_data_sama5d2 = { .ops = &sdhci_at91_sama5d2_ops, - .quirks2 = SDHCI_QUIRK2_NEED_DELAY_AFTER_INT_CLK_RST, }; static const struct of_device_id sdhci_at91_dt_match[] = { |