diff options
Diffstat (limited to 'drivers/mmc/host/sdhci-s3c.c')
| -rw-r--r-- | drivers/mmc/host/sdhci-s3c.c | 27 |
1 files changed, 27 insertions, 0 deletions
diff --git a/drivers/mmc/host/sdhci-s3c.c b/drivers/mmc/host/sdhci-s3c.c index d7058eee95f9..47138afea2b5 100644 --- a/drivers/mmc/host/sdhci-s3c.c +++ b/drivers/mmc/host/sdhci-s3c.c @@ -203,9 +203,36 @@ static void sdhci_s3c_set_clock(struct sdhci_host *host, unsigned int clock) } } +/** + * sdhci_s3c_get_min_clock - callback to get minimal supported clock value + * @host: The SDHCI host being queried + * + * To init mmc host properly a minimal clock value is needed. For high system + * bus clock's values the standard formula gives values out of allowed range. + * The clock still can be set to lower values, if clock source other then + * system bus is selected. +*/ +static unsigned int sdhci_s3c_get_min_clock(struct sdhci_host *host) +{ + struct sdhci_s3c *ourhost = to_s3c(host); + unsigned int delta, min = UINT_MAX; + int src; + + for (src = 0; src < MAX_BUS_CLK; src++) { + delta = sdhci_s3c_consider_clock(ourhost, src, 0); + if (delta == UINT_MAX) + continue; + /* delta is a negative value in this case */ + if (-delta < min) + min = -delta; + } + return min; +} + static struct sdhci_ops sdhci_s3c_ops = { .get_max_clock = sdhci_s3c_get_max_clk, .set_clock = sdhci_s3c_set_clock, + .get_min_clock = sdhci_s3c_get_min_clock, }; static int __devinit sdhci_s3c_probe(struct platform_device *pdev) |