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mmc: esdhc-imx: parse max-frequency from devicetree 

In order to make it possible to reduce the SD bus frequency,
parse the optional "max-frequency" attribute as documented in
devicetree/bindings/mmc/mmc.txt

Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
Acked-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Chris Ball <cjb@laptop.org>
This commit is contained in:
Lucas Stach 2013-06-05 15:13:26 +02:00 committed by Chris Ball
parent 8ba9580a80
commit 0ddf03c95b
2 changed files with 18 additions and 1 deletions
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18
drivers/mmc/host/sdhci-esdhc-imx.c
View File

@ -384,6 +384,20 @@ static void esdhc_writeb_le(struct sdhci_host *host, u8 val, int reg)
}
}
static unsigned int esdhc_pltfm_get_max_clock(struct sdhci_host *host)
{
struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
struct pltfm_imx_data *imx_data = pltfm_host->priv;
struct esdhc_platform_data *boarddata = &imx_data->boarddata;
u32 f_host = clk_get_rate(pltfm_host->clk);
if (boarddata->f_max && (boarddata->f_max < f_host))
return boarddata->f_max;
else
return f_host;
}
static unsigned int esdhc_pltfm_get_min_clock(struct sdhci_host *host)
{
struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
@ -447,7 +461,7 @@ static const struct sdhci_ops sdhci_esdhc_ops = {
.write_w = esdhc_writew_le,
.write_b = esdhc_writeb_le,
.set_clock = esdhc_pltfm_set_clock,
.get_max_clock = sdhci_pltfm_clk_get_max_clock,
.get_max_clock = esdhc_pltfm_get_max_clock,
.get_min_clock = esdhc_pltfm_get_min_clock,
.get_ro = esdhc_pltfm_get_ro,
.platform_bus_width = esdhc_pltfm_bus_width,
@ -490,6 +504,8 @@ sdhci_esdhc_imx_probe_dt(struct platform_device *pdev,
of_property_read_u32(np, "bus-width", &boarddata->max_bus_width);
of_property_read_u32(np, "max-frequency", &boarddata->f_max);
return 0;
}
#else

1
include/linux/platform_data/mmc-esdhc-imx.h
View File

@ -40,5 +40,6 @@ struct esdhc_platform_data {
enum wp_types wp_type;
enum cd_types cd_type;
int max_bus_width;
unsigned int f_max;
};
#endif /* __ASM_ARCH_IMX_ESDHC_H */