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>
diff --git a/drivers/mmc/host/sdhci-esdhc-imx.c b/drivers/mmc/host/sdhci-esdhc-imx.c
index eb1310c..1dd5ba8 100644
--- a/drivers/mmc/host/sdhci-esdhc-imx.c
+++ b/drivers/mmc/host/sdhci-esdhc-imx.c
@@ -384,6 +384,20 @@
}
}
+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 @@
.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 @@
of_property_read_u32(np, "bus-width", &boarddata->max_bus_width);
+ of_property_read_u32(np, "max-frequency", &boarddata->f_max);
+
return 0;
}
#else