mmc: dw_mmc: lookup for optional biu and ciu clocks

Some platforms allow for clock gating and control of bus interface unit
clock and card interface unit clock. Add support for clock lookup of
optional biu and ciu clocks for clock gating and clock speed
determination.

Signed-off-by: Abhilash Kesavan <a.kesavan@samsung.com>
Signed-off-by: Thomas Abraham <thomas.abraham@linaro.org>
Acked-by: Will Newton <will.newton@imgtec.com>
Signed-off-by: Chris Ball <cjb@laptop.org>

1 files changed, 49 insertions, 3 deletions

diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
index 227c42ef18c5..de45ad24becb 100644
--- a/drivers/mmc/host/dw_mmc.c
+++ b/drivers/mmc/host/dw_mmc.c
@@ -1960,13 +1960,42 @@ int dw_mci_probe(struct dw_mci *host)
 		return -ENODEV;
 	}
 
-	if (!host->pdata->bus_hz) {
+	host->biu_clk = clk_get(host->dev, "biu");
+	if (IS_ERR(host->biu_clk)) {
+		dev_dbg(host->dev, "biu clock not available\n");
+	} else {
+		ret = clk_prepare_enable(host->biu_clk);
+		if (ret) {
+			dev_err(host->dev, "failed to enable biu clock\n");
+			clk_put(host->biu_clk);
+			return ret;
+		}
+	}
+
+	host->ciu_clk = clk_get(host->dev, "ciu");
+	if (IS_ERR(host->ciu_clk)) {
+		dev_dbg(host->dev, "ciu clock not available\n");
+	} else {
+		ret = clk_prepare_enable(host->ciu_clk);
+		if (ret) {
+			dev_err(host->dev, "failed to enable ciu clock\n");
+			clk_put(host->ciu_clk);
+			goto err_clk_biu;
+		}
+	}
+
+	if (IS_ERR(host->ciu_clk))
+		host->bus_hz = host->pdata->bus_hz;
+	else
+		host->bus_hz = clk_get_rate(host->ciu_clk);
+
+	if (!host->bus_hz) {
 		dev_err(host->dev,
 			"Platform data must supply bus speed\n");
-		return -ENODEV;
+		ret = -ENODEV;
+		goto err_clk_ciu;
 	}
 
-	host->bus_hz = host->pdata->bus_hz;
 	host->quirks = host->pdata->quirks;
 
 	spin_lock_init(&host->lock);
@@ -2116,6 +2145,17 @@ err_dmaunmap:
 		regulator_disable(host->vmmc);
 		regulator_put(host->vmmc);
 	}
+
+err_clk_ciu:
+	if (!IS_ERR(host->ciu_clk)) {
+		clk_disable_unprepare(host->ciu_clk);
+		clk_put(host->ciu_clk);
+	}
+err_clk_biu:
+	if (!IS_ERR(host->biu_clk)) {
+		clk_disable_unprepare(host->biu_clk);
+		clk_put(host->biu_clk);
+	}
 	return ret;
 }
 EXPORT_SYMBOL(dw_mci_probe);
@@ -2149,6 +2189,12 @@ void dw_mci_remove(struct dw_mci *host)
 		regulator_put(host->vmmc);
 	}
 
+	if (!IS_ERR(host->ciu_clk))
+		clk_disable_unprepare(host->ciu_clk);
+	if (!IS_ERR(host->biu_clk))
+		clk_disable_unprepare(host->biu_clk);
+	clk_put(host->ciu_clk);
+	clk_put(host->biu_clk);
 }
 EXPORT_SYMBOL(dw_mci_remove);