[PATCH 3/7] mmc: msm_sdhci: handle bulk clock initialization error

[Jorge Ramirez-Ortiz <jorge.ramirez@oss.qualcomm.com>]

Some boards do not require all clocks to be available (i.e:
dragonboard820c).

This change provides a fallback to the core clock when the bulk cant be
retrived.

Signed-off-by: Jorge Ramirez-Ortiz <jorge.ramirez@oss.qualcomm.com>
---
 drivers/mmc/msm_sdhci.c | 27 +++++++++++++++++++++++++--
 1 file changed, 25 insertions(+), 2 deletions(-)

diff --git a/drivers/mmc/msm_sdhci.c b/drivers/mmc/msm_sdhci.c
index 27bb7052fca..8081330bd25 100644
--- a/drivers/mmc/msm_sdhci.c
+++ b/drivers/mmc/msm_sdhci.c
@@ -9,6 +9,7 @@
 
 #include <clk.h>
 #include <dm.h>
+#include <dm/devres.h>
 #include <malloc.h>
 #include <sdhci.h>
 #include <wait_bit.h>
@@ -56,6 +57,17 @@ struct msm_sdhc_variant_info {
 
 DECLARE_GLOBAL_DATA_PTR;
 
+static int get_core_clock(struct udevice *dev, struct clk_bulk *bulk)
+{
+	bulk->count = 1;
+
+	bulk->clks = devm_kcalloc(dev, 1, sizeof(struct clk), GFP_KERNEL);
+	if (!bulk->clks)
+		return -ENOMEM;
+
+	return clk_get_by_name(dev, "core", &bulk->clks[0]);
+}
+
 static int msm_sdc_clk_init(struct udevice *dev)
 {
 	struct msm_sdhc *prv = dev_get_priv(dev);
@@ -73,8 +85,15 @@ static int msm_sdc_clk_init(struct udevice *dev)
 
 	ret = clk_get_bulk(dev, &prv->clks);
 	if (ret) {
-		log_warning("Couldn't get mmc clocks: %d\n", ret);
-		return ret;
+		log_warning("Bulk clocks not available (%d), trying core clock\n", ret);
+
+		/* Sometimes not all clocks are needed - chainloading uboot */
+		ret = get_core_clock(dev, &prv->clks);
+		if (ret) {
+			log_warning("Core clock not available:(%d)\n", ret);
+			return ret;
+		}
+		n_clks = 1;
 	}
 
 	ret = clk_enable_bulk(&prv->clks);
@@ -83,6 +102,9 @@ static int msm_sdc_clk_init(struct udevice *dev)
 		return ret;
 	}
 
+	if (n_clks == 1)
+		goto set_rate;
+
 	/* If clock-names is unspecified, then the first clock is the core clock */
 	if (!ofnode_get_property(node, "clock-names", &n_clks)) {
 		if (!clk_set_rate(&prv->clks.clks[0], clk_rate)) {
@@ -105,6 +127,7 @@ static int msm_sdc_clk_init(struct udevice *dev)
 		return -EINVAL;
 	}
 
+set_rate:
 	/* The clock is already enabled by the clk_bulk above */
 	clk_rate = clk_set_rate(&prv->clks.clks[i], clk_rate);
 	/* If we get a rate of 0 then something has probably gone wrong. */
-- 
2.34.1