[PATCH v4 2/2] mmc: sdhci-of-aspeed: Handle optional controller reset

[Ryan Chen <ryan_chen@aspeedtech.com>]

Get the optional reset line for the ASPEED SD controller during probe by
using devm_reset_control_get_optional_exclusive_deasserted().

This allows platforms such as AST2700, which require the SD controller
to be taken out of reset before use, to work with the existing driver.

Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Ryan Chen <ryan_chen@aspeedtech.com>
---
Changes in v4:
- rebase git://git.kernel.org/pub/scm/linux/kernel/git/ulfh/mmc.git
  next branch fix the conflit.
Changes in v2:
- use devm_reset_control_get_optional_exclusive_deasserted replace
  reset_control_get_optional_exclusive.
- add include reset.h
---
 drivers/mmc/host/sdhci-of-aspeed.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/mmc/host/sdhci-of-aspeed.c b/drivers/mmc/host/sdhci-of-aspeed.c
index 4296def69436..f5d973783cbe 100644
--- a/drivers/mmc/host/sdhci-of-aspeed.c
+++ b/drivers/mmc/host/sdhci-of-aspeed.c
@@ -13,6 +13,7 @@
 #include <linux/of.h>
 #include <linux/of_platform.h>
 #include <linux/platform_device.h>
+#include <linux/reset.h>
 #include <linux/spinlock.h>
 
 #include "sdhci-pltfm.h"
@@ -519,6 +520,7 @@ static struct platform_driver aspeed_sdhci_driver = {
 static int aspeed_sdc_probe(struct platform_device *pdev)
 
 {
+	struct reset_control *reset;
 	struct device_node *parent;
 	struct aspeed_sdc *sdc;
 	int ret;
@@ -529,6 +531,10 @@ static int aspeed_sdc_probe(struct platform_device *pdev)
 
 	spin_lock_init(&sdc->lock);
 
+	reset = devm_reset_control_get_optional_exclusive_deasserted(&pdev->dev, NULL);
+	if (IS_ERR(reset))
+		return dev_err_probe(&pdev->dev, PTR_ERR(reset), "unable to acquire reset\n");
+
 	sdc->clk = devm_clk_get(&pdev->dev, NULL);
 	if (IS_ERR(sdc->clk))
 		return PTR_ERR(sdc->clk);

-- 
2.34.1