mmc: sunxi: Use devm_reset_control_get_optional() for reset control

The reset control for the sunxi mmc controller is optional. Some
newer platforms (sun6i, sun8i, sun9i) have it, while older ones
(sun4i, sun5i, sun7i) don't.

Use the properly stubbed _optional version so the driver does not
fail to compile when RESET_CONTROLLER=n.

This patch also adds a check for deferred probing on the reset
control.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Cc: <stable@vger.kernel.org> # 3.16+
Acked-by: David Lanzendörfer <david.lanzendoerfer@o2s.ch>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>

diff --git a/drivers/mmc/host/sunxi-mmc.c b/drivers/mmc/host/sunxi-mmc.c
index e8a4218b57267f508eb871f216de112e93707d31..459ed1b601dbe17c034fbf0338b6bb4987c603ac 100644 (file)
--- a/drivers/mmc/host/sunxi-mmc.c
+++ b/drivers/mmc/host/sunxi-mmc.c
@@ -930,7 +930,9 @@ static int sunxi_mmc_resource_request(struct sunxi_mmc_host *host,
                return PTR_ERR(host->clk_sample);
        }
 
-       host->reset = devm_reset_control_get(&pdev->dev, "ahb");
+       host->reset = devm_reset_control_get_optional(&pdev->dev, "ahb");
+       if (PTR_ERR(host->reset) == -EPROBE_DEFER)
+               return PTR_ERR(host->reset);
 
        ret = clk_prepare_enable(host->clk_ahb);
        if (ret) {