drm/msm: use devm_gpiod_get_optional for optional reset gpio

Since 39b2bbe3d715 (gpio: add flags argument to gpiod_get*() functions)
which appeared in v3.17-rc1, the gpiod_get* functions take an additional
parameter that allows to specify direction and initial value for output.

Also there is a variant to find optional gpios that returns NULL if
there is no gpio instead of -ENOENT.

Make use of both features to simplify the driver.

This makes error checking more strict because errors like -ENOSYS ("no
gpio support compiled in") or -EPROBE_DEFER ("gpio not ready yet") are
handled correctly now.

Furthermore this is one caller less that stops us making the flags
argument to gpiod_get*() mandatory.

Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Rob Clark <robdclark@gmail.com>

diff --git a/drivers/gpu/drm/msm/dsi/dsi_host.c b/drivers/gpu/drm/msm/dsi/dsi_host.c
index bc2e405758e3957b99342defbca1619ccdf6b529..604d80b85e4209f722222b912bcaf4fabf751dd0 100644 (file)
--- a/drivers/gpu/drm/msm/dsi/dsi_host.c
+++ b/drivers/gpu/drm/msm/dsi/dsi_host.c
@@ -1349,36 +1349,19 @@ static irqreturn_t dsi_host_irq(int irq, void *ptr)
 static int dsi_host_init_panel_gpios(struct msm_dsi_host *msm_host,
                        struct device *panel_device)
 {
-       int ret;
-
-       msm_host->disp_en_gpio = devm_gpiod_get(panel_device,
-                                               "disp-enable");
+       msm_host->disp_en_gpio = devm_gpiod_get_optional(panel_device,
+                                                        "disp-enable",
+                                                        GPIOD_OUT_LOW);
        if (IS_ERR(msm_host->disp_en_gpio)) {
                DBG("cannot get disp-enable-gpios %ld",
                                PTR_ERR(msm_host->disp_en_gpio));
-               msm_host->disp_en_gpio = NULL;
-       }
-       if (msm_host->disp_en_gpio) {
-               ret = gpiod_direction_output(msm_host->disp_en_gpio, 0);
-               if (ret) {
-                       pr_err("cannot set dir to disp-en-gpios %d\n", ret);
-                       return ret;
-               }
+               return PTR_ERR(msm_host->disp_en_gpio);
        }
 
-       msm_host->te_gpio = devm_gpiod_get(panel_device, "disp-te");
+       msm_host->te_gpio = devm_gpiod_get(panel_device, "disp-te", GPIOD_IN);
        if (IS_ERR(msm_host->te_gpio)) {
                DBG("cannot get disp-te-gpios %ld", PTR_ERR(msm_host->te_gpio));
-               msm_host->te_gpio = NULL;
-       }
-
-       if (msm_host->te_gpio) {
-               ret = gpiod_direction_input(msm_host->te_gpio);
-               if (ret) {
-                       pr_err("%s: cannot set dir to disp-te-gpios, %d\n",
-                               __func__, ret);
-                       return ret;
-               }
+               return PTR_ERR(msm_host->te_gpio);
        }
 
        return 0;