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.

Fixes: a689554ba6ed ("drm/msm: Initial add DSI connector support")
Signed-off-by: Uwe Kleine-König <u.kleine-koenig at pengutronix.de>
---
 drivers/gpu/drm/msm/dsi/dsi_host.c | 27 ++++++---------------------
 1 file changed, 6 insertions(+), 21 deletions(-)

diff --git a/drivers/gpu/drm/msm/dsi/dsi_host.c 
b/drivers/gpu/drm/msm/dsi/dsi_host.c
index 956b22492c9a..b3d8f4694bf2 100644
--- a/drivers/gpu/drm/msm/dsi/dsi_host.c
+++ b/drivers/gpu/drm/msm/dsi/dsi_host.c
@@ -1353,34 +1353,19 @@ static int dsi_host_init_panel_gpios(struct 
msm_dsi_host *msm_host,
 {
        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;
-- 
2.1.4

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