Commit 5c4381ee authored by Douglas Anderson's avatar Douglas Anderson
Browse files

drm/panel: panel-simple: Get rid of hacky HPD chicken-and-egg code 



When I added support for the hpd-gpio to simple-panel in commit
48834e60 ("drm/panel-simple: Support hpd-gpios for delaying
prepare()"), I added a special case to handle a circular dependency I
was running into on the ti-sn65dsi86 bridge chip. On my board the
hpd-gpio is actually provided by the bridge chip. That was causing
some circular dependency problems that I had to work around by getting
the hpd-gpio late.

I've now reorganized the ti-sn65dsi86 bridge chip driver to be a
collection of sub-drivers. Now the GPIO part can probe separately and
that breaks the chain. Let's get rid of the old code to clean things
up.

Signed-off-by: default avatarDouglas Anderson <dianders@chromium.org>
Reviewed-by: default avatarBjorn Andersson <bjorn.andersson@linaro.org>
Reviewed-by: default avatarSean Paul <seanpaul@chromium.org>
Acked-by: default avatarLinus Walleij <linus.walleij@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20210423095743.v5.10.I40eeedc23459d1e3fc96fa6cdad775d88c6e706c@changeid
parent bf73537f

drivers/gpu/drm/panel/panel-simple.c

+5 −19
Original line number Diff line number Diff line
@@ -366,8 +366,7 @@ static int panel_simple_unprepare(struct drm_panel *panel) 
	return 0;

}



static int panel_simple_get_hpd_gpio(struct device *dev,

				     struct panel_simple *p, bool from_probe)

static int panel_simple_get_hpd_gpio(struct device *dev, struct panel_simple *p)

{

	int err;
@@ -375,18 +374,11 @@ static int panel_simple_get_hpd_gpio(struct device *dev, 
	if (IS_ERR(p->hpd_gpio)) {

		err = PTR_ERR(p->hpd_gpio);



		/*

		 * If we're called from probe we won't consider '-EPROBE_DEFER'

		 * to be an error--we'll leave the error code in "hpd_gpio".

		 * When we try to use it we'll try again.  This allows for

		 * circular dependencies where the component providing the

		 * hpd gpio needs the panel to init before probing.

		 */

		if (err != -EPROBE_DEFER || !from_probe) {

		if (err != -EPROBE_DEFER)

			dev_err(dev, "failed to get 'hpd' GPIO: %d\n", err);



		return err;

	}

	}



	return 0;

}
@@ -416,12 +408,6 @@ static int panel_simple_prepare_once(struct panel_simple *p) 
		msleep(delay);



	if (p->hpd_gpio) {

		if (IS_ERR(p->hpd_gpio)) {

			err = panel_simple_get_hpd_gpio(dev, p, false);

			if (err)

				goto error;

		}



		if (p->desc->delay.hpd_absent_delay)

			hpd_wait_us = p->desc->delay.hpd_absent_delay * 1000UL;

		else
@@ -682,7 +668,7 @@ static int panel_simple_probe(struct device *dev, const struct panel_desc *desc) 


	panel->no_hpd = of_property_read_bool(dev->of_node, "no-hpd");

	if (!panel->no_hpd) {

		err = panel_simple_get_hpd_gpio(dev, panel, true);

		err = panel_simple_get_hpd_gpio(dev, panel);

		if (err)

			return err;

	}