Unverified Commit ee0285e1 authored by Adam Ford's avatar Adam Ford Committed by Robert Foss
Browse files

drm/bridge: adv7533: Fix adv7533_mode_valid for adv7533 and adv7535 



When dynamically switching lanes was removed, the intent of the code
was to check to make sure that higher speed items used 4 lanes, but
it had the unintended consequence of removing the slower speeds for
4-lane users.

This attempts to remedy this by doing a check to see that the
max frequency doesn't exceed the chip limit, and a second
check to make sure that the max bit-rate doesn't exceed the
number of lanes * max bit rate / lane.

Fixes: 9a0cdcd6 ("drm/bridge: adv7533: remove dynamic lane switching from adv7533 bridge")
Reviewed-by: default avatarRobert Foss <rfoss@kernel.org>
Signed-off-by: default avatarAdam Ford <aford173@gmail.com>
Signed-off-by: default avatarRobert Foss <rfoss@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20230319125524.58803-1-aford173@gmail.com
parent 5327469e

drivers/gpu/drm/bridge/adv7511/adv7533.c

+11 −14
Original line number Diff line number Diff line
@@ -103,22 +103,19 @@ void adv7533_dsi_power_off(struct adv7511 *adv) 
enum drm_mode_status adv7533_mode_valid(struct adv7511 *adv,

					const struct drm_display_mode *mode)

{

	int lanes;

	unsigned long max_lane_freq;

	struct mipi_dsi_device *dsi = adv->dsi;

	u8 bpp = mipi_dsi_pixel_format_to_bpp(dsi->format);



	if (mode->clock > 80000)

		lanes = 4;

	else

		lanes = 3;

	/* Check max clock for either 7533 or 7535 */

	if (mode->clock > (adv->type == ADV7533 ? 80000 : 148500))

		return MODE_CLOCK_HIGH;



	/*

	 * TODO: add support for dynamic switching of lanes

	 * by using the bridge pre_enable() op . Till then filter

	 * out the modes which shall need different number of lanes

	 * than what was configured in the device tree.

	 */

	if (lanes != dsi->lanes)

		return MODE_BAD;

	/* Check max clock for each lane */

	max_lane_freq = (adv->type == ADV7533 ? 800000 : 891000);



	if (mode->clock * bpp > max_lane_freq * adv->num_dsi_lanes)

		return MODE_CLOCK_HIGH;



	return MODE_OK;

}