[PATCH 08/18] drm/i915/power: use generic read_poll_timeout() instead of wait_for()

[Jani Nikula]

Prefer generic poll helpers over i915 custom helpers.

The functional change is losing the exponentially growing sleep of
wait_for(), which used to be 10, 20, 40, ..., 640, and 1280 us.

Use an arbitrary constant 100 us sleep instead. The timeout remains at 1
ms.

Signed-off-by: Jani Nikula <jani.nikula at intel.com>
---
 drivers/gpu/drm/i915/display/intel_display_power.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_display_power.c b/drivers/gpu/drm/i915/display/intel_display_power.c
index 273054c22325..b2b7b8ca64d2 100644
--- a/drivers/gpu/drm/i915/display/intel_display_power.c
+++ b/drivers/gpu/drm/i915/display/intel_display_power.c
@@ -3,6 +3,7 @@
  * Copyright © 2019 Intel Corporation
  */
 
+#include <linux/iopoll.h>
 #include <linux/string_helpers.h>
 
 #include "soc/intel_dram.h"
@@ -1278,6 +1279,7 @@ static void hsw_disable_lcpll(struct intel_display *display,
 			      bool switch_to_fclk, bool allow_power_down)
 {
 	u32 val;
+	int ret;
 
 	assert_can_disable_lcpll(display);
 
@@ -1306,8 +1308,11 @@ static void hsw_disable_lcpll(struct intel_display *display,
 	hsw_write_dcomp(display, val);
 	ndelay(100);
 
-	if (wait_for((hsw_read_dcomp(display) &
-		      D_COMP_RCOMP_IN_PROGRESS) == 0, 1))
+	ret = read_poll_timeout(hsw_read_dcomp, val,
+				(val & D_COMP_RCOMP_IN_PROGRESS) == 0,
+				100, 1000, false,
+				display);
+	if (ret)
 		drm_err(display->drm, "D_COMP RCOMP still in progress\n");
 
 	if (allow_power_down) {
-- 
2.39.5