This code causes a static checker warning because it treats "i == 0" as
a timeout but, because it's a post-op, the loop actually ends with "i"
set to -1. Philipp Zabel points out that it would be cleaner to use
readl_poll_timeout() instead.
Fixes: 21898816831f ("drm/mediatek: add dsi transfer function")
Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
---
v2: Use readl_poll_timeout(). Please review this carefully because I've
never used readl_poll_timeout() and could easily mess up.
diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c b/drivers/gpu/drm/mediatek/mtk_dsi.c
index 808b995a990f..b5cc6e12334c 100644
--- a/drivers/gpu/drm/mediatek/mtk_dsi.c
+++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
@@ -19,6 +19,7 @@
#include <drm/drm_of.h>
#include <linux/clk.h>
#include <linux/component.h>
+#include <linux/iopoll.h>
#include <linux/irq.h>
#include <linux/of.h>
#include <linux/of_platform.h>
@@ -900,16 +901,12 @@ static int mtk_dsi_host_detach(struct mipi_dsi_host *host,
static void mtk_dsi_wait_for_idle(struct mtk_dsi *dsi)
{
- u32 timeout_ms = 500000; /* total 1s ~ 2s timeout */
-
- while (timeout_ms--) {
- if (!(readl(dsi->regs + DSI_INTSTA) & DSI_BUSY))
- break;
-
- usleep_range(2, 4);
- }
+ int ret;
+ u32 val;
- if (timeout_ms == 0) {
+ ret = readl_poll_timeout(dsi->regs + DSI_INTSTA, val, !(val & DSI_BUSY),
+ 4, 2000000);
+ if (ret) {
DRM_WARN("polling dsi wait not busy timeout!\n");
mtk_dsi_enable(dsi);
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