On Fri, 2017-04-21 at 13:51 +0300, Dan Carpenter wrote:
> 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>
Reviewed-by: Philipp Zabel <p.zabel@xxxxxxxxxxxxxx>
> ---
> 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);
>
regards
Philipp
--
To unsubscribe from this list: send the line "unsubscribe kernel-janitors" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
