linux-kernel - [PATCH 09/22] platform/chrome: cros_typec_switch: Use read_poll

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Message-ID: <20240210070934.2549994-10-swboyd@chromium.org>
Date: Fri,  9 Feb 2024 23:09:20 -0800
From: Stephen Boyd <swboyd@...omium.org>
To: chrome-platform@...ts.linux.dev
Cc: linux-kernel@...r.kernel.org,
	patches@...ts.linux.dev,
	linux-arm-kernel@...ts.infradead.org,
	devicetree@...r.kernel.org,
	linux-arm-msm@...r.kernel.org,
	Douglas Anderson <dianders@...omium.org>,
	Pin-yen Lin <treapking@...omium.org>,
	Prashant Malani <pmalani@...omium.org>,
	Benson Leung <bleung@...omium.org>,
	Tzung-Bi Shih <tzungbi@...nel.org>
Subject: [PATCH 09/22] platform/chrome: cros_typec_switch: Use read_poll_timeout helper

It's possible for this polling loop to get scheduled away for a long
time right after checking the status on the EC. If that happens, we will
never try to check the status at least one more time before giving up
and saying that it timed out. Let's use the read_poll_timeout() macro to
construct the loop with a proper timeout mechanism and the ability to
check that the condition is true once more when the timeout hits.

Cc: Prashant Malani <pmalani@...omium.org>
Cc: Benson Leung <bleung@...omium.org>
Cc: Tzung-Bi Shih <tzungbi@...nel.org>
Cc: <chrome-platform@...ts.linux.dev>
Cc: Pin-yen Lin <treapking@...omium.org>
Signed-off-by: Stephen Boyd <swboyd@...omium.org>
---
 drivers/platform/chrome/cros_typec_switch.c | 21 ++++++++-------------
 1 file changed, 8 insertions(+), 13 deletions(-)

diff --git a/drivers/platform/chrome/cros_typec_switch.c b/drivers/platform/chrome/cros_typec_switch.c
index 07a19386dc4e..a23fe80d9d4b 100644
--- a/drivers/platform/chrome/cros_typec_switch.c
+++ b/drivers/platform/chrome/cros_typec_switch.c
@@ -8,7 +8,7 @@
 
 #include <linux/acpi.h>
 #include <linux/delay.h>
-#include <linux/jiffies.h>
+#include <linux/iopoll.h>
 #include <linux/module.h>
 #include <linux/platform_data/cros_ec_commands.h>
 #include <linux/platform_data/cros_ec_proto.h>
@@ -108,7 +108,6 @@ static bool cros_typec_check_event(struct cros_typec_switch_data *sdata, int por
 static int cros_typec_configure_mux(struct cros_typec_switch_data *sdata, int port_num, int index,
 				    unsigned long mode, struct typec_altmode *alt)
 {
-	unsigned long end;
 	u32 event_mask;
 	u8 mux_state;
 	int ret;
@@ -134,18 +133,14 @@ static int cros_typec_configure_mux(struct cros_typec_switch_data *sdata, int po
 		return ret;
 
 	/* Check for the mux set done event. */
-	end = jiffies + msecs_to_jiffies(1000);
-	do {
-		if (cros_typec_check_event(sdata, port_num, event_mask))
-			return 0;
+	if (read_poll_timeout(cros_typec_check_event, ret, ret == 0, 1000,
+			      1000 * 1000UL, false, sdata, port_num, event_mask)) {
+		dev_err(sdata->dev, "Timed out waiting for mux set done on index: %d, state: %d\n",
+			index, mux_state);
+		return -ETIMEDOUT;
+	}
 
-		usleep_range(500, 1000);
-	} while (time_before(jiffies, end));
-
-	dev_err(sdata->dev, "Timed out waiting for mux set done on index: %d, state: %d\n",
-		index, mux_state);
-
-	return -ETIMEDOUT;
+	return 0;
 }
 
 static int cros_typec_mode_switch_set(struct typec_mux_dev *mode_switch,
-- 
https://chromeos.dev