From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To: Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
linux-kernel@vger.kernel.org
Cc: Andy Shevchenko <andy@kernel.org>,
Geert Uytterhoeven <geert@linux-m68k.org>
Subject: [PATCH v1 5/7] auxdisplay: arm-charlcd: Use readl_poll_timeout
Date: Mon, 29 Dec 2025 14:52:38 +0100 [thread overview]
Message-ID: <20251229142349.1251843-6-andriy.shevchenko@linux.intel.com> (raw)
In-Reply-To: <20251229142349.1251843-1-andriy.shevchenko@linux.intel.com>
Use readl_poll_timeout_atomic() from <iopoll.h> instead of using
custom poll loops.
The timeout settings are different, but that shouldn't be much of a
problem. Instead of polling 10 times in a close loop, it polls for
one millisecond.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
drivers/auxdisplay/arm-charlcd.c | 24 +++++++-----------------
1 file changed, 7 insertions(+), 17 deletions(-)
diff --git a/drivers/auxdisplay/arm-charlcd.c b/drivers/auxdisplay/arm-charlcd.c
index ac8604d3b9a0..a537126f5d6a 100644
--- a/drivers/auxdisplay/arm-charlcd.c
+++ b/drivers/auxdisplay/arm-charlcd.c
@@ -13,7 +13,7 @@
#include <linux/err.h>
#include <linux/init.h>
#include <linux/interrupt.h>
-#include <linux/io.h>
+#include <linux/iopoll.h>
#include <linux/mod_devicetable.h>
#include <linux/platform_device.h>
#include <linux/string.h>
@@ -115,20 +115,14 @@ static u8 charlcd_4bit_read_char(struct charlcd *lcd)
{
u8 data;
u32 val;
- int i;
/* If we can, use an IRQ to wait for the data, else poll */
if (lcd->irq >= 0)
charlcd_wait_complete_irq(lcd);
else {
- i = 0;
- val = 0;
- while (!(val & CHAR_RAW_VALID) && i < 10) {
- udelay(100);
- val = readl(lcd->virtbase + CHAR_RAW);
- i++;
- }
-
+ udelay(100);
+ readl_poll_timeout_atomic(lcd->virtbase + CHAR_RAW, val,
+ val & CHAR_RAW_VALID, 100, 1000);
writel(CHAR_RAW_CLEAR, lcd->virtbase + CHAR_RAW);
}
msleep(1);
@@ -140,13 +134,9 @@ static u8 charlcd_4bit_read_char(struct charlcd *lcd)
* The second read for the low bits does not trigger an IRQ
* so in this case we have to poll for the 4 lower bits
*/
- i = 0;
- val = 0;
- while (!(val & CHAR_RAW_VALID) && i < 10) {
- udelay(100);
- val = readl(lcd->virtbase + CHAR_RAW);
- i++;
- }
+ udelay(100);
+ readl_poll_timeout_atomic(lcd->virtbase + CHAR_RAW, val,
+ val & CHAR_RAW_VALID, 100, 1000);
writel(CHAR_RAW_CLEAR, lcd->virtbase + CHAR_RAW);
msleep(1);
--
2.50.1
next prev parent reply other threads:[~2025-12-29 14:23 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-12-29 13:52 [PATCH v1 0/7] auxdisplay: arm-charlcd: refactor with modern APIs Andy Shevchenko
2025-12-29 13:52 ` [PATCH v1 1/7] auxdisplay: arm-charlcd: convert to use device managed APIs Andy Shevchenko
2025-12-29 13:52 ` [PATCH v1 2/7] auxdisplay: arm-charlcd: Remove unneeded info message Andy Shevchenko
2025-12-29 13:52 ` [PATCH v1 3/7] auxdisplay: arm-charlcd: drop of_match_ptr() Andy Shevchenko
2025-12-29 13:52 ` [PATCH v1 4/7] auxdisplay: arm-charlcd: Don't use "proxy" headers Andy Shevchenko
2025-12-29 13:52 ` Andy Shevchenko [this message]
2025-12-29 13:52 ` [PATCH v1 6/7] auxdisplay: arm-charlcd: Join string literals back Andy Shevchenko
2025-12-29 13:52 ` [PATCH v1 7/7] auxdisplay: arm-charlcd: Remove redundant ternary operators Andy Shevchenko
2026-01-07 21:06 ` [PATCH v1 0/7] auxdisplay: arm-charlcd: refactor with modern APIs Andy Shevchenko
2026-01-07 21:08 ` Andy Shevchenko
2026-01-09 11:30 ` Andy Shevchenko
2026-01-09 14:29 ` Linus Walleij
2026-01-09 16:15 ` Andy Shevchenko
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