linux-kernel - [PATCH] staging: fbtft: fb_ra8875: replace udelay with usleep

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Message-Id: <20251020-staging-fbtft-ra8875-usleep-v1-1-9592dd390c13@lukowski.dev>
Date: Mon, 20 Oct 2025 22:15:36 +0300
From: Olle Lukowski <olle@...owski.dev>
To: Andy Shevchenko <andy@...nel.org>, 
 Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc: dri-devel@...ts.freedesktop.org, linux-fbdev@...r.kernel.org, 
 linux-staging@...ts.linux.dev, linux-kernel@...r.kernel.org, 
 Olle Lukowski <olle@...owski.dev>
Subject: [PATCH] staging: fbtft: fb_ra8875: replace udelay with
 usleep_range

Replace udelay(100) calls with usleep_range(100, 200) to allow the
scheduler to yield instead of busy-waiting. This is the preferred API for
sleep durations above 10 microseconds.

Signed-off-by: Olle Lukowski <olle@...owski.dev>
---
This patch replaces udelay() with usleep_range() in fb_ra8875.
---
 drivers/staging/fbtft/fb_ra8875.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/staging/fbtft/fb_ra8875.c b/drivers/staging/fbtft/fb_ra8875.c
index 0ab1de664..d2400bb44 100644
--- a/drivers/staging/fbtft/fb_ra8875.c
+++ b/drivers/staging/fbtft/fb_ra8875.c
@@ -210,7 +210,7 @@ static void write_reg8_bus8(struct fbtft_par *par, int len, ...)
 	}
 	len--;
 
-	udelay(100);
+	usleep_range(100, 200);
 
 	if (len) {
 		buf = (u8 *)par->buf;
@@ -231,7 +231,7 @@ static void write_reg8_bus8(struct fbtft_par *par, int len, ...)
 
 	/* restore user spi-speed */
 	par->fbtftops.write = fbtft_write_spi;
-	udelay(100);
+	usleep_range(100, 200);
 }
 
 static int write_vmem16_bus8(struct fbtft_par *par, size_t offset, size_t len)

---
base-commit: 211ddde0823f1442e4ad052a2f30f050145ccada
change-id: 20251020-staging-fbtft-ra8875-usleep-77306ea543c7

Best regards,
-- 
Olle Lukowski <olle@...owski.dev>