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From: "Jose A. Perez de Azpillaga" <azpijr@gmail.com>
To: andy@kernel.org, gregkh@linuxfoundation.org
Cc: dri-devel@lists.freedesktop.org, linux-fbdev@vger.kernel.org,
	linux-staging@lists.linux.dev, linux-kernel@vger.kernel.org,
	azpijr@gmail.com
Subject: [PATCH] staging: fbtft: fb_ra8875: replace udelays with usleep_range
Date: Wed, 25 Feb 2026 21:45:59 +0100	[thread overview]
Message-ID: <20260225204602.134218-1-azpijr@gmail.com> (raw)

The write_reg8_bus8 function uses udelay(100) twice to wait for the
display controller. For delays of this duration in non-atomic context,
usleep_range() is preferred as it avoids busy-waiting.

Update both instances to use usleep_range(100, 120), allowing the
scheduler to utilize the CPU during these wait periods.

Signed-off-by: Jose A. Perez de Azpillaga <azpijr@gmail.com>
---
 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 0ab1de6647d0..6058934e2ca2 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, 120);
 
 	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, 120);
 }
 
 static int write_vmem16_bus8(struct fbtft_par *par, size_t offset, size_t len)
-- 
2.53.0


             reply	other threads:[~2026-02-25 20:46 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-02-25 20:45 Jose A. Perez de Azpillaga [this message]
2026-02-25 21:14 ` [PATCH] staging: fbtft: fb_ra8875: replace udelays with usleep_range Greg KH
2026-02-25 23:40 ` [PATCH v2] staging: fbtft: fb_ra8875: replace udelays with fsleep Jose A. Perez de Azpillaga
2026-02-26  7:46   ` Andy Shevchenko
2026-02-26  8:31     ` Jose A. Perez de Azpillaga

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