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Tue, 13 Jan 2026 13:06:05 -0800 (PST) Received: from ubuntu.localdomain ([154.161.44.196]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-47ed98abad1sm59042205e9.10.2026.01.13.13.06.02 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 13 Jan 2026 13:06:04 -0800 (PST) From: Gideon Adjei To: Andy Shevchenko , Greg Kroah-Hartman Cc: Abdun Nihaal , Dan Carpenter , Jianglei Nie , Matthew Wilcox , dri-devel@lists.freedesktop.org, linux-fbdev@vger.kernel.org, linux-staging@lists.linux.dev, linux-kernel@vger.kernel.org, Gideon Adjei Subject: [PATCH v2] staging: fbtft: Change udelay() to usleep_range() Date: Tue, 13 Jan 2026 13:05:59 -0800 Message-Id: <20260113210559.3020-1-gideonadjei.dev@gmail.com> X-Mailer: git-send-email 2.34.1 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Replace udelay() calls >=3D 100us with usleep_range() to avoid busy-waiting. The delays are used in init_display() callbacks. These callbacks are invoked by fbtft_probe_common() during the driver's probe path. the probe path runs in process context which already uses sleeping APIs. This makes usleep_range() safe to use in these situations. Signed-off-by: Gideon Adjei --- drivers/staging/fbtft/fb_tinylcd.c | 2 +- drivers/staging/fbtft/fb_upd161704.c | 4 ++-- 2 files changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/staging/fbtft/fb_tinylcd.c b/drivers/staging/fbtft/fb_= tinylcd.c index 9469248f2c50..ee8d6b10374a 100644 --- a/drivers/staging/fbtft/fb_tinylcd.c +++ b/drivers/staging/fbtft/fb_tinylcd.c @@ -41,7 +41,7 @@ static int init_display(struct fbtft_par *par) 0x00, 0x35, 0x33, 0x00, 0x00, 0x00); write_reg(par, MIPI_DCS_SET_PIXEL_FORMAT, 0x55); write_reg(par, MIPI_DCS_EXIT_SLEEP_MODE); - udelay(250); + usleep_range(250, 400); write_reg(par, MIPI_DCS_SET_DISPLAY_ON); =20 return 0; diff --git a/drivers/staging/fbtft/fb_upd161704.c b/drivers/staging/fbtft/f= b_upd161704.c index c680160d6380..aed5cc7cabde 100644 --- a/drivers/staging/fbtft/fb_upd161704.c +++ b/drivers/staging/fbtft/fb_upd161704.c @@ -32,7 +32,7 @@ static int init_display(struct fbtft_par *par) =20 /* oscillator start */ write_reg(par, 0x003A, 0x0001); /*Oscillator 0: stop, 1: operation */ - udelay(100); + usleep_range(100, 200); =20 /* y-setting */ write_reg(par, 0x0024, 0x007B); /* amplitude setting */ @@ -60,7 +60,7 @@ static int init_display(struct fbtft_par *par) =20 /* Power supply setting */ write_reg(par, 0x0019, 0x0000); /* DC/DC output setting */ - udelay(200); + usleep_range(200, 400); write_reg(par, 0x001A, 0x1000); /* DC/DC frequency setting */ write_reg(par, 0x001B, 0x0023); /* DC/DC rising setting */ write_reg(par, 0x001C, 0x0C01); /* Regulator voltage setting */ --=20 2.34.1