Re: [PATCH] staging: fbtft: fb_tinylcd: replace udelay() with usleep_range()

From: Greg KH

Date: Wed Mar 11 2026 - 11:04:47 EST


On Wed, Mar 11, 2026 at 02:24:07PM +0000, Anas Iqbal wrote:
> Replace udelay() with usleep_range() for a 250 microsecond delay
> as recommended by checkpatch.pl. usleep_range() avoids busy
> waiting and allows the scheduler to schedule other tasks.
>
> Signed-off-by: Anas Iqbal <mohd.abd.6602@xxxxxxxxx>
> ---
> drivers/staging/fbtft/fb_tinylcd.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/staging/fbtft/fb_tinylcd.c b/drivers/staging/fbtft/fb_tinylcd.c
> index 9469248f2c50..51e6493b050f 100644
> --- a/drivers/staging/fbtft/fb_tinylcd.c
> +++ b/drivers/staging/fbtft/fb_tinylcd.c
> @@ -38,10 +38,10 @@ static int init_display(struct fbtft_par *par)
> write_reg(par, 0xE5, 0x00);
> write_reg(par, 0xF0, 0x36, 0xA5, 0x53);
> write_reg(par, 0xE0, 0x00, 0x35, 0x33, 0x00, 0x00, 0x00,
> - 0x00, 0x35, 0x33, 0x00, 0x00, 0x00);
> + 0x00, 0x35, 0x33, 0x00, 0x00, 0x00);

Don't you think the original formatting makes more sense? And you did
not describe this change in the changelog :(

> write_reg(par, MIPI_DCS_SET_PIXEL_FORMAT, 0x55);
> write_reg(par, MIPI_DCS_EXIT_SLEEP_MODE);
> - udelay(250);
> + usleep_range(250, 500);

This is a totally different change than above. And also one that keeps
getting rejected, please see the mailing list archives for details.

thanks,

greg k-h