linux-kernel - Re: Input: cyttsp4 - SPI driver for Cypress TMA4XX touchscreen devices

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Date:	Sun, 7 Jul 2013 21:15:24 +0200
From:	Geert Uytterhoeven <geert@...ux-m68k.org>
To:	Ferruh Yigit <fery@...ress.com>,
	Javier Martinez Canillas <javier@...hile0.org>,
	Dmitry Torokhov <dmitry.torokhov@...il.com>
Cc:	"linux-input@...r.kernel.org" <linux-input@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: Input: cyttsp4 - SPI driver for Cypress TMA4XX touchscreen devices

On Fri, Jul 5, 2013 at 1:51 AM, Linux Kernel Mailing List
<linux-kernel@...r.kernel.org> wrote:
> +++ b/drivers/input/touchscreen/cyttsp4_spi.c

> +static int cyttsp_spi_xfer(struct device *dev, u8 *xfer_buf,
> +                          u8 op, u8 reg, u8 *buf, int length)
> +{

> +       if (reg > 255)

As "reg" is "u8", this is never true:

drivers/input/touchscreen/cyttsp4_spi.c: In function ‘cyttsp_spi_xfer’:
drivers/input/touchscreen/cyttsp4_spi.c:66: warning: comparison is
always false due to limited range of data type

> +               wr_buf[0] = op + CY_SPI_A8_BIT;
> +       else
> +               wr_buf[0] = op;

Can the if-clause and the first branch just be removed, or is there a real bug
involved (e.g. wrong type for "reg")?

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@...ux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds
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