linux-kernel - Re: [PATCH v1 1/3] Input: ili210x - do not retrieve/print chip firmware version

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Message-ID: <20191112233421.eh44mv6ji2tk6ki2@earth.universe>
Date:   Wed, 13 Nov 2019 00:34:21 +0100
From:   Sebastian Reichel <sre@...nel.org>
To:     Sven Van Asbroeck <thesven73@...il.com>
Cc:     Dmitry Torokhov <dmitry.torokhov@...il.com>,
        Marek Vasut <marex@...x.de>, Adam Ford <aford173@...il.com>,
        linux-kernel@...r.kernel.org, linux-input@...r.kernel.org
Subject: Re: [PATCH v1 1/3] Input: ili210x - do not retrieve/print chip
 firmware version

Hi,

On Tue, Nov 12, 2019 at 11:44:27AM -0500, Sven Van Asbroeck wrote:
> The driver's method to retrieve the firmware version on ili2117/
> ili2118 chip flavours is incorrect. The firmware version register
> address and layout are wrong.
> 
> The firmware version is not actually used anywhere inside or
> outside this driver. There is a dev_dbg() print, but that is
> only visible when the developer explicitly compiles in debug
> support.
> 
> Don't make the code more complicated to preserve a feature that
> no-one is using. Remove all code associated with chip firmware
> version.
> 
> Link: https://lore.kernel.org/lkml/20191111181657.GA57214@dtor-ws/
> Cc: Marek Vasut <marex@...x.de>
> Cc: Adam Ford <aford173@...il.com>
> Cc: <linux-kernel@...r.kernel.org>
> Cc: linux-input@...r.kernel.org
> Tree: https://git.kernel.org/pub/scm/linux/kernel/git/dtor/input.git/log/?h=next
> Signed-off-by: Sven Van Asbroeck <TheSven73@...il.com>
> ---

The firmware version check does one relevant thing: It tests
the I2C communication, which tends to be useful for board
bringup and development boards (which often allow to disconnect
(touch-)screens).

-- Sebastian

>  drivers/input/touchscreen/ili210x.c | 21 ---------------------
>  1 file changed, 21 deletions(-)
> 
> diff --git a/drivers/input/touchscreen/ili210x.c b/drivers/input/touchscreen/ili210x.c
> index 0ed6014af6d7..a6feae5ce887 100644
> --- a/drivers/input/touchscreen/ili210x.c
> +++ b/drivers/input/touchscreen/ili210x.c
> @@ -21,15 +21,8 @@
>  /* Touchscreen commands */
>  #define REG_TOUCHDATA		0x10
>  #define REG_PANEL_INFO		0x20
> -#define REG_FIRMWARE_VERSION	0x40
>  #define REG_CALIBRATE		0xcc
>  
> -struct firmware_version {
> -	u8 id;
> -	u8 major;
> -	u8 minor;
> -} __packed;
> -
>  struct ili2xxx_chip {
>  	int (*read_reg)(struct i2c_client *client, u8 reg,
>  			void *buf, size_t len);
> @@ -342,7 +335,6 @@ static int ili210x_i2c_probe(struct i2c_client *client,
>  	struct ili210x *priv;
>  	struct gpio_desc *reset_gpio;
>  	struct input_dev *input;
> -	struct firmware_version firmware;
>  	int error;
>  
>  	dev_dbg(dev, "Probing for ILI210X I2C Touschreen driver");
> @@ -389,15 +381,6 @@ static int ili210x_i2c_probe(struct i2c_client *client,
>  	priv->chip = chip;
>  	i2c_set_clientdata(client, priv);
>  
> -	/* Get firmware version */
> -	error = chip->read_reg(client, REG_FIRMWARE_VERSION,
> -			       &firmware, sizeof(firmware));
> -	if (error) {
> -		dev_err(dev, "Failed to get firmware version, err: %d\n",
> -			error);
> -		return error;
> -	}
> -
>  	/* Setup input device */
>  	input->name = "ILI210x Touchscreen";
>  	input->id.bustype = BUS_I2C;
> @@ -439,10 +422,6 @@ static int ili210x_i2c_probe(struct i2c_client *client,
>  		return error;
>  	}
>  
> -	dev_dbg(dev,
> -		"ILI210x initialized (IRQ: %d), firmware version %d.%d.%d",
> -		client->irq, firmware.id, firmware.major, firmware.minor);
> -
>  	return 0;
>  }
>  
> -- 
> 2.17.1
> 

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