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Subject: Re: [PATCH v2 1/1] Input: atmel_mxt_ts - allow specification of
 firmware file name
To:     Jiada Wang <jiada_wang@mentor.com>, nick@shmanahar.org,
        dmitry.torokhov@gmail.com
Cc:     linux-input@vger.kernel.org, linux-kernel@vger.kernel.org,
        erosca@de.adit-jv.com, Andrew_Gabbasov@mentor.com
References: <20200821075410.8250-1-jiada_wang@mentor.com>
From:   Dmitry Osipenko <digetx@gmail.com>
Message-ID: <081a63b6-b34e-1e52-50ac-b44255c8ed40@gmail.com>
Date:   Fri, 28 Aug 2020 11:08:14 +0300
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21.08.2020 10:54, Jiada Wang пишет:
> From: Nick Dyer <nick.dyer@itdev.co.uk>
> 
> On platforms which have multiple device instances using this driver, the
> firmware may be different on each device. This patch makes the user give
> the name of the firmware file when flashing.
> 
> If user specified firmware file can't be found, then driver will try to
> flash default firmware "maxtouch.fw".
> 
> Signed-off-by: Nick Dyer <nick.dyer@itdev.co.uk>
> Acked-by: Benson Leung <bleung@chromium.org>
> Acked-by: Yufeng Shen <miletus@chromium.org>
> (cherry picked from ndyer/linux/for-upstream commit 76ebb7cee971cb42dfb0a3a9224403b8b09abcf1)
> [gdavis: Forward port and fix conflicts.]
> Signed-off-by: George G. Davis <george_davis@mentor.com>
> [jiada: change to flash default firmware file, when user specified firmware can't be found]
> Signed-off-by: Jiada Wang <jiada_wang@mentor.com>
> ---
>  drivers/input/touchscreen/atmel_mxt_ts.c | 33 +++++++++++++++++++++++-
>  1 file changed, 32 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/input/touchscreen/atmel_mxt_ts.c b/drivers/input/touchscreen/atmel_mxt_ts.c
> index a2189739e30f..a20bc1bf8d52 100644
> --- a/drivers/input/touchscreen/atmel_mxt_ts.c
> +++ b/drivers/input/touchscreen/atmel_mxt_ts.c
> @@ -34,6 +34,7 @@
>  #define MXT_FW_NAME		"maxtouch.fw"
>  #define MXT_CFG_NAME		"maxtouch.cfg"
>  #define MXT_CFG_MAGIC		"OBP_RAW V1"
> +#define MAX_FILENAME_SIZE	64
>  
>  /* Registers */
>  #define MXT_OBJECT_START	0x07
> @@ -308,6 +309,7 @@ struct mxt_data {
>  	struct t7_config t7_cfg;
>  	struct mxt_dbg dbg;
>  	struct gpio_desc *reset_gpio;
> +	char fw_name[MAX_FILENAME_SIZE];
>  
>  	/* Cached parameters from object table */
>  	u16 T5_address;
> @@ -2887,6 +2889,26 @@ static int mxt_load_fw(struct device *dev, const char *fn)
>  	return ret;
>  }
>  
> +static int mxt_update_file_name(struct device *dev, char *file_name,
> +				const char *buf, size_t count)
> +{
> +	size_t len = count;
> +
> +	/* Echo into the sysfs entry may append newline at the end of buf */
> +	if (buf[count - 1] == '\n')
> +		len = count - 1;
> +
> +	/* Simple sanity check */
> +	if (len > MAX_FILENAME_SIZE - 1) {
> +		dev_warn(dev, "File name too long\n");
> +		return -EINVAL;
> +	}
> +
> +	strscpy(file_name, buf, len + 1);
> +
> +	return 0;
> +}
> +
>  static ssize_t mxt_update_fw_store(struct device *dev,
>  					struct device_attribute *attr,
>  					const char *buf, size_t count)
> @@ -2894,7 +2916,16 @@ static ssize_t mxt_update_fw_store(struct device *dev,
>  	struct mxt_data *data = dev_get_drvdata(dev);
>  	int error;
>  
> -	error = mxt_load_fw(dev, MXT_FW_NAME);
> +	error = mxt_update_file_name(dev, data->fw_name, buf, count);
> +	if (error)
> +		return error;
> +
> +	error = mxt_load_fw(dev, data->fw_name);
> +	if (error) {
> +		dev_warn(dev, "try %s instead\n", MXT_FW_NAME);

Hello, Jiada!

Will this message be printed even if fw_name is an empty string or
whatever string that is already used by existing userspace for writing
to update_fw?

Maybe it actually should be better to add a new device attribute that
will take the fw_name? Then the old attribute will continue to work like
it worked before.

> +		error = mxt_load_fw(dev, MXT_FW_NAME);
> +	}
> +
>  	if (error) {
>  		dev_err(dev, "The firmware update failed(%d)\n", error);
>  		count = error;
>