linux-kernel - Re: [PATCH 06/10] Input: atmel_mxt_ts - destroy state before fw update and restore after

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Date:	Wed, 13 Feb 2013 13:47:42 -0800
From:	Dmitry Torokhov <dmitry.torokhov@...il.com>
To:	Daniel Kurtz <djkurtz@...omium.org>
Cc:	Henrik Rydberg <rydberg@...omail.se>,
	Benson Leung <bleung@...omium.org>,
	Yufeng Shen <miletus@...omium.org>,
	Nick Dyer <nick.dyer@...ev.co.uk>,
	Joonyoung Shim <jy0922.shim@...sung.com>,
	linux-input@...r.kernel.org, linux-kernel@...r.kernel.org,
	olofj@...omium.org
Subject: Re: [PATCH 06/10] Input: atmel_mxt_ts - destroy state before fw
 update and restore after

On Fri, Feb 01, 2013 at 04:11:48PM +0800, Daniel Kurtz wrote:
> After firmware update, the device may have a completely different object
> table which corresponds to an input device with different properties.
> So, destroy the old state before firmware update, and completely
> reinitialize the driver afterward.
> 
> Two benefits of this:
>  1) Since there is no input device during fw update, no need to worry
> about device open/close events.
>  2) If firmware update fails, the device and driver will still be in
> bootloader mode and an improperly configured input device will not exist.
> 
> Signed-off-by: Daniel Kurtz <djkurtz@...omium.org>
> ---
>  drivers/input/touchscreen/atmel_mxt_ts.c | 10 ++++++++--
>  1 file changed, 8 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/input/touchscreen/atmel_mxt_ts.c b/drivers/input/touchscreen/atmel_mxt_ts.c
> index 76a25d3..c74f5a5 100644
> --- a/drivers/input/touchscreen/atmel_mxt_ts.c
> +++ b/drivers/input/touchscreen/atmel_mxt_ts.c
> @@ -1001,6 +1001,13 @@ static int mxt_load_fw(struct device *dev, const char *fn)
>  		client->addr = MXT_BOOT_HIGH;
>  
>  bootloader_ready:
> +	/* Free any driver state. It will get reinitialized after fw update. */
> +	mxt_free_object_table(data);
> +	if (data->input_dev) {
> +		input_unregister_device(data->input_dev);
> +		data->input_dev = NULL;
> +	}
> +
>  	ret = mxt_check_bootloader(client, MXT_WAITING_BOOTLOAD_CMD);
>  	if (ret)
>  		goto out;
> @@ -1068,9 +1075,8 @@ static ssize_t mxt_update_fw_store(struct device *dev,
>  		/* Wait for reset */
>  		msleep(MXT_FWRESET_TIME);
>  
> -		mxt_free_object_table(data);
> -
>  		mxt_initialize(data);
> +		mxt_input_dev_create(data);

What if it fails?

>  	}
>  
>  	enable_irq(data->irq);
> -- 
> 1.8.1
> 

-- 
Dmitry
--
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