linux-kernel - Re: [PATCH 2/4] Input: goodix - Allow tweaking of configuration file dynamically

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Date:   Thu, 27 Oct 2016 11:58:59 -0500
From:   Franklin S Cooper Jr <fcooper@...com>
To:     Bastien Nocera <hadess@...ess.net>, <dmitry.torokhov@...il.com>,
        <robh+dt@...nel.org>, <octavian.purdila@...el.com>,
        <irina.tirdea@...el.com>, <merker@...ian.org>,
        <linux-input@...r.kernel.org>, <devicetree@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>, <nsekhar@...com>, <nm@...com>
Subject: Re: [PATCH 2/4] Input: goodix - Allow tweaking of configuration file
 dynamically



On 10/27/2016 05:33 AM, Bastien Nocera wrote:
> On Thu, 2016-10-20 at 14:59 -0500, Franklin S Cooper Jr wrote:
>> Some goodix touchscreen controllers don't have the correct
>> configuration
>> firmware for the display panel it is attached to. Therefore, settings
>> such
>> as touchscreen x and y size may need to be passed in via DT and have
>> the
>> panel reprogrammed for the updated touchscreen resolution.
>>
>> This patchset adds support for reading the current configuration
>> firmware
>> on the panel and allowing it to be modified and rewritten back to the
>> device.
>>
>> Currently this function is unused but later patches will make use of
>> it.
>>
>> Signed-off-by: Franklin S Cooper Jr <fcooper@...com>
>> ---
>>  drivers/input/touchscreen/goodix.c | 28 ++++++++++++++++++++++++++++
>>  1 file changed, 28 insertions(+)
>>
>> diff --git a/drivers/input/touchscreen/goodix.c
>> b/drivers/input/touchscreen/goodix.c
>> index a43c8ca..01e12f8 100644
>> --- a/drivers/input/touchscreen/goodix.c
>> +++ b/drivers/input/touchscreen/goodix.c
>> @@ -478,6 +478,34 @@ static int goodix_get_gpio_config(struct
>> goodix_ts_data *ts)
>>  	return 0;
>>  }
>>  
>> +static void goodix_tweak_config(struct goodix_ts_data *ts)
>> +{
>> +	u8 config[GOODIX_CONFIG_MAX_LENGTH];
>> +	int error;
>> +	int raw_cfg_len;
>> +	u8 check_sum = 0;
>> +
>> +	raw_cfg_len = ts->cfg_len - 2;
>> +
>> +	error = goodix_i2c_read(ts->client, GOODIX_REG_CONFIG_DATA,
>> +				config, ts->cfg_len);
>> +	if (error) {
>> +		dev_warn(&ts->client->dev,
>> +			 "Error reading config (%d), avoid tweaking
>> config\n",
>> +			 error);
>> +		return;
>> +	}
> 
> Please add a placeholder comment here, to go along with the commit
> message explanation.

You just want a comment here stating that changes to the firmware should
be made here?
> 
>> +	check_sum = goodix_calculate_checksum(ts->cfg_len, config);
>> +
>> +	config[raw_cfg_len] = check_sum;
>> +	config[raw_cfg_len + 1] = 1;
>> +
>> +	error = goodix_send_cfg(ts, ts->cfg_len, config);
>> +	if (error)
>> +		dev_warn(&ts->client->dev,
>> +			 "Error writing config (%d)\n", error);
>> +}
>>  /**
>>   * goodix_read_config - Read the embedded configuration of the panel
>>   *