linux-kernel - Re: [PATCH v2] Input: pixcir_i2c_ts - add support for one-time total calibration

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Message-ID: <07b84348-edb1-442f-822a-2e2c6275a8ad@ysoft.com>
Date: Mon, 26 Jan 2026 11:17:38 +0100
From: Michal Vokáč <michal.vokac@...ft.com>
To: Dmitry Torokhov <dmitry.torokhov@...il.com>
Cc: linux-input@...r.kernel.org, linux-kernel@...r.kernel.org,
 Fabio Estevam <festevam@...il.com>
Subject: Re: [PATCH v2] Input: pixcir_i2c_ts - add support for one-time total
 calibration

Hi Dmitry,

second polite ping. Is this falling through the cracks or did I miss to answer/resolve
some of your comments to v1?

On 18. 12. 25 11:22, Michal Vokáč wrote:
> Hi Dmitry,
> 
> gentle ping on this.
> 
> On 19. 11. 25 18:51, Michal Vokáč wrote:
>> The Pixcir Tango controller has support for a one-time total calibration
>> (manual calibration) procedure. Its purpose is to measure the capacitance
>> offsets of the electrode system and to store these values into EEPROM.
>>
>> During normal operation this calibration data is subtracted from the values
>> measured. This calibration should be necessary only once in the product
>> lifetime. It should be performed as part of the final adjustment after
>> the panel is mounted in the product.
>>
>> Add support for the calibration with sysfs interface.
>>
>> Signed-off-by: Michal Vokáč <michal.vokac@...ft.com>
>> ---
>> changes in v2:
>>   - Removed redundant lock from calibrate_store().
>>
>>   drivers/input/touchscreen/pixcir_i2c_ts.c | 26 +++++++++++++++++++++++
>>   1 file changed, 26 insertions(+)
>>
>> diff --git a/drivers/input/touchscreen/pixcir_i2c_ts.c b/drivers/input/touchscreen/pixcir_i2c_ts.c
>> index dad5786e82a4..e52ec8d8e392 100644
>> --- a/drivers/input/touchscreen/pixcir_i2c_ts.c
>> +++ b/drivers/input/touchscreen/pixcir_i2c_ts.c
>> @@ -24,6 +24,7 @@
>>    */
>>   #define PIXCIR_REG_POWER_MODE    51
>>   #define PIXCIR_REG_INT_MODE    52
>> +#define PIXCIR_REG_SPECOP    58
>>   /*
>>    * Power modes:
>> @@ -462,6 +463,30 @@ static int pixcir_i2c_ts_resume(struct device *dev)
>>   static DEFINE_SIMPLE_DEV_PM_OPS(pixcir_dev_pm_ops,
>>                   pixcir_i2c_ts_suspend, pixcir_i2c_ts_resume);
>> +static ssize_t calibrate_store(struct device *dev,
>> +                   struct device_attribute *attr,
>> +                   const char *buf, size_t count)
>> +{
>> +    struct i2c_client *client = to_i2c_client(dev);
>> +    struct pixcir_i2c_ts_data *ts = i2c_get_clientdata(client);
>> +    static const u8 cmd = 0x03;
>> +    int error;
>> +
>> +    error = i2c_smbus_write_byte_data(ts->client, PIXCIR_REG_SPECOP, cmd);
>> +    if (error)
>> +        dev_err(dev, "calibrate command failed: %d\n", error);
>> +
>> +    return error ?: count;
>> +}
>> +
>> +static DEVICE_ATTR_WO(calibrate);
>> +
>> +static struct attribute *pixcir_i2c_ts_attrs[] = {
>> +    &dev_attr_calibrate.attr,
>> +    NULL,
>> +};
>> +ATTRIBUTE_GROUPS(pixcir_i2c_ts);
>> +
>>   static int pixcir_i2c_ts_probe(struct i2c_client *client)
>>   {
>>       const struct i2c_device_id *id = i2c_client_get_device_id(client);
>> @@ -600,6 +625,7 @@ MODULE_DEVICE_TABLE(of, pixcir_of_match);
>>   static struct i2c_driver pixcir_i2c_ts_driver = {
>>       .driver = {
>>           .name    = "pixcir_ts",
>> +        .dev_groups = pixcir_i2c_ts_groups,
>>           .pm    = pm_sleep_ptr(&pixcir_dev_pm_ops),
>>           .of_match_table = of_match_ptr(pixcir_of_match),
>>       },

Best regards,
Michal