linux-kernel - Re: [PATCH v1 04/63] Input: atmel_mxt_ts - split large i2c transfers into blocks

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Date:   Thu, 22 Aug 2019 14:24:39 +0900
From:   Jiada Wang <jiada_wang@...tor.com>
To:     Dmitry Torokhov <dmitry.torokhov@...il.com>
CC:     <nick@...anahar.org>, <linux-input@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>, <george_davis@...tor.com>
Subject: Re: [PATCH v1 04/63] Input: atmel_mxt_ts - split large i2c transfers
 into blocks

Hi Dmitry

On 2019/08/17 2:18, Dmitry Torokhov wrote:
> On Fri, Aug 16, 2019 at 05:28:53PM +0900, Jiada Wang wrote:
>> From: Nick Dyer <nick.dyer@...ev.co.uk>
>>
>> On some firmware variants, the size of the info block exceeds what can
>> be read in a single transfer.
>>
>> Signed-off-by: Nick Dyer <nick.dyer@...ev.co.uk>
>> (cherry picked from ndyer/linux/for-upstream commit 74c4f5277cfa403d43fafc404119dc57a08677db)
>> [gdavis: Forward port and fix conflicts due to v4.14.51 commit
>> 	 960fe000b1d3 ("Input: atmel_mxt_ts - fix the firmware
>> 	 update").]
>> Signed-off-by: George G. Davis <george_davis@...tor.com>
>> Signed-off-by: Jiada Wang <jiada_wang@...tor.com>
>> ---
>>   drivers/input/touchscreen/atmel_mxt_ts.c | 27 +++++++++++++++++++++---
>>   1 file changed, 24 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/input/touchscreen/atmel_mxt_ts.c b/drivers/input/touchscreen/atmel_mxt_ts.c
>> index 9b165d23e092..2d70ddf71cd9 100644
>> --- a/drivers/input/touchscreen/atmel_mxt_ts.c
>> +++ b/drivers/input/touchscreen/atmel_mxt_ts.c
>> @@ -40,7 +40,7 @@
>>   #define MXT_OBJECT_START	0x07
>>   #define MXT_OBJECT_SIZE		6
>>   #define MXT_INFO_CHECKSUM_SIZE	3
>> -#define MXT_MAX_BLOCK_WRITE	256
>> +#define MXT_MAX_BLOCK_WRITE	255
>>   
>>   /* Object types */
>>   #define MXT_DEBUG_DIAGNOSTIC_T37	37
>> @@ -659,6 +659,27 @@ static int __mxt_read_reg(struct i2c_client *client,
>>   	return ret;
>>   }
>>   
>> +static int mxt_read_blks(struct mxt_data *data, u16 start, u16 count, u8 *buf)
> 
> Can we call this __mxt_read_reg() and the original read reg call
> __mxt_read_chunk()?
>
yes, I will update in v2 patch-set,
so that every call to __mxt_read_reg() in atmel driver,
can have the feature to split large size transfer.

Thanks,
Jiada

>> +{
>> +	u16 offset = 0;
>> +	int error;
>> +	u16 size;
>> +
>> +	while (offset < count) {
>> +		size = min(MXT_MAX_BLOCK_WRITE, count - offset);
>> +
>> +		error = __mxt_read_reg(data->client,
>> +				       start + offset,
>> +				       size, buf + offset);
>> +		if (error)
>> +			return error;
>> +
>> +		offset += size;
>> +	}
>> +
>> +	return 0;
>> +}
> 
> Thanks.
>