H Hartley Sweeten wrote on 2010-05-19:
> On Wednesday, May 19, 2010 3:01 AM, Michael Hennerich wrote:
>> Similar patch as reported by Oskar Schirmer <os@xxxxxxxxx> for the
>> AD7877.
>>
>> With no word size given in the users platform data, a generic spi host
>> controller driver will assume a default word size of eight bit. Ensure
>> spi->bits_per_word is set for 16-bit transfers.
>>
>> Signed-off-by: Michael Hennerich <Michael.hennerich@xxxxxxxxxx>
>> ---
>> drivers/input/touchscreen/ad7879.c | 10 ++++++++++
>> 1 files changed, 10 insertions(+), 0 deletions(-)
>> diff --git a/drivers/input/touchscreen/ad7879.c
>> b/drivers/input/touchscreen/ad7879.c
>> index 794d070..ff490c0 100644
>> --- a/drivers/input/touchscreen/ad7879.c
>> +++ b/drivers/input/touchscreen/ad7879.c
>> @@ -715,6 +715,16 @@ static int __devinit ad7879_probe(struct
>> spi_device
>> *spi)
>> return -EINVAL;
>> }
>> + if (spi->bits_per_word != 16) {
>
> The master never sets this field so this test isn't needed. The
> platform specific spi_board_info "could" set the field but I don't
> think any currently do.
Blackfin does!
Originally my assumption was that everyone does it - that's why this
haven't been fixed earlier.
>
> If the bits_per_word field is not set when spi_setup is called, it is
> set to the default value (8) before calling the spi master drivers
> setup routine.
> You just need to set the value since that is what the protocol
> requires. The spi_setup call is still needed since part of the probe
> for this driver does generate a spi transaction, you need to make sure
> the master driver will support the protocol before that happens.
>
>> + spi->bits_per_word = 16;
>> + error = spi_setup(spi);
>> + if (error) {
>> + dev_dbg(&spi->dev,
>> + "spi master doesn't support 16 bits/word\n");
>> + return error;
>> + }
>> + }
>> +
>> ts = kzalloc(sizeof(struct ad7879), GFP_KERNEL);
>> if (!ts)
>> return -ENOMEM;
>
> Regards,
> Hartley
Greetings,
Michael
Analog Devices GmbH Wilhelm-Wagenfeld-Str. 6 80807 Muenchen
Sitz der Gesellschaft Muenchen, Registergericht Muenchen HRB 4036 Geschaeftsfuehrer Thomas Wessel, William A. Martin, Margaret Seif
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