[PATCH] SPI: DUAL and QUAD support

[yuhang wang]

Hi,

2013/7/29 Matthieu CASTET <matthieu.castet at parrot.com>:
> Le Mon, 29 Jul 2013 11:53:14 +0100,
> wangyuhang <wangyuhang2014 at gmail.com> a écrit :
>
>> Hi,
>>
>> modify two things.
>> 1:
>> >> @@ -1316,6 +1324,12 @@ int spi_setup(struct spi_device *spi)
>> >>         /* help drivers fail *cleanly* when they need options
>> >>          * that aren't supported with their current master
>> >>          */
>> >> +       if (((spi->mode >> 8) & 0x03) == 0x03 ||
>> >> +               ((spi->mode >> 10) & 0x03) == 0x03) {
>> >> +               dev_err(&spi->dev,
>> >> +               "setup: can not select dual and quad at the same
>> >> time\n")
>> >> +               return -EINVAL;
>> >> +       }
>> >> +               return -EINVAL;
>> >> +       }
>>
>> >This code won't work if the constants you added for mode flags change
>> >value.  More importantly, anyone searching the code for SPI_TX_DUAL,
>> >etc. won't find this code.
>>
>> so use the certain macro to replace.
>>
>> 2:
>> >You need to make sure that existing userspace binaries can run
>> >unmodified, changing the types will change the layout of the ioctl
>> >arguments.  This may mean that you need to add new ioctls if you
>> >need to change types.
>>
>> I recovered the SPI_IOC_RD_LSB_FIRST ioctl.
>> Add new ioctl to fit u16 mode.
>> In addition,may SPI_IOC_RD_LSB_FIRST should be del in a better way.
>>
>> Signed-off-by: wangyuhang <wangyuhang2014 at gmail.com>
>> ---
>
>>  /* IOCTL commands */
>> @@ -54,6 +61,8 @@
>>   * @tx_buf: Holds pointer to userspace buffer with transmit data, or
>> null.
>>   *     If no data is provided, zeroes are shifted out.
>>   * @rx_buf: Holds pointer to userspace buffer for receive data, or
>> null.
>> + * @tx_nbits: number of bits used for writting.
>> + * @rx_nbits: number of bits used for reading.
>>   * @len: Length of tx and rx buffers, in bytes.
>>   * @speed_hz: Temporary override of the device's bitrate.
>>   * @bits_per_word: Temporary override of the device's wordsize.
>> @@ -85,6 +94,8 @@
>>  struct spi_ioc_transfer {
>>         __u64           tx_buf;
>>         __u64           rx_buf;
>> +       __u8            tx_nbits;
>> +       __u8            rx_nbits;
>>
>>         __u32           len;
>>         __u32           speed_hz;
> You still break old userspace ABI.
>
> You need to create a new structure, if you need to add fields.
>
I dont think adding the members will cause the program in userspace
any errors. User do not have to set these members.
Thanks