Hi,
2013/7/29 Matthieu CASTET <matthieu.cas...@parrot.com>:
> Le Mon, 29 Jul 2013 11:53:14 +0100,
> wangyuhang <wangyuhang2...@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 <wangyuhang2...@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
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