tree 982a73f273d6c72d7bb25c7474a15706b2ba9e5f
parent 079e7f8709bb41cd0dc13efaffb24a0f17841955
author Hoan Nguyen An <na-hoan@jinso.co.jp> 1545295722 +0900
committer Mark Brown <broonie@kernel.org> 1545317771 +0000
gpgsig -----BEGIN PGP SIGNATURE-----
 
 iQFHBAABCgAxFiEEreZoqmdXGLWf4p/qJNaLcl1Uh9AFAlwbrYsTHGJyb29uaWVA
 a2VybmVsLm9yZwAKCRAk1otyXVSH0GLSB/0TyyKv9Ec2fuUahV5pjLRGBfgxZWpS
 b7k7K6Y0JBHa4mRmaYdTxgsDw6OXU7AtMAecUHBMoa3s0D+uzSn9jzxYg4+cLlsb
 09rvxtwzhiJgN/setCOaej4yLtj6LNjXgHdYpZjNHW66Gn+dMUfXHdlPXnd6g3Br
 xAp2Ju2EXVmS8yHEbHwqH5gj7dvpYLUPLucJY4GEuOF6skTORJbdE5uCM0iizTKf
 4TXWvIm95prbW9gjL9Vnh3PLqD3FlsWyXh8lWfeiBiSxeB3YR/84dyOx0qSqOvMN
 csTd3KAza7pJUqs68A81vksHH1bZBT42i7uVPQyvPBPiUrLiHmYctXGo
 =RMpy
 -----END PGP SIGNATURE-----

spi: sh-msiof: Reduce the number of times write to and perform the transmission from FIFO

The current state of the spi-sh-msiof, in master transfer mode: if t-> bits_per_word <= 8,
if the data length is divisible by 4 ((len & 3) = 0), the length of each word will be 32 bits
In case of data length can not be divisible by 4 ((len & 3) != 0), always set each word to be
8 bits, this will increase the number of times that write to FIFO, increasing the number of
times it should be transmitted. Assume that the number of bytes of data length more than 64 bytes,
each transmission will write 64 times into the TFDR then transmit, a maximum one-time
transmission will transmit 64 bytes if each word is 8 bits long.

Switch to setting if t->bits_per_word <= 8, the word length will be 32 bits although the data
length is not divisible by 4, then if leftover, will transmit the balance and the length of each
words is 1 byte. The maximum each can transmit up to 64 x 4 (Data Size = 32 bits (4 bytes)) = 256 bytes.
TMDR2 : Bits 28 to 24  BITLEN1[4:0] Data Size (8 to 32 bits)
        Bits 23 to 16  WDLEN1[7:0]  Word Count (1 to 64 words)

Signed-off-by: Hoan Nguyen An <na-hoan@jinso.co.jp>
Signed-off-by: Mark Brown <broonie@kernel.org>