openkylin
/
linux
mirror of https://gitee.com/openkylin/linux.git
9
0
Fork 0
Code Issues Projects Releases Wiki Activity

spi: a3700: Change SPI mode before asserting chip-select 

The spi device mode should be configured in the controller before the
chip-select is asserted, so that a clock polarity configuration change
is not interpreted as a clock tick by the device.

This patch moves the mode setting to the 'prepare_message' function
instead of the 'transfer_one' function.

By doing so, this patch also removes redundant code in
a3700_spi_clock_set.

This was tested on EspressoBin board, with spidev.

Signed-off-by: Maxime Chevallier <maxime.chevallier@smile.fr>
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Maxime Chevallier 2017-10-10 10:43:18 +02:00 committed by Mark Brown
parent 5a866ec001
commit dd7aa8d4b5
1 changed files with 4 additions and 13 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

17
drivers/spi/spi-armada-3700.c
View File

@ -213,7 +213,7 @@ static void a3700_spi_mode_set(struct a3700_spi *a3700_spi,
}
static void a3700_spi_clock_set(struct a3700_spi *a3700_spi,
unsigned int speed_hz, u16 mode)
unsigned int speed_hz)
{
u32 val;
u32 prescale;
@ -231,17 +231,6 @@ static void a3700_spi_clock_set(struct a3700_spi *a3700_spi,
val |= A3700_SPI_CLK_CAPT_EDGE;
spireg_write(a3700_spi, A3700_SPI_IF_TIME_REG, val);
}
val = spireg_read(a3700_spi, A3700_SPI_IF_CFG_REG);
val &= ~(A3700_SPI_CLK_POL | A3700_SPI_CLK_PHA);
if (mode & SPI_CPOL)
val |= A3700_SPI_CLK_POL;
if (mode & SPI_CPHA)
val |= A3700_SPI_CLK_PHA;
spireg_write(a3700_spi, A3700_SPI_IF_CFG_REG, val);
}
static void a3700_spi_bytelen_set(struct a3700_spi *a3700_spi, unsigned int len)
@ -423,7 +412,7 @@ static void a3700_spi_transfer_setup(struct spi_device *spi,
a3700_spi = spi_master_get_devdata(spi->master);
a3700_spi_clock_set(a3700_spi, xfer->speed_hz, spi->mode);
a3700_spi_clock_set(a3700_spi, xfer->speed_hz);
byte_len = xfer->bits_per_word >> 3;
@ -584,6 +573,8 @@ static int a3700_spi_prepare_message(struct spi_master *master,
a3700_spi_bytelen_set(a3700_spi, 4);
a3700_spi_mode_set(a3700_spi, spi->mode);
return 0;
}