mpc8xxx_spi: Fix polarity inversion in chipselect
PATCH 1/1 mpc8xxx_spi: Fix polarity inversion in chipselect
If we use open firmware, then alow_flags handles active-low chipselects, which is the same as SPI_CS_HIGH. This patch fixes the double negative.
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Anton,
thanks to your device table matching support patch I can use open firmware to configure two spi devices on 8360E. I use the gpios node, with flags set to 1, matching OF_GPIO_ACTIVE_LOW. When I do this I notice that the polarity was already handled in a different way. Did some searching and didn't find it had been discussed. Here's what I am doing now - feel free to use it or abuse it :) (based in galak-powerpc/next plus your patches 1 and 2)
drivers/spi/spi_mpc8xxx.c | 10 ++-------- 1 files changed, 2 insertions(+), 8 deletions(-)
drivers/spi/spi_mpc8xxx.c +2 -8
@@ -159,14 +159,8 @@ static void mpc8xxx_spi_chipselect(struct spi_device *spi, int value) {struct mpc8xxx_spi *mpc8xxx_spi =spi_master_get_devdata (spi->master);struct fsl_spi_platform_data *pdata = spi->dev.parent->platform_data; -bool pol = spi->mode &SPI_CS_HIGH ;struct spi_mpc8xxx_cs *cs = spi->controller_state; -if (value ==BITBANG_CS_INACTIVE ) { -if (pdata->cs_control) - pdata->cs_control (spi, !pol); - } -if (value ==BITBANG_CS_ACTIVE ) {u32 regval =mpc8xxx_spi_read_reg (&mpc8xxx_spi->base->mode);
@@ -189,9 +183,9 @@ static void mpc8xxx_spi_chipselect(struct spi_device *spi, int value)mpc8xxx_spi_write_reg (mode, regval);local_irq_restore (flags); } -if (pdata->cs_control) - pdata->cs_control (spi, pol); } +if (pdata->cs_control) + pdata->cs_control (spi, value); } static
Signature · 1 line
1.6.3.3
Quoted 3 lines · Michael Barkowski
If we use open firmware, then
alow_flagshandles active-low chipselects, which is the same asSPI_CS_HIGH. This patch fixes the double negative.
Hang on - I missed your most recent patches to spi_mpc8xxx
--Michael
Anton - thanks for the offline correction.
SPI_CS_HIGH means that the device interprets high as active. The alow flag means there is an inverter somewhere.
My mistake - patch retracted.
Signature · 1 line
Michael