| Message ID | 20190716204651.7743-1-linus.walleij@linaro.org |
|---|---|
| State | Accepted |
| Commit | 2922d1cc1696200a3e1fd6d82a7798fcd2cadf12 |
| Headers | show |
| Series | spi: gpio: Add SPI_MASTER_GPIO_SS flag | expand |
diff --git a/drivers/spi/spi-gpio.c b/drivers/spi/spi-gpio.c index eca9d52ecf65..9eb82150666e 100644 --- a/drivers/spi/spi-gpio.c +++ b/drivers/spi/spi-gpio.c @@ -410,6 +410,12 @@ static int spi_gpio_probe(struct platform_device *pdev) bb = &spi_gpio->bitbang; bb->master = master; + /* + * There is some additional business, apart from driving the CS GPIO + * line, that we need to do on selection. This makes the local + * callback for chipselect always get called. + */ + master->flags |= SPI_MASTER_GPIO_SS; bb->chipselect = spi_gpio_chipselect; bb->set_line_direction = spi_gpio_set_direction;
The GPIO SPI master has some code in its local CS callback to set the initial sck GPIO value. This was lost in the commit converting it to use SPI core GPIO handling as this callback isn't called if the internal GPIO handling is active. Add the special SPI_MASTER_GPIO_SS to ascertain it gets called anyway so we get the initial SCK setting right. There is some platform provided GPIO handling there as well but this will be skipped as the cs_gpios will be NULL. My test targets seem not to care about the initial SCK value so I am uncertain if this is a regression, but to preserve the previous semantic we better do this. Cc: Andrey Smirnov <andrew.smirnov@gmail.com> Fixes: 249e2632dcd0 ("spi: gpio: Don't request CS GPIO in DT use-case") Signed-off-by: Linus Walleij <linus.walleij@linaro.org> --- drivers/spi/spi-gpio.c | 6 ++++++ 1 file changed, 6 insertions(+) -- 2.21.0