From 48c29d0d27fbbb4c78d3c14c50067d7e8919ed95 Mon Sep 17 00:00:00 2001 From: YueHaibing Date: Thu, 6 Sep 2018 01:38:45 +0000 Subject: spi: spi-gpio: Remove set but not used variable 'pdata' Fixes gcc '-Wunused-but-set-variable' warning: drivers/spi/spi-gpio.c: In function 'spi_gpio_remove': drivers/spi/spi-gpio.c:450:33: warning: variable 'pdata' set but not used [-Wunused-but-set-variable] Signed-off-by: YueHaibing Signed-off-by: Mark Brown --- drivers/spi/spi-gpio.c | 2 -- 1 file changed, 2 deletions(-) (limited to 'drivers/spi/spi-gpio.c') diff --git a/drivers/spi/spi-gpio.c b/drivers/spi/spi-gpio.c index 0626e6e3ea0c..d0c6d71b6c0f 100644 --- a/drivers/spi/spi-gpio.c +++ b/drivers/spi/spi-gpio.c @@ -447,10 +447,8 @@ static int spi_gpio_probe(struct platform_device *pdev) static int spi_gpio_remove(struct platform_device *pdev) { struct spi_gpio *spi_gpio; - struct spi_gpio_platform_data *pdata; spi_gpio = platform_get_drvdata(pdev); - pdata = dev_get_platdata(&pdev->dev); /* stop() unregisters child devices too */ spi_bitbang_stop(&spi_gpio->bitbang); -- cgit v1.2.3 From abf5feef3ff0cefade0c76be53b59e55fdd46093 Mon Sep 17 00:00:00 2001 From: Linus Walleij Date: Mon, 10 Sep 2018 00:28:05 +0200 Subject: spi: gpio: No MISO does not imply no RX There is a logical problem in spi-gpio with host just assigning a MOSI line and no MISO: this is interpreted as the host cannot do RX and the host is flagged with SPI_MASTER_NO_RX. This is wrong: since GPIO lines can switch direction, in 3WIRE operation the host will simply reverse the direction of the GPIO line and start reading from it, there is even code for doing this in the driver, but it went unnoticed because it was tested by using a master with 4 wires but a device using just 3 wires. Remove the offending flag. Cc: Andrzej Hajda Cc: Lorenzo Bianconi Signed-off-by: Linus Walleij Signed-off-by: Mark Brown --- drivers/spi/spi-gpio.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) (limited to 'drivers/spi/spi-gpio.c') diff --git a/drivers/spi/spi-gpio.c b/drivers/spi/spi-gpio.c index d0c6d71b6c0f..a2b08b464857 100644 --- a/drivers/spi/spi-gpio.c +++ b/drivers/spi/spi-gpio.c @@ -295,9 +295,11 @@ static int spi_gpio_request(struct device *dev, spi_gpio->miso = devm_gpiod_get_optional(dev, "miso", GPIOD_IN); if (IS_ERR(spi_gpio->miso)) return PTR_ERR(spi_gpio->miso); - if (!spi_gpio->miso) - /* HW configuration without MISO pin */ - *mflags |= SPI_MASTER_NO_RX; + /* + * No setting SPI_MASTER_NO_RX here - if there is only a MOSI + * pin connected the host can still do RX by changing the + * direction of the line. + */ spi_gpio->sck = devm_gpiod_get(dev, "sck", GPIOD_OUT_LOW); if (IS_ERR(spi_gpio->mosi)) @@ -423,7 +425,7 @@ static int spi_gpio_probe(struct platform_device *pdev) spi_gpio->bitbang.chipselect = spi_gpio_chipselect; spi_gpio->bitbang.set_line_direction = spi_gpio_set_direction; - if ((master_flags & (SPI_MASTER_NO_TX | SPI_MASTER_NO_RX)) == 0) { + if ((master_flags & SPI_MASTER_NO_TX) == 0) { spi_gpio->bitbang.txrx_word[SPI_MODE_0] = spi_gpio_txrx_word_mode0; spi_gpio->bitbang.txrx_word[SPI_MODE_1] = spi_gpio_txrx_word_mode1; spi_gpio->bitbang.txrx_word[SPI_MODE_2] = spi_gpio_txrx_word_mode2; -- cgit v1.2.3