From 0e793ba77c18382f08e440260fe72bc6fce2a3cb Mon Sep 17 00:00:00 2001 From: Charles Keepax Date: Wed, 21 Apr 2021 11:14:02 +0100 Subject: [PATCH 1/3] spi: Make of_register_spi_device also set the fwnode Currently, the SPI core doesn't set the struct device fwnode pointer when it creates a new SPI device. This means when the device is registered the fwnode is NULL and the check in device_add which sets the fwnode->dev pointer is skipped. This wasn't previously an issue, however these two patches: commit 4731210c09f5 ("gpiolib: Bind gpio_device to a driver to enable fw_devlink=on by default") commit ced2af419528 ("gpiolib: Don't probe gpio_device if it's not the primary device") Added some code to the GPIO core which relies on using that fwnode->dev pointer to determine if a driver is bound to the fwnode and if not bind a stub GPIO driver. This means the GPIO providers behind SPI will get both the expected driver and this stub driver causing the stub driver to fail if it attempts to request any pin configuration. For example on my system: madera-pinctrl madera-pinctrl: pin gpio5 already requested by madera-pinctrl; cannot claim for gpiochip3 madera-pinctrl madera-pinctrl: pin-4 (gpiochip3) status -22 madera-pinctrl madera-pinctrl: could not request pin 4 (gpio5) from group aif1 on device madera-pinctrl gpio_stub_drv gpiochip3: Error applying setting, reverse things back gpio_stub_drv: probe of gpiochip3 failed with error -22 The firmware node on the device created by the GPIO framework is set through the of_node pointer hence things generally actually work, however that fwnode->dev is never set, as the check was skipped at device_add time. This fix appears to match how the I2C subsystem handles the same situation. Signed-off-by: Charles Keepax Link: https://lore.kernel.org/r/20210421101402.8468-1-ckeepax@opensource.cirrus.com Signed-off-by: Mark Brown --- drivers/spi/spi.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index 904a353798b6..862a9bb69129 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -2047,6 +2047,7 @@ of_register_spi_device(struct spi_controller *ctlr, struct device_node *nc) /* Store a pointer to the node in the device structure */ of_node_get(nc); spi->dev.of_node = nc; + spi->dev.fwnode = of_fwnode_handle(nc); /* Register the new device */ rc = spi_add_device(spi); From dbaca8e56ea3f23fa215f48c2d46dd03ede06e02 Mon Sep 17 00:00:00 2001 From: Andy Shevchenko Date: Tue, 20 Apr 2021 19:44:24 +0300 Subject: [PATCH 2/3] spi: Allow to have all native CSs in use along with GPIOs The commit 7d93aecdb58d ("spi: Add generic support for unused native cs with cs-gpios") excludes the valid case for the controllers that doesn't need to switch native CS in order to perform the transfer, i.e. when 0 native ... ... - 1 native GPIO + 1 GPIO ... ... where defines maximum of native CSs supported by the controller. To allow this, bail out from spi_get_gpio_descs() conditionally for the controllers which explicitly marked with SPI_MASTER_GPIO_SS. Fixes: 7d93aecdb58d ("spi: Add generic support for unused native cs with cs-gpios") Signed-off-by: Andy Shevchenko Link: https://lore.kernel.org/r/20210420164425.40287-1-andriy.shevchenko@linux.intel.com Signed-off-by: Mark Brown --- drivers/spi/spi.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index 862a9bb69129..2e5dca20c8d0 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -2612,8 +2612,9 @@ static int spi_get_gpio_descs(struct spi_controller *ctlr) } ctlr->unused_native_cs = ffz(native_cs_mask); - if (num_cs_gpios && ctlr->max_native_cs && - ctlr->unused_native_cs >= ctlr->max_native_cs) { + + if ((ctlr->flags & SPI_MASTER_GPIO_SS) && num_cs_gpios && + ctlr->max_native_cs && ctlr->unused_native_cs >= ctlr->max_native_cs) { dev_err(dev, "No unused native chip select available\n"); return -EINVAL; } From f60d7270c8a3d2beb1c23ae0da42497afa3584c2 Mon Sep 17 00:00:00 2001 From: Andy Shevchenko Date: Tue, 20 Apr 2021 19:44:25 +0300 Subject: [PATCH 3/3] spi: Avoid undefined behaviour when counting unused native CSs ffz(), that has been used to count unused native CSs, might cause undefined behaviour when called against ~0U. To fix that, open code it with ffs(~value) - 1. Fixes: 7d93aecdb58d ("spi: Add generic support for unused native cs with cs-gpios") Signed-off-by: Andy Shevchenko Link: https://lore.kernel.org/r/20210420164425.40287-2-andriy.shevchenko@linux.intel.com Signed-off-by: Mark Brown --- drivers/spi/spi.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index 2e5dca20c8d0..6fe2a9509675 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -2611,7 +2611,7 @@ static int spi_get_gpio_descs(struct spi_controller *ctlr) native_cs_mask |= BIT(i); } - ctlr->unused_native_cs = ffz(native_cs_mask); + ctlr->unused_native_cs = ffs(~native_cs_mask) - 1; if ((ctlr->flags & SPI_MASTER_GPIO_SS) && num_cs_gpios && ctlr->max_native_cs && ctlr->unused_native_cs >= ctlr->max_native_cs) {