From 32f0def83290cc30a921ff9ff0e8f57071035799 Mon Sep 17 00:00:00 2001 From: Mika Westerberg Date: Thu, 9 Jan 2014 15:23:55 +0200 Subject: [PATCH] spi: Check conflicting CS based on spi->chip_select instead of device name Commit 931461c71c8e (spi: Use stable dev_name for ACPI enumerated SPI slaves) changed the SPI device naming to be based on ACPI device name instead of carrying bus number and chip select for devices enumerated from ACPI namespace. In case of a buggy BIOS that lists multiple SPI devices sharing the same chip select (even though they should use different) the current code fails to detect that and allows the devices to be added to the bus. Fix this by walking through the bus and comparing spi->chip_select instead of device name. This should work regardless what the device name will be in future. Signed-off-by: Mika Westerberg Acked-by: Jarkko Nikula Signed-off-by: Mark Brown --- drivers/spi/spi.c | 18 +++++++++++++----- 1 file changed, 13 insertions(+), 5 deletions(-) diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index 0e215237383b5..51e00c6436aa5 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -370,6 +370,17 @@ static void spi_dev_set_name(struct spi_device *spi) spi->chip_select); } +static int spi_dev_check(struct device *dev, void *data) +{ + struct spi_device *spi = to_spi_device(dev); + struct spi_device *new_spi = data; + + if (spi->master == new_spi->master && + spi->chip_select == new_spi->chip_select) + return -EBUSY; + return 0; +} + /** * spi_add_device - Add spi_device allocated with spi_alloc_device * @spi: spi_device to register @@ -384,7 +395,6 @@ int spi_add_device(struct spi_device *spi) static DEFINE_MUTEX(spi_add_lock); struct spi_master *master = spi->master; struct device *dev = master->dev.parent; - struct device *d; int status; /* Chipselects are numbered 0..max; validate. */ @@ -404,12 +414,10 @@ int spi_add_device(struct spi_device *spi) */ mutex_lock(&spi_add_lock); - d = bus_find_device_by_name(&spi_bus_type, NULL, dev_name(&spi->dev)); - if (d != NULL) { + status = bus_for_each_dev(&spi_bus_type, NULL, spi, spi_dev_check); + if (status) { dev_err(dev, "chipselect %d already in use\n", spi->chip_select); - put_device(d); - status = -EBUSY; goto done; } -- 2.39.5