From 12bfb2e05fc29bfbec7eb76ea8cc02e130268801 Mon Sep 17 00:00:00 2001 From: Simon Goldschmidt Date: Tue, 30 Oct 2018 21:09:48 +0100 Subject: [PATCH] dm: spi: prevent setting a speed of 0 Hz When the device tree is missing a correct spi slave description below the bus (compatible "spi-flash" or spi-max-frequency are missing), the 'set_speed' callback can be called with 'speed' == 0 Hz. At least with cadence qspi, this leads to a division by zero. Prevent this by initializing speed to 100 kHz in this case (same fallback value as is done in 'dm_spi_claim_bus') and issue a warning to console. Signed-off-by: Simon Goldschmidt Reviewed-by: Simon Glass --- drivers/spi/spi-uclass.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) diff --git a/drivers/spi/spi-uclass.c b/drivers/spi/spi-uclass.c index b84255bd27..2bc289a74c 100644 --- a/drivers/spi/spi-uclass.c +++ b/drivers/spi/spi-uclass.c @@ -15,6 +15,8 @@ DECLARE_GLOBAL_DATA_PTR; +#define SPI_DEFAULT_SPEED_HZ 100000 + static int spi_set_speed_mode(struct udevice *bus, int speed, int mode) { struct dm_spi_ops *ops; @@ -58,7 +60,7 @@ int dm_spi_claim_bus(struct udevice *dev) speed = spi->max_hz; } if (!speed) - speed = 100000; + speed = SPI_DEFAULT_SPEED_HZ; if (speed != slave->speed) { int ret = spi_set_speed_mode(bus, speed, slave->mode); @@ -300,7 +302,13 @@ int spi_get_bus_and_cs(int busnum, int cs, int speed, int mode, } plat = dev_get_parent_platdata(dev); plat->cs = cs; - plat->max_hz = speed; + if (speed) { + plat->max_hz = speed; + } else { + printf("Warning: SPI speed fallback to %u kHz\n", + SPI_DEFAULT_SPEED_HZ / 1000); + plat->max_hz = SPI_DEFAULT_SPEED_HZ; + } plat->mode = mode; created = true; } else if (ret) { @@ -374,7 +382,8 @@ int spi_slave_ofdata_to_platdata(struct udevice *dev, int value; plat->cs = dev_read_u32_default(dev, "reg", -1); - plat->max_hz = dev_read_u32_default(dev, "spi-max-frequency", 0); + plat->max_hz = dev_read_u32_default(dev, "spi-max-frequency", + SPI_DEFAULT_SPEED_HZ); if (dev_read_bool(dev, "spi-cpol")) mode |= SPI_CPOL; if (dev_read_bool(dev, "spi-cpha")) -- 2.25.1