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dm: spi: prevent setting a speed of 0 Hz

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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 <simon.k.r.goldschmidt@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
This commit is contained in:
Simon Goldschmidt 2018-10-30 21:09:48 +01:00 committed by Simon Glass
parent b23644858b
commit 12bfb2e05f
1 changed files with 12 additions and 3 deletions
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15
drivers/spi/spi-uclass.c
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@ -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"))