Hi Simon,
I think I'm not very clear with this code in common/cmd_sf.c:
"
# ifdef CONFIG_DM_SPI_FLASH
/* Remove the old device, otherwise probe will just be a nop */
ret = spi_find_bus_and_cs(bus, cs, &bus_dev, &new);
if (!ret) {
device_remove(new);
device_unbind(new);
}
"
I may understand the remove but why need to unbind the device?
The unbind would cause a series of free operations on the device list, correct?
Then if I probe a flash twice, at the second time the driver model will create
a new flash named 'spi_flash@xx:xx' using default settings because it doesn't
find such a device in the device list and never probes it from the board's fdt
again.
=> dm tree
Class Probed Name
----------------------------------------
root [ + ] root_driver
simple_bus [ + ] `-- soc
spi [ + ] |-- dspi@2100000
spi_flash [ ] | |-- n25q128a
spi_flash [ + ] | |-- spi_flash@1:1
spi_flash [ + ] | `-- spi_flash@1:2
Fortunately the default SPI mode set by U-Boot is SPI_MODE_3 so it doesn't cause
issues on our boards. But if an SPI flash which only supports SPI_MODE_0 is
used,
I think it wouldn't work properly from the second probe.
Sorry if there is something wrong with my understandings.
Just because I found my flash's name was changed to spi-flash@xx:xx in dm tree
after several probes, I began to read something about driver model.:)
Regards,
Qianyu
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