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spi: Update speed/mode on change 

The spi_get_bus_and_cs() may be called on the same bus and chipselect
with different frequency or mode. This is valid usecase, but the code
fails to notify the controller of such a configuration change. Call
spi_set_speed_mode() in case bus frequency or bus mode changed to let
the controller update the configuration.

The problem can easily be triggered using the sspi command:
=> sspi 0:0@1000
=> sspi 0:0@2000
Without this patch, both transfers happen at 1000 Hz. With this patch,
the later transfer happens correctly at 2000 Hz.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Jagan Teki <jagan@amarulasolutions.com>
Cc: Patrick Delaunay <patrick.delaunay@foss.st.com>
This commit is contained in:
Marek Vasut 2021-06-10 14:00:00 +02:00 committed by Tom Rini
parent 605cbcb0a4
commit e2e95e5e25
1 changed files with 12 additions and 0 deletions
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12
drivers/spi/spi-uclass.c
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@ -391,6 +391,8 @@ int spi_get_bus_and_cs(int busnum, int cs, int speed, int mode,
} else if (ret) {
dev_err(bus, "Invalid chip select %d:%d (err=%d)\n", busnum, cs, ret);
return ret;
} else if (dev) {
plat = dev_get_parent_plat(dev);
}
if (!device_active(dev)) {
@ -416,12 +418,22 @@ int spi_get_bus_and_cs(int busnum, int cs, int speed, int mode,
goto err;
}
/* In case bus frequency or mode changed, update it. */
if ((speed && bus_data->speed && bus_data->speed != speed) ||
(plat && plat->mode != mode)) {
ret = spi_set_speed_mode(bus, speed, mode);
if (ret)
goto err_speed_mode;
}
*busp = bus;
*devp = slave;
log_debug("%s: bus=%p, slave=%p\n", __func__, bus, *devp);
return 0;
err_speed_mode:
spi_release_bus(slave);
err:
log_debug("%s: Error path, created=%d, device '%s'\n", __func__,
created, dev->name);