From f7dd5370986087af9b9cfa601f34b344ec910b87 Mon Sep 17 00:00:00 2001 From: Marcin Wojtas Date: Thu, 21 Nov 2019 05:38:47 +0100 Subject: [PATCH] spi: prevent overriding established bus settings The SPI stack relies on a proper bus speed/mode configuration by calling dm_spi_claim_bus(). However the hitherto code allowed to accidentally override those settings in the spi_get_bus_and_cs() routine. The initially established speed could be discarded by using the slave platdata, which turned out to be an issue on the platforms whose slave maximum supported frequency is not on par with the maximum frequency of the bus controller. This patch fixes above issue by configuring the bus from spi_get_bus_and_cs() only in case it was not done before. Signed-off-by: Marcin Wojtas Reviewed-by: Simon Glass Acked-by: Jagan Teki --- drivers/spi/spi-uclass.c | 20 +++++++++++--------- 1 file changed, 11 insertions(+), 9 deletions(-) diff --git a/drivers/spi/spi-uclass.c b/drivers/spi/spi-uclass.c index 5ced8905f8..9208b16db4 100644 --- a/drivers/spi/spi-uclass.c +++ b/drivers/spi/spi-uclass.c @@ -323,6 +323,7 @@ int spi_get_bus_and_cs(int busnum, int cs, int speed, int mode, { struct udevice *bus, *dev; struct dm_spi_slave_platdata *plat; + struct spi_slave *slave; bool created = false; int ret; @@ -378,19 +379,20 @@ int spi_get_bus_and_cs(int busnum, int cs, int speed, int mode, slave->dev = dev; } - plat = dev_get_parent_platdata(dev); + slave = dev_get_parent_priv(dev); - /* get speed and mode from platdata when available */ - if (plat->max_hz) { - speed = plat->max_hz; - mode = plat->mode; + /* + * In case the operation speed is not yet established by + * dm_spi_claim_bus() ensure the bus is configured properly. + */ + if (!slave->speed) { + ret = spi_claim_bus(slave); + if (ret) + goto err; } - ret = spi_set_speed_mode(bus, speed, mode); - if (ret) - goto err; *busp = bus; - *devp = dev_get_parent_priv(dev); + *devp = slave; debug("%s: bus=%p, slave=%p\n", __func__, bus, *devp); return 0; -- 2.25.1