Hello!
On 28.02.2020 18:18, John Garry wrote:
Currently ACPI firmware description for a SPI device does not have any
method to describe the data buswidth on the board.
So even through the controller and device may support higher modes than
^^^^^^^
Though?
standard SPI, it cannot be assumed that the board does - as such, that
device is limited to standard SPI in such a circumstance.
As a workaround, allow the controller driver supply buswidth override bits,
which are used inform the core code that the controller driver knows the
buswidth supported on that board for that device.
A host controller driver might know this info from DMI tables, for example.
Signed-off-by: John Garry <john.garry@xxxxxxxxxx>
---
drivers/spi/spi.c | 4 +++-
include/linux/spi/spi.h | 3 +++
2 files changed, 6 insertions(+), 1 deletion(-)
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 38b4c78df506..292f26807b41 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -510,6 +510,7 @@ struct spi_device *spi_alloc_device(struct spi_controller *ctlr)
spi->dev.bus = &spi_bus_type;
spi->dev.release = spidev_release;
spi->cs_gpio = -ENOENT;
+ spi->mode = ctlr->buswidth_override_bits;
spin_lock_init(&spi->statistics.lock);
@@ -2181,9 +2182,10 @@ static acpi_status acpi_register_spi_device(struct spi_controller *ctlr,
return AE_NO_MEMORY;
}
+
What for?
ACPI_COMPANION_SET(&spi->dev, adev);
spi->max_speed_hz = lookup.max_speed_hz;
- spi->mode = lookup.mode;
+ spi->mode |= lookup.mode;
spi->irq = lookup.irq;
spi->bits_per_word = lookup.bits_per_word;
spi->chip_select = lookup.chip_select;
[...]
MBR, Sergei
