Hello.
On 28/08/15 09:50, Alexander Aring wrote:
Hi,
On Thu, Aug 27, 2015 at 03:14:31PM +0200, Stefan Schmidt wrote:
Hello.
On 13/08/15 14:22, Alexander Aring wrote:
This patch removes spi settings while mrf24j40 probing. These settings
cannot be overwrite while device probing where spi controller should be
already configured. These settings need to be setup by device tree or
platform data.
Signed-off-by: Alexander Aring <alex.aring@xxxxxxxxx>
---
drivers/net/ieee802154/mrf24j40.c | 4 ----
1 file changed, 4 deletions(-)
diff --git a/drivers/net/ieee802154/mrf24j40.c b/drivers/net/ieee802154/mrf24j40.c
index de63cba..d16bef3 100644
--- a/drivers/net/ieee802154/mrf24j40.c
+++ b/drivers/net/ieee802154/mrf24j40.c
@@ -746,10 +746,6 @@ static int mrf24j40_probe(struct spi_device *spi)
if (!devrec->buf)
goto err_register_device;
- spi->mode = SPI_MODE_0; /* TODO: Is this appropriate for right here? */
- if (spi->max_speed_hz > MAX_SPI_SPEED_HZ)
- spi->max_speed_hz = MAX_SPI_SPEED_HZ;
-
mutex_init(&devrec->buffer_mutex);
init_completion(&devrec->tx_complete);
So far I only have been setting the SPI speed but never the mode via
devicetree. Digging for it I found that we can set the various modes easily
via devicetree.
Documentation/devicetree/bindings/spi/spi-bus.txt
- spi-cpol - (optional) Empty property indicating device requires
inverse clock polarity (CPOL) mode
- spi-cpha - (optional) Empty property indicating device requires
shifted clock phase (CPHA) mode
- spi-cs-high - (optional) Empty property indicating device requires
chip select active high
- spi-3wire - (optional) Empty property indicating device requires
3-wire mode.
- spi-lsb-first - (optional) Empty property indicating device requires
LSB first mode.
Platform data could always do that anyway so we are good here.
I think, that changing the attribute only, will not change the spi bus
controller. This setup was before any spi device will be probed.
One reason is here because we already access the spi device inside
probing of mrf24j40 -> spi need to be setup correctly. It can't be
changed again in any device probing, or we need to call some other
function that we can tell the spi controller these spi attributes
was changed, if possible.
For the SPI_MODE think, it's mostly SPI_MODE_0 which sets non of these
flags. They call it "original MicroWire".
#define SPI_MODE_0 (0|0) /* (original MicroWire) */
Yeah, I can think we can safely remove the SPI_MODE part here.
What we could do is to make some
"WARN_ON(spi->max_speed_hz > MAX_SPI_SPEED_HZ, "foobar\n");
if the SPI clock is above maximum.
That sounds like a good idea to me. While it is mentioned in the
devicetree binding we are not enforcing it anymore. A warning would be good.
regards
Stefan Schmidt
- Alex
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