Re: [PATCH 4/4] can: flexcan: add transceiver switch support when use device tree

[Marc Kleine-Budde <mkl@pengutronix.de>]

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On 06/27/2012 11:55 AM, Hui Wang wrote:
> Marc Kleine-Budde wrote:
>> On 06/27/2012 10:19 AM, Hui Wang wrote:
>>  
>>> Some platforms (like i.MX6) has an external PHY, the PHY is operated
>>> by some gpios. If the system registers a platform_data, we can
>>> set a callback function pointer to pdata->transceiver_switch to
>>> implement PHY switch. If we use device tree, we couldn't pass
>>> platform_data to the driver, so i move the switch function to the
>>> driver and add device tree entries to let user set which gpios
>>> are used to operate PHY.
>>>
>>> This design doesn't break existing platforms, if a platform doesn't
>>> need PHY switch, it doesn't need to set dt entries just as before,
>>> if a platform has platform_data, the pdata->transceiver_switch has
>>> higher priority.
>>>
>>> Cc: linux-can@vger.kernel.org
>>> Cc: Marc Kleine-Budde <mkl@pengutronix.de>
>>> Cc: David S. Miller <davem@davemloft.net>
>>> Cc: Shawn Guo <shawn.guo@linaro.org>
>>> Signed-off-by: Hui Wang <jason77.wang@gmail.com>
>>>     
>>
>> please coordinate whith Shawn Guo, he has posted a similar patch some
>> days ago. http://www.spinics.net/lists/netdev/msg202442.html
>>
>> Marc
>>
>>   
> After read and compared with his patch:
> 1. Shawn use gpio_is_valid(gpio) instead of (gpio >= 0), it is good.

yes

> 2. Shawn add a flag to record active level, it is good.

yes - have a look at the device tree if there is a common symbol name
for this.

> 3. Shawn only add 1 gpio, this is not enough for imx6 sabre lite board.

improve your patch to work with 1 or 2 gpios.

> 4. Shawn forget to call gpio_release()

good catch.

Marc

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