On Thu, Jun 14, 2012 at 19:27:50, Wei Ni wrote: >On Thu, Jun 14, 2012 at 05:17:06, Stephen Warren wrote: >>On 06/13/2012 04:40 AM, Wei Ni wrote: >>> Hi, all >>> I'm working on the tegra30 wifi upstream issue. >>> >>> The tegra30 board (Cardhu) use Broadcom 4329 as wifi device, and use brcmfmac as the wifi driver. >>> >>> In the brcmfmac init routine, it call sdio_register_driver() to >>> register driver, if the wifi device >is powered on, then the mmc driver will enumerate it, and call the probe callback routine. >>> >>> On the Cardhu, the wifi's power is controlled by two gpios >>> (power-gpio and reset-gpio), the default state is power-off. So we >>> need to power on it before >calling sdio_register_driver(), if not, the mmc driver can't enumerate >it, and will not call the probe routine. >>> This power on sequence is: >>> set power-gpio to 1 ; >>> mdelay(100) ; >>> set reset-gpio to 1 ; >>> mdelay(200); >>> >>> My question is where to power on the wifi. We may have three places to power on it: >>> 1. power on it in the brcmfmac driver before calling >>> sdio_register_driver(). But I think this power sequence is special >>> for tegra30 cardhu, it's not >good to add it in the generic wifi driver, because different board may >use the different way to power on the wifi. >>> 2. power on it in the mmc driver. In our tegra SD driver, it has >>> power-gpios property, which allow the slot to be powered. But this >>> power is for mmc slot, could we >add this wifi power sequence in the tegra SD driver? >>> 3. hard-coded into DT. Set these gpios in the DT, something like >>> pinmux settings, but in this way, >it's not good to put the mdelay() value in the DT. >>> >>> I have no good idea for it, does anyone has suggestion? >> >>The core of the issue is that: >> >>* Tegra30 support is via device tree. >>* We have an SDIO bus, and the WiFi device attached to that bus is enumerable. >>* Since the WiFi device is enumerable, no node exists in the DT to represent it. >>* However, the driver for the WiFi device needs certain information, >>such as the reset GPIO ID and perhaps power GPIO. >> >>For the power GPIO, it seems reasonable to either use the existing >>Tegra SD controller's power-gpios DT property, or replace that >>property with a real regulator binding. The SD driver would then control this. >>Still, that approach would mean the WiFi driver wouldn't be able to >>control power to the device >directly, which might not be a good thing. >> >>However, I'm not sure that the reset GPIO is also something that >>should be controlled by the SD card driver; it seems like it's much >>more closely related to the WiFi >device/driver. >> >>I wonder if the power and reset GPIO shouldn't be represented as a >>combined custom regulator type, which knows how to sequence multiple GPIOs. >> >>Perhaps SDIO "client" devices also need a way to communicate with >>their "host port" to obtain services such as power and reset control? >> >>This is all very similar to the WiFi rfkill discussion we have re: the >>Toshiba AC100 a little while back, although that was USB rather than SDIO. > >In the rfkill-gpio, it already have the reset-gpio and shutdown-gpio. >I test it, add a device node in the DT to pass the gpio properties. >It will use these gpios to power up/off , but its default power sequence is different with the 4329. >It block==0, it mean power up, it will set reset-gpio first, then set power-gpio next. >I think it should set power-gpio first, is it right? > I test with the rfkill-gpio's default power sequence just now, it also can power up the device. It seems we can use this rfkill-gpio driver. --- nvpublic -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
