Hi Guennadi, I don't know if you are the right person to ask this query (since it is also related to GPIO stuff), but here goes: Our board has a I2C controlled camera sensor whose Chip Enable (CE) pin is driven via a GPIO. This GPIO is made available by a I2C-to-GPIO expander chip (STMPE801, see user manual [1]) Now, when we implement the 's_power' routines as specified by the soc-camera framework, a peculiar issue arises: The 's_power' routine simply toggles the CE of the sensor as per the power-on/off command received from the framework/bridge driver. And this works absolutely fine in normal cases. As we have a GPIO on a external chip (STMPE801) we need to use *_cansleep variants of the gpio_set/get routines (see [2] for reference) to toggle the GPIO values to power-on/off the sensor chip. Now, when we terminate a user application (a standard application like 'capture' available as a reference v4l2 test application) which was capturing a large number of frames from the sensor, using 'ctrl-c', I see that 's_power' is correctly called with a power-off argument. However, the I2C controller driver (we use the standard SYNOPSYS designware device driver present in mainline, see [3]) returns -ERESTARTSYS in response to the write command we had requested for putting the sensor to power-off state (as it has received the <ctrl-c> kill signal). But as the gpio_set_val_* variants are inherently 'void' implementations, we have no mechanism to use and handle the -ERESTARTSYS value in the 's_power' implementation. I also found that the standard 'soc_camera.c' does not check the return value in 'soc_camera_power_off' routines, but that is a easily fixable issue. Now, I want your opinions on how to get out of this mess. Perhaps changes in GPIO implementations? Or am I missing something here. References: [1] http://www.st.com/internet/analog/product/154542.jsp [2] http://lxr.linux.no/linux+v3.1.5/Documentation/gpio.txt#L195 [3] http://lxr.linux.no/linux+v3.1.5/drivers/i2c/busses/i2c-designware.c Regards, Bhupesh -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
