On Friday 10 January 2014 16:08:36, Gerhard Sittig wrote: > On Fri, Jan 10, 2014 at 15:22 +0100, Lars Poeschel wrote: > > --- a/Documentation/devicetree/bindings/gpio/gpio-mcp23s08.txt > > +++ b/Documentation/devicetree/bindings/gpio/gpio-mcp23s08.txt > > > > @@ -38,12 +38,37 @@ Required device specific properties (only for SPI chips): > > removed. > > > > - spi-max-frequency = The maximum frequency this chip is able to handle > > > > -Example I2C: > > +Optional properties: > > +- #interrupt-cells : Should be two. > > + - first cell is the pin number > > + - second cell is used to specify flags. > > +- interrupt-controller: Marks the device node as a interrupt controller. > > +NOTE: The interrupt functionality is only supported for i2c versions of > > the +chips yet. > > Is this "IRQ feature for I2C chips only" limitation specific to > the hardware or an implementation detail of the Linux driver? I > could not determine this from either the binding text nor the > driver source. Ok, you're right. My description is not 100% clear about this. I will update this. It is currently an implementation detail of the linux driver. According to the datasheet the spi chips should also be able to do the interrupts. > If it's just the status of the Linux driver, then it should not > be in the binding document. If it's a limitation of the > hardware, then it's appropriate in the binding but I suggest to > adjust the text to avoid the next person to ask the same > question. :) I do not agree. I remember a rule that every binding has to be documented, so this should be documented, but you are right: The description has to be a bit more clear about this beeing a (current) limitation of the driver. I will update this and do a v3, but I will wait a bit for further comments. > > --- a/drivers/gpio/Kconfig > > +++ b/drivers/gpio/Kconfig > > @@ -697,6 +697,7 @@ config GPIO_MCP23S08 > > > > SPI/I2C driver for Microchip MCP23S08/MCP23S17/MCP23008/MCP23017 > > I/O expanders. > > This provides a GPIO interface supporting inputs and outputs. > > > > + The I2C versions of the chips can be used as interrupt-controller. > > > > config GPIO_MC33880 > > > > tristate "Freescale MC33880 high-side/low-side switch" > > > > diff --git a/drivers/gpio/gpio-mcp23s08.c b/drivers/gpio/gpio-mcp23s08.c > > index 2deb0c5..1346ea6 100644 > > --- a/drivers/gpio/gpio-mcp23s08.c > > +++ b/drivers/gpio/gpio-mcp23s08.c > > @@ -1,5 +1,10 @@ > > > > /* > > > > - * MCP23S08 SPI/GPIO gpio expander driver > > + * MCP23S08 SPI/I2C GPIO gpio expander driver > > + * > > + * The inputs and outputs of the mcp23s08, mcp23s17, mcp23008 and > > mcp23017 are + * supported. > > + * For the I2C versions of the chips (mcp23008 and mcp23017) generation > > of > > + * interrupts is also supported. > > > > */ > > Adjust these as well to reflect whether it's hardware or software > which limits the feature. Yes,I will do that too. Lars -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
