Re: [PATCH v2 3/4] pinctrl: mcp23s08: work around GPIO line naming

["Jan Kundrát" <jan.kundrat@cesnet.cz>]

Sorry for missing the DT maintainers on this one.

Jan

On čtvrtek 7. března 2019 14:31:02 CET, Jan Kundrát wrote:
> This driver is a bit weird because it can hide several gpio_chip
> instances underneath a single SPI slave. One cannot put the
> gpio-line-names DT stanza directly to the SPI slave when the
> spi-present-mask has more than one bit set.
>
> I'm making up the `gpio-bank` DT child name as well as its `address`
> property. We need something to match the DT entries with the SPI
> address.
>
> Signed-off-by: Jan Kundrát <jan.kundrat@cesnet.cz>
> Reviewed-by: Phil Reid <preid@electromag.com.au>
> Cc: Linus Walleij <linus.walleij@linaro.org>
> ---
> v2: Depend on exported devprop_gpiochip_set_names
> ---
>  .../bindings/pinctrl/pinctrl-mcp23s08.txt     | 35 +++++++++++++++++++
>  drivers/pinctrl/pinctrl-mcp23s08.c            | 11 ++++++
>  2 files changed, 46 insertions(+)
>
> diff --git 
> a/Documentation/devicetree/bindings/pinctrl/pinctrl-mcp23s08.txt 
> b/Documentation/devicetree/bindings/pinctrl/pinctrl-mcp23s08.txt
> index 625a22e2f211..a0b1eb9aedad 100644
> --- a/Documentation/devicetree/bindings/pinctrl/pinctrl-mcp23s08.txt
> +++ b/Documentation/devicetree/bindings/pinctrl/pinctrl-mcp23s08.txt
> @@ -144,3 +144,38 @@ gpio21: gpio@21 {
>  		bias-pull-up;
>  	};
>  };
> +
> +Line naming
> +===========
> +
> +Because several gpio_chip instances are hidden below a single device tree
> +node, it is necessary to split the names into several child nodes. Ensure
> +that the configured addresses match those in the 
> microchip,spi-present-mask:
> +
> +gpio@0 {
> +	compatible = "microchip,mcp23s17";
> +	gpio-controller;
> +	#gpio-cells = <2>;
> +	/* this bitmask has bits #0 (0x01) and #2 (0x04) set */
> +	spi-present-mask = <0x05>;
> +	reg = <0>;
> +	spi-max-frequency = <1000000>;
> +
> +	gpio-bank@1 {
> +		address = <0>;
> +		gpio-line-names =
> +			"GPA0",
> +			"GPA1",
> +			...
> +			"GPA7",
> +			"GPB0",
> +			"GPB1",
> +			...
> +			"GPB7";
> +	};
> +
> +	gpio-bank@2 {
> +		address = <2>;
> +		gpio-line-names = ...
> +	};
> +};
> diff --git a/drivers/pinctrl/pinctrl-mcp23s08.c 
> b/drivers/pinctrl/pinctrl-mcp23s08.c
> index fd9d6f026d70..7810f56f8dd1 100644
> --- a/drivers/pinctrl/pinctrl-mcp23s08.c
> +++ b/drivers/pinctrl/pinctrl-mcp23s08.c
> @@ -1102,6 +1102,7 @@ static int mcp23s08_probe(struct spi_device *spi)
>  	int				status, type;
>  	unsigned			ngpio = 0;
>  	const struct			of_device_id *match;
> +	struct device_node		*np;
>  
>  	match = of_match_device(of_match_ptr(mcp23s08_spi_of_match), &spi->dev);
>  	if (match)
> @@ -1170,6 +1171,16 @@ static int mcp23s08_probe(struct spi_device *spi)
>  		if (pdata->base != -1)
>  			pdata->base += data->mcp[addr]->chip.ngpio;
>  		ngpio += data->mcp[addr]->chip.ngpio;
> +
> +		for_each_available_child_of_node(spi->dev.of_node, np) {
> +			u32 chip_addr;
> +			status = of_property_read_u32(np, "address", &chip_addr);
> +			if (status)
> +				continue;
> +			if (chip_addr != addr)
> +				continue;
> +			devprop_gpiochip_set_names(&data->mcp[addr]->chip, 
> of_fwnode_handle(np));
> +		}
>  	}
>  	data->ngpio = ngpio;
>