[PATCH RFT v2 2/6] gpio: mmio: get chip label and GPIO base from device properties

[Bartosz Golaszewski <brgl@bgdev.pl>]

From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

Ahead of removing struct bgpio_pdata support from the gpio-mmio generic
module, let's add support for getting the relevant values from generic
device properties. "label" is a semi-standardized property in some GPIO
drivers so let's go with it. There's no standard "base" property, so
let's use the name "gpio-mmio,base" to tie it to this driver
specifically. The number of GPIOs will be retrieved using
gpiochip_get_ngpios() so there's no need to look it up in the software
node.

Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
---
 drivers/gpio/gpio-mmio.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/drivers/gpio/gpio-mmio.c b/drivers/gpio/gpio-mmio.c
index ffe6b6f6cc9b1e9341e1c42cf8fee917e0147bf3..f66137caa245b14e6e8dbd043243224bc47c9609 100644
--- a/drivers/gpio/gpio-mmio.c
+++ b/drivers/gpio/gpio-mmio.c
@@ -737,6 +737,9 @@ MODULE_DEVICE_TABLE(of, bgpio_of_match);
 static struct bgpio_pdata *bgpio_parse_fw(struct device *dev, unsigned long *flags)
 {
 	struct bgpio_pdata *pdata;
+	const char *label;
+	unsigned int base;
+	int ret;
 
 	if (!dev_fwnode(dev))
 		return NULL;
@@ -753,6 +756,18 @@ static struct bgpio_pdata *bgpio_parse_fw(struct device *dev, unsigned long *fla
 	if (device_property_read_bool(dev, "no-output"))
 		*flags |= BGPIOF_NO_OUTPUT;
 
+	ret = device_property_read_string(dev, "label", &label);
+	if (!ret)
+		pdata->label = label;
+
+	/*
+	 * This property *must not* be used in device-tree sources, it's only
+	 * meant to be passed to the driver from board files and MFD core.
+	 */
+	ret = device_property_read_u32(dev, "gpio-mmio,base", &base);
+	if (!ret && base <= INT_MAX)
+		pdata->base = base;
+
 	return pdata;
 }
 

-- 
2.48.1