[PATCH v2] gpio: mockup: use device properties instead of platform_data

[PATCH v2] gpio: mockup: use device properties instead of platform_data

[Bartosz Golaszewski]

Some users want to introduce device tree support to the mockup driver.
Let's make it easier by switching to using generic device properties.
The driver stays compatible with previous use cases and after this
conversion there'll be no need to change the way probing of mockup
GPIO chips works.

Tested with libgpiod test suite.

Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
---
v1 -> v2:
- dropped an unnecessary check when reading the base gpio number property

 drivers/gpio/gpio-mockup.c | 82 ++++++++++++++++++++++++--------------
 1 file changed, 51 insertions(+), 31 deletions(-)

diff --git a/drivers/gpio/gpio-mockup.c b/drivers/gpio/gpio-mockup.c
index d66b7a768ecd..8269cffc2967 100644
--- a/drivers/gpio/gpio-mockup.c
+++ b/drivers/gpio/gpio-mockup.c
@@ -18,6 +18,7 @@
 #include <linux/irq_sim.h>
 #include <linux/debugfs.h>
 #include <linux/uaccess.h>
+#include <linux/property.h>
 
 #include "gpiolib.h"
 
@@ -28,6 +29,8 @@
  * of GPIO lines.
  */
 #define GPIO_MOCKUP_MAX_RANGES	(GPIO_MOCKUP_MAX_GC * 2)
+/* Maximum of three properties + the sentinel. */
+#define GPIO_MOCKUP_MAX_PROP	4
 
 #define gpio_mockup_err(...)	pr_err(GPIO_MOCKUP_NAME ": " __VA_ARGS__)
 
@@ -59,13 +62,6 @@ struct gpio_mockup_dbgfs_private {
 	int offset;
 };
 
-struct gpio_mockup_platform_data {
-	int base;
-	int ngpio;
-	int index;
-	bool named_lines;
-};
-
 static int gpio_mockup_ranges[GPIO_MOCKUP_MAX_RANGES];
 static int gpio_mockup_num_ranges;
 module_param_array(gpio_mockup_ranges, int, &gpio_mockup_num_ranges, 0400);
@@ -255,26 +251,37 @@ static int gpio_mockup_name_lines(struct device *dev,
 
 static int gpio_mockup_probe(struct platform_device *pdev)
 {
-	struct gpio_mockup_platform_data *pdata;
 	struct gpio_mockup_chip *chip;
 	struct gpio_chip *gc;
-	int rv, base, ngpio;
 	struct device *dev;
-	char *name;
+	const char *name;
+	int rv, base;
+	u16 ngpio;
 
 	dev = &pdev->dev;
-	pdata = dev_get_platdata(dev);
-	base = pdata->base;
-	ngpio = pdata->ngpio;
+
+	rv = device_property_read_u32(dev, "gpio-base", &base);
+	if (rv)
+		base = -1;
+
+	rv = device_property_read_u16(dev, "nr-gpios", &ngpio);
+	if (rv)
+		return rv;
+
+	rv = device_property_read_string(dev, "chip-name", &name);
+	if (rv)
+		name = NULL;
 
 	chip = devm_kzalloc(dev, sizeof(*chip), GFP_KERNEL);
 	if (!chip)
 		return -ENOMEM;
 
-	name = devm_kasprintf(dev, GFP_KERNEL, "%s-%c",
-			      pdev->name, pdata->index);
-	if (!name)
-		return -ENOMEM;
+	if (!name) {
+		name = devm_kasprintf(dev, GFP_KERNEL,
+				      "%s-%c", pdev->name, pdev->id + 'A');
+		if (!name)
+			return -ENOMEM;
+	}
 
 	gc = &chip->gc;
 	gc->base = base;
@@ -295,7 +302,7 @@ static int gpio_mockup_probe(struct platform_device *pdev)
 	if (!chip->lines)
 		return -ENOMEM;
 
-	if (pdata->named_lines) {
+	if (device_property_read_bool(dev, "named-gpio-lines")) {
 		rv = gpio_mockup_name_lines(dev, chip);
 		if (rv)
 			return rv;
@@ -339,9 +346,11 @@ static void gpio_mockup_unregister_pdevs(void)
 
 static int __init gpio_mockup_init(void)
 {
-	int i, num_chips, err = 0, index = 'A';
-	struct gpio_mockup_platform_data pdata;
+	struct property_entry properties[GPIO_MOCKUP_MAX_PROP];
+	int i, prop, num_chips, err = 0, base;
+	struct platform_device_info pdevinfo;
 	struct platform_device *pdev;
+	u16 ngpio;
 
 	if ((gpio_mockup_num_ranges < 2) ||
 	    (gpio_mockup_num_ranges % 2) ||
@@ -371,17 +380,28 @@ static int __init gpio_mockup_init(void)
 	}
 
 	for (i = 0; i < num_chips; i++) {
-		pdata.index = index++;
-		pdata.base = gpio_mockup_range_base(i);
-		pdata.ngpio = pdata.base < 0
-				? gpio_mockup_range_ngpio(i)
-				: gpio_mockup_range_ngpio(i) - pdata.base;
-		pdata.named_lines = gpio_mockup_named_lines;
-
-		pdev = platform_device_register_resndata(NULL,
-							 GPIO_MOCKUP_NAME,
-							 i, NULL, 0, &pdata,
-							 sizeof(pdata));
+		memset(properties, 0, sizeof(properties));
+		memset(&pdevinfo, 0, sizeof(pdevinfo));
+		prop = 0;
+
+		base = gpio_mockup_range_base(i);
+		if (base >= 0)
+			properties[prop++] = PROPERTY_ENTRY_U32("gpio-base",
+								base);
+
+		ngpio = base < 0 ? gpio_mockup_range_ngpio(i)
+				 : gpio_mockup_range_ngpio(i) - base;
+		properties[prop++] = PROPERTY_ENTRY_U16("nr-gpios", ngpio);
+
+		if (gpio_mockup_named_lines)
+			properties[prop++] = PROPERTY_ENTRY_BOOL(
+						"named-gpio-lines");
+
+		pdevinfo.name = GPIO_MOCKUP_NAME;
+		pdevinfo.id = i;
+		pdevinfo.properties = properties;
+
+		pdev = platform_device_register_full(&pdevinfo);
 		if (IS_ERR(pdev)) {
 			gpio_mockup_err("error registering device");
 			platform_driver_unregister(&gpio_mockup_driver);
-- 
2.18.0

Re: [PATCH v2] gpio: mockup: use device properties instead of platform_data

[Linus Walleij]

On Tue, Sep 25, 2018 at 1:29 PM Bartosz Golaszewski <brgl@bgdev.pl> wrote:

> Some users want to introduce device tree support to the mockup driver.
> Let's make it easier by switching to using generic device properties.
> The driver stays compatible with previous use cases and after this
> conversion there'll be no need to change the way probing of mockup
> GPIO chips works.
>
> Tested with libgpiod test suite.
>
> Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
> ---
> v1 -> v2:
> - dropped an unnecessary check when reading the base gpio number property

Patch applied.

Vincent, could you rebase your work on top of this
when/if you resend?

Yours,
Linus Walleij