[PATCH linux dev-4.10] leds: pca955x: map gpio offset to led index correctly

[Cédric Le Goater]

From: Andrea Scian <andrea.scian at dave.eu>

We need to map gpio offset to led index of this device otherwise we
cannot mix led and gpios into device tree definition

Signed-off-by: Andrea Scian <andrea.scian at dave.eu>
[clg: ported on linux openbmc 4.10 kernel ]
Signed-off-by: Cédric Le Goater <clg at kaod.org>
---

 This should help in defining mixed GPIO/LED pca9952 devices. I don't
 think we need to change our bindings but could we include this patch
 to chek is it not breaking anything. I only tested the basics under
 QEMU.

 drivers/leds/leds-pca955x.c |   38 ++++++++++++++++++++++++++++++--------
 1 file changed, 30 insertions(+), 8 deletions(-)

Index: linux-openbmc-4.10.git/drivers/leds/leds-pca955x.c
===================================================================
--- linux-openbmc-4.10.git.orig/drivers/leds/leds-pca955x.c
+++ linux-openbmc-4.10.git/drivers/leds/leds-pca955x.c
@@ -126,6 +126,7 @@ struct pca955x {
 	struct i2c_client	*client;
 #ifdef CONFIG_LEDS_PCA955X_GPIO
 	struct gpio_chip gpio;
+	int *gpio_to_index;
 #endif
 };
 
@@ -315,22 +316,34 @@ static int pca955x_read_input(struct i2c
 
 }
 
+/*
+ * Map from gpio offset to led index.
+ * Return NULL in case of unmapped GPIO (even if it should never happens)
+ */
+static struct pca955x_led *
+pca955x_gpio_get_led_index(struct pca955x *pca955x, unsigned int offset)
+{
+	int index = pca955x->gpio_to_index[offset];
+
+	return index < 0 ? NULL : &pca955x->leds[index];
+}
+
 static int pca955x_gpio_request_pin(struct gpio_chip *gc, unsigned int offset)
 {
 	struct pca955x *pca955x = gpiochip_get_data(gc);
-	struct pca955x_led *led = &pca955x->leds[offset];
-
-	if (led->type == PCA955X_TYPE_GPIO)
-		return 0;
+	struct pca955x_led *led = pca955x_gpio_get_led_index(pca955x, offset);
 
-	return -EBUSY;
+	return led == NULL ? -EBUSY : 0;
 }
 
 static int pca955x_set_value(struct gpio_chip *gc, unsigned int offset,
 			     int val)
 {
 	struct pca955x *pca955x = gpiochip_get_data(gc);
-	struct pca955x_led *led = &pca955x->leds[offset];
+	struct pca955x_led *led = pca955x_gpio_get_led_index(pca955x, offset);
+
+	if (led == NULL)
+		return -EINVAL;
 
 	if (val)
 		return pca955x_led_set(&led->led_cdev, PCA955X_GPIO_HIGH);
@@ -347,10 +360,13 @@ static void pca955x_gpio_set_value(struc
 static int pca955x_gpio_get_value(struct gpio_chip *gc, unsigned int offset)
 {
 	struct pca955x *pca955x = gpiochip_get_data(gc);
-	struct pca955x_led *led = &pca955x->leds[offset];
+	struct pca955x_led *led = pca955x_gpio_get_led_index(pca955x, offset);
 	u8 reg = 0;
 
 	/* There is nothing we can do about errors */
+	if (led == NULL)
+		return 0;
+
 	pca955x_read_input(pca955x->client, led->led_num / 8, &reg);
 
 	return !!(reg & (1 << (led->led_num % 8)));
@@ -499,6 +515,11 @@ static int pca955x_probe(struct i2c_clie
 	if (!pca955x->leds)
 		return -ENOMEM;
 
+	pca955x->gpio_to_index = devm_kzalloc(&client->dev,
+			sizeof(int) * chip->bits, GFP_KERNEL);
+	if (!pca955x->gpio_to_index)
+		return -ENOMEM;
+
 	i2c_set_clientdata(client, pca955x);
 
 	mutex_init(&pca955x->lock);
@@ -510,12 +531,13 @@ static int pca955x_probe(struct i2c_clie
 		pca955x_led->led_num = i;
 		pca955x_led->pca955x = pca955x;
 		pca955x_led->type = pdata->leds[i].type;
+		pca955x->gpio_to_index[i] = -ENOENT;
 
 		switch (pca955x_led->type) {
 		case PCA955X_TYPE_NONE:
 			break;
 		case PCA955X_TYPE_GPIO:
-			ngpios++;
+			pca955x->gpio_to_index[ngpios++] = i;
 			break;
 		case PCA955X_TYPE_LED:
 			/*