pinctrl: at91: allow to have disabled gpio bank

Today we expect that all the bank are enabled, and count the number of banks
used by the pinctrl based on it instead of using the last bank id enabled.

So switch to it, set the chained IRQ at runtime based on enabled banks
and wait only the number of enabled gpio controllers at probe time.

Cc: <stable@vger.kernel.org> # 3.18
Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
diff --git a/drivers/pinctrl/pinctrl-at91.c b/drivers/pinctrl/pinctrl-at91.c
index dfd021e..f4cd0b9 100644
--- a/drivers/pinctrl/pinctrl-at91.c
+++ b/drivers/pinctrl/pinctrl-at91.c
@@ -177,7 +177,7 @@
 	struct device		*dev;
 	struct pinctrl_dev	*pctl;
 
-	int			nbanks;
+	int			nactive_banks;
 
 	uint32_t		*mux_mask;
 	int			nmux;
@@ -653,12 +653,18 @@
 	int mux;
 
 	/* check if it's a valid config */
-	if (pin->bank >= info->nbanks) {
+	if (pin->bank >= gpio_banks) {
 		dev_err(info->dev, "%s: pin conf %d bank_id %d >= nbanks %d\n",
-			name, index, pin->bank, info->nbanks);
+			name, index, pin->bank, gpio_banks);
 		return -EINVAL;
 	}
 
+	if (!gpio_chips[pin->bank]) {
+		dev_err(info->dev, "%s: pin conf %d bank_id %d not enabled\n",
+			name, index, pin->bank);
+		return -ENXIO;
+	}
+
 	if (pin->pin >= MAX_NB_GPIO_PER_BANK) {
 		dev_err(info->dev, "%s: pin conf %d pin_bank_id %d >= %d\n",
 			name, index, pin->pin, MAX_NB_GPIO_PER_BANK);
@@ -981,7 +987,8 @@
 
 	for_each_child_of_node(np, child) {
 		if (of_device_is_compatible(child, gpio_compat)) {
-			info->nbanks++;
+			if (of_device_is_available(child))
+				info->nactive_banks++;
 		} else {
 			info->nfunctions++;
 			info->ngroups += of_get_child_count(child);
@@ -1003,11 +1010,11 @@
 	}
 
 	size /= sizeof(*list);
-	if (!size || size % info->nbanks) {
-		dev_err(info->dev, "wrong mux mask array should be by %d\n", info->nbanks);
+	if (!size || size % gpio_banks) {
+		dev_err(info->dev, "wrong mux mask array should be by %d\n", gpio_banks);
 		return -EINVAL;
 	}
-	info->nmux = size / info->nbanks;
+	info->nmux = size / gpio_banks;
 
 	info->mux_mask = devm_kzalloc(info->dev, sizeof(u32) * size, GFP_KERNEL);
 	if (!info->mux_mask) {
@@ -1131,7 +1138,7 @@
 		of_match_device(at91_pinctrl_of_match, &pdev->dev)->data;
 	at91_pinctrl_child_count(info, np);
 
-	if (info->nbanks < 1) {
+	if (gpio_banks < 1) {
 		dev_err(&pdev->dev, "you need to specify at least one gpio-controller\n");
 		return -EINVAL;
 	}
@@ -1144,7 +1151,7 @@
 
 	dev_dbg(&pdev->dev, "mux-mask\n");
 	tmp = info->mux_mask;
-	for (i = 0; i < info->nbanks; i++) {
+	for (i = 0; i < gpio_banks; i++) {
 		for (j = 0; j < info->nmux; j++, tmp++) {
 			dev_dbg(&pdev->dev, "%d:%d\t0x%x\n", i, j, tmp[0]);
 		}
@@ -1162,7 +1169,7 @@
 	if (!info->groups)
 		return -ENOMEM;
 
-	dev_dbg(&pdev->dev, "nbanks = %d\n", info->nbanks);
+	dev_dbg(&pdev->dev, "nbanks = %d\n", gpio_banks);
 	dev_dbg(&pdev->dev, "nfunctions = %d\n", info->nfunctions);
 	dev_dbg(&pdev->dev, "ngroups = %d\n", info->ngroups);
 
@@ -1185,7 +1192,7 @@
 {
 	struct at91_pinctrl *info;
 	struct pinctrl_pin_desc *pdesc;
-	int ret, i, j, k;
+	int ret, i, j, k, ngpio_chips_enabled = 0;
 
 	info = devm_kzalloc(&pdev->dev, sizeof(*info), GFP_KERNEL);
 	if (!info)
@@ -1200,23 +1207,27 @@
 	 * to obtain references to the struct gpio_chip * for them, and we
 	 * need this to proceed.
 	 */
-	for (i = 0; i < info->nbanks; i++) {
-		if (!gpio_chips[i]) {
-			dev_warn(&pdev->dev, "GPIO chip %d not registered yet\n", i);
-			devm_kfree(&pdev->dev, info);
-			return -EPROBE_DEFER;
-		}
+	for (i = 0; i < gpio_banks; i++)
+		if (gpio_chips[i])
+			ngpio_chips_enabled++;
+
+	if (ngpio_chips_enabled < info->nactive_banks) {
+		dev_warn(&pdev->dev,
+			 "All GPIO chips are not registered yet (%d/%d)\n",
+			 ngpio_chips_enabled, info->nactive_banks);
+		devm_kfree(&pdev->dev, info);
+		return -EPROBE_DEFER;
 	}
 
 	at91_pinctrl_desc.name = dev_name(&pdev->dev);
-	at91_pinctrl_desc.npins = info->nbanks * MAX_NB_GPIO_PER_BANK;
+	at91_pinctrl_desc.npins = gpio_banks * MAX_NB_GPIO_PER_BANK;
 	at91_pinctrl_desc.pins = pdesc =
 		devm_kzalloc(&pdev->dev, sizeof(*pdesc) * at91_pinctrl_desc.npins, GFP_KERNEL);
 
 	if (!at91_pinctrl_desc.pins)
 		return -ENOMEM;
 
-	for (i = 0 , k = 0; i < info->nbanks; i++) {
+	for (i = 0, k = 0; i < gpio_banks; i++) {
 		for (j = 0; j < MAX_NB_GPIO_PER_BANK; j++, k++) {
 			pdesc->number = k;
 			pdesc->name = kasprintf(GFP_KERNEL, "pio%c%d", i + 'A', j);
@@ -1234,8 +1245,9 @@
 	}
 
 	/* We will handle a range of GPIO pins */
-	for (i = 0; i < info->nbanks; i++)
-		pinctrl_add_gpio_range(info->pctl, &gpio_chips[i]->range);
+	for (i = 0; i < gpio_banks; i++)
+		if (gpio_chips[i])
+			pinctrl_add_gpio_range(info->pctl, &gpio_chips[i]->range);
 
 	dev_info(&pdev->dev, "initialized AT91 pinctrl driver\n");
 
@@ -1613,9 +1625,10 @@
 static int at91_gpio_of_irq_setup(struct platform_device *pdev,
 				  struct at91_gpio_chip *at91_gpio)
 {
+	struct gpio_chip	*gpiochip_prev = NULL;
 	struct at91_gpio_chip   *prev = NULL;
 	struct irq_data		*d = irq_get_irq_data(at91_gpio->pioc_virq);
-	int ret;
+	int ret, i;
 
 	at91_gpio->pioc_hwirq = irqd_to_hwirq(d);
 
@@ -1641,24 +1654,33 @@
 		return ret;
 	}
 
-	/* Setup chained handler */
-	if (at91_gpio->pioc_idx)
-		prev = gpio_chips[at91_gpio->pioc_idx - 1];
-
 	/* The top level handler handles one bank of GPIOs, except
 	 * on some SoC it can handle up to three...
 	 * We only set up the handler for the first of the list.
 	 */
-	if (prev && prev->next == at91_gpio)
+	gpiochip_prev = irq_get_handler_data(at91_gpio->pioc_virq);
+	if (!gpiochip_prev) {
+		/* Then register the chain on the parent IRQ */
+		gpiochip_set_chained_irqchip(&at91_gpio->chip,
+					     &gpio_irqchip,
+					     at91_gpio->pioc_virq,
+					     gpio_irq_handler);
 		return 0;
+	}
 
-	/* Then register the chain on the parent IRQ */
-	gpiochip_set_chained_irqchip(&at91_gpio->chip,
-				     &gpio_irqchip,
-				     at91_gpio->pioc_virq,
-				     gpio_irq_handler);
+	prev = container_of(gpiochip_prev, struct at91_gpio_chip, chip);
 
-	return 0;
+	/* we can only have 2 banks before */
+	for (i = 0; i < 2; i++) {
+		if (prev->next) {
+			prev = prev->next;
+		} else {
+			prev->next = at91_gpio;
+			return 0;
+		}
+	}
+
+	return -EINVAL;
 }
 
 /* This structure is replicated for each GPIO block allocated at probe time */
@@ -1675,24 +1697,6 @@
 	.ngpio			= MAX_NB_GPIO_PER_BANK,
 };
 
-static void at91_gpio_probe_fixup(void)
-{
-	unsigned i;
-	struct at91_gpio_chip *at91_gpio, *last = NULL;
-
-	for (i = 0; i < gpio_banks; i++) {
-		at91_gpio = gpio_chips[i];
-
-		/*
-		 * GPIO controller are grouped on some SoC:
-		 * PIOC, PIOD and PIOE can share the same IRQ line
-		 */
-		if (last && last->pioc_virq == at91_gpio->pioc_virq)
-			last->next = at91_gpio;
-		last = at91_gpio;
-	}
-}
-
 static struct of_device_id at91_gpio_of_match[] = {
 	{ .compatible = "atmel,at91sam9x5-gpio", .data = &at91sam9x5_ops, },
 	{ .compatible = "atmel,at91rm9200-gpio", .data = &at91rm9200_ops },
@@ -1805,8 +1809,6 @@
 	gpio_chips[alias_idx] = at91_chip;
 	gpio_banks = max(gpio_banks, alias_idx + 1);
 
-	at91_gpio_probe_fixup();
-
 	ret = at91_gpio_of_irq_setup(pdev, at91_chip);
 	if (ret)
 		goto irq_setup_err;