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>

drivers/pinctrl/pinctrl-at91.c

@@ -177,7 +177,7 @@ struct at91_pinctrl {
 	struct device		*dev;
 	struct pinctrl_dev	*pctl;
 
-	int			nbanks;
+	int			nactive_banks;
 
 	uint32_t		*mux_mask;
 	int			nmux;
@@ -653,12 +653,18 @@ static int pin_check_config(struct at91_pinctrl *info, const char *name,
 	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 @@ static void at91_pinctrl_child_count(struct at91_pinctrl *info,
 
 	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 @@ static int at91_pinctrl_mux_mask(struct at91_pinctrl *info,
 	}
 
 	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 @@ static int at91_pinctrl_probe_dt(struct platform_device *pdev,
 		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 @@ static int at91_pinctrl_probe_dt(struct platform_device *pdev,
 
 	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 @@ static int at91_pinctrl_probe_dt(struct platform_device *pdev,
 	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 @@ static int at91_pinctrl_probe(struct platform_device *pdev)
 {
 	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 @@ static int at91_pinctrl_probe(struct platform_device *pdev)
 	 * 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 @@ static int at91_pinctrl_probe(struct platform_device *pdev)
 	}
 
 	/* 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 void gpio_irq_handler(unsigned irq, struct irq_desc *desc)
 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 @@ static int at91_gpio_of_irq_setup(struct platform_device *pdev,
 		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 @@ static struct gpio_chip at91_gpio_template = {
 	.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 @@ static int at91_gpio_probe(struct platform_device *pdev)
 	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;