pinctrl/msm: Setup GPIO chip in hierarchy

Some GPIOs are marked as wakeup capable and are routed to another
interrupt controller that is an always-domain and can detect interrupts
even when most of the SoC is powered off. The wakeup interrupt
controller wakes up the GIC and replays the interrupt at the GIC.

Setup the TLMM irqchip in hierarchy with the wakeup interrupt controller
and ensure the wakeup GPIOs are handled correctly.

Co-developed-by: Maulik Shah <mkshah@codeaurora.org>

Signed-off-by: Lina Iyer <ilina@codeaurora.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Link: https://lore.kernel.org/r/1573855915-9841-9-git-send-email-ilina@codeaurora.org

----
Changes in v2:
	- Address review comments
	- Fix Co-developed-by tag
Changes in v1:
	- Address minor review comments
	- Remove redundant call to set irq handler
	- Move irq_domain_qcom_handle_wakeup() to this patch
Changes in RFC v2:
	- Rebase on top of GPIO hierarchy support in linux-next
	- Set the chained irq handler for summary line

drivers/pinctrl/qcom/pinctrl-msm.c

@@ -23,6 +23,8 @@
 #include <linux/pm.h>
 #include <linux/log2.h>
 
+#include <linux/soc/qcom/irq.h>
+
 #include "../core.h"
 #include "../pinconf.h"
 #include "pinctrl-msm.h"
@@ -44,6 +46,7 @@
  * @enabled_irqs:   Bitmap of currently enabled irqs.
  * @dual_edge_irqs: Bitmap of irqs that need sw emulated dual edge
  *                  detection.
+ * @skip_wake_irqs: Skip IRQs that are handled by wakeup interrupt controller
  * @soc;            Reference to soc_data of platform specific data.
  * @regs:           Base addresses for the TLMM tiles.
  */
@@ -61,6 +64,7 @@ struct msm_pinctrl {
 
 	DECLARE_BITMAP(dual_edge_irqs, MAX_NR_GPIO);
 	DECLARE_BITMAP(enabled_irqs, MAX_NR_GPIO);
+	DECLARE_BITMAP(skip_wake_irqs, MAX_NR_GPIO);
 
 	const struct msm_pinctrl_soc_data *soc;
 	void __iomem *regs[MAX_NR_TILES];
@@ -707,6 +711,12 @@ static void msm_gpio_irq_mask(struct irq_data *d)
 	unsigned long flags;
 	u32 val;
 
+	if (d->parent_data)
+		irq_chip_mask_parent(d);
+
+	if (test_bit(d->hwirq, pctrl->skip_wake_irqs))
+		return;
+
 	g = &pctrl->soc->groups[d->hwirq];
 
 	raw_spin_lock_irqsave(&pctrl->lock, flags);
@@ -751,6 +761,12 @@ static void msm_gpio_irq_clear_unmask(struct irq_data *d, bool status_clear)
 	unsigned long flags;
 	u32 val;
 
+	if (d->parent_data)
+		irq_chip_unmask_parent(d);
+
+	if (test_bit(d->hwirq, pctrl->skip_wake_irqs))
+		return;
+
 	g = &pctrl->soc->groups[d->hwirq];
 
 	raw_spin_lock_irqsave(&pctrl->lock, flags);
@@ -778,10 +794,35 @@ static void msm_gpio_irq_clear_unmask(struct irq_data *d, bool status_clear)
 
 static void msm_gpio_irq_enable(struct irq_data *d)
 {
+	/*
+	 * Clear the interrupt that may be pending before we enable
+	 * the line.
+	 * This is especially a problem with the GPIOs routed to the
+	 * PDC. These GPIOs are direct-connect interrupts to the GIC.
+	 * Disabling the interrupt line at the PDC does not prevent
+	 * the interrupt from being latched at the GIC. The state at
+	 * GIC needs to be cleared before enabling.
+	 */
+	if (d->parent_data) {
+		irq_chip_set_parent_state(d, IRQCHIP_STATE_PENDING, 0);
+		irq_chip_enable_parent(d);
+	}
 
 	msm_gpio_irq_clear_unmask(d, true);
 }
 
+static void msm_gpio_irq_disable(struct irq_data *d)
+{
+	struct gpio_chip *gc = irq_data_get_irq_chip_data(d);
+	struct msm_pinctrl *pctrl = gpiochip_get_data(gc);
+
+	if (d->parent_data)
+		irq_chip_disable_parent(d);
+
+	if (!test_bit(d->hwirq, pctrl->skip_wake_irqs))
+		msm_gpio_irq_mask(d);
+}
+
 static void msm_gpio_irq_unmask(struct irq_data *d)
 {
 	msm_gpio_irq_clear_unmask(d, false);
@@ -795,6 +836,9 @@ static void msm_gpio_irq_ack(struct irq_data *d)
 	unsigned long flags;
 	u32 val;
 
+	if (test_bit(d->hwirq, pctrl->skip_wake_irqs))
+		return;
+
 	g = &pctrl->soc->groups[d->hwirq];
 
 	raw_spin_lock_irqsave(&pctrl->lock, flags);
@@ -820,6 +864,12 @@ static int msm_gpio_irq_set_type(struct irq_data *d, unsigned int type)
 	unsigned long flags;
 	u32 val;
 
+	if (d->parent_data)
+		irq_chip_set_type_parent(d, type);
+
+	if (test_bit(d->hwirq, pctrl->skip_wake_irqs))
+		return 0;
+
 	g = &pctrl->soc->groups[d->hwirq];
 
 	raw_spin_lock_irqsave(&pctrl->lock, flags);
@@ -912,6 +962,15 @@ static int msm_gpio_irq_set_wake(struct irq_data *d, unsigned int on)
 	struct msm_pinctrl *pctrl = gpiochip_get_data(gc);
 	unsigned long flags;
 
+	/*
+	 * While they may not wake up when the TLMM is powered off,
+	 * some GPIOs would like to wakeup the system from suspend
+	 * when TLMM is powered on. To allow that, enable the GPIO
+	 * summary line to be wakeup capable at GIC.
+	 */
+	if (d->parent_data)
+		irq_chip_set_wake_parent(d, on);
+
 	raw_spin_lock_irqsave(&pctrl->lock, flags);
 
 	irq_set_irq_wake(pctrl->irq, on);
@@ -990,6 +1049,30 @@ static void msm_gpio_irq_handler(struct irq_desc *desc)
 	chained_irq_exit(chip, desc);
 }
 
+static int msm_gpio_wakeirq(struct gpio_chip *gc,
+			    unsigned int child,
+			    unsigned int child_type,
+			    unsigned int *parent,
+			    unsigned int *parent_type)
+{
+	struct msm_pinctrl *pctrl = gpiochip_get_data(gc);
+	const struct msm_gpio_wakeirq_map *map;
+	int i;
+
+	*parent = GPIO_NO_WAKE_IRQ;
+	*parent_type = IRQ_TYPE_EDGE_RISING;
+
+	for (i = 0; i < pctrl->soc->nwakeirq_map; i++) {
+		map = &pctrl->soc->wakeirq_map[i];
+		if (map->gpio == child) {
+			*parent = map->wakeirq;
+			break;
+		}
+	}
+
+	return 0;
+}
+
 static bool msm_gpio_needs_valid_mask(struct msm_pinctrl *pctrl)
 {
 	if (pctrl->soc->reserved_gpios)
@@ -1002,8 +1085,10 @@ static int msm_gpio_init(struct msm_pinctrl *pctrl)
 {
 	struct gpio_chip *chip;
 	struct gpio_irq_chip *girq;
-	int ret;
-	unsigned ngpio = pctrl->soc->ngpios;
+	int i, ret;
+	unsigned gpio, ngpio = pctrl->soc->ngpios;
+	struct device_node *np;
+	bool skip;
 
 	if (WARN_ON(ngpio > MAX_NR_GPIO))
 		return -EINVAL;
@@ -1020,17 +1105,40 @@ static int msm_gpio_init(struct msm_pinctrl *pctrl)
 
 	pctrl->irq_chip.name = "msmgpio";
 	pctrl->irq_chip.irq_enable = msm_gpio_irq_enable;
+	pctrl->irq_chip.irq_disable = msm_gpio_irq_disable;
 	pctrl->irq_chip.irq_mask = msm_gpio_irq_mask;
 	pctrl->irq_chip.irq_unmask = msm_gpio_irq_unmask;
 	pctrl->irq_chip.irq_ack = msm_gpio_irq_ack;
+	pctrl->irq_chip.irq_eoi = irq_chip_eoi_parent;
 	pctrl->irq_chip.irq_set_type = msm_gpio_irq_set_type;
 	pctrl->irq_chip.irq_set_wake = msm_gpio_irq_set_wake;
 	pctrl->irq_chip.irq_request_resources = msm_gpio_irq_reqres;
 	pctrl->irq_chip.irq_release_resources = msm_gpio_irq_relres;
 
+	np = of_parse_phandle(pctrl->dev->of_node, "wakeup-parent", 0);
+	if (np) {
+		chip->irq.parent_domain = irq_find_matching_host(np,
+						 DOMAIN_BUS_WAKEUP);
+		of_node_put(np);
+		if (!chip->irq.parent_domain)
+			return -EPROBE_DEFER;
+		chip->irq.child_to_parent_hwirq = msm_gpio_wakeirq;
+
+		/*
+		 * Let's skip handling the GPIOs, if the parent irqchip
+		 * is handling the direct connect IRQ of the GPIO.
+		 */
+		skip = irq_domain_qcom_handle_wakeup(chip->irq.parent_domain);
+		for (i = 0; skip && i < pctrl->soc->nwakeirq_map; i++) {
+			gpio = pctrl->soc->wakeirq_map[i].gpio;
+			set_bit(gpio, pctrl->skip_wake_irqs);
+		}
+	}
+
 	girq = &chip->irq;
 	girq->chip = &pctrl->irq_chip;
 	girq->parent_handler = msm_gpio_irq_handler;
+	girq->fwnode = pctrl->dev->fwnode;
 	girq->num_parents = 1;
 	girq->parents = devm_kcalloc(pctrl->dev, 1, sizeof(*girq->parents),
 				     GFP_KERNEL);

drivers/pinctrl/qcom/pinctrl-msm.h

@@ -91,6 +91,16 @@ struct msm_pingroup {
 	unsigned intr_detection_width:5;
 };
 
+/**
+ * struct msm_gpio_wakeirq_map - Map of GPIOs and their wakeup pins
+ * @gpio:          The GPIOs that are wakeup capable
+ * @wakeirq:       The interrupt at the always-on interrupt controller
+ */
+struct msm_gpio_wakeirq_map {
+	unsigned int gpio;
+	unsigned int wakeirq;
+};
+
 /**
  * struct msm_pinctrl_soc_data - Qualcomm pin controller driver configuration
  * @pins:	    An array describing all pins the pin controller affects.
@@ -101,6 +111,8 @@ struct msm_pingroup {
  * @ngroups:	    The numbmer of entries in @groups.
  * @ngpio:	    The number of pingroups the driver should expose as GPIOs.
  * @pull_no_keeper: The SoC does not support keeper bias.
+ * @wakeirq_map:    The map of wakeup capable GPIOs and the pin at PDC/MPM
+ * @nwakeirq_map:   The number of entries in @wakeirq_map
  */
 struct msm_pinctrl_soc_data {
 	const struct pinctrl_pin_desc *pins;
@@ -114,6 +126,8 @@ struct msm_pinctrl_soc_data {
 	const char *const *tiles;
 	unsigned int ntiles;
 	const int *reserved_gpios;
+	const struct msm_gpio_wakeirq_map *wakeirq_map;
+	unsigned int nwakeirq_map;
 };
 
 extern const struct dev_pm_ops msm_pinctrl_dev_pm_ops;

include/linux/soc/qcom/irq.h

@@ -18,4 +18,17 @@
 #define IRQ_DOMAIN_FLAG_QCOM_PDC_WAKEUP		(IRQ_DOMAIN_FLAG_NONCORE << 0)
 #define IRQ_DOMAIN_FLAG_QCOM_MPM_WAKEUP		(IRQ_DOMAIN_FLAG_NONCORE << 1)
 
+/**
+ * irq_domain_qcom_handle_wakeup: Return if the domain handles interrupt
+ *                                configuration
+ * @d: irq domain
+ *
+ * This QCOM specific irq domain call returns if the interrupt controller
+ * requires the interrupt be masked at the child interrupt controller.
+ */
+static inline bool irq_domain_qcom_handle_wakeup(const struct irq_domain *d)
+{
+	return (d->flags & IRQ_DOMAIN_FLAG_QCOM_PDC_WAKEUP);
+}
+
 #endif