mfd: Convert wm831x to irq_domain

The modern idiom is to use irq_domain to allocate interrupts. This is
useful partly to allow further infrastructure to be based on the domains
and partly because it makes it much easier to allocate virtual interrupts
to devices as we don't need to allocate a contiguous range of interrupt
numbers.

Convert the wm831x driver over to this infrastructure, using a legacy
IRQ mapping if an irq_base is specified in platform data and otherwise
using a linear mapping, always registering the interrupts even if they
won't ever be used. Only boards which need to use the GPIOs as
interrupts should need to use an irq_base.

This means that we can't use the MFD irq_base management since the
unless we're using an explicit irq_base from platform data we can't rely
on a linear mapping of interrupts.  Instead we need to map things via
the irq_domain - provide a conveniencem function wm831x_irq() to save a
small amount of typing when doing so. Looking at this I couldn't clearly
see anything the MFD core could do to make this nicer.

Since we're not supporting device tree yet there's no meaningful
advantage if we don't do this conversion in one, the fact that the
interrupt resources are used for repeated IP blocks makes accessor
functions for the irq_domain more trouble to do than they're worth.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

1 files changed, 64 insertions, 37 deletions

diff --git a/drivers/mfd/wm831x-irq.c b/drivers/mfd/wm831x-irq.c
index 2be9628074bd..ecc9d6d62fad 100644
--- a/drivers/mfd/wm831x-irq.c
+++ b/drivers/mfd/wm831x-irq.c
@@ -18,6 +18,7 @@
 #include <linux/irq.h>
 #include <linux/mfd/core.h>
 #include <linux/interrupt.h>
+#include <linux/irqdomain.h>
 
 #include <linux/mfd/wm831x/core.h>
 #include <linux/mfd/wm831x/pdata.h>
@@ -328,7 +329,7 @@ static inline int irq_data_to_status_reg(struct wm831x_irq_data *irq_data)
 static inline struct wm831x_irq_data *irq_to_wm831x_irq(struct wm831x *wm831x,
                                                         int irq)
 {
-        return &wm831x_irqs[irq - wm831x->irq_base];
+        return &wm831x_irqs[irq];
 }
 
 static void wm831x_irq_lock(struct irq_data *data)
@@ -374,7 +375,7 @@ static void wm831x_irq_enable(struct irq_data *data)
 {
         struct wm831x *wm831x = irq_data_get_irq_chip_data(data);
         struct wm831x_irq_data *irq_data = irq_to_wm831x_irq(wm831x,
-                                                             data->irq);
+                                                             data->hwirq);
 
         wm831x->irq_masks_cur[irq_data->reg - 1] &= ~irq_data->mask;
 }
@@ -383,7 +384,7 @@ static void wm831x_irq_disable(struct irq_data *data)
 {
         struct wm831x *wm831x = irq_data_get_irq_chip_data(data);
         struct wm831x_irq_data *irq_data = irq_to_wm831x_irq(wm831x,
-                                                             data->irq);
+                                                             data->hwirq);
 
         wm831x->irq_masks_cur[irq_data->reg - 1] |= irq_data->mask;
 }
@@ -393,7 +394,7 @@ static int wm831x_irq_set_type(struct irq_data *data, unsigned int type)
         struct wm831x *wm831x = irq_data_get_irq_chip_data(data);
         int irq;
 
-        irq = data->irq - wm831x->irq_base;
+        irq = data->hwirq;
 
         if (irq < WM831X_IRQ_GPIO_1 || irq > WM831X_IRQ_GPIO_11) {
                 /* Ignore internal-only IRQs */
@@ -469,9 +470,11 @@ static irqreturn_t wm831x_irq_thread(int irq, void *data)
          * descriptors.
          */
         if (primary & WM831X_TCHPD_INT)
-                handle_nested_irq(wm831x->irq_base + WM831X_IRQ_TCHPD);
+                handle_nested_irq(irq_find_mapping(wm831x->irq_domain,
+                                                   WM831X_IRQ_TCHPD));
         if (primary & WM831X_TCHDATA_INT)
-                handle_nested_irq(wm831x->irq_base + WM831X_IRQ_TCHDATA);
+                handle_nested_irq(irq_find_mapping(wm831x->irq_domain,
+                                                   WM831X_IRQ_TCHDATA));
         primary &= ~(WM831X_TCHDATA_EINT | WM831X_TCHPD_EINT);
 
         for (i = 0; i < ARRAY_SIZE(wm831x_irqs); i++) {
@@ -507,7 +510,8 @@ static irqreturn_t wm831x_irq_thread(int irq, void *data)
                 }
 
                 if (*status & wm831x_irqs[i].mask)
-                        handle_nested_irq(wm831x->irq_base + i);
+                        handle_nested_irq(irq_find_mapping(wm831x->irq_domain,
+                                                           i));
 
                 /* Simulate an edge triggered IRQ by polling the input
                  * status.  This is sucky but improves interoperability.
@@ -516,7 +520,8 @@ static irqreturn_t wm831x_irq_thread(int irq, void *data)
                     wm831x->gpio_level[i - WM831X_IRQ_GPIO_1]) {
                         ret = wm831x_reg_read(wm831x, WM831X_GPIO_LEVEL);
                         while (ret & 1 << (i - WM831X_IRQ_GPIO_1)) {
-                                handle_nested_irq(wm831x->irq_base + i);
+                                handle_nested_irq(irq_find_mapping(wm831x->irq_domain,
+                                                                   i));
                                 ret = wm831x_reg_read(wm831x,
                                                       WM831X_GPIO_LEVEL);
                         }
@@ -527,10 +532,34 @@ out:
         return IRQ_HANDLED;
 }
 
+static int wm831x_irq_map(struct irq_domain *h, unsigned int virq,
+                          irq_hw_number_t hw)
+{
+        irq_set_chip_data(virq, h->host_data);
+        irq_set_chip_and_handler(virq, &wm831x_irq_chip, handle_edge_irq);
+        irq_set_nested_thread(virq, 1);
+
+        /* ARM needs us to explicitly flag the IRQ as valid
+         * and will set them noprobe when we do so. */
+#ifdef CONFIG_ARM
+        set_irq_flags(virq, IRQF_VALID);
+#else
+        irq_set_noprobe(virq);
+#endif
+
+        return 0;
+}
+
+static struct irq_domain_ops wm831x_irq_domain_ops = {
+        .map    = wm831x_irq_map,
+        .xlate  = irq_domain_xlate_twocell,
+};
+
 int wm831x_irq_init(struct wm831x *wm831x, int irq)
 {
         struct wm831x_pdata *pdata = wm831x->dev->platform_data;
-        int i, cur_irq, ret;
+        struct irq_domain *domain;
+        int i, ret, irq_base;
 
         mutex_init(&wm831x->irq_lock);
 
@@ -543,18 +572,33 @@ int wm831x_irq_init(struct wm831x *wm831x, int irq)
         }
 
         /* Try to dynamically allocate IRQs if no base is specified */
-        if (!pdata || !pdata->irq_base)
-                wm831x->irq_base = -1;
+        if (pdata && pdata->irq_base) {
+                irq_base = irq_alloc_descs(pdata->irq_base, 0,
+                                           WM831X_NUM_IRQS, 0);
+                if (irq_base < 0) {
+                        dev_warn(wm831x->dev, "Failed to allocate IRQs: %d\n",
+                                 irq_base);
+                        irq_base = 0;
+                }
+        } else {
+                irq_base = 0;
+        }
+
+        if (irq_base)
+                domain = irq_domain_add_legacy(wm831x->dev->of_node,
+                                               ARRAY_SIZE(wm831x_irqs),
+                                               irq_base, 0,
+                                               &wm831x_irq_domain_ops,
+                                               wm831x);
         else
-                wm831x->irq_base = pdata->irq_base;
+                domain = irq_domain_add_linear(wm831x->dev->of_node,
+                                               ARRAY_SIZE(wm831x_irqs),
+                                               &wm831x_irq_domain_ops,
+                                               wm831x);
 
-        wm831x->irq_base = irq_alloc_descs(wm831x->irq_base, 0,
-                                           WM831X_NUM_IRQS, 0);
-        if (wm831x->irq_base < 0) {
-                dev_warn(wm831x->dev, "Failed to allocate IRQs: %d\n",
-                         wm831x->irq_base);
-                wm831x->irq_base = 0;
-                return 0;
+        if (!domain) {
+                dev_warn(wm831x->dev, "Failed to allocate IRQ domain\n");
+                return -EINVAL;
         }
 
         if (pdata && pdata->irq_cmos)
@@ -566,24 +610,7 @@ int wm831x_irq_init(struct wm831x *wm831x, int irq)
                         WM831X_IRQ_OD, i);
 
         wm831x->irq = irq;
-
-        /* Register them with genirq */
-        for (cur_irq = wm831x->irq_base;
-             cur_irq < ARRAY_SIZE(wm831x_irqs) + wm831x->irq_base;
-             cur_irq++) {
-                irq_set_chip_data(cur_irq, wm831x);
-                irq_set_chip_and_handler(cur_irq, &wm831x_irq_chip,
-                                         handle_edge_irq);
-                irq_set_nested_thread(cur_irq, 1);
-
-                /* ARM needs us to explicitly flag the IRQ as valid
-                 * and will set them noprobe when we do so. */
-#ifdef CONFIG_ARM
-                set_irq_flags(cur_irq, IRQF_VALID);
-#else
-                irq_set_noprobe(cur_irq);
-#endif
-        }
+        wm831x->irq_domain = domain;
 
         if (irq) {
                 /* Try to flag /IRQ as a wake source; there are a number of