mfd: Move WM831x to generic IRQ

Replace the wm831x-local IRQ infrastructure with genirq, allowing access
to the diagnostic infrastructure of genirq and allowing us to implement
interrupt support for the GPIOs.  The switchover is done within the
wm831x specific IRQ API, further patches will convert the individual
drivers to use genirq directly.

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

1 files changed, 87 insertions, 122 deletions

diff --git a/drivers/mfd/wm831x-irq.c b/drivers/mfd/wm831x-irq.c
index ac056ea6b66e..301327697117 100644
--- a/drivers/mfd/wm831x-irq.c
+++ b/drivers/mfd/wm831x-irq.c
@@ -15,6 +15,7 @@
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/i2c.h>
+#include <linux/irq.h>
 #include <linux/mfd/core.h>
 #include <linux/interrupt.h>
 
@@ -339,110 +340,71 @@ static inline int irq_data_to_mask_reg(struct wm831x_irq_data *irq_data)
         return WM831X_INTERRUPT_STATUS_1_MASK - 1 + irq_data->reg;
 }
 
-static void __wm831x_enable_irq(struct wm831x *wm831x, int irq)
+static inline struct wm831x_irq_data *irq_to_wm831x_irq(struct wm831x *wm831x,
+                                                        int irq)
 {
-        struct wm831x_irq_data *irq_data = &wm831x_irqs[irq];
-
-        wm831x->irq_masks[irq_data->reg - 1] &= ~irq_data->mask;
-        wm831x_reg_write(wm831x, irq_data_to_mask_reg(irq_data),
-                         wm831x->irq_masks[irq_data->reg - 1]);
+        return &wm831x_irqs[irq - wm831x->irq_base];
 }
 
-void wm831x_enable_irq(struct wm831x *wm831x, int irq)
+static void wm831x_irq_lock(unsigned int irq)
 {
-        mutex_lock(&wm831x->irq_lock);
-        __wm831x_enable_irq(wm831x, irq);
-        mutex_unlock(&wm831x->irq_lock);
-}
-EXPORT_SYMBOL_GPL(wm831x_enable_irq);
+        struct wm831x *wm831x = get_irq_chip_data(irq);
 
-static void __wm831x_disable_irq(struct wm831x *wm831x, int irq)
-{
-        struct wm831x_irq_data *irq_data = &wm831x_irqs[irq];
-
-        wm831x->irq_masks[irq_data->reg - 1] |= irq_data->mask;
-        wm831x_reg_write(wm831x, irq_data_to_mask_reg(irq_data),
-                         wm831x->irq_masks[irq_data->reg - 1]);
-}
-
-void wm831x_disable_irq(struct wm831x *wm831x, int irq)
-{
         mutex_lock(&wm831x->irq_lock);
-        __wm831x_disable_irq(wm831x, irq);
-        mutex_unlock(&wm831x->irq_lock);
 }
-EXPORT_SYMBOL_GPL(wm831x_disable_irq);
 
-int wm831x_request_irq(struct wm831x *wm831x,
-                       unsigned int irq, irq_handler_t handler,
-                       unsigned long flags, const char *name,
-                       void *dev)
+static void wm831x_irq_sync_unlock(unsigned int irq)
 {
-        int ret = 0;
-
-        if (irq < 0 || irq >= WM831X_NUM_IRQS)
-                return -EINVAL;
-
-        mutex_lock(&wm831x->irq_lock);
-
-        if (wm831x_irqs[irq].handler) {
-                dev_err(wm831x->dev, "Already have handler for IRQ %d\n", irq);
-                ret = -EINVAL;
-                goto out;
+        struct wm831x *wm831x = get_irq_chip_data(irq);
+        int i;
+
+        for (i = 0; i < ARRAY_SIZE(wm831x->irq_masks_cur); i++) {
+                /* If there's been a change in the mask write it back
+                 * to the hardware. */
+                if (wm831x->irq_masks_cur[i] != wm831x->irq_masks_cache[i]) {
+                        wm831x->irq_masks_cache[i] = wm831x->irq_masks_cur[i];
+                        wm831x_reg_write(wm831x,
+                                         WM831X_INTERRUPT_STATUS_1_MASK + i,
+                                         wm831x->irq_masks_cur[i]);
+                }
         }
 
-        wm831x_irqs[irq].handler = handler;
-        wm831x_irqs[irq].handler_data = dev;
-
-        __wm831x_enable_irq(wm831x, irq);
-
-out:
         mutex_unlock(&wm831x->irq_lock);
-
-        return ret;
 }
-EXPORT_SYMBOL_GPL(wm831x_request_irq);
 
-void wm831x_free_irq(struct wm831x *wm831x, unsigned int irq, void *data)
+static void wm831x_irq_unmask(unsigned int irq)
 {
-        if (irq < 0 || irq >= WM831X_NUM_IRQS)
-                return;
-
-        mutex_lock(&wm831x->irq_lock);
+        struct wm831x *wm831x = get_irq_chip_data(irq);
+        struct wm831x_irq_data *irq_data = irq_to_wm831x_irq(wm831x, irq);
 
-        wm831x_irqs[irq].handler = NULL;
-        wm831x_irqs[irq].handler_data = NULL;
-
-        __wm831x_disable_irq(wm831x, irq);
-
-        mutex_unlock(&wm831x->irq_lock);
+        wm831x->irq_masks_cur[irq_data->reg - 1] &= ~irq_data->mask;
 }
-EXPORT_SYMBOL_GPL(wm831x_free_irq);
 
-
-static void wm831x_handle_irq(struct wm831x *wm831x, int irq, int status)
+static void wm831x_irq_mask(unsigned int irq)
 {
-        struct wm831x_irq_data *irq_data = &wm831x_irqs[irq];
-
-        if (irq_data->handler) {
-                irq_data->handler(irq, irq_data->handler_data);
-                wm831x_reg_write(wm831x, irq_data_to_status_reg(irq_data),
-                                 irq_data->mask);
-        } else {
-                dev_err(wm831x->dev, "Unhandled IRQ %d, masking\n", irq);
-                __wm831x_disable_irq(wm831x, irq);
-        }
+        struct wm831x *wm831x = get_irq_chip_data(irq);
+        struct wm831x_irq_data *irq_data = irq_to_wm831x_irq(wm831x, irq);
+
+        wm831x->irq_masks_cur[irq_data->reg - 1] |= irq_data->mask;
 }
 
-/* Main interrupt handling occurs in a workqueue since we need
- * interrupts enabled to interact with the chip. */
-static void wm831x_irq_worker(struct work_struct *work)
+static struct irq_chip wm831x_irq_chip = {
+        .name = "wm831x",
+        .bus_lock = wm831x_irq_lock,
+        .bus_sync_unlock = wm831x_irq_sync_unlock,
+        .mask = wm831x_irq_mask,
+        .unmask = wm831x_irq_unmask,
+};
+
+/* The processing of the primary interrupt occurs in a thread so that
+ * we can interact with the device over I2C or SPI. */
+static irqreturn_t wm831x_irq_thread(int irq, void *data)
 {
-        struct wm831x *wm831x = container_of(work, struct wm831x, irq_work);
+        struct wm831x *wm831x = data;
         unsigned int i;
         int primary;
-        int status_regs[5];
-        int read[5] = { 0 };
+        int status_regs[WM831X_NUM_IRQ_REGS] = { 0 };
+        int read[WM831X_NUM_IRQ_REGS] = { 0 };
         int *status;
 
         primary = wm831x_reg_read(wm831x, WM831X_SYSTEM_INTERRUPTS);
@@ -452,8 +414,6 @@ static void wm831x_irq_worker(struct work_struct *work)
                 goto out;
         }
 
-        mutex_lock(&wm831x->irq_lock);
-
         for (i = 0; i < ARRAY_SIZE(wm831x_irqs); i++) {
                 int offset = wm831x_irqs[i].reg - 1;
 
@@ -471,41 +431,34 @@ static void wm831x_irq_worker(struct work_struct *work)
                                 dev_err(wm831x->dev,
                                         "Failed to read IRQ status: %d\n",
                                         *status);
-                                goto out_lock;
+                                goto out;
                         }
 
-                        /* Mask out the disabled IRQs */
-                        *status &= ~wm831x->irq_masks[offset];
                         read[offset] = 1;
                 }
 
-                if (*status & wm831x_irqs[i].mask)
-                        wm831x_handle_irq(wm831x, i, *status);
+                /* Report it if it isn't masked, or forget the status. */
+                if ((*status & ~wm831x->irq_masks_cur[offset])
+                    & wm831x_irqs[i].mask)
+                        handle_nested_irq(wm831x->irq_base + i);
+                else
+                        *status &= ~wm831x_irqs[i].mask;
         }
 
-out_lock:
-        mutex_unlock(&wm831x->irq_lock);
 out:
-        enable_irq(wm831x->irq);
-}
-
-
-static irqreturn_t wm831x_cpu_irq(int irq, void *data)
-{
-        struct wm831x *wm831x = data;
-
-        /* Shut the interrupt to the CPU up and schedule the actual
-         * handler; we can't check that the IRQ is asserted. */
-        disable_irq_nosync(irq);
-
-        queue_work(wm831x->irq_wq, &wm831x->irq_work);
+        for (i = 0; i < ARRAY_SIZE(status_regs); i++) {
+                if (status_regs[i])
+                        wm831x_reg_write(wm831x, WM831X_INTERRUPT_STATUS_1 + i,
+                                         status_regs[i]);
+        }
 
         return IRQ_HANDLED;
 }
 
 int wm831x_irq_init(struct wm831x *wm831x, int irq)
 {
-        int i, ret;
+        struct wm831x_pdata *pdata = wm831x->dev->platform_data;
+        int i, cur_irq, ret;
 
         mutex_init(&wm831x->irq_lock);
 
@@ -515,41 +468,53 @@ int wm831x_irq_init(struct wm831x *wm831x, int irq)
                 return 0;
         }
 
-
-        wm831x->irq_wq = create_singlethread_workqueue("wm831x-irq");
-        if (!wm831x->irq_wq) {
-                dev_err(wm831x->dev, "Failed to allocate IRQ worker\n");
-                return -ESRCH;
+        if (!pdata || !pdata->irq_base) {
+                dev_err(wm831x->dev,
+                        "No interrupt base specified, no interrupts\n");
+                return 0;
         }
 
         wm831x->irq = irq;
-        INIT_WORK(&wm831x->irq_work, wm831x_irq_worker);
+        wm831x->irq_base = pdata->irq_base;
 
         /* Mask the individual interrupt sources */
-        for (i = 0; i < ARRAY_SIZE(wm831x->irq_masks); i++) {
-                wm831x->irq_masks[i] = 0xffff;
+        for (i = 0; i < ARRAY_SIZE(wm831x->irq_masks_cur); i++) {
+                wm831x->irq_masks_cur[i] = 0xffff;
+                wm831x->irq_masks_cache[i] = 0xffff;
                 wm831x_reg_write(wm831x, WM831X_INTERRUPT_STATUS_1_MASK + i,
                                  0xffff);
         }
 
-        /* Enable top level interrupts, we mask at secondary level */
-        wm831x_reg_write(wm831x, WM831X_SYSTEM_INTERRUPTS_MASK, 0);
+        /* Register them with genirq */
+        for (cur_irq = wm831x->irq_base;
+             cur_irq < ARRAY_SIZE(wm831x_irqs) + wm831x->irq_base;
+             cur_irq++) {
+                set_irq_chip_data(cur_irq, wm831x);
+                set_irq_chip_and_handler(cur_irq, &wm831x_irq_chip,
+                                         handle_edge_irq);
+                set_irq_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
+                set_irq_noprobe(cur_irq);
+#endif
+        }
 
-        /* We're good to go.  We set IRQF_SHARED since there's a
-         * chance the driver will interoperate with another driver but
-         * the need to disable the IRQ while handing via I2C/SPI means
-         * that this may break and performance will be impacted.  If
-         * this does happen it's a hardware design issue and the only
-         * other alternative would be polling.
-         */
-        ret = request_irq(irq, wm831x_cpu_irq, IRQF_TRIGGER_LOW | IRQF_SHARED,
-                          "wm831x", wm831x);
+        ret = request_threaded_irq(irq, NULL, wm831x_irq_thread,
+                                   IRQF_TRIGGER_LOW | IRQF_ONESHOT,
+                                   "wm831x", wm831x);
         if (ret != 0) {
                 dev_err(wm831x->dev, "Failed to request IRQ %d: %d\n",
                         irq, ret);
                 return ret;
         }
 
+        /* Enable top level interrupts, we mask at secondary level */
+        wm831x_reg_write(wm831x, WM831X_SYSTEM_INTERRUPTS_MASK, 0);
+
         return 0;
 }