regmap: irq: Use a bulk read for interrupt status where possible

If the interrupt status registers are a single block of registers and the
chip supports bulk reads then do a single bulk read rather than pay the
extra I/O cost. This restores the original behaviour which was lost when
support for register striding was added.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

1 files changed, 60 insertions, 7 deletions

diff --git a/drivers/base/regmap/regmap-irq.c b/drivers/base/regmap/regmap-irq.c
index 329be9836716..aaf599a320b3 100644
--- a/drivers/base/regmap/regmap-irq.c
+++ b/drivers/base/regmap/regmap-irq.c
@@ -34,6 +34,7 @@ struct regmap_irq_chip_data {
         int irq;
         int wake_count;
 
+        void *status_reg_buf;
         unsigned int *status_buf;
         unsigned int *mask_buf;
         unsigned int *mask_buf_def;
@@ -170,18 +171,60 @@ static irqreturn_t regmap_irq_thread(int irq, void *d)
                 }
         }
 
-        for (i = 0; i < data->chip->num_regs; i++) {
-                ret = regmap_read(map, chip->status_base + (i * map->reg_stride
-                                   * data->irq_reg_stride),
-                                   &data->status_buf[i]);
+        /*
+         * Read in the statuses, using a single bulk read if possible
+         * in order to reduce the I/O overheads.
+         */
+        if (!map->use_single_rw && map->reg_stride == 1 &&
+            data->irq_reg_stride == 1) {
+                u8 *buf8 = data->status_reg_buf;
+                u16 *buf16 = data->status_reg_buf;
+                u32 *buf32 = data->status_reg_buf;
 
+                BUG_ON(!data->status_reg_buf);
+
+                ret = regmap_bulk_read(map, chip->status_base,
+                                       data->status_reg_buf,
+                                       chip->num_regs);
                 if (ret != 0) {
                         dev_err(map->dev, "Failed to read IRQ status: %d\n",
-                                        ret);
-                        if (chip->runtime_pm)
-                                pm_runtime_put(map->dev);
+                                ret);
                         return IRQ_NONE;
                 }
+
+                for (i = 0; i < data->chip->num_regs; i++) {
+                        switch (map->format.val_bytes) {
+                        case 1:
+                                data->status_buf[i] = buf8[i];
+                                break;
+                        case 2:
+                                data->status_buf[i] = buf16[i];
+                                break;
+                        case 4:
+                                data->status_buf[i] = buf32[i];
+                                break;
+                        default:
+                                BUG();
+                                return IRQ_NONE;
+                        }
+                }
+
+        } else {
+                for (i = 0; i < data->chip->num_regs; i++) {
+                        ret = regmap_read(map, chip->status_base +
+                                          (i * map->reg_stride
+                                           * data->irq_reg_stride),
+                                          &data->status_buf[i]);
+
+                        if (ret != 0) {
+                                dev_err(map->dev,
+                                        "Failed to read IRQ status: %d\n",
+                                        ret);
+                                if (chip->runtime_pm)
+                                        pm_runtime_put(map->dev);
+                                return IRQ_NONE;
+                        }
+                }
         }
 
         /*
@@ -327,6 +370,14 @@ int regmap_add_irq_chip(struct regmap *map, int irq, int irq_flags,
         else
                 d->irq_reg_stride = 1;
 
+        if (!map->use_single_rw && map->reg_stride == 1 &&
+            d->irq_reg_stride == 1) {
+                d->status_reg_buf = kmalloc(map->format.val_bytes *
+                                            chip->num_regs, GFP_KERNEL);
+                if (!d->status_reg_buf)
+                        goto err_alloc;
+        }
+
         mutex_init(&d->lock);
 
         for (i = 0; i < chip->num_irqs; i++)
@@ -397,6 +448,7 @@ err_alloc:
         kfree(d->mask_buf_def);
         kfree(d->mask_buf);
         kfree(d->status_buf);
+        kfree(d->status_reg_buf);
         kfree(d);
         return ret;
 }
@@ -418,6 +470,7 @@ void regmap_del_irq_chip(int irq, struct regmap_irq_chip_data *d)
         kfree(d->wake_buf);
         kfree(d->mask_buf_def);
         kfree(d->mask_buf);
+        kfree(d->status_reg_buf);
         kfree(d->status_buf);
         kfree(d);
 }