platform/mellanox: mlxreg-hotplug: Add support for new capability register

Add support for capability register, which is used for detection of the
actual number of interrupt capable components within the particular
group, supported by the specific system.
Such components could be for example the number of power units and
interrupts related to these units.
The motivation is to avoid adding a new code in the future in order to
distinct between the systems type supported different number of the
components like power supplies, FANs, ASICs, line cards.
Signed-off-by: Vadim Pasternak <vadimp@mellanox.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

drivers/platform/mellanox/mlxreg-hotplug.c

@@ -504,6 +504,20 @@ static int mlxreg_hotplug_set_irq(struct mlxreg_hotplug_priv_data *priv)
 	item = pdata->items;
 
 	for (i = 0; i < pdata->counter; i++, item++) {
+		if (item->capability) {
+			/*
+			 * Read group capability register to get actual number
+			 * of interrupt capable components and set group mask
+			 * accordingly.
+			 */
+			ret = regmap_read(priv->regmap, item->capability,
+					  &regval);
+			if (ret)
+				goto out;
+
+			item->mask = GENMASK((regval & item->mask) - 1, 0);
+		}
+
 		/* Clear group presense event. */
 		ret = regmap_write(priv->regmap, item->reg +
 				   MLXREG_HOTPLUG_EVENT_OFF, 0);

include/linux/platform_data/mlxreg.h

@@ -101,6 +101,7 @@ struct mlxreg_core_data {
  * @aggr_mask: group aggregation mask;
  * @reg: group interrupt status register;
  * @mask: group interrupt mask;
+ * @capability: group capability register;
  * @cache: last status value for elements fro the same group;
  * @count: number of available elements in the group;
  * @ind: element's index inside the group;
@@ -112,6 +113,7 @@ struct mlxreg_core_item {
 	u32 aggr_mask;
 	u32 reg;
 	u32 mask;
+	u32 capability;
 	u32 cache;
 	u8 count;
 	u8 ind;