mfd: Allow mapping regulator supplies to MFD device from children

Occasionally, it is useful to map supplies from a child device onto the
MFD device. A typical usecase for this would be if the MFD device is
represented as a single node in device tree. All supplies will be
defined in device tree as existing on the MFD device. When a child
depends on frameworks which might have no knowledge of MFD to lookup
supplies on its behalf the supply will not be found.

This patch adds a list of supplies that should be looked up on the
parent rather than the child as part of the mfd_cell structure.

Signed-off-by: Charles Keepax <ckeepax@opensource.wolfsonmicro.com>
Acked-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Mark Brown <broonie@linaro.org>

2 files changed, 23 insertions, 5 deletions

diff --git a/drivers/mfd/mfd-core.c b/drivers/mfd/mfd-core.c
index f421586f29fb..adc8ea36e7c4 100644
--- a/drivers/mfd/mfd-core.c
+++ b/drivers/mfd/mfd-core.c
@@ -20,6 +20,7 @@
 #include <linux/module.h>
 #include <linux/irqdomain.h>
 #include <linux/of.h>
+#include <linux/regulator/consumer.h>
 
 static struct device_type mfd_dev_type = {
         .name   = "mfd_device",
@@ -99,6 +100,13 @@ static int mfd_add_device(struct device *parent, int id,
         pdev->dev.dma_mask = parent->dma_mask;
         pdev->dev.dma_parms = parent->dma_parms;
 
+        ret = devm_regulator_bulk_register_supply_alias(
+                        &pdev->dev, cell->parent_supplies,
+                        parent, cell->parent_supplies,
+                        cell->num_parent_supplies);
+        if (ret < 0)
+                goto fail_res;
+
         if (parent->of_node && cell->of_compatible) {
                 for_each_child_of_node(parent->of_node, np) {
                         if (of_device_is_compatible(np, cell->of_compatible)) {
@@ -112,12 +120,12 @@ static int mfd_add_device(struct device *parent, int id,
                 ret = platform_device_add_data(pdev,
                                         cell->platform_data, cell->pdata_size);
                 if (ret)
-                        goto fail_res;
+                        goto fail_alias;
         }
 
         ret = mfd_platform_add_cell(pdev, cell);
         if (ret)
-                goto fail_res;
+                goto fail_alias;
 
         for (r = 0; r < cell->num_resources; r++) {
                 res[r].name = cell->resources[r].name;
@@ -152,17 +160,17 @@ static int mfd_add_device(struct device *parent, int id,
                 if (!cell->ignore_resource_conflicts) {
                         ret = acpi_check_resource_conflict(&res[r]);
                         if (ret)
-                                goto fail_res;
+                                goto fail_alias;
                 }
         }
 
         ret = platform_device_add_resources(pdev, res, cell->num_resources);
         if (ret)
-                goto fail_res;
+                goto fail_alias;
 
         ret = platform_device_add(pdev);
         if (ret)
-                goto fail_res;
+                goto fail_alias;
 
         if (cell->pm_runtime_no_callbacks)
                 pm_runtime_no_callbacks(&pdev->dev);
@@ -171,6 +179,10 @@ static int mfd_add_device(struct device *parent, int id,
 
         return 0;
 
+fail_alias:
+        devm_regulator_bulk_unregister_supply_alias(&pdev->dev,
+                                                    cell->parent_supplies,
+                                                    cell->num_parent_supplies);
 fail_res:
         kfree(res);
 fail_device:
diff --git a/include/linux/mfd/core.h b/include/linux/mfd/core.h
index cebe97ee98b8..7314fc4e6d25 100644
--- a/include/linux/mfd/core.h
+++ b/include/linux/mfd/core.h
@@ -59,6 +59,12 @@ struct mfd_cell {
          * pm_runtime_no_callbacks().
          */
         bool                    pm_runtime_no_callbacks;
+
+        /* A list of regulator supplies that should be mapped to the MFD
+         * device rather than the child device when requested
+         */
+        const char              **parent_supplies;
+        int                     num_parent_supplies;
 };
 
 /*