mfd: mfd-core: Remove usage counting for .{en,dis}able() call-backs

The MFD implementation for reference counting was complex and unnecessary.
There was only one bona fide user which has now been converted to handle
the process in a different way. Any future resource protection, shared
enablement functions should be handed by the parent device, rather than
through the MFD subsystem API.

Signed-off-by: Lee Jones <lee.jones@linaro.org>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Reviewed-by: Mark Brown <broonie@kernel.org>

diff --git a/drivers/mfd/mfd-core.c b/drivers/mfd/mfd-core.c
index e38e411ca775af807f823b56b0280d390ed05c9d..2535dd3605c026084d960bf9a15fe6ee49b6467c 100644 (file)
--- a/drivers/mfd/mfd-core.c
+++ b/drivers/mfd/mfd-core.c
@@ -26,53 +26,31 @@ static struct device_type mfd_dev_type = {
 int mfd_cell_enable(struct platform_device *pdev)
 {
        const struct mfd_cell *cell = mfd_get_cell(pdev);
-       int err = 0;
 
        if (!cell->enable) {
                dev_dbg(&pdev->dev, "No .enable() call-back registered\n");
                return 0;
        }
 
-       /* only call enable hook if the cell wasn't previously enabled */
-       if (atomic_inc_return(cell->usage_count) == 1)
-               err = cell->enable(pdev);
-
-       /* if the enable hook failed, decrement counter to allow retries */
-       if (err)
-               atomic_dec(cell->usage_count);
-
-       return err;
+       return cell->enable(pdev);
 }
 EXPORT_SYMBOL(mfd_cell_enable);
 
 int mfd_cell_disable(struct platform_device *pdev)
 {
        const struct mfd_cell *cell = mfd_get_cell(pdev);
-       int err = 0;
 
        if (!cell->disable) {
                dev_dbg(&pdev->dev, "No .disable() call-back registered\n");
                return 0;
        }
 
-       /* only disable if no other clients are using it */
-       if (atomic_dec_return(cell->usage_count) == 0)
-               err = cell->disable(pdev);
-
-       /* if the disable hook failed, increment to allow retries */
-       if (err)
-               atomic_inc(cell->usage_count);
-
-       /* sanity check; did someone call disable too many times? */
-       WARN_ON(atomic_read(cell->usage_count) < 0);
-
-       return err;
+       return cell->disable(pdev);
 }
 EXPORT_SYMBOL(mfd_cell_disable);
 
 static int mfd_platform_add_cell(struct platform_device *pdev,
-                                const struct mfd_cell *cell,
-                                atomic_t *usage_count)
+                                const struct mfd_cell *cell)
 {
        if (!cell)
                return 0;
@@ -81,7 +59,6 @@ static int mfd_platform_add_cell(struct platform_device *pdev,
        if (!pdev->mfd_cell)
                return -ENOMEM;
 
-       pdev->mfd_cell->usage_count = usage_count;
        return 0;
 }
 
@@ -144,7 +121,7 @@ static inline void mfd_acpi_add_device(const struct mfd_cell *cell,
 #endif
 
 static int mfd_add_device(struct device *parent, int id,
-                         const struct mfd_cell *cell, atomic_t *usage_count,
+                         const struct mfd_cell *cell,
                          struct resource *mem_base,
                          int irq_base, struct irq_domain *domain)
 {
@@ -206,7 +183,7 @@ static int mfd_add_device(struct device *parent, int id,
                        goto fail_alias;
        }
 
-       ret = mfd_platform_add_cell(pdev, cell, usage_count);
+       ret = mfd_platform_add_cell(pdev, cell);
        if (ret)
                goto fail_alias;
 
@@ -296,16 +273,9 @@ int mfd_add_devices(struct device *parent, int id,
 {
        int i;
        int ret;
-       atomic_t *cnts;
-
-       /* initialize reference counting for all cells */
-       cnts = kcalloc(n_devs, sizeof(*cnts), GFP_KERNEL);
-       if (!cnts)
-               return -ENOMEM;
 
        for (i = 0; i < n_devs; i++) {
-               atomic_set(&cnts[i], 0);
-               ret = mfd_add_device(parent, id, cells + i, cnts + i, mem_base,
+               ret = mfd_add_device(parent, id, cells + i, mem_base,
                                     irq_base, domain);
                if (ret)
                        goto fail;
@@ -316,17 +286,15 @@ int mfd_add_devices(struct device *parent, int id,
 fail:
        if (i)
                mfd_remove_devices(parent);
-       else
-               kfree(cnts);
+
        return ret;
 }
 EXPORT_SYMBOL(mfd_add_devices);
 
-static int mfd_remove_devices_fn(struct device *dev, void *c)
+static int mfd_remove_devices_fn(struct device *dev, void *data)
 {
        struct platform_device *pdev;
        const struct mfd_cell *cell;
-       atomic_t **usage_count = c;
 
        if (dev->type != &mfd_dev_type)
                return 0;
@@ -337,20 +305,13 @@ static int mfd_remove_devices_fn(struct device *dev, void *c)
        regulator_bulk_unregister_supply_alias(dev, cell->parent_supplies,
                                               cell->num_parent_supplies);
 
-       /* find the base address of usage_count pointers (for freeing) */
-       if (!*usage_count || (cell->usage_count < *usage_count))
-               *usage_count = cell->usage_count;
-
        platform_device_unregister(pdev);
        return 0;
 }
 
 void mfd_remove_devices(struct device *parent)
 {
-       atomic_t *cnts = NULL;
-
-       device_for_each_child_reverse(parent, &cnts, mfd_remove_devices_fn);
-       kfree(cnts);
+       device_for_each_child_reverse(parent, NULL, mfd_remove_devices_fn);
 }
 EXPORT_SYMBOL(mfd_remove_devices);
 

diff --git a/include/linux/mfd/core.h b/include/linux/mfd/core.h
index 63ac3cc8660888b499dc2fc6ffaff367cfcd4354..d01d1299e49dcc69516f40d43180d4e795ca5743 100644 (file)
--- a/include/linux/mfd/core.h
+++ b/include/linux/mfd/core.h
@@ -59,8 +59,6 @@ struct mfd_cell {
        const char              *name;
        int                     id;
 
-       /* refcounting for multiple drivers to use a single cell */
-       atomic_t                *usage_count;
        int                     (*enable)(struct platform_device *dev);
        int                     (*disable)(struct platform_device *dev);