[PATCH] mfd-core: add mfd_clone_cell(), convert cs5535-mfd/olpc-xo1to it

From: Andres Salomon
Date: Mon Mar 21 2011 - 22:24:07 EST



Replace mfd_shared_platform_driver_register with mfd_clone_cell. The
former was called by an mfd client, and registered both a platform driver
and device. The latter is called by an mfd driver, and registers only a
platform device.

The downside of this is that mfd drivers need to be modified whenever
new clients are added that share a cell; the upside is that it fits
Linux's driver model better. It's also simpler.

This also converts cs5535-mfd/olpc-xo1 from the old API. cs5535-mfd
now creates the olpc-xo1-{acpi,pms} devices, while olpc-xo1 binds to
them via platform drivers.

Signed-off-by: Andres Salomon <dilinger@xxxxxxxxxx>
---
arch/x86/platform/olpc/olpc-xo1.c | 11 +++----
drivers/mfd/cs5535-mfd.c | 18 ++++++++++++
drivers/mfd/mfd-core.c | 53 +++++++-----------------------------
include/linux/mfd/core.h | 27 ++++++++++++------
4 files changed, 52 insertions(+), 57 deletions(-)

diff --git a/arch/x86/platform/olpc/olpc-xo1.c b/arch/x86/platform/olpc/olpc-xo1.c
index 9951364..386e3a1 100644
--- a/arch/x86/platform/olpc/olpc-xo1.c
+++ b/arch/x86/platform/olpc/olpc-xo1.c
@@ -121,22 +121,21 @@ static int __init olpc_xo1_init(void)
{
int r;

- r = mfd_shared_platform_driver_register(&cs5535_pms_drv, "cs5535-pms");
+ r = platform_driver_register(&cs5535_pms_drv);
if (r)
return r;

- r = mfd_shared_platform_driver_register(&cs5535_acpi_drv,
- "cs5535-acpi");
+ r = platform_driver_register(&cs5535_acpi_drv);
if (r)
- mfd_shared_platform_driver_unregister(&cs5535_pms_drv);
+ platform_driver_unregister(&cs5535_pms_drv);

return r;
}

static void __exit olpc_xo1_exit(void)
{
- mfd_shared_platform_driver_unregister(&cs5535_acpi_drv);
- mfd_shared_platform_driver_unregister(&cs5535_pms_drv);
+ platform_driver_unregister(&cs5535_acpi_drv);
+ platform_driver_unregister(&cs5535_pms_drv);
}

MODULE_AUTHOR("Daniel Drake <dsd@xxxxxxxxxx>");
diff --git a/drivers/mfd/cs5535-mfd.c b/drivers/mfd/cs5535-mfd.c
index 886a068..24959dd 100644
--- a/drivers/mfd/cs5535-mfd.c
+++ b/drivers/mfd/cs5535-mfd.c
@@ -27,6 +27,7 @@
#include <linux/mfd/core.h>
#include <linux/module.h>
#include <linux/pci.h>
+#include <asm/olpc.h>

#define DRV_NAME "cs5535-mfd"

@@ -111,6 +112,22 @@ static __devinitdata struct mfd_cell cs5535_mfd_cells[] = {
},
};

+#ifdef CONFIG_OLPC
+static void __devinit cs5535_clone_olpc_cells(void)
+{
+ const char *acpi_clones[] = { "olpc-xo1-acpi" };
+ const char *pms_clones[] = { "olpc-xo1-pms" };
+
+ if (!machine_is_olpc())
+ return;
+
+ mfd_clone_cell("cs5535-acpi", acpi_clones, ARRAY_SIZE(acpi_clones));
+ mfd_clone_cell("cs5535-pms", pms_clones, ARRAY_SIZE(pms_clones));
+}
+#else
+static void cs5535_clone_olpc_cells(void) { }
+#endif
+
static int __devinit cs5535_mfd_probe(struct pci_dev *pdev,
const struct pci_device_id *id)
{
@@ -139,6 +156,7 @@ static int __devinit cs5535_mfd_probe(struct pci_dev *pdev,
dev_err(&pdev->dev, "MFD add devices failed: %d\n", err);
goto err_disable;
}
+ cs5535_clone_olpc_cells();

dev_info(&pdev->dev, "%zu devices registered.\n",
ARRAY_SIZE(cs5535_mfd_cells));
diff --git a/drivers/mfd/mfd-core.c b/drivers/mfd/mfd-core.c
index 79eda02..d01574d 100644
--- a/drivers/mfd/mfd-core.c
+++ b/drivers/mfd/mfd-core.c
@@ -184,16 +184,12 @@ void mfd_remove_devices(struct device *parent)
}
EXPORT_SYMBOL(mfd_remove_devices);

-static int add_shared_platform_device(const char *cell, const char *name)
+int mfd_clone_cell(const char *cell, const char **clones, size_t n_clones)
{
struct mfd_cell cell_entry;
struct device *dev;
struct platform_device *pdev;
- int err;
-
- /* check if we've already registered a device (don't fail if we have) */
- if (bus_find_device_by_name(&platform_bus_type, NULL, name))
- return 0;
+ int i;

/* fetch the parent cell's device (should already be registered!) */
dev = bus_find_device_by_name(&platform_bus_type, NULL, cell);
@@ -206,44 +202,17 @@ static int add_shared_platform_device(const char *cell, const char *name)

WARN_ON(!cell_entry.enable);

- cell_entry.name = name;
- err = mfd_add_device(pdev->dev.parent, -1, &cell_entry, NULL, 0);
- if (err)
- dev_err(dev, "MFD add devices failed: %d\n", err);
- return err;
-}
-
-int mfd_shared_platform_driver_register(struct platform_driver *drv,
- const char *cellname)
-{
- int err;
-
- err = add_shared_platform_device(cellname, drv->driver.name);
- if (err)
- printk(KERN_ERR "failed to add platform device %s\n",
- drv->driver.name);
-
- err = platform_driver_register(drv);
- if (err)
- printk(KERN_ERR "failed to add platform driver %s\n",
- drv->driver.name);
-
- return err;
-}
-EXPORT_SYMBOL(mfd_shared_platform_driver_register);
-
-void mfd_shared_platform_driver_unregister(struct platform_driver *drv)
-{
- struct device *dev;
-
- dev = bus_find_device_by_name(&platform_bus_type, NULL,
- drv->driver.name);
- if (dev)
- platform_device_unregister(to_platform_device(dev));
+ for (i = 0; i < n_clones; i++) {
+ cell_entry.name = clones[i];
+ /* don't give up if a single call fails; just report error */
+ if (mfd_add_device(pdev->dev.parent, -1, &cell_entry, NULL, 0))
+ dev_err(dev, "failed to create platform device '%s'\n",
+ clones[i]);
+ }

- platform_driver_unregister(drv);
+ return 0;
}
-EXPORT_SYMBOL(mfd_shared_platform_driver_unregister);
+EXPORT_SYMBOL(mfd_clone_cell);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Ian Molton, Dmitry Baryshkov");
diff --git a/include/linux/mfd/core.h b/include/linux/mfd/core.h
index 1408bf8..ad1b19a 100644
--- a/include/linux/mfd/core.h
+++ b/include/linux/mfd/core.h
@@ -63,6 +63,24 @@ extern int mfd_cell_enable(struct platform_device *pdev);
extern int mfd_cell_disable(struct platform_device *pdev);

/*
+ * "Clone" multiple platform devices for a single cell. This is to be used
+ * for devices that have multiple users of a cell. For example, if an mfd
+ * driver wants the cell "foo" to be used by a GPIO driver, an MTD driver,
+ * and a platform driver, the following bit of code would be use after first
+ * calling mfd_add_devices():
+ *
+ * const char *fclones[] = { "foo-gpio", "foo-mtd" };
+ * err = mfd_clone_cells("foo", fclones, ARRAY_SIZE(fclones));
+ *
+ * Each driver (MTD, GPIO, and platform driver) would then register
+ * platform_drivers for "foo-mtd", "foo-gpio", and "foo", respectively.
+ * The cell's .enable/.disable hooks should be used to deal with hardware
+ * resource contention.
+ */
+extern int mfd_clone_cell(const char *cell, const char **clones,
+ size_t n_clones);
+
+/*
* Given a platform device that's been created by mfd_add_devices(), fetch
* the mfd_cell that created it.
*/
@@ -87,13 +105,4 @@ extern int mfd_add_devices(struct device *parent, int id,

extern void mfd_remove_devices(struct device *parent);

-/*
- * For MFD drivers with clients sharing access to resources, these create
- * multiple platform devices per cell. Contention handling must still be
- * handled via drivers (ie, with enable/disable hooks).
- */
-extern int mfd_shared_platform_driver_register(struct platform_driver *drv,
- const char *cellname);
-extern void mfd_shared_platform_driver_unregister(struct platform_driver *drv);
-
#endif
--
1.7.2.5

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