[PATCH v2 05/11] mfd: Add cell device name

From: Théo Lebrun
Date: Fri May 03 2024 - 10:23:11 EST


Current device name is picked from pdev->name, coming from cell->name.
pdev->name is sometimes used to match driver so cannot be changed.
Add cell->devname field to let MFDs configure their sub-devices names
using newly introduced platform_device_add_with_name().

This comes in handy when MFDs instantiate the same platform driver.
First solution is to use auto IDs:

// MFD device A generates sub-device named "foo.0.auto"
struct mfd_cell cell = { .name = "foo" };
mfd_add_devices(dev, PLATFORM_DEVID_AUTO, &cell, 1, ...);

// MFD device B generates sub-device named "foo.1.auto"
struct mfd_cell cell = { .name = "foo" };
mfd_add_devices(dev, PLATFORM_DEVID_AUTO, &cell, 1, ...);

An alternative is to manually pick IDs using cell->id:

// MFD device A generates sub-device named "foo.0"
struct mfd_cell cell = { .name = "foo", .id = 0 };
mfd_add_devices(dev, 0, &cell, 1, ...);

// MFD device B generates sub-device named "foo.1"
struct mfd_cell cell = { .name = "foo", .id = 1 };
mfd_add_devices(dev, 0, &cell, 1, ...);

Devices still have obscure names. With changes, two MFD devices can do:

// MFD device A generates sub-device named "foo-a"
struct mfd_cell cell = { .name = "foo", .devname = "foo-a" };
mfd_add_devices(dev, PLATFORM_DEVID_NONE, &cell, 1, ...);

// MFD device B generates sub-device named "foo-b"
struct mfd_cell cell = { .name = "foo", .devname = "foo-b" };
mfd_add_devices(dev, PLATFORM_DEVID_NONE, &cell, 1, ...);

Device names are explicit and facilitate identification.
Benefit increases with more instances.

No shorthand MFD_CELL_*() macro is created to exploit this field.

Signed-off-by: Théo Lebrun <theo.lebrun@xxxxxxxxxxx>
---
drivers/mfd/mfd-core.c | 2 +-
include/linux/mfd/core.h | 19 ++++++++++++-------
2 files changed, 13 insertions(+), 8 deletions(-)

diff --git a/drivers/mfd/mfd-core.c b/drivers/mfd/mfd-core.c
index 6ad5c93027af..bdfbe860295a 100644
--- a/drivers/mfd/mfd-core.c
+++ b/drivers/mfd/mfd-core.c
@@ -271,7 +271,7 @@ static int mfd_add_device(struct device *parent, int id,
if (ret)
goto fail_res_conflict;

- ret = platform_device_add(pdev);
+ ret = platform_device_add_with_name(pdev, cell->devname);
if (ret)
goto fail_res_conflict;

diff --git a/include/linux/mfd/core.h b/include/linux/mfd/core.h
index e8bcad641d8c..a2040372ca91 100644
--- a/include/linux/mfd/core.h
+++ b/include/linux/mfd/core.h
@@ -14,7 +14,8 @@

#define MFD_RES_SIZE(arr) (sizeof(arr) / sizeof(struct resource))

-#define MFD_CELL_ALL(_name, _res, _pdata, _pdsize, _id, _compat, _of_reg, _use_of_reg, _match) \
+#define MFD_CELL_ALL(_name, _res, _pdata, _pdsize, _id, _compat, \
+ _of_reg, _use_of_reg, _match, _devname) \
{ \
.name = (_name), \
.resources = (_res), \
@@ -26,25 +27,26 @@
.use_of_reg = (_use_of_reg), \
.acpi_match = (_match), \
.id = (_id), \
+ .devname = (_devname), \
}

#define MFD_CELL_OF_REG(_name, _res, _pdata, _pdsize, _id, _compat, _of_reg) \
- MFD_CELL_ALL(_name, _res, _pdata, _pdsize, _id, _compat, _of_reg, true, NULL)
+ MFD_CELL_ALL(_name, _res, _pdata, _pdsize, _id, _compat, _of_reg, true, NULL, NULL)

#define MFD_CELL_OF(_name, _res, _pdata, _pdsize, _id, _compat) \
- MFD_CELL_ALL(_name, _res, _pdata, _pdsize, _id, _compat, 0, false, NULL)
+ MFD_CELL_ALL(_name, _res, _pdata, _pdsize, _id, _compat, 0, false, NULL, NULL)

#define MFD_CELL_ACPI(_name, _res, _pdata, _pdsize, _id, _match) \
- MFD_CELL_ALL(_name, _res, _pdata, _pdsize, _id, NULL, 0, false, _match)
+ MFD_CELL_ALL(_name, _res, _pdata, _pdsize, _id, NULL, 0, false, _match, NULL)

#define MFD_CELL_BASIC(_name, _res, _pdata, _pdsize, _id) \
- MFD_CELL_ALL(_name, _res, _pdata, _pdsize, _id, NULL, 0, false, NULL)
+ MFD_CELL_ALL(_name, _res, _pdata, _pdsize, _id, NULL, 0, false, NULL, NULL)

#define MFD_CELL_RES(_name, _res) \
- MFD_CELL_ALL(_name, _res, NULL, 0, 0, NULL, 0, false, NULL)
+ MFD_CELL_ALL(_name, _res, NULL, 0, 0, NULL, 0, false, NULL, NULL)

#define MFD_CELL_NAME(_name) \
- MFD_CELL_ALL(_name, NULL, NULL, 0, 0, NULL, 0, false, NULL)
+ MFD_CELL_ALL(_name, NULL, NULL, 0, 0, NULL, 0, false, NULL, NULL)

#define MFD_DEP_LEVEL_NORMAL 0
#define MFD_DEP_LEVEL_HIGH 1
@@ -118,6 +120,9 @@ struct mfd_cell {
*/
int num_parent_supplies;
const char * const *parent_supplies;
+
+ /* Optional struct device name. */
+ const char *devname;
};

/*

--
2.45.0