On Thu, 2018-05-03 at 23:08 +0800, John Garry wrote:
Currently for ACPI support the driver models the host as
an MFD. For a device connected to the LPC bus, we dynamically
create an MFD cell for that device, configuring the cell
name and ACPI match parameters manually. This makes supporting
named devices and also special setup handling for certain devices
awkward, as we would need to introduce some special ACPI device
handling according to device HID.
To avoid this, create reference static MFD cells for known
child devices, so when adding an MFD cell we can fix the cell
platform data as required. For this, a setup callback function
is added.
For now, only the IPMI cell is added.
+static const struct mfd_cell *hisi_lpc_acpi_mfd_get_cell(const char
*hid)
+{
+ const struct hisi_lpc_acpi_mfd_cell *cell =
hisi_lpc_acpi_mfd_cells;
+
+ for (; cell && cell->mfd_cell.name; cell++) {
+ const struct mfd_cell *mfd_cell = &cell->mfd_cell;
+ const struct mfd_cell_acpi_match *acpi_match;
+
+ acpi_match = mfd_cell->acpi_match;
+ if (!strcmp(acpi_match->pnpid, hid))
+ return mfd_cell;
+ }
+
+ return NULL;
+}
I'm not sure I understand why MFD core can't do it (as seen in lines
drivers/mfd/core.c:105 and below).
+ /* allocate the mfd cells, one per child */
+ size = sizeof(*mfd_cells);
mfd_cells = devm_kcalloc(hostdev, cell_num, size,
GFP_KERNEL);
if (!mfd_cells)
return -ENOMEM;
And since you have structures already, I'm not sure why you need another
allocation for them. Only what you would need is to apply resources and
call devm_mfd_add_devices() per each found device.
+ cell = container_of(mfd_cell_ref, typeof(*cell),
mfd_cell);
Why we can't iterate over inherited type of objects directly?