powerpc: Convert power off logic to pm_power_off

The generic Linux framework to power off the machine is a function pointer
called pm_power_off. The trick about this pointer is that device drivers can
potentially implement it rather than board files.

Today on powerpc we set pm_power_off to invoke our generic full machine power
off logic which then calls ppc_md.power_off to invoke machine specific power
off.

However, when we want to add a power off GPIO via the "gpio-poweroff" driver,
this card house falls apart. That driver only registers itself if pm_power_off
is NULL to ensure it doesn't override board specific logic. However, since we
always set pm_power_off to the generic power off logic (which will just not
power off the machine if no ppc_md.power_off call is implemented), we can't
implement power off via the generic GPIO power off driver.

To fix this up, let's get rid of the ppc_md.power_off logic and just always use
pm_power_off as was intended. Then individual drivers such as the GPIO power off
driver can implement power off logic via that function pointer.

With this patch set applied and a few patches on top of QEMU that implement a
power off GPIO on the virt e500 machine, I can successfully turn off my virtual
machine after halt.

Signed-off-by: Alexander Graf <agraf@suse.de>
[mpe: Squash into one patch and update changelog based on cover letter]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

1 files changed, 4 insertions, 4 deletions

diff --git a/arch/powerpc/platforms/83xx/mcu_mpc8349emitx.c b/arch/powerpc/platforms/83xx/mcu_mpc8349emitx.c
index 463fa91ee5b6..15e8021ddef9 100644
--- a/arch/powerpc/platforms/83xx/mcu_mpc8349emitx.c
+++ b/arch/powerpc/platforms/83xx/mcu_mpc8349emitx.c
@@ -167,10 +167,10 @@ static int mcu_probe(struct i2c_client *client, const struct i2c_device_id *id)
 	if (ret)
 		goto err;
 
-	/* XXX: this is potentially racy, but there is no lock for ppc_md */
-	if (!ppc_md.power_off) {
+	/* XXX: this is potentially racy, but there is no lock for pm_power_off */
+	if (!pm_power_off) {
 		glob_mcu = mcu;
-		ppc_md.power_off = mcu_power_off;
+		pm_power_off = mcu_power_off;
 		dev_info(&client->dev, "will provide power-off service\n");
 	}
 
@@ -197,7 +197,7 @@ static int mcu_remove(struct i2c_client *client)
 	device_remove_file(&client->dev, &dev_attr_status);
 
 	if (glob_mcu == mcu) {
-		ppc_md.power_off = NULL;
+		pm_power_off = NULL;
 		glob_mcu = NULL;
 	}