ARM: 7366/3: amba: Remove AMBA level regulator support

The AMBA bus regulator support is being used to model on/off switches
for power domains which isn't terribly idiomatic for modern kernels with
the generic power domain code and creates integration problems on platforms
which don't use regulators for their power domains as it's hard to tell
the difference between a regulator that is needed but failed to be provided
and one that isn't supposed to be there (though DT does make that easier).

Platforms that wish to use the regulator API to manage their power domains
can indirect via the power domain interface.

This feature is only used with the vape supply of the db8500 PRCMU
driver which supplies the UARTs and MMC controllers, none of which have
support for managing vcore at runtime in mainline (only pl022 SPI
controller does).  Update that supply to have an always_on constraint
until the power domain support for the system is updated so that it is
enabled for these users, this is likely to have no impact on practical
systems as probably at least one of these devices will be active and
cause AMBA to hold the supply on anyway.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Tested-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

drivers/amba/bus.c

@@ -247,8 +247,7 @@ static int amba_pm_restore(struct device *dev)
 /*
  * Hooks to provide runtime PM of the pclk (bus clock).  It is safe to
  * enable/disable the bus clock at runtime PM suspend/resume as this
- * does not result in loss of context.  However, disabling vcore power
- * would do, so we leave that to the driver.
+ * does not result in loss of context.
  */
 static int amba_pm_runtime_suspend(struct device *dev)
 {
@@ -354,39 +353,6 @@ static void amba_put_disable_pclk(struct amba_device *pcdev)
 	clk_put(pclk);
 }
 
-static int amba_get_enable_vcore(struct amba_device *pcdev)
-{
-	struct regulator *vcore = regulator_get(&pcdev->dev, "vcore");
-	int ret;
-
-	pcdev->vcore = vcore;
-
-	if (IS_ERR(vcore)) {
-		/* It is OK not to supply a vcore regulator */
-		if (PTR_ERR(vcore) == -ENODEV)
-			return 0;
-		return PTR_ERR(vcore);
-	}
-
-	ret = regulator_enable(vcore);
-	if (ret) {
-		regulator_put(vcore);
-		pcdev->vcore = ERR_PTR(-ENODEV);
-	}
-
-	return ret;
-}
-
-static void amba_put_disable_vcore(struct amba_device *pcdev)
-{
-	struct regulator *vcore = pcdev->vcore;
-
-	if (!IS_ERR(vcore)) {
-		regulator_disable(vcore);
-		regulator_put(vcore);
-	}
-}
-
 /*
  * These are the device model conversion veneers; they convert the
  * device model structures to our more specific structures.
@@ -399,10 +365,6 @@ static int amba_probe(struct device *dev)
 	int ret;
 
 	do {
-		ret = amba_get_enable_vcore(pcdev);
-		if (ret)
-			break;
-
 		ret = amba_get_enable_pclk(pcdev);
 		if (ret)
 			break;
@@ -420,7 +382,6 @@ static int amba_probe(struct device *dev)
 		pm_runtime_put_noidle(dev);
 
 		amba_put_disable_pclk(pcdev);
-		amba_put_disable_vcore(pcdev);
 	} while (0);
 
 	return ret;
@@ -442,7 +403,6 @@ static int amba_remove(struct device *dev)
 	pm_runtime_put_noidle(dev);
 
 	amba_put_disable_pclk(pcdev);
-	amba_put_disable_vcore(pcdev);
 
 	return ret;
 }

drivers/mfd/db8500-prcmu.c

@@ -2788,6 +2788,7 @@ static struct regulator_init_data db8500_regulators[DB8500_NUM_REGULATORS] = {
 		.constraints = {
 			.name = "db8500-vape",
 			.valid_ops_mask = REGULATOR_CHANGE_STATUS,
+			.always_on = true,
 		},
 		.consumer_supplies = db8500_vape_consumers,
 		.num_consumer_supplies = ARRAY_SIZE(db8500_vape_consumers),

drivers/spi/spi-pl022.c

@@ -2195,7 +2195,6 @@ static int pl022_runtime_suspend(struct device *dev)
 	struct pl022 *pl022 = dev_get_drvdata(dev);
 
 	clk_disable(pl022->clk);
-	amba_vcore_disable(pl022->adev);
 
 	return 0;
 }
@@ -2204,7 +2203,6 @@ static int pl022_runtime_resume(struct device *dev)
 {
 	struct pl022 *pl022 = dev_get_drvdata(dev);
 
-	amba_vcore_enable(pl022->adev);
 	clk_enable(pl022->clk);
 
 	return 0;

include/linux/amba/bus.h

@@ -30,7 +30,6 @@ struct amba_device {
 	struct device		dev;
 	struct resource		res;
 	struct clk		*pclk;
-	struct regulator	*vcore;
 	u64			dma_mask;
 	unsigned int		periphid;
 	unsigned int		irq[AMBA_NR_IRQS];
@@ -75,12 +74,6 @@ void amba_release_regions(struct amba_device *);
 #define amba_pclk_disable(d)	\
 	do { if (!IS_ERR((d)->pclk)) clk_disable((d)->pclk); } while (0)
 
-#define amba_vcore_enable(d)	\
-	(IS_ERR((d)->vcore) ? 0 : regulator_enable((d)->vcore))
-
-#define amba_vcore_disable(d)	\
-	do { if (!IS_ERR((d)->vcore)) regulator_disable((d)->vcore); } while (0)
-
 /* Some drivers don't use the struct amba_device */
 #define AMBA_CONFIG_BITS(a) (((a) >> 24) & 0xff)
 #define AMBA_REV_BITS(a) (((a) >> 20) & 0x0f)