spi/pl022: disable core voltage when idle

This utilizes the new core voltage switch to power off the PL022
core voltage when it's not in use transmitting packets, if and
only if a core voltage switch is available.

Cc: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>

drivers/spi/amba-pl022.c

@@ -508,9 +508,10 @@ static void giveback(struct pl022 *pl022)
 	msg->state = NULL;
 	if (msg->complete)
 		msg->complete(msg->context);
-	/* This message is completed, so let's turn off the clocks! */
+	/* This message is completed, so let's turn off the clocks & power */
 	clk_disable(pl022->clk);
 	amba_pclk_disable(pl022->adev);
+	amba_vcore_disable(pl022->adev);
 }
 
 /**
@@ -1475,9 +1476,11 @@ static void pump_messages(struct work_struct *work)
 	/* Setup the SPI using the per chip configuration */
 	pl022->cur_chip = spi_get_ctldata(pl022->cur_msg->spi);
 	/*
-	 * We enable the clocks here, then the clocks will be disabled when
-	 * giveback() is called in each method (poll/interrupt/DMA)
+	 * We enable the core voltage and clocks here, then the clocks
+	 * and core will be disabled when giveback() is called in each method
+	 * (poll/interrupt/DMA)
 	 */
+	amba_vcore_enable(pl022->adev);
 	amba_pclk_enable(pl022->adev);
 	clk_enable(pl022->clk);
 	restore_state(pl022);
@@ -2123,8 +2126,12 @@ pl022_probe(struct amba_device *adev, struct amba_id *id)
 		goto err_spi_register;
 	}
 	dev_dbg(dev, "probe succeded\n");
-	/* Disable the silicon block pclk and clock it when needed */
+	/*
+	 * Disable the silicon block pclk and any voltage domain and just
+	 * power it up and clock it when it's needed
+	 */
 	amba_pclk_disable(adev);
+	amba_vcore_disable(adev);
 	return 0;
 
  err_spi_register:
@@ -2189,9 +2196,11 @@ static int pl022_suspend(struct amba_device *adev, pm_message_t state)
 		return status;
 	}
 
+	amba_vcore_enable(adev);
 	amba_pclk_enable(adev);
 	load_ssp_default_config(pl022);
 	amba_pclk_disable(adev);
+	amba_vcore_disable(adev);
 	dev_dbg(&adev->dev, "suspended\n");
 	return 0;
 }