[PATCH v2 3/4] spi: dw: Add basic runtime PM support

[Gareth Williams]

From: Phil Edworthy <phil.edwor...@renesas.com>

Enable runtime PM so that the clock used to access the registers in the
peripheral is turned on using a clock domain.

Signed-off-by: Phil Edworthy <phil.edwor...@renesas.com>
Signed-off-by: Gareth Williams <gareth.williams...@renesas.com>
---
v2:
 - set spi_controller.auto_runtime_pm instead of using
   pm_runtime_get_sync.
 - Added pm_runtime_disable calls to dw_spi_remove_host and the error
   condition of dw_spi_add_host.
---
 drivers/spi/spi-dw.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/spi/spi-dw.c b/drivers/spi/spi-dw.c
index 9a49e07..54ed6eb 100644
--- a/drivers/spi/spi-dw.c
+++ b/drivers/spi/spi-dw.c
@@ -10,6 +10,7 @@
 #include <linux/module.h>
 #include <linux/highmem.h>
 #include <linux/delay.h>
+#include <linux/pm_runtime.h>
 #include <linux/slab.h>
 #include <linux/spi/spi.h>
 
@@ -493,10 +494,13 @@ int dw_spi_add_host(struct device *dev, struct dw_spi 
*dws)
        master->dev.of_node = dev->of_node;
        master->dev.fwnode = dev->fwnode;
        master->flags = SPI_MASTER_GPIO_SS;
+       master->auto_runtime_pm = true;
 
        if (dws->set_cs)
                master->set_cs = dws->set_cs;
 
+       pm_runtime_enable(dev);
+
        /* Basic HW init */
        spi_hw_init(dev, dws);
 
@@ -525,6 +529,7 @@ int dw_spi_add_host(struct device *dev, struct dw_spi *dws)
        spi_enable_chip(dws, 0);
        free_irq(dws->irq, master);
 err_free_master:
+       pm_runtime_disable(dev);
        spi_controller_put(master);
        return ret;
 }
@@ -539,6 +544,9 @@ void dw_spi_remove_host(struct dw_spi *dws)
 
        spi_shutdown_chip(dws);
 
+       if (dws->master)
+               pm_runtime_disable(&dws->master->dev);
+
        free_irq(dws->irq, dws->master);
 }
 EXPORT_SYMBOL_GPL(dw_spi_remove_host);
-- 
2.7.4