mfd: intel-lpss: Save register context on suspend

commit 41a3da2b8e1639d983192e3650670df4ecc94cf7 upstream.

All configurations are lost and the registers will have
default values when the hardware is suspended and resumed,
so saving the private register space context on suspend, and
restoring it on resume.

Fixes: 4b45efe85263 (mfd: Add support for Intel Sunrisepoint LPSS devices)
Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/mfd/intel-lpss.c b/drivers/mfd/intel-lpss.c
index 68aa31ae553a64c2aff19668d7a6e3b8e34c53c4..88e80ec772f6eebb0045cbea0a1ddff84eeb44fc 100644 (file)
--- a/drivers/mfd/intel-lpss.c
+++ b/drivers/mfd/intel-lpss.c
@@ -33,6 +33,7 @@
 #define LPSS_DEV_SIZE          0x200
 #define LPSS_PRIV_OFFSET       0x200
 #define LPSS_PRIV_SIZE         0x100
+#define LPSS_PRIV_REG_COUNT    (LPSS_PRIV_SIZE / 4)
 #define LPSS_IDMA64_OFFSET     0x800
 #define LPSS_IDMA64_SIZE       0x800
 
@@ -75,6 +76,7 @@ struct intel_lpss {
        const struct mfd_cell *cell;
        struct device *dev;
        void __iomem *priv;
+       u32 priv_ctx[LPSS_PRIV_REG_COUNT];
        int devid;
        u32 caps;
        u32 active_ltr;
@@ -485,6 +487,16 @@ EXPORT_SYMBOL_GPL(intel_lpss_prepare);
 
 int intel_lpss_suspend(struct device *dev)
 {
+       struct intel_lpss *lpss = dev_get_drvdata(dev);
+       unsigned int i;
+
+       /* Save device context */
+       for (i = 0; i < LPSS_PRIV_REG_COUNT; i++)
+               lpss->priv_ctx[i] = readl(lpss->priv + i * 4);
+
+       /* Put the device into reset state */
+       writel(0, lpss->priv + LPSS_PRIV_RESETS);
+
        return 0;
 }
 EXPORT_SYMBOL_GPL(intel_lpss_suspend);
@@ -492,8 +504,13 @@ EXPORT_SYMBOL_GPL(intel_lpss_suspend);
 int intel_lpss_resume(struct device *dev)
 {
        struct intel_lpss *lpss = dev_get_drvdata(dev);
+       unsigned int i;
 
-       intel_lpss_init_dev(lpss);
+       intel_lpss_deassert_reset(lpss);
+
+       /* Restore device context */
+       for (i = 0; i < LPSS_PRIV_REG_COUNT; i++)
+               writel(lpss->priv_ctx[i], lpss->priv + i * 4);
 
        return 0;
 }