mfd: intel-lpss: Save register context on suspend

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)
Cc: stable@vger.kernel.org # v4.3+
Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

diff --git a/drivers/mfd/intel-lpss.c b/drivers/mfd/intel-lpss.c
index 1bbbe877ba7e7c1702107fa062f208c089151f60..807a3e3ec29a66352a84d48ac9d1d28a673ca0ee 100644 (file)
--- a/drivers/mfd/intel-lpss.c
+++ b/drivers/mfd/intel-lpss.c
@@ -34,6 +34,7 @@
 #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
 
@@ -76,6 +77,7 @@ struct intel_lpss {
        struct mfd_cell *cell;
        struct device *dev;
        void __iomem *priv;
+       u32 priv_ctx[LPSS_PRIV_REG_COUNT];
        int devid;
        u32 caps;
        u32 active_ltr;
@@ -493,6 +495,16 @@ 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);
@@ -500,8 +512,13 @@ 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;
 }