mfd: Refactor WM8350 chip identification

Since the WM8350 driver was originally written the semantics for the
identification registers of the chip have been clarified, allowing
us to do an exact match on all the fields. This avoids mistakenly
running on unsupported hardware.

Also change to using the datasheet names more consistently for
legibility and fix a printk() that should be dev_err().

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Samuel Ortiz <sameo@openedhand.com>

2 files changed, 43 insertions, 17 deletions

diff --git a/drivers/mfd/wm8350-core.c b/drivers/mfd/wm8350-core.c
index 764bf15ea684..2188d759cbde 100644
--- a/drivers/mfd/wm8350-core.c
+++ b/drivers/mfd/wm8350-core.c
@@ -1227,52 +1227,72 @@ int wm8350_device_init(struct wm8350 *wm8350, int irq,
                        struct wm8350_platform_data *pdata)
 {
         int ret = -EINVAL;
-        u16 id1, id2, mask, mode;
+        u16 id1, id2, mask_rev;
+        u16 cust_id, mode, chip_rev;
 
         /* get WM8350 revision and config mode */
         wm8350->read_dev(wm8350, WM8350_RESET_ID, sizeof(id1), &id1);
         wm8350->read_dev(wm8350, WM8350_ID, sizeof(id2), &id2);
+        wm8350->read_dev(wm8350, WM8350_REVISION, sizeof(mask_rev), &mask_rev);
 
         id1 = be16_to_cpu(id1);
         id2 = be16_to_cpu(id2);
+        mask_rev = be16_to_cpu(mask_rev);
 
-        if (id1 == 0x6143) {
-                switch ((id2 & WM8350_CHIP_REV_MASK) >> 12) {
+        if (id1 != 0x6143) {
+                dev_err(wm8350->dev,
+                        "Device with ID %x is not a WM8350\n", id1);
+                ret = -ENODEV;
+                goto err;
+        }
+
+        mode = id2 & WM8350_CONF_STS_MASK >> 10;
+        cust_id = id2 & WM8350_CUST_ID_MASK;
+        chip_rev = (id2 & WM8350_CHIP_REV_MASK) >> 12;
+        dev_info(wm8350->dev,
+                 "CONF_STS %d, CUST_ID %d, MASK_REV %d, CHIP_REV %d\n",
+                 mode, cust_id, mask_rev, chip_rev);
+
+        if (cust_id != 0) {
+                dev_err(wm8350->dev, "Unsupported CUST_ID\n");
+                ret = -ENODEV;
+                goto err;
+        }
+
+        switch (mask_rev) {
+        case 0:
+                switch (chip_rev) {
                 case WM8350_REV_E:
-                        dev_info(wm8350->dev, "Found Rev E device\n");
+                        dev_info(wm8350->dev, "WM8350 Rev E\n");
                         break;
                 case WM8350_REV_F:
-                        dev_info(wm8350->dev, "Found Rev F device\n");
+                        dev_info(wm8350->dev, "WM8350 Rev F\n");
                         break;
                 case WM8350_REV_G:
-                        dev_info(wm8350->dev, "Found Rev G device\n");
+                        dev_info(wm8350->dev, "WM8350 Rev G\n");
                         wm8350->power.rev_g_coeff = 1;
                         break;
                 case WM8350_REV_H:
-                        dev_info(wm8350->dev, "Found Rev H device\n");
+                        dev_info(wm8350->dev, "WM8350 Rev H\n");
                         wm8350->power.rev_g_coeff = 1;
                         break;
                 default:
                         /* For safety we refuse to run on unknown hardware */
-                        dev_info(wm8350->dev, "Found unknown rev %x\n",
-                                 (id2 & WM8350_CHIP_REV_MASK) >> 12);
+                        dev_err(wm8350->dev, "Unknown WM8350 CHIP_REV\n");
                         ret = -ENODEV;
                         goto err;
                 }
-        } else {
-                dev_info(wm8350->dev, "Device with ID %x is not a WM8350\n",
-                         id1);
+                break;
+
+        default:
+                dev_err(wm8350->dev, "Unknown MASK_REV\n");
                 ret = -ENODEV;
                 goto err;
         }
 
-        mode = id2 & WM8350_CONF_STS_MASK >> 10;
-        mask = id2 & WM8350_CUST_ID_MASK;
-        dev_info(wm8350->dev, "Config mode %d, ROM mask %d\n", mode, mask);
-
         ret = wm8350_create_cache(wm8350, mode);
         if (ret < 0) {
-                printk(KERN_ERR "wm8350: failed to create register cache\n");
+                dev_err(wm8350->dev, "Failed to create register cache\n");
                 return ret;
         }
 
diff --git a/include/linux/mfd/wm8350/core.h b/include/linux/mfd/wm8350/core.h
index 3c9735663f36..2a7abeebe777 100644
--- a/include/linux/mfd/wm8350/core.h
+++ b/include/linux/mfd/wm8350/core.h
@@ -29,6 +29,7 @@
  */
 #define WM8350_RESET_ID                         0x00
 #define WM8350_ID                               0x01
+#define WM8350_REVISION                         0x02
 #define WM8350_SYSTEM_CONTROL_1                 0x03
 #define WM8350_SYSTEM_CONTROL_2                 0x04
 #define WM8350_SYSTEM_HIBERNATE                 0x05
@@ -80,6 +81,11 @@
 #define WM8350_CUST_ID_MASK                     0x00FF
 
 /*
+ * R2 (0x02) - Revision
+ */
+#define WM8350_MASK_REV_MASK                    0x00FF
+
+/*
  * R3 (0x03) - System Control 1
  */
 #define WM8350_CHIP_ON                          0x8000