USB: otg/ulpi: improve ulpi phy detection.

Improve ulpi phy detection by utilizing the "scratch" register.
Allow unknown ulpi phy work without the need to hard-code the id.

Signed-off-by: Igor Grinberg <grinberg@compulab.co.il>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 32 insertions, 3 deletions

diff --git a/drivers/usb/otg/ulpi.c b/drivers/usb/otg/ulpi.c
index ccc81950822b..e0d2a5c504cc 100644
--- a/drivers/usb/otg/ulpi.c
+++ b/drivers/usb/otg/ulpi.c
@@ -137,6 +137,32 @@ static int ulpi_set_flags(struct otg_transceiver *otg)
         return ulpi_set_fc_flags(otg);
 }
 
+static int ulpi_check_integrity(struct otg_transceiver *otg)
+{
+        int ret, i;
+        unsigned int val = 0x55;
+
+        for (i = 0; i < 2; i++) {
+                ret = otg_io_write(otg, val, ULPI_SCRATCH);
+                if (ret < 0)
+                        return ret;
+
+                ret = otg_io_read(otg, ULPI_SCRATCH);
+                if (ret < 0)
+                        return ret;
+
+                if (ret != val) {
+                        pr_err("ULPI integrity check: failed!");
+                        return -ENODEV;
+                }
+                val = val << 1;
+        }
+
+        pr_info("ULPI integrity check: passed.\n");
+
+        return 0;
+}
+
 static int ulpi_init(struct otg_transceiver *otg)
 {
         int i, vid, pid, ret;
@@ -155,10 +181,13 @@ static int ulpi_init(struct otg_transceiver *otg)
 
         for (i = 0; i < ARRAY_SIZE(ulpi_ids); i++)
                 if (ulpi_ids[i] == ULPI_ID(vid, pid))
-                        return ulpi_set_flags(otg);
+                        break;
+
+        ret = ulpi_check_integrity(otg);
+        if (ret)
+                return ret;
 
-        pr_err("ULPI ID does not match any known transceiver.\n");
-        return -ENODEV;
+        return ulpi_set_flags(otg);
 }
 
 static int ulpi_set_host(struct otg_transceiver *otg, struct usb_bus *host)