NFC: st21nfca: Improve st21nfca initialization by handling reboot properly

Change in st21nfca_hci_platform_init in order to handle in a better way the
internal reboot command.
Once the reboot is completed, the driver expect to receive a 0x7e filled
buffer.

Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

diff --git a/drivers/nfc/st21nfca/i2c.c b/drivers/nfc/st21nfca/i2c.c
index 4cbd8fb..6c4d0a0 100644 (file)
--- a/drivers/nfc/st21nfca/i2c.c
+++ b/drivers/nfc/st21nfca/i2c.c
@@ -98,23 +98,49 @@ do {                                                                \
                       16, 1, (skb)->data, (skb)->len, 0);      \
 } while (0)
 
-static void st21nfca_hci_platform_init(struct st21nfca_i2c_phy *phy)
+/*
+ * In order to get the CLF in a known state we generate an internal reboot
+ * using a proprietary command.
+ * Once the reboot is completed, we expect to receive a ST21NFCA_SOF_EOF
+ * fill buffer.
+ */
+static int st21nfca_hci_platform_init(struct st21nfca_i2c_phy *phy)
 {
        u16 wait_reboot[] = { 50, 300, 1000 };
        char reboot_cmd[] = { 0x7E, 0x66, 0x48, 0xF6, 0x7E };
        u8 tmp[ST21NFCA_HCI_LLC_MAX_SIZE];
        int i, r = -1;
 
-       for (i = 0; i < ARRAY_SIZE(wait_reboot) && r < 0; i++)
+       for (i = 0; i < ARRAY_SIZE(wait_reboot) && r < 0; i++) {
+               r = i2c_master_send(phy->i2c_dev, reboot_cmd,
+                                   sizeof(reboot_cmd));
+               if (r < 0)
+                       msleep(wait_reboot[i]);
+       }
+       if (r < 0)
+               return r;
+
+       /* CLF is spending about 20ms to do an internal reboot */
+       msleep(20);
+       r = -1;
+       for (i = 0; i < ARRAY_SIZE(wait_reboot) && r < 0; i++) {
                r = i2c_master_recv(phy->i2c_dev, tmp,
                                    ST21NFCA_HCI_LLC_MAX_SIZE);
+               if (r < 0)
+                       msleep(wait_reboot[i]);
+       }
+       if (r < 0)
+               return r;
 
-       r = -1;
-       for (i = 0; i < ARRAY_SIZE(wait_reboot) && r < 0; i++)
-               r = i2c_master_send(phy->i2c_dev, reboot_cmd,
-                                   sizeof(reboot_cmd));
-       usleep_range(1000, 1500);
+       for (i = 0; i < ST21NFCA_HCI_LLC_MAX_SIZE &&
+               tmp[i] == ST21NFCA_SOF_EOF; i++)
+               ;
+
+       if (r != ST21NFCA_HCI_LLC_MAX_SIZE)
+               return -ENODEV;
 
+       usleep_range(1000, 1500);
+       return 0;
 }
 
 static int st21nfca_hci_i2c_enable(void *phy_id)
@@ -554,7 +580,12 @@ static int st21nfca_hci_i2c_probe(struct i2c_client *client,
        }
        client->irq = irq;
 
-       st21nfca_hci_platform_init(phy);
+       r = st21nfca_hci_platform_init(phy);
+       if (r < 0) {
+               nfc_err(&client->dev, "Unable to reboot st21nfca\n");
+               return -ENODEV;
+       }
+
        r = devm_request_threaded_irq(&client->dev, client->irq, NULL,
                                st21nfca_hci_irq_thread_fn,
                                phy->irq_polarity | IRQF_ONESHOT,