[media] lirc_zilog: z8 on usb doesn't like back-to-back i2c_master_send

Both the HD-PVR and HVR-1950, driven by the hdpvr and pvrusb2 drivers
respectively, have a zilog z8 chip exposed via i2c. These are both
usb-connected devices, and on both of them, back-to-back i2c_master_send
calls that work fine with a z8 on a pci card fail with a -EIO, as the
chip isn't yet ready from the prior command. To cope with that, add a
delay and retry loop where necessary.

Acked-by: Andy Walls <awalls@md.metrocast.net>
Signed-off-by: Jarod Wilson <jarod@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

diff --git a/drivers/staging/lirc/lirc_zilog.c b/drivers/staging/lirc/lirc_zilog.c
index 3fe5f41..0aad0d7 100644 (file)
--- a/drivers/staging/lirc/lirc_zilog.c
+++ b/drivers/staging/lirc/lirc_zilog.c
@@ -495,7 +495,7 @@ static int send_data_block(struct IR_tx *tx, unsigned char *data_block)
 /* send boot data to the IR TX device */
 static int send_boot_data(struct IR_tx *tx)
 {
-       int ret;
+       int ret, i;
        unsigned char buf[4];
 
        /* send the boot block */
@@ -503,7 +503,7 @@ static int send_boot_data(struct IR_tx *tx)
        if (ret != 0)
                return ret;
 
-       /* kick it off? */
+       /* Hit the go button to activate the new boot data */
        buf[0] = 0x00;
        buf[1] = 0x20;
        ret = i2c_master_send(tx->c, buf, 2);
@@ -511,7 +511,19 @@ static int send_boot_data(struct IR_tx *tx)
                zilog_error("i2c_master_send failed with %d\n", ret);
                return ret < 0 ? ret : -EFAULT;
        }
-       ret = i2c_master_send(tx->c, buf, 1);
+
+       /*
+        * Wait for zilog to settle after hitting go post boot block upload.
+        * Without this delay, the HD-PVR and HVR-1950 both return an -EIO
+        * upon attempting to get firmware revision, and tx probe thus fails.
+        */
+       for (i = 0; i < 10; i++) {
+               ret = i2c_master_send(tx->c, buf, 1);
+               if (ret == 1)
+                       break;
+               udelay(100);
+       }
+
        if (ret != 1) {
                zilog_error("i2c_master_send failed with %d\n", ret);
                return ret < 0 ? ret : -EFAULT;
@@ -523,8 +535,8 @@ static int send_boot_data(struct IR_tx *tx)
                zilog_error("i2c_master_recv failed with %d\n", ret);
                return 0;
        }
-       if (buf[0] != 0x80) {
-               zilog_error("unexpected IR TX response: %02x\n", buf[0]);
+       if ((buf[0] != 0x80) && (buf[0] != 0xa0)) {
+               zilog_error("unexpected IR TX init response: %02x\n", buf[0]);
                return 0;
        }
        zilog_notify("Zilog/Hauppauge IR blaster firmware version "
@@ -827,7 +839,15 @@ static int send_code(struct IR_tx *tx, unsigned int code, unsigned int key)
                zilog_error("i2c_master_send failed with %d\n", ret);
                return ret < 0 ? ret : -EFAULT;
        }
-       ret = i2c_master_send(tx->c, buf, 1);
+
+       /* Give the z8 a moment to process data block */
+       for (i = 0; i < 10; i++) {
+               ret = i2c_master_send(tx->c, buf, 1);
+               if (ret == 1)
+                       break;
+               udelay(100);
+       }
+
        if (ret != 1) {
                zilog_error("i2c_master_send failed with %d\n", ret);
                return ret < 0 ? ret : -EFAULT;