[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>

1 files changed, 26 insertions, 6 deletions

diff --git a/drivers/staging/lirc/lirc_zilog.c b/drivers/staging/lirc/lirc_zilog.c
index 3fe5f4160194..0aad0d7a74a3 100644
--- 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;