[media] hdpvr: i2c master enhancements

Make the hdpvr's i2c master implementation more closely mirror that of
the pvrusb2 driver. Currently makes no significant difference in IR
reception behavior with ir-kbd-i2c (i.e., it still sucks).

Signed-off-by: Jarod Wilson <jarod@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

1 files changed, 50 insertions, 17 deletions

diff --git a/drivers/media/video/hdpvr/hdpvr-i2c.c b/drivers/media/video/hdpvr/hdpvr-i2c.c
index e53fa55d56a1..3e0658768135 100644
--- a/drivers/media/video/hdpvr/hdpvr-i2c.c
+++ b/drivers/media/video/hdpvr/hdpvr-i2c.c
@@ -62,15 +62,25 @@ struct i2c_client *hdpvr_register_ir_rx_i2c(struct hdpvr_device *dev)
 }
 
 static int hdpvr_i2c_read(struct hdpvr_device *dev, int bus,
-                          unsigned char addr, char *data, int len)
+                          unsigned char addr, char *wdata, int wlen,
+                          char *data, int len)
 {
         int ret;
 
-        if (len > sizeof(dev->i2c_buf))
+        if ((len > sizeof(dev->i2c_buf)) || (wlen > sizeof(dev->i2c_buf)))
                 return -EINVAL;
 
-        ret = usb_control_msg(dev->udev,
-                              usb_rcvctrlpipe(dev->udev, 0),
+        if (wlen) {
+                memcpy(&dev->i2c_buf, wdata, wlen);
+                ret = usb_control_msg(dev->udev, usb_sndctrlpipe(dev->udev, 0),
+                                      REQTYPE_I2C_WRITE, CTRL_WRITE_REQUEST,
+                                      (bus << 8) | addr, 0, &dev->i2c_buf,
+                                      wlen, 1000);
+                if (ret < 0)
+                        return ret;
+        }
+
+        ret = usb_control_msg(dev->udev, usb_rcvctrlpipe(dev->udev, 0),
                               REQTYPE_I2C_READ, CTRL_READ_REQUEST,
                               (bus << 8) | addr, 0, &dev->i2c_buf, len, 1000);
 
@@ -92,16 +102,14 @@ static int hdpvr_i2c_write(struct hdpvr_device *dev, int bus,
                 return -EINVAL;
 
         memcpy(&dev->i2c_buf, data, len);
-        ret = usb_control_msg(dev->udev,
-                              usb_sndctrlpipe(dev->udev, 0),
+        ret = usb_control_msg(dev->udev, usb_sndctrlpipe(dev->udev, 0),
                               REQTYPE_I2C_WRITE, CTRL_WRITE_REQUEST,
                               (bus << 8) | addr, 0, &dev->i2c_buf, len, 1000);
 
         if (ret < 0)
                 return ret;
 
-        ret = usb_control_msg(dev->udev,
-                              usb_rcvctrlpipe(dev->udev, 0),
+        ret = usb_control_msg(dev->udev, usb_rcvctrlpipe(dev->udev, 0),
                               REQTYPE_I2C_WRITE_STATT, CTRL_READ_REQUEST,
                               0, 0, &dev->i2c_buf, 2, 1000);
 
@@ -117,24 +125,49 @@ static int hdpvr_transfer(struct i2c_adapter *i2c_adapter, struct i2c_msg *msgs,
                           int num)
 {
         struct hdpvr_device *dev = i2c_get_adapdata(i2c_adapter);
-        int retval = 0, i, addr;
+        int retval = 0, addr;
 
         if (num <= 0)
                 return 0;
 
         mutex_lock(&dev->i2c_mutex);
 
-        for (i = 0; i < num && !retval; i++) {
-                addr = msgs[i].addr << 1;
+        addr = msgs[0].addr << 1;
 
-                if (msgs[i].flags & I2C_M_RD)
-                        retval = hdpvr_i2c_read(dev, 1, addr, msgs[i].buf,
-                                                msgs[i].len);
+        if (num == 1) {
+                if (msgs[0].flags & I2C_M_RD)
+                        retval = hdpvr_i2c_read(dev, 1, addr, NULL, 0,
+                                                msgs[0].buf, msgs[0].len);
                 else
-                        retval = hdpvr_i2c_write(dev, 1, addr, msgs[i].buf,
-                                                 msgs[i].len);
+                        retval = hdpvr_i2c_write(dev, 1, addr, msgs[0].buf,
+                                                 msgs[0].len);
+        } else if (num == 2) {
+                if (msgs[0].addr != msgs[1].addr) {
+                        v4l2_warn(&dev->v4l2_dev, "refusing 2-phase i2c xfer "
+                                  "with conflicting target addresses\n");
+                        retval = -EINVAL;
+                        goto out;
+                }
+
+                if ((msgs[0].flags & I2C_M_RD) || !(msgs[1].flags & I2C_M_RD)) {
+                        v4l2_warn(&dev->v4l2_dev, "refusing complex xfer with "
+                                  "r0=%d, r1=%d\n", msgs[0].flags & I2C_M_RD,
+                                  msgs[1].flags & I2C_M_RD);
+                        retval = -EINVAL;
+                        goto out;
+                }
+
+                /*
+                 * Write followed by atomic read is the only complex xfer that
+                 * we actually support here.
+                 */
+                retval = hdpvr_i2c_read(dev, 1, addr, msgs[0].buf, msgs[0].len,
+                                        msgs[1].buf, msgs[1].len);
+        } else {
+                v4l2_warn(&dev->v4l2_dev, "refusing %d-phase i2c xfer\n", num);
         }
 
+out:
         mutex_unlock(&dev->i2c_mutex);
 
         return retval ? retval : num;
@@ -162,7 +195,7 @@ static int hdpvr_activate_ir(struct hdpvr_device *dev)
 
         mutex_lock(&dev->i2c_mutex);
 
-        hdpvr_i2c_read(dev, 0, 0x54, buffer, 1);
+        hdpvr_i2c_read(dev, 0, 0x54, NULL, 0, buffer, 1);
 
         buffer[0] = 0;
         buffer[1] = 0x8;