diff options
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/media/usb/em28xx/em28xx-i2c.c | 104 | ||||
| -rw-r--r-- | drivers/media/usb/em28xx/em28xx.h | 2 |
2 files changed, 58 insertions, 48 deletions
diff --git a/drivers/media/usb/em28xx/em28xx-i2c.c b/drivers/media/usb/em28xx/em28xx-i2c.c index c508c1297a26..67a8e623dd8c 100644 --- a/drivers/media/usb/em28xx/em28xx-i2c.c +++ b/drivers/media/usb/em28xx/em28xx-i2c.c @@ -73,12 +73,14 @@ static int em2800_i2c_send_bytes(struct em28xx *dev, u8 addr, u8 *buf, u16 len) if (len > 3) b2[0] = buf[3]; + /* trigger write */ ret = dev->em28xx_write_regs(dev, 4 - len, &b2[4 - len], 2 + len); if (ret != 2 + len) { em28xx_warn("writing to i2c device failed (error=%i)\n", ret); return -EIO; } - for (write_timeout = EM2800_I2C_WRITE_TIMEOUT; write_timeout > 0; + /* wait for completion */ + for (write_timeout = EM2800_I2C_XFER_TIMEOUT; write_timeout > 0; write_timeout -= 5) { ret = dev->em28xx_read_reg(dev, 0x05); if (ret == 0x80 + len - 1) @@ -90,66 +92,74 @@ static int em2800_i2c_send_bytes(struct em28xx *dev, u8 addr, u8 *buf, u16 len) } /* - * em2800_i2c_check_for_device() - * check if there is a i2c_device at the supplied address + * em2800_i2c_recv_bytes() + * read up to 4 bytes from the em2800 i2c device */ -static int em2800_i2c_check_for_device(struct em28xx *dev, u8 addr) +static int em2800_i2c_recv_bytes(struct em28xx *dev, u8 addr, u8 *buf, u16 len) { - u8 msg; + u8 buf2[4]; int ret; - int write_timeout; - msg = addr; - ret = dev->em28xx_write_regs(dev, 0x04, &msg, 1); - if (ret < 0) { - em28xx_warn("setting i2c device address failed (error=%i)\n", - ret); - return ret; - } - msg = 0x84; - ret = dev->em28xx_write_regs(dev, 0x05, &msg, 1); - if (ret < 0) { - em28xx_warn("preparing i2c read failed (error=%i)\n", ret); - return ret; + int read_timeout; + int i; + + if (len < 1 || len > 4) + return -EOPNOTSUPP; + + /* trigger read */ + buf2[1] = 0x84 + len - 1; + buf2[0] = addr; + ret = dev->em28xx_write_regs(dev, 0x04, buf2, 2); + if (ret != 2) { + em28xx_warn("failed to trigger read from i2c address 0x%x " + "(error=%i)\n", addr, ret); + return (ret < 0) ? ret : -EIO; } - for (write_timeout = EM2800_I2C_WRITE_TIMEOUT; write_timeout > 0; - write_timeout -= 5) { - unsigned reg = dev->em28xx_read_reg(dev, 0x5); - if (reg == 0x94) + /* wait for completion */ + for (read_timeout = EM2800_I2C_XFER_TIMEOUT; read_timeout > 0; + read_timeout -= 5) { + ret = dev->em28xx_read_reg(dev, 0x05); + if (ret == 0x84 + len - 1) { + break; + } else if (ret == 0x94 + len - 1) { return -ENODEV; - else if (reg == 0x84) - return 0; + } else if (ret < 0) { + em28xx_warn("failed to get i2c transfer status from " + "bridge register (error=%i)\n", ret); + return ret; + } msleep(5); } - return -ENODEV; + if (ret != 0x84 + len - 1) + em28xx_warn("read from i2c device at 0x%x timed out\n", addr); + + /* get the received message */ + ret = dev->em28xx_read_reg_req_len(dev, 0x00, 4-len, buf2, len); + if (ret != len) { + em28xx_warn("reading from i2c device at 0x%x failed: " + "couldn't get the received message from the bridge " + "(error=%i)\n", addr, ret); + return (ret < 0) ? ret : -EIO; + } + for (i = 0; i < len; i++) + buf[i] = buf2[len - 1 - i]; + + return ret; } /* - * em2800_i2c_recv_bytes() - * read from the i2c device + * em2800_i2c_check_for_device() + * check if there is an i2c device at the supplied address */ -static int em2800_i2c_recv_bytes(struct em28xx *dev, u8 addr, u8 *buf, u16 len) +static int em2800_i2c_check_for_device(struct em28xx *dev, u8 addr) { + u8 buf; int ret; - if (len < 1 || len > 4) - return -EOPNOTSUPP; - - /* check for the device and set i2c read address */ - ret = em2800_i2c_check_for_device(dev, addr); - if (ret) { - em28xx_warn - ("preparing read at i2c address 0x%x failed (error=%i)\n", - addr, ret); - return ret; - } - ret = dev->em28xx_read_reg_req_len(dev, 0x0, 0x3, buf, len); - if (ret < 0) { - em28xx_warn("reading from i2c device at 0x%x failed (error=%i)", - addr, ret); - return ret; - } - return ret; + ret = em2800_i2c_recv_bytes(dev, addr, &buf, 1); + if (ret == 1) + return 0; + return (ret < 0) ? ret : -EIO; } /* @@ -167,7 +177,7 @@ static int em28xx_i2c_send_bytes(struct em28xx *dev, u16 addr, u8 *buf, wrcount = dev->em28xx_write_regs_req(dev, stop ? 2 : 3, addr, buf, len); /* Seems to be required after a write */ - for (write_timeout = EM2800_I2C_WRITE_TIMEOUT; write_timeout > 0; + for (write_timeout = EM2800_I2C_XFER_TIMEOUT; write_timeout > 0; write_timeout -= 5) { ret = dev->em28xx_read_reg(dev, 0x05); if (!ret) diff --git a/drivers/media/usb/em28xx/em28xx.h b/drivers/media/usb/em28xx/em28xx.h index f891a28706f5..2aa4b8472a62 100644 --- a/drivers/media/usb/em28xx/em28xx.h +++ b/drivers/media/usb/em28xx/em28xx.h @@ -194,7 +194,7 @@ */ /* time in msecs to wait for i2c writes to finish */ -#define EM2800_I2C_WRITE_TIMEOUT 20 +#define EM2800_I2C_XFER_TIMEOUT 20 enum em28xx_mode { EM28XX_SUSPEND, |