diff options
Diffstat (limited to 'drivers/gpu/drm/i915/intel_i2c.c')
| -rw-r--r-- | drivers/gpu/drm/i915/intel_i2c.c | 86 |
1 files changed, 73 insertions, 13 deletions
diff --git a/drivers/gpu/drm/i915/intel_i2c.c b/drivers/gpu/drm/i915/intel_i2c.c index b31088a551f2..ae628001fd97 100644 --- a/drivers/gpu/drm/i915/intel_i2c.c +++ b/drivers/gpu/drm/i915/intel_i2c.c @@ -270,18 +270,17 @@ gmbus_wait_idle(struct drm_i915_private *dev_priv) } static int -gmbus_xfer_read(struct drm_i915_private *dev_priv, struct i2c_msg *msg, - u32 gmbus1_index) +gmbus_xfer_read_chunk(struct drm_i915_private *dev_priv, + unsigned short addr, u8 *buf, unsigned int len, + u32 gmbus1_index) { int reg_offset = dev_priv->gpio_mmio_base; - u16 len = msg->len; - u8 *buf = msg->buf; I915_WRITE(GMBUS1 + reg_offset, gmbus1_index | GMBUS_CYCLE_WAIT | (len << GMBUS_BYTE_COUNT_SHIFT) | - (msg->addr << GMBUS_SLAVE_ADDR_SHIFT) | + (addr << GMBUS_SLAVE_ADDR_SHIFT) | GMBUS_SLAVE_READ | GMBUS_SW_RDY); while (len) { int ret; @@ -303,11 +302,35 @@ gmbus_xfer_read(struct drm_i915_private *dev_priv, struct i2c_msg *msg, } static int -gmbus_xfer_write(struct drm_i915_private *dev_priv, struct i2c_msg *msg) +gmbus_xfer_read(struct drm_i915_private *dev_priv, struct i2c_msg *msg, + u32 gmbus1_index) { - int reg_offset = dev_priv->gpio_mmio_base; - u16 len = msg->len; u8 *buf = msg->buf; + unsigned int rx_size = msg->len; + unsigned int len; + int ret; + + do { + len = min(rx_size, GMBUS_BYTE_COUNT_MAX); + + ret = gmbus_xfer_read_chunk(dev_priv, msg->addr, + buf, len, gmbus1_index); + if (ret) + return ret; + + rx_size -= len; + buf += len; + } while (rx_size != 0); + + return 0; +} + +static int +gmbus_xfer_write_chunk(struct drm_i915_private *dev_priv, + unsigned short addr, u8 *buf, unsigned int len) +{ + int reg_offset = dev_priv->gpio_mmio_base; + unsigned int chunk_size = len; u32 val, loop; val = loop = 0; @@ -319,8 +342,8 @@ gmbus_xfer_write(struct drm_i915_private *dev_priv, struct i2c_msg *msg) I915_WRITE(GMBUS3 + reg_offset, val); I915_WRITE(GMBUS1 + reg_offset, GMBUS_CYCLE_WAIT | - (msg->len << GMBUS_BYTE_COUNT_SHIFT) | - (msg->addr << GMBUS_SLAVE_ADDR_SHIFT) | + (chunk_size << GMBUS_BYTE_COUNT_SHIFT) | + (addr << GMBUS_SLAVE_ADDR_SHIFT) | GMBUS_SLAVE_WRITE | GMBUS_SW_RDY); while (len) { int ret; @@ -337,6 +360,29 @@ gmbus_xfer_write(struct drm_i915_private *dev_priv, struct i2c_msg *msg) if (ret) return ret; } + + return 0; +} + +static int +gmbus_xfer_write(struct drm_i915_private *dev_priv, struct i2c_msg *msg) +{ + u8 *buf = msg->buf; + unsigned int tx_size = msg->len; + unsigned int len; + int ret; + + do { + len = min(tx_size, GMBUS_BYTE_COUNT_MAX); + + ret = gmbus_xfer_write_chunk(dev_priv, msg->addr, buf, len); + if (ret) + return ret; + + buf += len; + tx_size -= len; + } while (tx_size != 0); + return 0; } @@ -389,7 +435,7 @@ gmbus_xfer(struct i2c_adapter *adapter, struct intel_gmbus, adapter); struct drm_i915_private *dev_priv = bus->dev_priv; - int i, reg_offset; + int i = 0, inc, try = 0, reg_offset; int ret = 0; intel_aux_display_runtime_get(dev_priv); @@ -402,12 +448,14 @@ gmbus_xfer(struct i2c_adapter *adapter, reg_offset = dev_priv->gpio_mmio_base; +retry: I915_WRITE(GMBUS0 + reg_offset, bus->reg0); - for (i = 0; i < num; i++) { + for (; i < num; i += inc) { + inc = 1; if (gmbus_is_index_read(msgs, i, num)) { ret = gmbus_xfer_index_read(dev_priv, &msgs[i]); - i += 1; /* set i to the index of the read xfer */ + inc = 2; /* an index read is two msgs */ } else if (msgs[i].flags & I2C_M_RD) { ret = gmbus_xfer_read(dev_priv, &msgs[i], 0); } else { @@ -479,6 +527,18 @@ clear_err: adapter->name, msgs[i].addr, (msgs[i].flags & I2C_M_RD) ? 'r' : 'w', msgs[i].len); + /* + * Passive adapters sometimes NAK the first probe. Retry the first + * message once on -ENXIO for GMBUS transfers; the bit banging algorithm + * has retries internally. See also the retry loop in + * drm_do_probe_ddc_edid, which bails out on the first -ENXIO. + */ + if (ret == -ENXIO && i == 0 && try++ == 0) { + DRM_DEBUG_KMS("GMBUS [%s] NAK on first message, retry\n", + adapter->name); + goto retry; + } + goto out; timeout: |
