This patch enables the indexed write feature of the GMBUS to concatenate 2 consecutive messages into one. The criteria for an indexed write is that both messages are writes, the first is length == 1, and the second is length > 0. The first message is sent out by the GMBUS as the slave command, and the second one is sent via the GMBUS FIFO as usual.
Changes in v3: - Added to series Changes in v4: - Combine indexed reads and writes (Ville) Changes in v5: - checkpatch whitespace nits Changes in v6: - None
Reviewed-by: Daniel Vetter daniel.vetter@ffwll.ch Suggested-by: Ville Syrjälä ville.syrjala@linux.intel.com Signed-off-by: Sean Paul seanpaul@chromium.org --- drivers/gpu/drm/i915/intel_i2c.c | 34 ++++++++++++++++++++-------------- 1 file changed, 20 insertions(+), 14 deletions(-)
diff --git a/drivers/gpu/drm/i915/intel_i2c.c b/drivers/gpu/drm/i915/intel_i2c.c index ef9f91a0b0c9..d9e6993fa718 100644 --- a/drivers/gpu/drm/i915/intel_i2c.c +++ b/drivers/gpu/drm/i915/intel_i2c.c @@ -402,7 +402,8 @@ gmbus_xfer_read(struct drm_i915_private *dev_priv, struct i2c_msg *msg,
static int gmbus_xfer_write_chunk(struct drm_i915_private *dev_priv, - unsigned short addr, u8 *buf, unsigned int len) + unsigned short addr, u8 *buf, unsigned int len, + u32 gmbus1_index) { unsigned int chunk_size = len; u32 val, loop; @@ -415,7 +416,7 @@ gmbus_xfer_write_chunk(struct drm_i915_private *dev_priv,
I915_WRITE_FW(GMBUS3, val); I915_WRITE_FW(GMBUS1, - GMBUS_CYCLE_WAIT | + gmbus1_index | GMBUS_CYCLE_WAIT | (chunk_size << GMBUS_BYTE_COUNT_SHIFT) | (addr << GMBUS_SLAVE_ADDR_SHIFT) | GMBUS_SLAVE_WRITE | GMBUS_SW_RDY); @@ -438,7 +439,8 @@ gmbus_xfer_write_chunk(struct drm_i915_private *dev_priv, }
static int -gmbus_xfer_write(struct drm_i915_private *dev_priv, struct i2c_msg *msg) +gmbus_xfer_write(struct drm_i915_private *dev_priv, struct i2c_msg *msg, + u32 gmbus1_index) { u8 *buf = msg->buf; unsigned int tx_size = msg->len; @@ -448,7 +450,8 @@ gmbus_xfer_write(struct drm_i915_private *dev_priv, struct i2c_msg *msg) do { len = min(tx_size, GMBUS_BYTE_COUNT_MAX);
- ret = gmbus_xfer_write_chunk(dev_priv, msg->addr, buf, len); + ret = gmbus_xfer_write_chunk(dev_priv, msg->addr, buf, len, + gmbus1_index); if (ret) return ret;
@@ -460,21 +463,21 @@ gmbus_xfer_write(struct drm_i915_private *dev_priv, struct i2c_msg *msg) }
/* - * The gmbus controller can combine a 1 or 2 byte write with a read that - * immediately follows it by using an "INDEX" cycle. + * The gmbus controller can combine a 1 or 2 byte write with another read/write + * that immediately follows it by using an "INDEX" cycle. */ static bool -gmbus_is_index_read(struct i2c_msg *msgs, int i, int num) +gmbus_is_index_xfer(struct i2c_msg *msgs, int i, int num) { return (i + 1 < num && msgs[i].addr == msgs[i + 1].addr && !(msgs[i].flags & I2C_M_RD) && (msgs[i].len == 1 || msgs[i].len == 2) && - (msgs[i + 1].flags & I2C_M_RD)); + msgs[i + 1].len > 0); }
static int -gmbus_xfer_index_read(struct drm_i915_private *dev_priv, struct i2c_msg *msgs) +gmbus_index_xfer(struct drm_i915_private *dev_priv, struct i2c_msg *msgs) { u32 gmbus1_index = 0; u32 gmbus5 = 0; @@ -491,7 +494,10 @@ gmbus_xfer_index_read(struct drm_i915_private *dev_priv, struct i2c_msg *msgs) if (gmbus5) I915_WRITE_FW(GMBUS5, gmbus5);
- ret = gmbus_xfer_read(dev_priv, &msgs[1], gmbus1_index); + if (msgs[1].flags & I2C_M_RD) + ret = gmbus_xfer_read(dev_priv, &msgs[1], gmbus1_index); + else + ret = gmbus_xfer_write(dev_priv, &msgs[1], gmbus1_index);
/* Clear GMBUS5 after each index transfer */ if (gmbus5) @@ -522,13 +528,13 @@ do_gmbus_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs, int num)
for (; i < num; i += inc) { inc = 1; - if (gmbus_is_index_read(msgs, i, num)) { - ret = gmbus_xfer_index_read(dev_priv, &msgs[i]); - inc = 2; /* an index read is two msgs */ + if (gmbus_is_index_xfer(msgs, i, num)) { + ret = gmbus_index_xfer(dev_priv, &msgs[i]); + inc = 2; /* an index transmission is two msgs */ } else if (msgs[i].flags & I2C_M_RD) { ret = gmbus_xfer_read(dev_priv, &msgs[i], 0); } else { - ret = gmbus_xfer_write(dev_priv, &msgs[i]); + ret = gmbus_xfer_write(dev_priv, &msgs[i], 0); }
if (!ret)