Save the GMBUS2 value read while polling for state changes, and then reuse this value when determining for which reason the loops were exited. This is a small optimization which saves a couple of bus accesses for memory mapped IO registers.
To avoid "assigning in if clause" checkpatch errors", use a ret variable to store the wait_for macro return value.
Signed-off-by: Daniel Kurtz djkurtz@chromium.org --- drivers/gpu/drm/i915/intel_i2c.c | 34 ++++++++++++++++++++++------------ 1 files changed, 22 insertions(+), 12 deletions(-)
diff --git a/drivers/gpu/drm/i915/intel_i2c.c b/drivers/gpu/drm/i915/intel_i2c.c index 9c07ff2..60f90cb 100644 --- a/drivers/gpu/drm/i915/intel_i2c.c +++ b/drivers/gpu/drm/i915/intel_i2c.c @@ -219,13 +219,16 @@ gmbus_xfer_read(struct drm_i915_private *dev_priv, struct i2c_msg *msg, GMBUS_SLAVE_READ | GMBUS_SW_RDY); POSTING_READ(GMBUS2 + reg_offset); do { + int ret; u32 val, loop = 0; + u32 gmbus2;
- if (wait_for(I915_READ(GMBUS2 + reg_offset) & - (GMBUS_SATOER | GMBUS_HW_RDY), - 50)) + ret = wait_for((gmbus2 = I915_READ(GMBUS2 + reg_offset)) & + (GMBUS_SATOER | GMBUS_HW_RDY), + 50); + if (ret) return -ETIMEDOUT; - if (I915_READ(GMBUS2 + reg_offset) & GMBUS_SATOER) + if (gmbus2 & GMBUS_SATOER) return -ENXIO;
val = I915_READ(GMBUS3 + reg_offset); @@ -260,6 +263,9 @@ gmbus_xfer_write(struct drm_i915_private *dev_priv, struct i2c_msg *msg) GMBUS_SLAVE_WRITE | GMBUS_SW_RDY); POSTING_READ(GMBUS2 + reg_offset); while (len) { + int ret; + u32 gmbus2; + val = loop = 0; do { val |= *buf++ << (8 * loop); @@ -268,11 +274,12 @@ gmbus_xfer_write(struct drm_i915_private *dev_priv, struct i2c_msg *msg) I915_WRITE(GMBUS3 + reg_offset, val); POSTING_READ(GMBUS2 + reg_offset);
- if (wait_for(I915_READ(GMBUS2 + reg_offset) & - (GMBUS_SATOER | GMBUS_HW_RDY), - 50)) + ret = wait_for((gmbus2 = I915_READ(GMBUS2 + reg_offset)) & + (GMBUS_SATOER | GMBUS_HW_RDY), + 50); + if (ret) return -ETIMEDOUT; - if (I915_READ(GMBUS2 + reg_offset) & GMBUS_SATOER) + if (gmbus2 & GMBUS_SATOER) return -ENXIO; } return 0; @@ -342,6 +349,8 @@ gmbus_xfer(struct i2c_adapter *adapter, I915_WRITE(GMBUS0 + reg_offset, bus->reg0);
for (i = 0; i < num; i++) { + u32 gmbus2; + 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 */ @@ -356,11 +365,12 @@ gmbus_xfer(struct i2c_adapter *adapter, if (ret == -ENXIO) goto clear_err;
- if (wait_for(I915_READ(GMBUS2 + reg_offset) & - (GMBUS_SATOER | GMBUS_HW_WAIT_PHASE), - 50)) + ret = wait_for((gmbus2 = I915_READ(GMBUS2 + reg_offset)) & + (GMBUS_SATOER | GMBUS_HW_WAIT_PHASE), + 50); + if (ret) goto timeout; - if (I915_READ(GMBUS2 + reg_offset) & GMBUS_SATOER) + if (gmbus2 & GMBUS_SATOER) goto clear_err; }