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Commit 90e6b26d authored by Daniel Kurtz's avatar Daniel Kurtz Committed by Daniel Vetter
Browse files

drm/i915/intel_i2c: reuse GMBUS2 value read in polling loop 



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: default avatarDaniel Kurtz <djkurtz@chromium.org>
Reviewed-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
parent 56f9eac0

drivers/gpu/drm/i915/intel_i2c.c

+22 −12
Original line number Diff line number Diff line
@@ -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) &

		ret = wait_for((gmbus2 = I915_READ(GMBUS2 + reg_offset)) &

			       (GMBUS_SATOER | GMBUS_HW_RDY),

			     50))

			       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) &

		ret = wait_for((gmbus2 = I915_READ(GMBUS2 + reg_offset)) &

			       (GMBUS_SATOER | GMBUS_HW_RDY),

			     50))

			       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) &

		ret = wait_for((gmbus2 = I915_READ(GMBUS2 + reg_offset)) &

			       (GMBUS_SATOER | GMBUS_HW_WAIT_PHASE),

			     50))

			       50);

		if (ret)

			goto timeout;

		if (I915_READ(GMBUS2 + reg_offset) & GMBUS_SATOER)

		if (gmbus2 & GMBUS_SATOER)

			goto clear_err;

	}