drm/i915/intel_i2c: refactor gmbus_xfer

Split out gmbus_xfer_read/write() helper functions.

Signed-off-by: Daniel Kurtz <djkurtz@chromium.org>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

diff --git a/drivers/gpu/drm/i915/intel_i2c.c b/drivers/gpu/drm/i915/intel_i2c.c
index 0713cc2..30675ce 100644 (file)
--- a/drivers/gpu/drm/i915/intel_i2c.c
+++ b/drivers/gpu/drm/i915/intel_i2c.c
@@ -198,6 +198,82 @@ intel_i2c_quirk_xfer(struct intel_gmbus *bus,
 }
 
 static int
+gmbus_xfer_read(struct drm_i915_private *dev_priv, struct i2c_msg *msg,
+               bool last)
+{
+       int reg_offset = dev_priv->gpio_mmio_base;
+       u16 len = msg->len;
+       u8 *buf = msg->buf;
+
+       I915_WRITE(GMBUS1 + reg_offset,
+                  GMBUS_CYCLE_WAIT |
+                  (last ? GMBUS_CYCLE_STOP : 0) |
+                  (len << GMBUS_BYTE_COUNT_SHIFT) |
+                  (msg->addr << GMBUS_SLAVE_ADDR_SHIFT) |
+                  GMBUS_SLAVE_READ | GMBUS_SW_RDY);
+       POSTING_READ(GMBUS2 + reg_offset);
+       do {
+               u32 val, loop = 0;
+
+               if (wait_for(I915_READ(GMBUS2 + reg_offset) &
+                            (GMBUS_SATOER | GMBUS_HW_RDY),
+                            50))
+                       return -ETIMEDOUT;
+               if (I915_READ(GMBUS2 + reg_offset) & GMBUS_SATOER)
+                       return -ENXIO;
+
+               val = I915_READ(GMBUS3 + reg_offset);
+               do {
+                       *buf++ = val & 0xff;
+                       val >>= 8;
+               } while (--len && ++loop < 4);
+       } while (len);
+
+       return 0;
+}
+
+static int
+gmbus_xfer_write(struct drm_i915_private *dev_priv, struct i2c_msg *msg,
+               bool last)
+{
+       int reg_offset = dev_priv->gpio_mmio_base;
+       u16 len = msg->len;
+       u8 *buf = msg->buf;
+       u32 val, loop;
+
+       val = loop = 0;
+       do {
+               val |= *buf++ << (8 * loop);
+       } while (--len && ++loop < 4);
+
+       I915_WRITE(GMBUS3 + reg_offset, val);
+       I915_WRITE(GMBUS1 + reg_offset,
+                  GMBUS_CYCLE_WAIT |
+                  (last ? GMBUS_CYCLE_STOP : 0) |
+                  (msg->len << GMBUS_BYTE_COUNT_SHIFT) |
+                  (msg->addr << GMBUS_SLAVE_ADDR_SHIFT) |
+                  GMBUS_SLAVE_WRITE | GMBUS_SW_RDY);
+       POSTING_READ(GMBUS2 + reg_offset);
+       while (len) {
+               if (wait_for(I915_READ(GMBUS2 + reg_offset) &
+                            (GMBUS_SATOER | GMBUS_HW_RDY),
+                            50))
+                       return -ETIMEDOUT;
+               if (I915_READ(GMBUS2 + reg_offset) & GMBUS_SATOER)
+                       return -ENXIO;
+
+               val = loop = 0;
+               do {
+                       val |= *buf++ << (8 * loop);
+               } while (--len && ++loop < 4);
+
+               I915_WRITE(GMBUS3 + reg_offset, val);
+               POSTING_READ(GMBUS2 + reg_offset);
+       }
+       return 0;
+}
+
+static int
 gmbus_xfer(struct i2c_adapter *adapter,
           struct i2c_msg *msgs,
           int num)
@@ -220,65 +296,22 @@ gmbus_xfer(struct i2c_adapter *adapter,
        I915_WRITE(GMBUS0 + reg_offset, bus->reg0);
 
        for (i = 0; i < num; i++) {
-               u16 len = msgs[i].len;
-               u8 *buf = msgs[i].buf;
-
-               if (msgs[i].flags & I2C_M_RD) {
-                       I915_WRITE(GMBUS1 + reg_offset,
-                                  GMBUS_CYCLE_WAIT |
-                                  (i + 1 == num ? GMBUS_CYCLE_STOP : 0) |
-                                  (len << GMBUS_BYTE_COUNT_SHIFT) |
-                                  (msgs[i].addr << GMBUS_SLAVE_ADDR_SHIFT) |
-                                  GMBUS_SLAVE_READ | GMBUS_SW_RDY);
-                       POSTING_READ(GMBUS2+reg_offset);
-                       do {
-                               u32 val, loop = 0;
-
-                               if (wait_for(I915_READ(GMBUS2 + reg_offset) & (GMBUS_SATOER | GMBUS_HW_RDY), 50))
-                                       goto timeout;
-                               if (I915_READ(GMBUS2 + reg_offset) & GMBUS_SATOER)
-                                       goto clear_err;
-
-                               val = I915_READ(GMBUS3 + reg_offset);
-                               do {
-                                       *buf++ = val & 0xff;
-                                       val >>= 8;
-                               } while (--len && ++loop < 4);
-                       } while (len);
-               } else {
-                       u32 val, loop;
-
-                       val = loop = 0;
-                       do {
-                               val |= *buf++ << (8 * loop);
-                       } while (--len && ++loop < 4);
-
-                       I915_WRITE(GMBUS3 + reg_offset, val);
-                       I915_WRITE(GMBUS1 + reg_offset,
-                                  GMBUS_CYCLE_WAIT |
-                                  (i + 1 == num ? GMBUS_CYCLE_STOP : 0) |
-                                  (msgs[i].len << GMBUS_BYTE_COUNT_SHIFT) |
-                                  (msgs[i].addr << GMBUS_SLAVE_ADDR_SHIFT) |
-                                  GMBUS_SLAVE_WRITE | GMBUS_SW_RDY);
-                       POSTING_READ(GMBUS2+reg_offset);
-
-                       while (len) {
-                               if (wait_for(I915_READ(GMBUS2 + reg_offset) & (GMBUS_SATOER | GMBUS_HW_RDY), 50))
-                                       goto timeout;
-                               if (I915_READ(GMBUS2 + reg_offset) & GMBUS_SATOER)
-                                       goto clear_err;
-
-                               val = loop = 0;
-                               do {
-                                       val |= *buf++ << (8 * loop);
-                               } while (--len && ++loop < 4);
-
-                               I915_WRITE(GMBUS3 + reg_offset, val);
-                               POSTING_READ(GMBUS2+reg_offset);
-                       }
-               }
-
-               if (i + 1 < num && wait_for(I915_READ(GMBUS2 + reg_offset) & (GMBUS_SATOER | GMBUS_HW_WAIT_PHASE), 50))
+               bool last = i + 1 == num;
+
+               if (msgs[i].flags & I2C_M_RD)
+                       ret = gmbus_xfer_read(dev_priv, &msgs[i], last);
+               else
+                       ret = gmbus_xfer_write(dev_priv, &msgs[i], last);
+
+               if (ret == -ETIMEDOUT)
+                       goto timeout;
+               if (ret == -ENXIO)
+                       goto clear_err;
+
+               if (!last &&
+                   wait_for(I915_READ(GMBUS2 + reg_offset) &
+                            (GMBUS_SATOER | GMBUS_HW_WAIT_PHASE),
+                            50))
                        goto timeout;
                if (I915_READ(GMBUS2 + reg_offset) & GMBUS_SATOER)
                        goto clear_err;