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drm/i915/intel_i2c: refactor gmbus_xfer
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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>
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Daniel Kurtz authored and Daniel Vetter committed Mar 28, 2012
1 parent e7e58eb commit 924a93e
Showing 1 changed file with 92 additions and 59 deletions.
151 changes: 92 additions & 59 deletions drivers/gpu/drm/i915/intel_i2c.c
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Original file line number Diff line number Diff line change
Expand Up @@ -197,6 +197,82 @@ intel_i2c_quirk_xfer(struct intel_gmbus *bus,
return ret;
}

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,
Expand All @@ -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;
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