diff options
| author | Jani Nikula <jani.nikula@intel.com> | 2015-12-01 16:29:26 +0200 |
|---|---|---|
| committer | Jani Nikula <jani.nikula@intel.com> | 2015-12-02 13:29:41 +0200 |
| commit | bffce907d64042b5683ed3076e839d0249606264 (patch) | |
| tree | 6bda4975b36467d0f4460f824ff201751e9eb7b2 /drivers/gpu/drm/i915/intel_i2c.c | |
| parent | 0aeb904888f52f48ca0cc7dfec2c2f540d2a762a (diff) | |
drm/i915: abstract i2c bit banging fallback in gmbus xfer
Choose between i2c bit banging and gmbus in a new higher level function,
and let the i2c core retry the first time we fall back to bit banging.
The i2c core imposes a timeout on -EAGAIN, but it defaults to 1 second,
and shouldn't be a problem for us.
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1448980166-23055-2-git-send-email-jani.nikula@intel.com
Diffstat (limited to 'drivers/gpu/drm/i915/intel_i2c.c')
| -rw-r--r-- | drivers/gpu/drm/i915/intel_i2c.c | 39 |
1 files changed, 25 insertions, 14 deletions
diff --git a/drivers/gpu/drm/i915/intel_i2c.c b/drivers/gpu/drm/i915/intel_i2c.c index ccb522c176bd..e26e22a72e3b 100644 --- a/drivers/gpu/drm/i915/intel_i2c.c +++ b/drivers/gpu/drm/i915/intel_i2c.c @@ -472,9 +472,7 @@ gmbus_xfer_index_read(struct drm_i915_private *dev_priv, struct i2c_msg *msgs) } static int -gmbus_xfer(struct i2c_adapter *adapter, - struct i2c_msg *msgs, - int num) +do_gmbus_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs, int num) { struct intel_gmbus *bus = container_of(adapter, struct intel_gmbus, @@ -483,14 +481,6 @@ gmbus_xfer(struct i2c_adapter *adapter, int i = 0, inc, try = 0; int ret = 0; - intel_display_power_get(dev_priv, POWER_DOMAIN_GMBUS); - mutex_lock(&dev_priv->gmbus_mutex); - - if (bus->force_bit) { - ret = i2c_bit_algo.master_xfer(adapter, msgs, num); - goto out; - } - retry: I915_WRITE(GMBUS0, bus->reg0); @@ -585,13 +575,34 @@ timeout: bus->adapter.name, bus->reg0 & 0xff); I915_WRITE(GMBUS0, 0); - /* Hardware may not support GMBUS over these pins? Try GPIO bitbanging instead. */ + /* + * Hardware may not support GMBUS over these pins? Try GPIO bitbanging + * instead. Use EAGAIN to have i2c core retry. + */ bus->force_bit = 1; - ret = i2c_bit_algo.master_xfer(adapter, msgs, num); + ret = -EAGAIN; out: - mutex_unlock(&dev_priv->gmbus_mutex); + return ret; +} + +static int +gmbus_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs, int num) +{ + struct intel_gmbus *bus = container_of(adapter, struct intel_gmbus, + adapter); + struct drm_i915_private *dev_priv = bus->dev_priv; + int ret; + + intel_display_power_get(dev_priv, POWER_DOMAIN_GMBUS); + mutex_lock(&dev_priv->gmbus_mutex); + + if (bus->force_bit) + ret = i2c_bit_algo.master_xfer(adapter, msgs, num); + else + ret = do_gmbus_xfer(adapter, msgs, num); + mutex_unlock(&dev_priv->gmbus_mutex); intel_display_power_put(dev_priv, POWER_DOMAIN_GMBUS); return ret; |