diff options
| author | David Box <david.e.box@linux.intel.com> | 2015-01-15 01:12:16 -0800 |
|---|---|---|
| committer | Wolfram Sang <wsa@the-dreams.de> | 2015-01-26 12:26:16 +0100 |
| commit | c0601d285efe063def984f91b04de2d227f89526 (patch) | |
| tree | f405abc5b7a41d51893e3e59821781075b1571e6 /drivers/i2c | |
| parent | 72f0271576eeef40c81c2949e0a8abeaef9a7690 (diff) | |
i2c: designware: Add i2c bus locking support
Adds support for acquiring and releasing a hardware bus lock in the i2c
designware core transfer function. This is needed for i2c bus controllers
that are shared with but not controlled by the kernel.
Signed-off-by: David E. Box <david.e.box@linux.intel.com>
Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Diffstat (limited to 'drivers/i2c')
| -rw-r--r-- | drivers/i2c/busses/i2c-designware-core.c | 26 | ||||
| -rw-r--r-- | drivers/i2c/busses/i2c-designware-core.h | 6 |
2 files changed, 32 insertions, 0 deletions
diff --git a/drivers/i2c/busses/i2c-designware-core.c b/drivers/i2c/busses/i2c-designware-core.c index e2799483dc45..fbb48fb138e7 100644 --- a/drivers/i2c/busses/i2c-designware-core.c +++ b/drivers/i2c/busses/i2c-designware-core.c @@ -285,6 +285,15 @@ int i2c_dw_init(struct dw_i2c_dev *dev) u32 hcnt, lcnt; u32 reg; u32 sda_falling_time, scl_falling_time; + int ret; + + if (dev->acquire_lock) { + ret = dev->acquire_lock(dev); + if (ret) { + dev_err(dev->dev, "couldn't acquire bus ownership\n"); + return ret; + } + } input_clock_khz = dev->get_clk_rate_khz(dev); @@ -298,6 +307,8 @@ int i2c_dw_init(struct dw_i2c_dev *dev) } else if (reg != DW_IC_COMP_TYPE_VALUE) { dev_err(dev->dev, "Unknown Synopsys component type: " "0x%08x\n", reg); + if (dev->release_lock) + dev->release_lock(dev); return -ENODEV; } @@ -364,6 +375,9 @@ int i2c_dw_init(struct dw_i2c_dev *dev) /* configure the i2c master */ dw_writel(dev, dev->master_cfg , DW_IC_CON); + + if (dev->release_lock) + dev->release_lock(dev); return 0; } EXPORT_SYMBOL_GPL(i2c_dw_init); @@ -627,6 +641,14 @@ i2c_dw_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num) dev->abort_source = 0; dev->rx_outstanding = 0; + if (dev->acquire_lock) { + ret = dev->acquire_lock(dev); + if (ret) { + dev_err(dev->dev, "couldn't acquire bus ownership\n"); + goto done_nolock; + } + } + ret = i2c_dw_wait_bus_not_busy(dev); if (ret < 0) goto done; @@ -672,6 +694,10 @@ i2c_dw_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num) ret = -EIO; done: + if (dev->release_lock) + dev->release_lock(dev); + +done_nolock: pm_runtime_mark_last_busy(dev->dev); pm_runtime_put_autosuspend(dev->dev); mutex_unlock(&dev->lock); diff --git a/drivers/i2c/busses/i2c-designware-core.h b/drivers/i2c/busses/i2c-designware-core.h index 5a410ef17abd..ef8ba839e2d3 100644 --- a/drivers/i2c/busses/i2c-designware-core.h +++ b/drivers/i2c/busses/i2c-designware-core.h @@ -61,6 +61,9 @@ * @ss_lcnt: standard speed LCNT value * @fs_hcnt: fast speed HCNT value * @fs_lcnt: fast speed LCNT value + * @acquire_lock: function to acquire a hardware lock on the bus + * @release_lock: function to release a hardware lock on the bus + * @pm_runtime_disabled: true if pm runtime is disabled * * HCNT and LCNT parameters can be used if the platform knows more accurate * values than the one computed based only on the input clock frequency. @@ -101,6 +104,9 @@ struct dw_i2c_dev { u16 ss_lcnt; u16 fs_hcnt; u16 fs_lcnt; + int (*acquire_lock)(struct dw_i2c_dev *dev); + void (*release_lock)(struct dw_i2c_dev *dev); + bool pm_runtime_disabled; }; #define ACCESS_SWAP 0x00000001 |