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....@linux.intel.com>
---
drivers/i2c/busses/i2c-designware-core.c | 26 ++++++++++++++++++++++++++
drivers/i2c/busses/i2c-designware-core.h | 6 ++++++
2 files changed, 32 insertions(+)
diff --git a/drivers/i2c/busses/i2c-designware-core.c
b/drivers/i2c/busses/i2c-designware-core.c
index 3c20e4b..3d3ac4d 100644
--- a/drivers/i2c/busses/i2c-designware-core.c
+++ b/drivers/i2c/busses/i2c-designware-core.c
@@ -289,6 +289,15 @@ 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);
@@ -302,6 +311,8 @@ 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;
}
@@ -368,6 +379,9 @@ 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);
@@ -631,6 +645,14 @@ 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;
@@ -676,6 +698,10 @@ 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 d66b6cb..a472c91 100644
--- a/drivers/i2c/busses/i2c-designware-core.h
+++ b/drivers/i2c/busses/i2c-designware-core.h
@@ -65,6 +65,9 @@
* @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.
@@ -105,6 +108,9 @@ 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
--
1.9.1
--
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