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 <[email protected]> --- drivers/i2c/busses/i2c-designware-core.c | 11 +++++++++++ drivers/i2c/busses/i2c-designware-core.h | 6 ++++++ drivers/i2c/busses/i2c-designware-platdrv.c | 18 +++++++++++++----- 3 files changed, 30 insertions(+), 5 deletions(-) diff --git a/drivers/i2c/busses/i2c-designware-core.c b/drivers/i2c/busses/i2c-designware-core.c index 3c20e4b..377deeb 100644 --- a/drivers/i2c/busses/i2c-designware-core.c +++ b/drivers/i2c/busses/i2c-designware-core.c @@ -631,6 +631,14 @@ 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; + } + } + ret = i2c_dw_wait_bus_not_busy(dev); if (ret < 0) goto done; @@ -676,6 +684,9 @@ i2c_dw_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num) ret = -EIO; done: + if (dev->release_lock) + dev->release_lock(dev); + 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 diff --git a/drivers/i2c/busses/i2c-designware-platdrv.c b/drivers/i2c/busses/i2c-designware-platdrv.c index a743115..afdff3b 100644 --- a/drivers/i2c/busses/i2c-designware-platdrv.c +++ b/drivers/i2c/busses/i2c-designware-platdrv.c @@ -261,10 +261,16 @@ static int dw_i2c_probe(struct platform_device *pdev) return r; } - pm_runtime_set_autosuspend_delay(&pdev->dev, 1000); - pm_runtime_use_autosuspend(&pdev->dev); - pm_runtime_set_active(&pdev->dev); - pm_runtime_enable(&pdev->dev); + i2c_dw_eval_lock_support(dev); + + if (dev->pm_runtime_disabled) { + pm_runtime_forbid(&pdev->dev); + } else { + pm_runtime_set_autosuspend_delay(&pdev->dev, 1000); + pm_runtime_use_autosuspend(&pdev->dev); + pm_runtime_set_active(&pdev->dev); + pm_runtime_enable(&pdev->dev); + } return 0; } @@ -314,7 +320,9 @@ static int dw_i2c_resume(struct device *dev) struct dw_i2c_dev *i_dev = platform_get_drvdata(pdev); clk_prepare_enable(i_dev->clk); - i2c_dw_init(i_dev); + + if (!i_dev->pm_runtime_disabled) + i2c_dw_init(i_dev); return 0; } -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
