On Mon, Dec 01, 2014 at 04:09:32PM -0800, David E. Box wrote:
> 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@xxxxxxxxxxxxxxx>
> ---
> 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;
I wonder what happens now since you failed to acquire the lock...
> + }
> + }
> +
> 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);
... but here you unconditionally release it?
Otherwise the patch looks good to me.
> +
> 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
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