On Thu, 2019-02-21 at 16:25 +0100, Thierry Reding wrote:
> From: Thierry Reding <treding@xxxxxxxxxx>
>
> By implementing the acquire/release protocol, the SOR reset can be
> shared with other drivers that also adhere to this protocol, such as the
> PMC driver that uses the same reset as part of the powergate and -ungate
> implementation using generic power domains.
>
> Runtime PM makes sure that the operations are executed in the right
> order, and the reset core has error handling and WARNs in place to make
> sure the acquire/release protocol is followed.
>
> Signed-off-by: Thierry Reding <treding@xxxxxxxxxx>
> ---
> drivers/gpu/drm/tegra/sor.c | 21 ++++++++++++++++++++-
> 1 file changed, 20 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/tegra/sor.c b/drivers/gpu/drm/tegra/sor.c
> index 40057106f5f3..5be5a0817dfe 100644
> --- a/drivers/gpu/drm/tegra/sor.c
> +++ b/drivers/gpu/drm/tegra/sor.c
> @@ -2871,6 +2871,13 @@ static int tegra_sor_init(struct host1x_client *client)
> * kernel is possible.
> */
> if (sor->rst) {
> + err = reset_control_acquire(sor->rst);
> + if (err < 0) {
> + dev_err(sor->dev, "failed to acquire SOR reset: %d\n",
> + err);
> + return err;
> + }
> +
> err = reset_control_assert(sor->rst);
> if (err < 0) {
> dev_err(sor->dev, "failed to assert SOR reset: %d\n",
> @@ -2894,6 +2901,8 @@ static int tegra_sor_init(struct host1x_client *client)
> err);
> return err;
> }
> +
> + reset_control_release(sor->rst);
> }
>
> err = clk_prepare_enable(sor->clk_safe);
> @@ -3331,7 +3340,7 @@ static int tegra_sor_probe(struct platform_device *pdev)
> goto remove;
> }
>
> - sor->rst = devm_reset_control_get(&pdev->dev, "sor");
> + sor->rst = devm_reset_control_get_exclusive_released(&pdev->dev, "sor");
> if (IS_ERR(sor->rst)) {
> err = PTR_ERR(sor->rst);
>
> @@ -3519,6 +3528,8 @@ static int tegra_sor_suspend(struct device *dev)
> dev_err(dev, "failed to assert reset: %d\n", err);
> return err;
> }
> +
> + reset_control_release(sor->rst);
> }
>
> usleep_range(1000, 2000);
> @@ -3542,9 +3553,17 @@ static int tegra_sor_resume(struct device *dev)
> usleep_range(1000, 2000);
>
> if (sor->rst) {
> + err = reset_control_acquire(sor->rst);
> + if (err < 0) {
> + dev_err(dev, "failed to acquire reset: %d\n", err);
> + clk_disable_unprepare(sor->clk);
> + return err;
> + }
> +
> err = reset_control_deassert(sor->rst);
> if (err < 0) {
> dev_err(dev, "failed to deassert reset: %d\n", err);
> + reset_control_release(sor->rst);
> clk_disable_unprepare(sor->clk);
> return err;
> }
Reviewed-by: Philipp Zabel <p.zabel@xxxxxxxxxxxxxx>
regards
Philipp
