Some SoCs might have a reset controller which disables clocks
by default in reset state which then drivers need to unreset
before being able to ungate a specific clock.
In this specific case, the hantro driver needs to ensure the
peripheral clock can be properly ungated otherwise MMIO reg
values can't be accessed.
If the SoC has no reset controller or there is no "resets" DT
property defined, this new code will have no effect.
Signed-off-by: Adrian Ratiu <[email protected]>
Signed-off-by: Ezequiel Garcia <[email protected]>
---
drivers/staging/media/hantro/hantro.h | 1 +
drivers/staging/media/hantro/hantro_drv.c | 8 ++++++++
2 files changed, 9 insertions(+)
diff --git a/drivers/staging/media/hantro/hantro.h b/drivers/staging/media/hantro/hantro.h
index 65f9f7ea7dcf..bb442eb1974e 100644
--- a/drivers/staging/media/hantro/hantro.h
+++ b/drivers/staging/media/hantro/hantro.h
@@ -183,6 +183,7 @@ struct hantro_dev {
struct platform_device *pdev;
struct device *dev;
struct clk_bulk_data *clocks;
+ struct reset_control *reset;
void __iomem **reg_bases;
void __iomem *enc_base;
void __iomem *dec_base;
diff --git a/drivers/staging/media/hantro/hantro_drv.c b/drivers/staging/media/hantro/hantro_drv.c
index 3cd00cc0a364..c2ea54552ce9 100644
--- a/drivers/staging/media/hantro/hantro_drv.c
+++ b/drivers/staging/media/hantro/hantro_drv.c
@@ -17,6 +17,7 @@
#include <linux/pm.h>
#include <linux/pm_runtime.h>
#include <linux/slab.h>
+#include <linux/reset.h>
#include <linux/videodev2.h>
#include <linux/workqueue.h>
#include <media/v4l2-event.h>
@@ -747,6 +748,13 @@ static int hantro_probe(struct platform_device *pdev)
INIT_DELAYED_WORK(&vpu->watchdog_work, hantro_watchdog);
+ vpu->reset = devm_reset_control_get_optional_exclusive(&pdev->dev,
+ NULL);
+ if (IS_ERR(vpu->reset))
+ vpu->reset = NULL;
+
+ reset_control_reset(vpu->reset);
+
vpu->clocks = devm_kcalloc(&pdev->dev, vpu->variant->num_clocks,
sizeof(*vpu->clocks), GFP_KERNEL);
if (!vpu->clocks)
--
2.28.0
Hi Adrian,
On Mon, 2020-10-12 at 23:59 +0300, Adrian Ratiu wrote:
> Some SoCs might have a reset controller which disables clocks
> by default in reset state which then drivers need to unreset
> before being able to ungate a specific clock.
>
> In this specific case, the hantro driver needs to ensure the
> peripheral clock can be properly ungated otherwise MMIO reg
> values can't be accessed.
>
> If the SoC has no reset controller or there is no "resets" DT
> property defined, this new code will have no effect.
>
> Signed-off-by: Adrian Ratiu <[email protected]>
> Signed-off-by: Ezequiel Garcia <[email protected]>
> ---
> drivers/staging/media/hantro/hantro.h | 1 +
> drivers/staging/media/hantro/hantro_drv.c | 8 ++++++++
> 2 files changed, 9 insertions(+)
>
> diff --git a/drivers/staging/media/hantro/hantro.h b/drivers/staging/media/hantro/hantro.h
> index 65f9f7ea7dcf..bb442eb1974e 100644
> --- a/drivers/staging/media/hantro/hantro.h
> +++ b/drivers/staging/media/hantro/hantro.h
> @@ -183,6 +183,7 @@ struct hantro_dev {
> struct platform_device *pdev;
> struct device *dev;
> struct clk_bulk_data *clocks;
> + struct reset_control *reset;
> void __iomem **reg_bases;
> void __iomem *enc_base;
> void __iomem *dec_base;
> diff --git a/drivers/staging/media/hantro/hantro_drv.c b/drivers/staging/media/hantro/hantro_drv.c
> index 3cd00cc0a364..c2ea54552ce9 100644
> --- a/drivers/staging/media/hantro/hantro_drv.c
> +++ b/drivers/staging/media/hantro/hantro_drv.c
> @@ -17,6 +17,7 @@
> #include <linux/pm.h>
> #include <linux/pm_runtime.h>
> #include <linux/slab.h>
> +#include <linux/reset.h>
> #include <linux/videodev2.h>
> #include <linux/workqueue.h>
> #include <media/v4l2-event.h>
> @@ -747,6 +748,13 @@ static int hantro_probe(struct platform_device *pdev)
>
> INIT_DELAYED_WORK(&vpu->watchdog_work, hantro_watchdog);
>
> + vpu->reset = devm_reset_control_get_optional_exclusive(&pdev->dev,
> + NULL);
> + if (IS_ERR(vpu->reset))
> + vpu->reset = NULL;
Please return the error. If the optional reset is missing from the
device tree, devm_reset_control_get_optional_exclusive() returns NULL
already.
regards
Philipp