| Message ID | 31e3daec5d5b703bd87ef9d77e353589daf6fa3e.1587742492.git-series.maxime@cerno.tech (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | drm/vc4: Support BCM2711 Display Pipeline | expand |
Hi Maxime, On Fri, 2020-04-24 at 17:34 +0200, Maxime Ripard wrote: > The reset-simple code lacks a reset callback that is still pretty easy to > implement. The only real thing to consider is the delay needed for a device > to be reset, so let's expose that as part of the reset-simple driver data. > > Cc: Philipp Zabel <p.zabel@pengutronix.de> > Signed-off-by: Maxime Ripard <maxime@cerno.tech> > --- > drivers/reset/reset-simple.c | 24 ++++++++++++++++++++++++ > include/linux/reset/reset-simple.h | 6 ++++++ > 2 files changed, 30 insertions(+) > > diff --git a/drivers/reset/reset-simple.c b/drivers/reset/reset-simple.c > index c854aa351640..602ed972b0a9 100644 > --- a/drivers/reset/reset-simple.c > +++ b/drivers/reset/reset-simple.c > @@ -11,6 +11,7 @@ > * Maxime Ripard <maxime.ripard@free-electrons.com> > */ > > +#include <linux/delay.h> > #include <linux/device.h> > #include <linux/err.h> > #include <linux/io.h> > @@ -63,6 +64,28 @@ static int reset_simple_deassert(struct reset_controller_dev *rcdev, > return reset_simple_update(rcdev, id, false); > } > > +static int reset_simple_reset(struct reset_controller_dev *rcdev, > + unsigned long id) > +{ > + struct reset_simple_data *data = to_reset_simple_data(rcdev); > + int ret; > + > + if (!data->reset_us) > + return -ENOTSUPP; > + > + ret = reset_simple_assert(rcdev, id); > + if (ret) > + return ret; > + > + usleep_range(data->reset_us, data->reset_us * 2); > + > + ret = reset_simple_deassert(rcdev, id); > + if (ret) > + return ret; > + > + return 0; Just return reset_simple_deassert(rcdev, id); here. > +} > + > static int reset_simple_status(struct reset_controller_dev *rcdev, > unsigned long id) > { > @@ -80,6 +103,7 @@ static int reset_simple_status(struct reset_controller_dev *rcdev, > const struct reset_control_ops reset_simple_ops = { > .assert = reset_simple_assert, > .deassert = reset_simple_deassert, > + .reset = reset_simple_reset, > .status = reset_simple_status, > }; > EXPORT_SYMBOL_GPL(reset_simple_ops); > diff --git a/include/linux/reset/reset-simple.h b/include/linux/reset/reset-simple.h > index 08ccb25a55e6..5eb83625a495 100644 > --- a/include/linux/reset/reset-simple.h > +++ b/include/linux/reset/reset-simple.h > @@ -27,6 +27,11 @@ > * @status_active_low: if true, bits read back as cleared while the reset is > * asserted. Otherwise, bits read back as set while the > * reset is asserted. > + * @reset_us: Minimum delay in microseconds needed that needs to be > + * waited for between an assert and a deassert to reset the > + * device. If multiple consumers with different delay > + * requirements are connected to this controller, it must > + * be the largest minimum delay. Please mention that 0 does not meen 0 µs delay, but unknown and thus reset callback not supported. With these two issues fixed Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de> regards Philipp
diff --git a/drivers/reset/reset-simple.c b/drivers/reset/reset-simple.c index c854aa351640..602ed972b0a9 100644 --- a/drivers/reset/reset-simple.c +++ b/drivers/reset/reset-simple.c @@ -11,6 +11,7 @@ * Maxime Ripard <maxime.ripard@free-electrons.com> */ +#include <linux/delay.h> #include <linux/device.h> #include <linux/err.h> #include <linux/io.h> @@ -63,6 +64,28 @@ static int reset_simple_deassert(struct reset_controller_dev *rcdev, return reset_simple_update(rcdev, id, false); } +static int reset_simple_reset(struct reset_controller_dev *rcdev, + unsigned long id) +{ + struct reset_simple_data *data = to_reset_simple_data(rcdev); + int ret; + + if (!data->reset_us) + return -ENOTSUPP; + + ret = reset_simple_assert(rcdev, id); + if (ret) + return ret; + + usleep_range(data->reset_us, data->reset_us * 2); + + ret = reset_simple_deassert(rcdev, id); + if (ret) + return ret; + + return 0; +} + static int reset_simple_status(struct reset_controller_dev *rcdev, unsigned long id) { @@ -80,6 +103,7 @@ static int reset_simple_status(struct reset_controller_dev *rcdev, const struct reset_control_ops reset_simple_ops = { .assert = reset_simple_assert, .deassert = reset_simple_deassert, + .reset = reset_simple_reset, .status = reset_simple_status, }; EXPORT_SYMBOL_GPL(reset_simple_ops); diff --git a/include/linux/reset/reset-simple.h b/include/linux/reset/reset-simple.h index 08ccb25a55e6..5eb83625a495 100644 --- a/include/linux/reset/reset-simple.h +++ b/include/linux/reset/reset-simple.h @@ -27,6 +27,11 @@ * @status_active_low: if true, bits read back as cleared while the reset is * asserted. Otherwise, bits read back as set while the * reset is asserted. + * @reset_us: Minimum delay in microseconds needed that needs to be + * waited for between an assert and a deassert to reset the + * device. If multiple consumers with different delay + * requirements are connected to this controller, it must + * be the largest minimum delay. */ struct reset_simple_data { spinlock_t lock; @@ -34,6 +39,7 @@ struct reset_simple_data { struct reset_controller_dev rcdev; bool active_low; bool status_active_low; + unsigned int reset_us; }; extern const struct reset_control_ops reset_simple_ops;
The reset-simple code lacks a reset callback that is still pretty easy to implement. The only real thing to consider is the delay needed for a device to be reset, so let's expose that as part of the reset-simple driver data. Cc: Philipp Zabel <p.zabel@pengutronix.de> Signed-off-by: Maxime Ripard <maxime@cerno.tech> --- drivers/reset/reset-simple.c | 24 ++++++++++++++++++++++++ include/linux/reset/reset-simple.h | 6 ++++++ 2 files changed, 30 insertions(+)