On Mon, 2020-11-30 at 18:35 +0800, Ikjoon Jang wrote:
> On Wed, Sep 30, 2020 at 10:21:58AM +0800, Crystal Guo wrote:
> > Introduce ti_syscon_reset() to integrate assert and deassert together.
> > If some modules need do serialized assert and deassert operations
> > to reset itself, reset_control_reset can be called for convenience.
> >
> > Such as reset-qcom-aoss.c, it integrates assert and deassert together
> > by 'reset' method. MTK Socs also need this method to perform reset.
> >
> > Signed-off-by: Crystal Guo <crystal.guo@xxxxxxxxxxxx>
>
> Reviewed-by: Ikjoon Jang <ikjn@xxxxxxxxxxxx>
>
> > ---
> > drivers/reset/reset-ti-syscon.c | 40 ++++++++++++++++++++++++++++++++-
> > 1 file changed, 39 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/reset/reset-ti-syscon.c b/drivers/reset/reset-ti-syscon.c
> > index a2635c21db7f..5d1f8306cd4f 100644
> > --- a/drivers/reset/reset-ti-syscon.c
> > +++ b/drivers/reset/reset-ti-syscon.c
> > @@ -15,15 +15,22 @@
> > * GNU General Public License for more details.
> > */
> >
> > +#include <linux/delay.h>
> > #include <linux/mfd/syscon.h>
> > #include <linux/module.h>
> > #include <linux/of.h>
> > +#include <linux/of_device.h>
> > #include <linux/platform_device.h>
> > #include <linux/regmap.h>
> > #include <linux/reset-controller.h>
> >
> > #include <dt-bindings/reset/ti-syscon.h>
> >
> > +struct mediatek_reset_data {
> > + unsigned char *reset_bits;
> > + unsigned int reset_duration_us;
> > +};
> > +
> > /**
> > * struct ti_syscon_reset_control - reset control structure
> > * @assert_offset: reset assert control register offset from syscon base
> > @@ -56,6 +63,7 @@ struct ti_syscon_reset_data {
> > struct regmap *regmap;
> > struct ti_syscon_reset_control *controls;
> > unsigned int nr_controls;
> > + const struct mediatek_reset_data *reset_data;
> > };
> >
> > #define to_ti_syscon_reset_data(rcdev) \
> > @@ -158,9 +166,29 @@ static int ti_syscon_reset_status(struct reset_controller_dev *rcdev,
> > !(control->flags & STATUS_SET);
> > }
> >
> > +static int ti_syscon_reset(struct reset_controller_dev *rcdev,
> > + unsigned long id)
> > +{
> > + struct ti_syscon_reset_data *data = to_ti_syscon_reset_data(rcdev);
> > + int ret;
> > +
> > + if (data->reset_data) {
> > + ret = ti_syscon_reset_assert(rcdev, id);
> > + if (ret)
> > + return ret;
> > + usleep_range(data->reset_data->reset_duration_us,
> > + data->reset_data->reset_duration_us * 2);
> > +
>
> There are many users using assert() and deassert() seperately
> without any delay between them.
>
> If there's a timing requirement between assertion and deassertion,
> shouldn't there be a same amount of delay in assert?
The "reset_duration_us" is an optional configuration to make the reset
operation more generic, which was added based on Philipp's comment in
[v2,4/6].
Thanks,
Crystal
>
> > + return ti_syscon_reset_deassert(rcdev, id);
> > + } else {
> > + return -ENOTSUPP;
> > + }
> > +}
> > +
> > static const struct reset_control_ops ti_syscon_reset_ops = {
> > .assert = ti_syscon_reset_assert,
> > .deassert = ti_syscon_reset_deassert,
> > + .reset = ti_syscon_reset,
> > .status = ti_syscon_reset_status,
> > };
> >
> > @@ -182,7 +210,11 @@ static int ti_syscon_reset_probe(struct platform_device *pdev)
> > if (IS_ERR(regmap))
> > return PTR_ERR(regmap);
> >
> > - list = of_get_property(np, "ti,reset-bits", &size);
> > + data->reset_data = of_device_get_match_data(&pdev->dev);
> > + if (data->reset_data)
> > + list = of_get_property(np, data->reset_data->reset_bits, &size);
> > + else
> > + list = of_get_property(np, "ti,reset-bits", &size);
> > if (!list || (size / sizeof(*list)) % 7 != 0) {
> > dev_err(dev, "invalid DT reset description\n");
> > return -EINVAL;
> > @@ -217,8 +249,14 @@ static int ti_syscon_reset_probe(struct platform_device *pdev)
> > return devm_reset_controller_register(dev, &data->rcdev);
> > }
> >
> > +static const struct mediatek_reset_data mtk_reset_data = {
> > + .reset_bits = "mediatek,reset-bits",
> > + .reset_duration_us = 10,
> > +};
> > +
> > static const struct of_device_id ti_syscon_reset_of_match[] = {
> > { .compatible = "ti,syscon-reset", },
> > + { .compatible = "mediatek,syscon-reset", .data = &mtk_reset_data},
> > { /* sentinel */ },
> > };
> > MODULE_DEVICE_TABLE(of, ti_syscon_reset_of_match);
