On Tue, 2021-06-01 at 19:09 +0200, Robert Marko wrote:
[...]
> Yes, it's self-clearing, per spec they will be cleared after 100ms.
Can you make sure the function only returns after the reset is
deasserted again, for example by using regmap_read_poll_timeout() on the
reset bit?
> Will drop assert then, I saw that reset was for self-clearing, but other
> drivers I looked for example implemented both which was confusing.
If you have full control over the reset line, you can implement .reset
by manually asserting and deasserting (possibly after a delay). But if
the reset is self-clearing, you can't properly implement .(de)assert,
which have an expectation about the state of the reset line after the
function returns.
> > > +}
> > > +
> > > +static int tn48m_control_status(struct reset_controller_dev *rcdev,
> > > + unsigned long id)
> > > +{
> > > + struct tn48_reset_data *data = to_tn48_reset_data(rcdev);
> > > + unsigned int regval;
> > > + int ret;
> > > +
> > > + ret = regmap_read(data->regmap, TN48M_RESET_REG, ®val);
> > > + if (ret < 0)
> > > + return ret;
> > > +
> > > + if (BIT(tn48m_resets[id].bit) & regval)
> > > + return 0;
> > > + else
> > > + return 1;
> > > +}
> > > +
> > > +static const struct reset_control_ops tn48_reset_ops = {
> > > + .reset = tn48m_control_reset,
> > > + .assert = tn48m_control_assert,
> > > + .status = tn48m_control_status,
> > > +};
> > > +
> > > +static int tn48m_reset_probe(struct platform_device *pdev)
> > > +{
> > > + struct tn48_reset_data *data;
> > > + struct regmap *regmap;
> > > +
> > > + if (!pdev->dev.parent)
> > > + return -ENODEV;
> >
> > That shouldn't be necessary.
>
> This driver depends on having a parent as it needs to get the
> regmap from it.
> The parent is a CPLD using simple-i2c-mfd.
> So it's nice to check.
pdev->dev.parent is always set to &platform_bus if there is no parent.
regards
Philipp
