lkml.org 
[lkml]   [2018]   [Jan]   [17]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [1/5] clk: divider: read-only divider can propagate rate change
From
Date
On Thu, 2018-01-11 at 16:55 -0600, David Lechner wrote:
> On 01/05/2018 11:09 AM, Jerome Brunet wrote:
> > When a divider clock has CLK_DIVIDER_READ_ONLY set, it means that the
> > register shall be left un-touched, but it does not mean the clock
> > should stop rate propagation if CLK_SET_RATE_PARENT is set
> >
> > This is properly handled in qcom clk-regmap-divider but it was not in
> > the generic divider
> >
> > Fixes: e6d5e7d90be9 ("clk-divider: Fix READ_ONLY when divider > 1")
> > Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
> > ---
> > drivers/clk/clk-divider.c | 10 ++++++++++
> > 1 file changed, 10 insertions(+)
> >
> > diff --git a/drivers/clk/clk-divider.c b/drivers/clk/clk-divider.c
> > index b49942b9fe50..a851d3e04c7f 100644
> > --- a/drivers/clk/clk-divider.c
> > +++ b/drivers/clk/clk-divider.c
> > @@ -348,6 +348,7 @@ static long clk_divider_round_rate(struct clk_hw *hw, unsigned long rate,
> > unsigned long *prate)
> > {
> > struct clk_divider *divider = to_clk_divider(hw);
> > + struct clk_hw *hw_parent = clk_hw_get_parent(hw);
>
> Very minor suggestion: This could be moved inside the if block since it is only used there.

Even if correct, this is something I have seen done in CCF. I tend to just
follow the way to be honest.

Stephen, do you have any preference ?

>
> > int bestdiv;
> >
> > /* if read only, just return current value */
> > @@ -356,6 +357,15 @@ static long clk_divider_round_rate(struct clk_hw *hw, unsigned long rate,
> > bestdiv &= div_mask(divider->width);
> > bestdiv = _get_div(divider->table, bestdiv, divider->flags,
> > divider->width);
> > +
> > + /* Even a read-only clock can propagate a rate change */
> > + if (clk_hw_get_flags(hw) & CLK_SET_RATE_PARENT) {
> > + if (!hw_parent)
> > + return -EINVAL;
> > +
> > + *prate = clk_hw_round_rate(hw_parent, rate * bestdiv);
> > + }
> > +
> > return DIV_ROUND_UP_ULL((u64)*prate, bestdiv);
> > }
> >
> >
>
> Tested-by: David Lechner <david@lechnology.com>

\
 
 \ /
  Last update: 2018-01-18 00:21    [W:0.085 / U:0.344 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site