Re: [PATCH] clk: imx: gate2: Fix the is_enabled op

[Abel Vesa]

On 20-10-28 11:15:52, Sascha Hauer wrote:
> On Wed, Oct 28, 2020 at 11:50:57AM +0200, Abel Vesa wrote:
> > On 20-10-28 09:24:12, Sascha Hauer wrote:
> > > Hi Abel,
> > > 
> > > On Mon, Oct 26, 2020 at 08:50:48PM +0200, Abel Vesa wrote:
> > > > The clock is considered to be enabled only if the controlling bits
> > > > match the cgr_val mask. Also make sure the is_enabled returns the
> > > > correct vaule by locking the access to the register.
> > > > 
> > > > Signed-off-by: Abel Vesa <abel.vesa@xxxxxxx>
> > > > Fixes: 1e54afe9fcfe ("clk: imx: gate2: Allow single bit gating clock")
> > > > ---
> > > >  drivers/clk/imx/clk-gate2.c | 60 ++++++++++++++++++++-------------------------
> > > >  drivers/clk/imx/clk.h       |  8 ++----
> > > >  2 files changed, 29 insertions(+), 39 deletions(-)
> > > > 
> > > > diff --git a/drivers/clk/imx/clk-gate2.c b/drivers/clk/imx/clk-gate2.c
> > > > index 7eed708..f320bd2b 100644
> > > > --- a/drivers/clk/imx/clk-gate2.c
> > > > +++ b/drivers/clk/imx/clk-gate2.c
> > > > @@ -37,10 +37,22 @@ struct clk_gate2 {
> > > >  
> > > >  #define to_clk_gate2(_hw) container_of(_hw, struct clk_gate2, hw)
> > > >  
> > > > +static void clk_gate2_do_shared_clks(struct clk_hw *hw, bool enable)
> > > > +{
> > > > +	struct clk_gate2 *gate = to_clk_gate2(hw);
> > > > +	u32 reg;
> > > > +
> > > > +	reg = readl(gate->reg);
> > > > +	if (enable)
> > > > +		reg |= gate->cgr_val << gate->bit_idx;
> > > > +	else
> > > > +		reg &= ~(gate->cgr_val << gate->bit_idx);
> > > 
> > > Shouldn't this be:
> > > 
> > > 	reg &= ~(3 << gate->bit_idx);
> > > 	if (enable)
> > > 		reg |= gate->cgr_val << gate->bit_idx;
> > > 
> > > At least that's how it was without this patch and that's how it makes
> > > sense to me with cgr_val != 3.
> > > 
> > 
> > Well, that's the actual problem. The value 3 forces all the clocks
> > that register with this clock type to have 2 bits for controlling the gate.
> > 
> > My patch (though now I think I should split it into 2 separate patches) allows
> > two HW gates to be controlled by as many bits necessary. For example, there
> > could be multiple HW gates that are controled by the same bit. By passing
> > the cgr_val when registering the clocks you can specify how many bits (as a mask)
> > control all those HW gates that share their control bits.
> 
> cgr_val is not a mask, it's a value that shall be written to the two
> bits to enable the clock. cgr_val could also be 0b10, see imx_clk_gate2_cgr().
> 

Oh, I see your point now.

Maybe we should add another member called cgr_mask. That should fix the issue.

> Sascha
> 
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