Re: [PATCH v1 1/5] clk: qcom: regmap-mux: add pipe clk implementation

[Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>]

On Tue, Apr 12, 2022 at 01:45:37PM -0500, Bjorn Andersson wrote:
> On Fri 08 Apr 06:15 CDT 2022, Lorenzo Pieralisi wrote:
> 
> > On Wed, Mar 23, 2022 at 11:50:06AM +0300, Dmitry Baryshkov wrote:
> > > On recent Qualcomm platforms the QMP PIPE clocks feed into a set of
> > > muxes which must be parked to the "safe" source (bi_tcxo) when
> > > corresponding GDSC is turned off and on again. Currently this is
> > > handcoded in the PCIe driver by reparenting the gcc_pipe_N_clk_src
> > > clock. However the same code sequence should be applied in the
> > > pcie-qcom endpoint, USB3 and UFS drivers.
> > > 
> > > Rather than copying this sequence over and over again, follow the
> > > example of clk_rcg2_shared_ops and implement this parking in the
> > > enable() and disable() clock operations. As we are changing the parent
> > > behind the back of the clock framework, also implement custom
> > > set_parent() and get_parent() operations behaving accroding to the clock
> > > framework expectations (cache the new parent if the clock is in disabled
> > > state, return cached parent).
> > > 
> > > Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
> > > ---
> > >  drivers/clk/qcom/clk-regmap-mux.c | 78 +++++++++++++++++++++++++++++++
> > >  drivers/clk/qcom/clk-regmap-mux.h |  3 ++
> > >  2 files changed, 81 insertions(+)
> > 
> > Need BjornA's ACK on this patch and I can pull the series then.
> > 
> 
> It seems I have a few more clock patches in the queue which depends on
> top of this, so I picked up the three clock branches and pushed a tag
> for you to pick up, Lorenzo.

There are still comments on v2 as of today that require attention.

https://lore.kernel.org/linux-pci/YlaUtCuMZZL4bM2U@hovoldconsulting.com

I will put this on hold waiting for the discussion to complete.

Lorenzo

> The following changes since commit a9ed9e2bf7940353d2ffa4faa2ad2b75a24f3ac0:
> 
>   clk: qcom: gcc-sc7280: use new clk_regmap_mux_safe_ops for PCIe pipe clocks (2022-04-12 13:32:58 -0500)
> 
> are available in the Git repository at:
> 
>   https://git.kernel.org/pub/scm/linux/kernel/git/qcom/linux.git tags/20220323085010.1753493-4-dmitry.baryshkov@linaro.org
> 
> for you to fetch changes up to a9ed9e2bf7940353d2ffa4faa2ad2b75a24f3ac0:
> 
>   clk: qcom: gcc-sc7280: use new clk_regmap_mux_safe_ops for PCIe pipe clocks (2022-04-12 13:32:58 -0500)
> 
> ----------------------------------------------------------------
> v5.18-rc1 +
> 20220323085010.1753493-2-dmitry.baryshkov@linaro.org +
> 20220323085010.1753493-3-dmitry.baryshkov@linaro.org +
> 20220323085010.1753493-4-dmitry.baryshkov@linaro.org
> 
> ----------------------------------------------------------------
> 
> Hope this works for you.
> 
> Regards,
> Bjorn
> 
> > Lorenzo
> > 
> > > diff --git a/drivers/clk/qcom/clk-regmap-mux.c b/drivers/clk/qcom/clk-regmap-mux.c
> > > index 45d9cca28064..c39ee783ee83 100644
> > > --- a/drivers/clk/qcom/clk-regmap-mux.c
> > > +++ b/drivers/clk/qcom/clk-regmap-mux.c
> > > @@ -49,9 +49,87 @@ static int mux_set_parent(struct clk_hw *hw, u8 index)
> > >  	return regmap_update_bits(clkr->regmap, mux->reg, mask, val);
> > >  }
> > >  
> > > +static u8 mux_safe_get_parent(struct clk_hw *hw)
> > > +{
> > > +	struct clk_regmap_mux *mux = to_clk_regmap_mux(hw);
> > > +	unsigned int val;
> > > +
> > > +	if (clk_hw_is_enabled(hw))
> > > +		return mux_get_parent(hw);
> > > +
> > > +	val = mux->stored_parent_cfg;
> > > +
> > > +	if (mux->parent_map)
> > > +		return qcom_find_cfg_index(hw, mux->parent_map, val);
> > > +
> > > +	return val;
> > > +}
> > > +
> > > +static int mux_safe_set_parent(struct clk_hw *hw, u8 index)
> > > +{
> > > +	struct clk_regmap_mux *mux = to_clk_regmap_mux(hw);
> > > +
> > > +	if (clk_hw_is_enabled(hw))
> > > +		return mux_set_parent(hw, index);
> > > +
> > > +	if (mux->parent_map)
> > > +		index = mux->parent_map[index].cfg;
> > > +
> > > +	mux->stored_parent_cfg = index;
> > > +
> > > +	return 0;
> > > +}
> > > +
> > > +static void mux_safe_disable(struct clk_hw *hw)
> > > +{
> > > +	struct clk_regmap_mux *mux = to_clk_regmap_mux(hw);
> > > +	struct clk_regmap *clkr = to_clk_regmap(hw);
> > > +	unsigned int mask = GENMASK(mux->width + mux->shift - 1, mux->shift);
> > > +	unsigned int val;
> > > +
> > > +	regmap_read(clkr->regmap, mux->reg, &val);
> > > +
> > > +	mux->stored_parent_cfg = (val & mask) >> mux->shift;
> > > +
> > > +	val = mux->safe_src_parent;
> > > +	if (mux->parent_map) {
> > > +		int index = qcom_find_src_index(hw, mux->parent_map, val);
> > > +
> > > +		if (WARN_ON(index < 0))
> > > +			return;
> > > +
> > > +		val = mux->parent_map[index].cfg;
> > > +	}
> > > +	val <<= mux->shift;
> > > +
> > > +	regmap_update_bits(clkr->regmap, mux->reg, mask, val);
> > > +}
> > > +
> > > +static int mux_safe_enable(struct clk_hw *hw)
> > > +{
> > > +	struct clk_regmap_mux *mux = to_clk_regmap_mux(hw);
> > > +	struct clk_regmap *clkr = to_clk_regmap(hw);
> > > +	unsigned int mask = GENMASK(mux->width + mux->shift - 1, mux->shift);
> > > +	unsigned int val;
> > > +
> > > +	val = mux->stored_parent_cfg;
> > > +	val <<= mux->shift;
> > > +
> > > +	return regmap_update_bits(clkr->regmap, mux->reg, mask, val);
> > > +}
> > > +
> > >  const struct clk_ops clk_regmap_mux_closest_ops = {
> > >  	.get_parent = mux_get_parent,
> > >  	.set_parent = mux_set_parent,
> > >  	.determine_rate = __clk_mux_determine_rate_closest,
> > >  };
> > >  EXPORT_SYMBOL_GPL(clk_regmap_mux_closest_ops);
> > > +
> > > +const struct clk_ops clk_regmap_mux_safe_ops = {
> > > +	.enable = mux_safe_enable,
> > > +	.disable = mux_safe_disable,
> > > +	.get_parent = mux_safe_get_parent,
> > > +	.set_parent = mux_safe_set_parent,
> > > +	.determine_rate = __clk_mux_determine_rate_closest,
> > > +};
> > > +EXPORT_SYMBOL_GPL(clk_regmap_mux_safe_ops);
> > > diff --git a/drivers/clk/qcom/clk-regmap-mux.h b/drivers/clk/qcom/clk-regmap-mux.h
> > > index db6f4cdd9586..f86c674ce139 100644
> > > --- a/drivers/clk/qcom/clk-regmap-mux.h
> > > +++ b/drivers/clk/qcom/clk-regmap-mux.h
> > > @@ -14,10 +14,13 @@ struct clk_regmap_mux {
> > >  	u32			reg;
> > >  	u32			shift;
> > >  	u32			width;
> > > +	u8			safe_src_parent;
> > > +	u8			stored_parent_cfg;
> > >  	const struct parent_map	*parent_map;
> > >  	struct clk_regmap	clkr;
> > >  };
> > >  
> > >  extern const struct clk_ops clk_regmap_mux_closest_ops;
> > > +extern const struct clk_ops clk_regmap_mux_safe_ops;
> > >  
> > >  #endif
> > > -- 
> > > 2.35.1
> > >