Re: [v4,3/4] reset-controller: ti: introduce a new reset handler

[Crystal Guo <crystal.guo@mediatek.com>]

On Wed, 2020-09-09 at 23:39 +0800, Suman Anna wrote:
> On 9/8/20 9:57 PM, Crystal Guo wrote:
> > On Thu, 2020-09-03 at 07:40 +0800, Suman Anna wrote:
> >> Hi Crystal,
> >>
> >> On 8/16/20 10:03 PM, 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.
> >>
> >> There are multiple changes in this same patch. I think you should split this
> >> functionality away from the change for the regmap_update_bits() to
> >> regmap_write_bits(), similar to what you have done in your v2 Patch 4.
> >>
> > 
> > Thanks for your suggestion.
> > I will split this patch in the next version.
> > 
> >>>
> >>> 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@mediatek.com>
> >>> ---
> >>>  drivers/reset/reset-ti-syscon.c | 26 ++++++++++++++++++++++++--
> >>>  1 file changed, 24 insertions(+), 2 deletions(-)
> >>>
> >>> diff --git a/drivers/reset/reset-ti-syscon.c b/drivers/reset/reset-ti-syscon.c
> >>> index a2635c21db7f..08289342f9af 100644
> >>> --- a/drivers/reset/reset-ti-syscon.c
> >>> +++ b/drivers/reset/reset-ti-syscon.c
> >>> @@ -15,6 +15,7 @@
> >>>   * GNU General Public License for more details.
> >>>   */
> >>>  
> >>> +#include <linux/delay.h>
> >>>  #include <linux/mfd/syscon.h>
> >>>  #include <linux/module.h>
> >>>  #include <linux/of.h>
> >>> @@ -56,6 +57,7 @@ struct ti_syscon_reset_data {
> >>>  	struct regmap *regmap;
> >>>  	struct ti_syscon_reset_control *controls;
> >>>  	unsigned int nr_controls;
> >>> +	unsigned int reset_duration_us;
> >>>  };
> >>>  
> >>>  #define to_ti_syscon_reset_data(rcdev)	\
> >>> @@ -89,7 +91,7 @@ static int ti_syscon_reset_assert(struct reset_controller_dev *rcdev,
> >>>  	mask = BIT(control->assert_bit);
> >>>  	value = (control->flags & ASSERT_SET) ? mask : 0x0;
> >>>  
> >>> -	return regmap_update_bits(data->regmap, control->assert_offset, mask, value);
> >>> +	return regmap_write_bits(data->regmap, control->assert_offset, mask, value);
> >>>  }
> >>>  
> >>>  /**
> >>> @@ -120,7 +122,7 @@ static int ti_syscon_reset_deassert(struct reset_controller_dev *rcdev,
> >>>  	mask = BIT(control->deassert_bit);
> >>>  	value = (control->flags & DEASSERT_SET) ? mask : 0x0;
> >>>  
> >>> -	return regmap_update_bits(data->regmap, control->deassert_offset, mask, value);
> >>> +	return regmap_write_bits(data->regmap, control->deassert_offset, mask, value);
> >>>  }
> >>>  
> >>>  /**
> >>> @@ -158,9 +160,26 @@ 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;
> >>> +
> >>> +	ret = ti_syscon_reset_assert(rcdev, id);
> >>> +	if (ret)
> >>> +		return ret;
> >>> +
> >>> +	if (data->reset_duration_us)
> >>> +		usleep_range(data->reset_duration_us, data->reset_duration_us * 2);
> >>> +
> >>> +	return ti_syscon_reset_deassert(rcdev, id);
> >>
> >> I echo Philipp's comments [1] from your original v1 series about this. We don't
> >> need a property to distinguish this, but you could add a flag using match data
> >> and Mediatek compatible, and use that within this function, or optionally set
> >> this ops based on compatible (whatever is preferred by Philipp).
> >>
> >> regards
> >> Suman
> >>
> >> [1] https://patchwork.kernel.org/comment/23519193/
> >>
> > Hi Suman, Philipp
> > 
> > Which method would you recommend more?
> > 1. like v2 patch, but assign the flag "data->assert_deassert_together"
> > directly (maybe rename "assert_deassert_together" to
> > "reset_op_available")
> > 
> > 2. use Mediatek compatible to decide the reset handler available or not.
> 
> I would go with this option. Anyway, I think you might have to add the reset SoC
> data as well, based on Rob's comment on the binding.
> 
> regards
> Suman


Thanks for your suggestions
I will add the following changes in the next version, 
please correct me if there is any misunderstanding.
1). revert ti-syscon-reset.txt add a new mediatek reset binding doc.
2). split the patch [v4,3/4] with the change for the
regmap_update_bits() to regmap_write_bits() and the change to integrate
assert and deassert together.
3). add the reset SoC data, which contains the flag "reset_op_available"
to decide the reset handler available or not.
4). separate the dts patch from this patch sets

> > 
> > Thanks
> > Crystal
> > 
> >>> +}
> >>> +
> >>>  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,
> >>>  };
> >>>  
> >>> @@ -204,6 +223,9 @@ static int ti_syscon_reset_probe(struct platform_device *pdev)
> >>>  		controls[i].flags = be32_to_cpup(list++);
> >>>  	}
> >>>  
> >>> +	of_property_read_u32(pdev->dev.of_node,	"reset-duration-us",
> >>> +				&data->reset_duration_us);
> >>> +
> >>>  	data->rcdev.ops = &ti_syscon_reset_ops;
> >>>  	data->rcdev.owner = THIS_MODULE;
> >>>  	data->rcdev.of_node = np;
> >>>
> >>
> > 
>