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Message-ID: <9d72aaef-49fe-ebb6-215d-05ad3ab27af4@ti.com>
Date: Thu, 10 Sep 2020 21:52:04 -0500
From: Suman Anna <s-anna@...com>
To: Crystal Guo <crystal.guo@...iatek.com>,
"p.zabel@...gutronix.de" <p.zabel@...gutronix.de>,
"robh+dt@...nel.org" <robh+dt@...nel.org>,
"matthias.bgg@...il.com" <matthias.bgg@...il.com>
CC: srv_heupstream <srv_heupstream@...iatek.com>,
"linux-mediatek@...ts.infradead.org"
<linux-mediatek@...ts.infradead.org>,
"linux-arm-kernel@...ts.infradead.org"
<linux-arm-kernel@...ts.infradead.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"devicetree@...r.kernel.org" <devicetree@...r.kernel.org>,
Seiya Wang (王迺君)
<seiya.wang@...iatek.com>,
Stanley Chu (朱原陞)
<stanley.chu@...iatek.com>,
Yingjoe Chen (陳英洲)
<Yingjoe.Chen@...iatek.com>,
Fan Chen (陳凡) <fan.chen@...iatek.com>,
Yong Liang (梁勇) <Yong.Liang@...iatek.com>
Subject: Re: [v4,3/4] reset-controller: ti: introduce a new reset handler
On 9/10/20 9:42 PM, Crystal Guo wrote:
> 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@...iatek.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.
You would also need to add your SoC-specific data equivalent of the current
ti,reset-bits in your infra node. Please see Rob's comments on patch 2. Also,
your new Mediatek binding should be in YAML format.
regards
Suman
> 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;
>>>>>
>>>>
>>>
>>
>
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