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Message-ID: <de1f3f33-0a8c-eb87-694c-16ebf2835720@quicinc.com>
Date:   Fri, 1 Jul 2022 12:16:29 +0530
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Subject: Re: [PATCH V15 6/9] mfd: pm8008: Use i2c_new_dummy_device() API
Content-Language: en-US
To:     Lee Jones <lee.jones@linaro.org>
CC:     Bjorn Andersson <bjorn.andersson@linaro.org>,
        Rob Herring <robh+dt@kernel.org>,
        Liam Girdwood <lgirdwood@gmail.com>,
        Mark Brown <broonie@kernel.org>,
        <linux-arm-msm@vger.kernel.org>, <devicetree@vger.kernel.org>,
        <linux-kernel@vger.kernel.org>, <swboyd@chromium.org>,
        <quic_collinsd@quicinc.com>, <quic_subbaram@quicinc.com>,
        <quic_jprakash@quicinc.com>
References: <eccbb030-97f7-3a6c-958e-05adcdca6210@quicinc.com>
 <YrAt6dq6ty9p8d05@google.com>
 <a11732d6-a9b1-7ead-e89a-564a57a7192b@quicinc.com>
 <503f1a8b-eadb-d3a6-6e24-d60437f778b6@quicinc.com>
 <YrlfF+DMlGFsVBdk@google.com>
 <a1c6e3c9-962d-411e-7fbf-9e760e9dc8c0@quicinc.com>
 <Yrqw1YRyCGG+d4GL@google.com>
 <4112b5af-15de-007c-fcc2-c31ce9f9e426@quicinc.com>
 <YrxtXdOsIZ5LKhdV@google.com>
 <f8e70198-d0d8-5500-2869-be9e3a34f3c1@quicinc.com>
 <Yr18M9dzTOWL0m2c@google.com>
From:   "Satya Priya Kakitapalli (Temp)" <quic_c_skakit@quicinc.com>
In-Reply-To: <Yr18M9dzTOWL0m2c@google.com>
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On 6/30/2022 4:04 PM, Lee Jones wrote:
> On Thu, 30 Jun 2022, Satya Priya Kakitapalli (Temp) wrote:
>
>> On 6/29/2022 8:48 PM, Lee Jones wrote:
>>> On Wed, 29 Jun 2022, Satya Priya Kakitapalli (Temp) wrote:
>>>
>>>> On 6/28/2022 1:12 PM, Lee Jones wrote:
>>>>> On Tue, 28 Jun 2022, Satya Priya Kakitapalli (Temp) wrote:
>>>>>
>>>>>> On 6/27/2022 1:11 PM, Lee Jones wrote:
>>>>>>> On Mon, 27 Jun 2022, Satya Priya Kakitapalli (Temp) wrote:
>>>>>>>
>>>>>>>> Hi Lee,
>>>>>>>>
>>>>>>>>
>>>>>>>> On 6/20/2022 4:37 PM, Satya Priya Kakitapalli (Temp) wrote:
>>>>>>>>> On 6/20/2022 1:50 PM, Lee Jones wrote:
>>>>>>>>>> On Mon, 20 Jun 2022, Satya Priya Kakitapalli (Temp) wrote:
>>>>>>>>>>
>>>>>>>>>>> On 6/17/2022 2:27 AM, Lee Jones wrote:
>>>>>>>>>>>> On Tue, 14 Jun 2022, Satya Priya wrote:
>>>>>>>>>>>>
>>>>>>>>>>>>> Use i2c_new_dummy_device() to register pm8008-regulator
>>>>>>>>>>>>> client present at a different address space, instead of
>>>>>>>>>>>>> defining a separate DT node. This avoids calling the probe
>>>>>>>>>>>>> twice for the same chip, once for each client pm8008-infra
>>>>>>>>>>>>> and pm8008-regulator.
>>>>>>>>>>>>>
>>>>>>>>>>>>> As a part of this define pm8008_regmap_init() to do regmap
>>>>>>>>>>>>> init for both the clients and define pm8008_get_regmap() to
>>>>>>>>>>>>> pass the regmap to the regulator driver.
>>>>>>>>>>>>>
>>>>>>>>>>>>> Signed-off-by: Satya Priya <quic_c_skakit@quicinc.com>
>>>>>>>>>>>>> Reviewed-by: Stephen Boyd <swboyd@chromium.org>
>>>>>>>>>>>>> ---
>>>>>>>>>>>>> Changes in V15:
>>>>>>>>>>>>>        - None.
>>>>>>>>>>>>>
>>>>>>>>>>>>> Changes in V14:
>>>>>>>>>>>>>        - None.
>>>>>>>>>>>>>
>>>>>>>>>>>>> Changes in V13:
>>>>>>>>>>>>>        - None.
>>>>>>>>>>>>>
>>>>>>>>>>>>>        drivers/mfd/qcom-pm8008.c       | 34
>>>>>>>>>>>>> ++++++++++++++++++++++++++++++++--
>>>>>>>>>>>>>        include/linux/mfd/qcom_pm8008.h |  9 +++++++++
>>>>>>>>>>>>>        2 files changed, 41 insertions(+), 2 deletions(-)
>>>>>>>>>>>>>        create mode 100644 include/linux/mfd/qcom_pm8008.h
>>>>>>>>>>>>>
>>>>>>>>>>>>> diff --git a/drivers/mfd/qcom-pm8008.c b/drivers/mfd/qcom-pm8008.c
>>>>>>>>>>>>> index 569ffd50..55e2a8e 100644
>>>>>>>>>>>>> --- a/drivers/mfd/qcom-pm8008.c
>>>>>>>>>>>>> +++ b/drivers/mfd/qcom-pm8008.c
>>>>>>>>>>>>> @@ -9,6 +9,7 @@
>>>>>>>>>>>>>        #include <linux/interrupt.h>
>>>>>>>>>>>>>        #include <linux/irq.h>
>>>>>>>>>>>>>        #include <linux/irqdomain.h>
>>>>>>>>>>>>> +#include <linux/mfd/qcom_pm8008.h>
>>>>>>>>>>>>>        #include <linux/module.h>
>>>>>>>>>>>>>        #include <linux/of_device.h>
>>>>>>>>>>>>>        #include <linux/of_platform.h>
>>>>>>>>>>>>> @@ -57,6 +58,7 @@ enum {
>>>>>>>>>>>>>        struct pm8008_data {
>>>>>>>>>>>>>            struct device *dev;
>>>>>>>>>>>>> +    struct regmap *regulators_regmap;
>>>>>>>>>>>>>            int irq;
>>>>>>>>>>>>>            struct regmap_irq_chip_data *irq_data;
>>>>>>>>>>>>>        };
>>>>>>>>>>>>> @@ -150,6 +152,12 @@ static struct regmap_config
>>>>>>>>>>>>> qcom_mfd_regmap_cfg = {
>>>>>>>>>>>>>            .max_register    = 0xFFFF,
>>>>>>>>>>>>>        };
>>>>>>>>>>>>> +struct regmap *pm8008_get_regmap(const struct pm8008_data *chip)
>>>>>>>>>>>>> +{
>>>>>>>>>>>>> +    return chip->regulators_regmap;
>>>>>>>>>>>>> +}
>>>>>>>>>>>>> +EXPORT_SYMBOL_GPL(pm8008_get_regmap);
>>>>>>>>>>>> Seems like abstraction for the sake of abstraction.
>>>>>>>>>>>>
>>>>>>>>>>>> Why not do the dereference inside the regulator driver?
>>>>>>>>>>> To derefer this in the regulator driver, we need to have the
>>>>>>>>>>> pm8008_data
>>>>>>>>>>> struct definition in the qcom_pm8008 header file.
>>>>>>>>>>>
>>>>>>>>>>> I think it doesn't look great to have only that structure in
>>>>>>>>>>> header and all
>>>>>>>>>>> other structs and enum in the mfd driver.
>>>>>>>>>> Then why pass 'pm8008_data' at all?
>>>>>>>>> There is one more option, instead of passing the pm8008_data, we could
>>>>>>>>> pass the pdev->dev.parent and get the pm8008 chip data directly in the
>>>>>>>>> pm8008_get_regmap() like below
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> struct regmap *pm8008_get_regmap(const struct device *dev)
>>>>>>>>>      {
>>>>>>>>>          const struct pm8008_data *chip = dev_get_drvdata(dev);
>>>>>>>>>
>>>>>>>>>          return chip->regulators_regmap;
>>>>>>>>> }
>>>>>>>>> EXPORT_SYMBOL_GPL(pm8008_get_regmap);
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> By doing this we can avoid having declaration of pm8008_data also in the
>>>>>>>>> header. Please let me know if this looks good.
>>>>>>>>>
>>>>>>>> Could you please confirm on this?
>>>>>>>>
>>>>>>>>>> What's preventing you from passing 'regmap'?
>>>>>>>>> I didn't get what you meant here, could you please elaborate a bit?
>>>>>>> Ah yes.  I authored you a patch, but became distracted. Here:
>>>>>>>
>>>>>>> -----8<--------------------8<-------
>>>>>>>
>>>>>>> From: Lee Jones <lee.jones@linaro.org>
>>>>>>>
>>>>>>> mfd: pm8008: Remove driver data structure pm8008_data
>>>>>>> Maintaining a local driver data structure that is never shared
>>>>>>> outside of the core device is an unnecessary complexity.  Half of the
>>>>>>> attributes were not used outside of a single function, one of which
>>>>>>> was not used at all.  The remaining 2 are generic and can be passed
>>>>>>> around as required.
>>>>>> Okay, but we still need to store the regulators_regmap, which is required in
>>>>>> the pm8008 regulator driver. Could we use a global variable for it?
>>>>> Look down ...
>>>>>
>>>>>>> Signed-off-by: Lee Jones <lee.jones@linaro.org>
>>>>>>> ---
>>>>>>>      drivers/mfd/qcom-pm8008.c | 53 ++++++++++++++++++-----------------------------
>>>>>>>      1 file changed, 20 insertions(+), 33 deletions(-)
>>>>>>>
>>>>>>> diff --git a/drivers/mfd/qcom-pm8008.c b/drivers/mfd/qcom-pm8008.c
>>>>>>> index c472d7f8103c4..4b8ff947762f2 100644
>>>>>>> --- a/drivers/mfd/qcom-pm8008.c
>>>>>>> +++ b/drivers/mfd/qcom-pm8008.c
>>>>>>> @@ -54,13 +54,6 @@ enum {
>>>>>>>      #define PM8008_PERIPH_OFFSET(paddr)	(paddr - PM8008_PERIPH_0_BASE)
>>>>>>> -struct pm8008_data {
>>>>>>> -	struct device *dev;
>>>>>>> -	struct regmap *regmap;
>>>>>>> -	int irq;
>>>>>>> -	struct regmap_irq_chip_data *irq_data;
>>>>>>> -};
>>>>>>> -
>>>>>>>      static unsigned int p0_offs[] = {PM8008_PERIPH_OFFSET(PM8008_PERIPH_0_BASE)};
>>>>>>>      static unsigned int p1_offs[] = {PM8008_PERIPH_OFFSET(PM8008_PERIPH_1_BASE)};
>>>>>>>      static unsigned int p2_offs[] = {PM8008_PERIPH_OFFSET(PM8008_PERIPH_2_BASE)};
>>>>>>> @@ -150,7 +143,7 @@ static struct regmap_config qcom_mfd_regmap_cfg = {
>>>>>>>      	.max_register	= 0xFFFF,
>>>>>>>      };
>>>>>>> -static int pm8008_init(struct pm8008_data *chip)
>>>>>>> +static int pm8008_init(struct regmap *regmap)
>>>>>>>      {
>>>>>>>      	int rc;
>>>>>>> @@ -160,34 +153,31 @@ static int pm8008_init(struct pm8008_data *chip)
>>>>>>>      	 * This is required to enable the writing of TYPE registers in
>>>>>>>      	 * regmap_irq_sync_unlock().
>>>>>>>      	 */
>>>>>>> -	rc = regmap_write(chip->regmap,
>>>>>>> -			 (PM8008_TEMP_ALARM_ADDR | INT_SET_TYPE_OFFSET),
>>>>>>> -			 BIT(0));
>>>>>>> +	rc = regmap_write(regmap, (PM8008_TEMP_ALARM_ADDR | INT_SET_TYPE_OFFSET), BIT(0));
>>>>>>>      	if (rc)
>>>>>>>      		return rc;
>>>>>>>      	/* Do the same for GPIO1 and GPIO2 peripherals */
>>>>>>> -	rc = regmap_write(chip->regmap,
>>>>>>> -			 (PM8008_GPIO1_ADDR | INT_SET_TYPE_OFFSET), BIT(0));
>>>>>>> +	rc = regmap_write(regmap, (PM8008_GPIO1_ADDR | INT_SET_TYPE_OFFSET), BIT(0));
>>>>>>>      	if (rc)
>>>>>>>      		return rc;
>>>>>>> -	rc = regmap_write(chip->regmap,
>>>>>>> -			 (PM8008_GPIO2_ADDR | INT_SET_TYPE_OFFSET), BIT(0));
>>>>>>> +	rc = regmap_write(regmap, (PM8008_GPIO2_ADDR | INT_SET_TYPE_OFFSET), BIT(0));
>>>>>>>      	return rc;
>>>>>>>      }
>>>>>>> -static int pm8008_probe_irq_peripherals(struct pm8008_data *chip,
>>>>>>> +static int pm8008_probe_irq_peripherals(struct device *dev,
>>>>>>> +					struct regmap *regmap,
>>>>>>>      					int client_irq)
>>>>>>>      {
>>>>>>>      	int rc, i;
>>>>>>>      	struct regmap_irq_type *type;
>>>>>>>      	struct regmap_irq_chip_data *irq_data;
>>>>>>> -	rc = pm8008_init(chip);
>>>>>>> +	rc = pm8008_init(regmap);
>>>>>>>      	if (rc) {
>>>>>>> -		dev_err(chip->dev, "Init failed: %d\n", rc);
>>>>>>> +		dev_err(dev, "Init failed: %d\n", rc);
>>>>>>>      		return rc;
>>>>>>>      	}
>>>>>>> @@ -207,10 +197,10 @@ static int pm8008_probe_irq_peripherals(struct pm8008_data *chip,
>>>>>>>      				IRQ_TYPE_LEVEL_HIGH | IRQ_TYPE_LEVEL_LOW);
>>>>>>>      	}
>>>>>>> -	rc = devm_regmap_add_irq_chip(chip->dev, chip->regmap, client_irq,
>>>>>>> +	rc = devm_regmap_add_irq_chip(dev, regmap, client_irq,
>>>>>>>      			IRQF_SHARED, 0, &pm8008_irq_chip, &irq_data);
>>>>>>>      	if (rc) {
>>>>>>> -		dev_err(chip->dev, "Failed to add IRQ chip: %d\n", rc);
>>>>>>> +		dev_err(dev, "Failed to add IRQ chip: %d\n", rc);
>>>>>>>      		return rc;
>>>>>>>      	}
>>>>>>> @@ -220,26 +210,23 @@ static int pm8008_probe_irq_peripherals(struct pm8008_data *chip,
>>>>>>>      static int pm8008_probe(struct i2c_client *client)
>>>>>>>      {
>>>>>>>      	int rc;
>>>>>>> -	struct pm8008_data *chip;
>>>>>>> -
>>>>>>> -	chip = devm_kzalloc(&client->dev, sizeof(*chip), GFP_KERNEL);
>>>>>>> -	if (!chip)
>>>>>>> -		return -ENOMEM;
>>>>>>> +	struct device *dev;
>>>>>>> +	struct regmap *regmap;
>>>>>>> -	chip->dev = &client->dev;
>>>>>>> -	chip->regmap = devm_regmap_init_i2c(client, &qcom_mfd_regmap_cfg);
>>>>>>> -	if (!chip->regmap)
>>>>>>> +	dev = &client->dev;
>>>>>>> +	regmap = devm_regmap_init_i2c(client, &qcom_mfd_regmap_cfg);
>>>>>>> +	if (!regmap)
>>>>>>>      		return -ENODEV;
>>>>>>> -	i2c_set_clientdata(client, chip);
>>>>>>> +	i2c_set_clientdata(client, regmap);
>>>>> Here ^
>>>> I have added a dummy device and set the client data by passing regmap, see
>>>> below:
>>>>
>>>> +       regulators_client = i2c_new_dummy_device(client->adapter,
>>>> client->addr + 1);
>>>> +       if (IS_ERR(regulators_client)) {
>>>> +               dev_err(dev, "can't attach client\n");
>>>> +               return PTR_ERR(regulators_client);
>>>> +       }
>>>> +
>>>> +       regulators_regmap = devm_regmap_init_i2c(regulators_client,
>>>> &qcom_mfd_regmap_cfg[1]);
>>>> +       if (!regmap)
>>>> +               return -ENODEV;
>>>> +
>>>> +       i2c_set_clientdata(client, regulators_regmap);
>>>>
>>>> Now if i try to get this regmap from regulator driver by doing
>>>>
>>>> struct regmap *regmap = dev_get_drvdata(pdev->dev.parent);
>>>>
>>>> it still gets me the regmap of pm8008@8 device and not the regulator device
>>>> regmap (0x9). Not sure if I'm missing something here.
>>> So you need to pass 2 regmap pointers?
>>>
>>> If you need to pass more than one item to the child devices, you do
>>> need to use a struct for that.
>> I need to pass only one regmap out of the two, but i am not able to retrieve
>> the correct regmap simply by doing i2c_set_clientdata
>>
>> probably because we are having all the child nodes under same DT node and
>> thus not able to distinguish based on the dev pointer
> You can only pull out (get) the pointer that you put in (set).
>
> Unless you over-wrote it later in the thread of execution, you are
> pulling out whatever regulators_regmap happens to be.
>
> Is qcom_mfd_regmap_cfg[1] definitely the one you want?


Yes, I need qcom_mfd_regmap_cfg[1]

Pasting code snippet for reference:

static struct regmap_config qcom_mfd_regmap_cfg[2] = {
      {

          .name = "infra",
          .reg_bits   = 16,
          .val_bits   = 8,
          .max_register   = 0xFFFF,
      },
      {
          .name = "regulators",
          .reg_bits   = 16,
          .val_bits   = 8,
          .max_register   = 0xFFFF,
      },

};


Inside pm8008_probe:


      regmap = devm_regmap_init_i2c(client, &qcom_mfd_regmap_cfg[0]);
      if (!regmap)
          return -ENODEV;

      i2c_set_clientdata(client, regmap);


      regulators_client = i2c_new_dummy_device(client->adapter, 
client->addr + 1);
      if (IS_ERR(regulators_client)) {
          dev_err(dev, "can't attach client\n");
          return PTR_ERR(regulators_client);
      }

      regulators_regmap = devm_regmap_init_i2c(regulators_client, 
&qcom_mfd_regmap_cfg[1]);
      if (!regmap)
          return -ENODEV;

      i2c_set_clientdata(regulators_client, regulators_regmap);

In qcom-pm8008-regulator.c I tried to get the regmap using


dev_get_regmap(pdev->dev.parent, "regulators");