diff mbox series

[3/3] hwmon: (pmbus/tda38640) Add workaround for bug in SVID mode

Message ID 20230725114030.1860571-3-Naresh.Solanki@9elements.com (mailing list archive)
State Superseded
Headers show
Series [1/3] dt-bindings: hwmon: Add Infineon TDA38640 | expand

Commit Message

Naresh Solanki July 25, 2023, 11:40 a.m. UTC 
From: Patrick Rudolph <patrick.rudolph@9elements.com>

The TDA38640 supports two operating modes to set the output voltage:
- PMBUS
- SVID

Due to an undocumented bug the regulator cannot be enabled using BIT7
of OPERATION(01h) register when in SVID mode.
It works when in PMBUS mode. In SVID mode the regulator only cares
about the ENABLE pin.

Add a workaround that needs the ENABLE pin to be left floating or
tied to a fixed level. The DT must contain the newly introduced
property 'infineon,en-pin-fixed-level' to enable this workaround.

The workaround will map the PB_OPERATION_CONTROL_ON bit to the
PB_ON_OFF_CONFIG_EN_PIN_REQ bit of the ON_OFF_CONFIG register.
In combination with the fixed level on the ENABLE pin the regulator
can be controlled as expected.

Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
Signed-off-by: Naresh Solanki <Naresh.Solanki@9elements.com>
---
 drivers/hwmon/pmbus/tda38640.c | 95 +++++++++++++++++++++++++++++++++-
 1 file changed, 93 insertions(+), 2 deletions(-)

Comments

Guenter Roeck July 25, 2023, 2:21 p.m. UTC | #1 
On 7/25/23 04:40, Naresh Solanki wrote:
> From: Patrick Rudolph <patrick.rudolph@9elements.com>
> 
> The TDA38640 supports two operating modes to set the output voltage:
> - PMBUS
> - SVID
> 
> Due to an undocumented bug the regulator cannot be enabled using BIT7
> of OPERATION(01h) register when in SVID mode.
> It works when in PMBUS mode. In SVID mode the regulator only cares
> about the ENABLE pin.
> 
> Add a workaround that needs the ENABLE pin to be left floating or
> tied to a fixed level. The DT must contain the newly introduced
> property 'infineon,en-pin-fixed-level' to enable this workaround.
> 

Why is that property even needed ? Isn't the workaround always (and only)
required if the chip is in SVID mode ?

Guenter

> The workaround will map the PB_OPERATION_CONTROL_ON bit to the
> PB_ON_OFF_CONFIG_EN_PIN_REQ bit of the ON_OFF_CONFIG register.
> In combination with the fixed level on the ENABLE pin the regulator
> can be controlled as expected.
> 
> Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
> Signed-off-by: Naresh Solanki <Naresh.Solanki@9elements.com>
> ---
>   drivers/hwmon/pmbus/tda38640.c | 95 +++++++++++++++++++++++++++++++++-
>   1 file changed, 93 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/hwmon/pmbus/tda38640.c b/drivers/hwmon/pmbus/tda38640.c
> index 450b0273fb59..9d3b89d9845c 100644
> --- a/drivers/hwmon/pmbus/tda38640.c
> +++ b/drivers/hwmon/pmbus/tda38640.c
> @@ -18,6 +18,72 @@ static const struct regulator_desc __maybe_unused tda38640_reg_desc[] = {
>   	PMBUS_REGULATOR("vout", 0),
>   };
>   
> +struct tda38640_data {
> +	struct pmbus_driver_info info;
> +	u32 en_pin_lvl;
> +};
> +
> +#define to_tda38640_data(x)  container_of(x, struct tda38640_data, info)
> +
> +/*
> + * Map PB_ON_OFF_CONFIG_POLARITY_HIGH to PB_OPERATION_CONTROL_ON.
> + */
> +static int tda38640_read_byte_data(struct i2c_client *client, int page, int reg)
> +{
> +	const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
> +	struct tda38640_data *data = to_tda38640_data(info);
> +	int ret, on_off_config, enabled;
> +
> +	if (reg != PMBUS_OPERATION)
> +		return -ENODATA;
> +
> +	ret = pmbus_read_byte_data(client, page, reg);
> +	if (ret < 0)
> +		return ret;
> +
> +	on_off_config = pmbus_read_byte_data(client, page,
> +					     PMBUS_ON_OFF_CONFIG);
> +	if (on_off_config < 0)
> +		return on_off_config;
> +
> +	enabled = !!(on_off_config & PB_ON_OFF_CONFIG_POLARITY_HIGH);
> +
> +	enabled ^= data->en_pin_lvl;
> +	if (enabled)
> +		ret &= ~PB_OPERATION_CONTROL_ON;
> +	else
> +		ret |= PB_OPERATION_CONTROL_ON;
> +
> +	return ret;
> +}
> +
> +/*
> + * Map PB_OPERATION_CONTROL_ON to PB_ON_OFF_CONFIG_POLARITY_HIGH.
> + */
> +static int tda38640_write_byte_data(struct i2c_client *client, int page,
> +				    int reg, u8 byte)
> +{
> +	const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
> +	struct tda38640_data *data = to_tda38640_data(info);
> +	int enable, ret;
> +
> +	if (reg != PMBUS_OPERATION)
> +		return -ENODATA;
> +
> +	enable = !!(byte & PB_OPERATION_CONTROL_ON);
> +
> +	byte &= ~PB_OPERATION_CONTROL_ON;
> +	ret = pmbus_write_byte_data(client, page, reg, byte);
> +	if (ret < 0)
> +		return ret;
> +
> +	enable ^= data->en_pin_lvl;
> +
> +	return pmbus_update_byte_data(client, page, PMBUS_ON_OFF_CONFIG,
> +				      PB_ON_OFF_CONFIG_POLARITY_HIGH,
> +				      enable ? 0 : PB_ON_OFF_CONFIG_POLARITY_HIGH);
> +}
> +
>   static struct pmbus_driver_info tda38640_info = {
>   	.pages = 1,
>   	.format[PSC_VOLTAGE_IN] = linear,
> @@ -26,7 +92,6 @@ static struct pmbus_driver_info tda38640_info = {
>   	.format[PSC_CURRENT_IN] = linear,
>   	.format[PSC_POWER] = linear,
>   	.format[PSC_TEMPERATURE] = linear,
> -
>   	.func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_STATUS_INPUT
>   	    | PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP
>   	    | PMBUS_HAVE_IIN
> @@ -41,7 +106,33 @@ static struct pmbus_driver_info tda38640_info = {
>   
>   static int tda38640_probe(struct i2c_client *client)
>   {
> -	return pmbus_do_probe(client, &tda38640_info);
> +	struct device *dev = &client->dev;
> +	struct device_node *np = dev_of_node(dev);
> +	struct tda38640_data *data;
> +
> +	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
> +	if (!data)
> +		return -ENOMEM;
> +	memcpy(&data->info, &tda38640_info, sizeof(tda38640_info));
> +
> +	if (!CONFIG_SENSORS_TDA38640_REGULATOR || !np ||
> +	    of_property_read_u32(np, "infineon,en-pin-fixed-level", &data->en_pin_lvl))
> +		return pmbus_do_probe(client, &data->info);
> +
> +	/*
> +	 * Apply ON_OFF_CONFIG workaround as enabling the regulator using the
> +	 * OPERATION register doesn't work in SVID mode.
> +	 */
> +	data->info.read_byte_data = tda38640_read_byte_data;
> +	data->info.write_byte_data = tda38640_write_byte_data;
> +	/*
> +	 * One should configure PMBUS_ON_OFF_CONFIG here, but
> +	 * PB_ON_OFF_CONFIG_POWERUP_CONTROL, PB_ON_OFF_CONFIG_EN_PIN_REQ and
> +	 * PB_ON_OFF_CONFIG_EN_PIN_REQ are ignored by the device.
> +	 * Only PB_ON_OFF_CONFIG_POLARITY_HIGH has an effect.
> +	 */
> +
> +	return pmbus_do_probe(client, &data->info);
>   }
>   
>   static const struct i2c_device_id tda38640_id[] = {
kernel test robot July 25, 2023, 4:19 p.m. UTC | #2 
Hi Naresh,

kernel test robot noticed the following build errors:

[auto build test ERROR on 55612007f16b5d7b1fb83a7b0f5bb686829db7c7]

url:    https://github.com/intel-lab-lkp/linux/commits/Naresh-Solanki/hwmon-pmbus-Add-ON_OFF_CONFIG-register-bits/20230725-194318
base:   55612007f16b5d7b1fb83a7b0f5bb686829db7c7
patch link:    https://lore.kernel.org/r/20230725114030.1860571-3-Naresh.Solanki%409elements.com
patch subject: [PATCH 3/3] hwmon: (pmbus/tda38640) Add workaround for bug in SVID mode
config: riscv-randconfig-r042-20230725 (https://download.01.org/0day-ci/archive/20230726/202307260005.nDX1xks3-lkp@intel.com/config)
compiler: riscv32-linux-gcc (GCC) 12.3.0
reproduce: (https://download.01.org/0day-ci/archive/20230726/202307260005.nDX1xks3-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202307260005.nDX1xks3-lkp@intel.com/

All errors (new ones prefixed by >>):

   drivers/hwmon/pmbus/tda38640.c: In function 'tda38640_probe':
>> drivers/hwmon/pmbus/tda38640.c:118:14: error: 'CONFIG_SENSORS_TDA38640_REGULATOR' undeclared (first use in this function); did you mean 'CONFIG_SENSORS_TDA38640'?
     118 |         if (!CONFIG_SENSORS_TDA38640_REGULATOR || !np ||
         |              ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
         |              CONFIG_SENSORS_TDA38640
   drivers/hwmon/pmbus/tda38640.c:118:14: note: each undeclared identifier is reported only once for each function it appears in


vim +118 drivers/hwmon/pmbus/tda38640.c

   106	
   107	static int tda38640_probe(struct i2c_client *client)
   108	{
   109		struct device *dev = &client->dev;
   110		struct device_node *np = dev_of_node(dev);
   111		struct tda38640_data *data;
   112	
   113		data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
   114		if (!data)
   115			return -ENOMEM;
   116		memcpy(&data->info, &tda38640_info, sizeof(tda38640_info));
   117	
 > 118		if (!CONFIG_SENSORS_TDA38640_REGULATOR || !np ||
   119		    of_property_read_u32(np, "infineon,en-pin-fixed-level", &data->en_pin_lvl))
   120			return pmbus_do_probe(client, &data->info);
   121	
   122		/*
   123		 * Apply ON_OFF_CONFIG workaround as enabling the regulator using the
   124		 * OPERATION register doesn't work in SVID mode.
   125		 */
   126		data->info.read_byte_data = tda38640_read_byte_data;
   127		data->info.write_byte_data = tda38640_write_byte_data;
   128		/*
   129		 * One should configure PMBUS_ON_OFF_CONFIG here, but
   130		 * PB_ON_OFF_CONFIG_POWERUP_CONTROL, PB_ON_OFF_CONFIG_EN_PIN_REQ and
   131		 * PB_ON_OFF_CONFIG_EN_PIN_REQ are ignored by the device.
   132		 * Only PB_ON_OFF_CONFIG_POLARITY_HIGH has an effect.
   133		 */
   134	
   135		return pmbus_do_probe(client, &data->info);
   136	}
   137
kernel test robot July 25, 2023, 6:54 p.m. UTC | #3 
Hi Naresh,

kernel test robot noticed the following build errors:

[auto build test ERROR on 55612007f16b5d7b1fb83a7b0f5bb686829db7c7]

url:    https://github.com/intel-lab-lkp/linux/commits/Naresh-Solanki/hwmon-pmbus-Add-ON_OFF_CONFIG-register-bits/20230725-194318
base:   55612007f16b5d7b1fb83a7b0f5bb686829db7c7
patch link:    https://lore.kernel.org/r/20230725114030.1860571-3-Naresh.Solanki%409elements.com
patch subject: [PATCH 3/3] hwmon: (pmbus/tda38640) Add workaround for bug in SVID mode
config: x86_64-randconfig-x014-20230725 (https://download.01.org/0day-ci/archive/20230726/202307260241.BetLbnxd-lkp@intel.com/config)
compiler: clang version 16.0.4 (https://github.com/llvm/llvm-project.git ae42196bc493ffe877a7e3dff8be32035dea4d07)
reproduce: (https://download.01.org/0day-ci/archive/20230726/202307260241.BetLbnxd-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202307260241.BetLbnxd-lkp@intel.com/

All errors (new ones prefixed by >>):

>> drivers/hwmon/pmbus/tda38640.c:118:7: error: use of undeclared identifier 'CONFIG_SENSORS_TDA38640_REGULATOR'
           if (!CONFIG_SENSORS_TDA38640_REGULATOR || !np ||
                ^
   1 error generated.


vim +/CONFIG_SENSORS_TDA38640_REGULATOR +118 drivers/hwmon/pmbus/tda38640.c

   106	
   107	static int tda38640_probe(struct i2c_client *client)
   108	{
   109		struct device *dev = &client->dev;
   110		struct device_node *np = dev_of_node(dev);
   111		struct tda38640_data *data;
   112	
   113		data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
   114		if (!data)
   115			return -ENOMEM;
   116		memcpy(&data->info, &tda38640_info, sizeof(tda38640_info));
   117	
 > 118		if (!CONFIG_SENSORS_TDA38640_REGULATOR || !np ||
   119		    of_property_read_u32(np, "infineon,en-pin-fixed-level", &data->en_pin_lvl))
   120			return pmbus_do_probe(client, &data->info);
   121	
   122		/*
   123		 * Apply ON_OFF_CONFIG workaround as enabling the regulator using the
   124		 * OPERATION register doesn't work in SVID mode.
   125		 */
   126		data->info.read_byte_data = tda38640_read_byte_data;
   127		data->info.write_byte_data = tda38640_write_byte_data;
   128		/*
   129		 * One should configure PMBUS_ON_OFF_CONFIG here, but
   130		 * PB_ON_OFF_CONFIG_POWERUP_CONTROL, PB_ON_OFF_CONFIG_EN_PIN_REQ and
   131		 * PB_ON_OFF_CONFIG_EN_PIN_REQ are ignored by the device.
   132		 * Only PB_ON_OFF_CONFIG_POLARITY_HIGH has an effect.
   133		 */
   134	
   135		return pmbus_do_probe(client, &data->info);
   136	}
   137
Naresh Solanki July 26, 2023, 12:22 p.m. UTC | #4 
Hi Guenter,

On 25-07-2023 07:51 pm, Guenter Roeck wrote:
> On 7/25/23 04:40, Naresh Solanki wrote:
>> From: Patrick Rudolph <patrick.rudolph@9elements.com>
>>
>> The TDA38640 supports two operating modes to set the output voltage:
>> - PMBUS
>> - SVID
>>
>> Due to an undocumented bug the regulator cannot be enabled using BIT7
>> of OPERATION(01h) register when in SVID mode.
>> It works when in PMBUS mode. In SVID mode the regulator only cares
>> about the ENABLE pin.
>>
>> Add a workaround that needs the ENABLE pin to be left floating or
>> tied to a fixed level. The DT must contain the newly introduced
>> property 'infineon,en-pin-fixed-level' to enable this workaround.
>>
> 
> Why is that property even needed ? Isn't the workaround always (and only)
> required if the chip is in SVID mode ?
Will add below function to detect SVID mode.
static bool svid_mode(struct i2c_client *client)
{
	/* PMBUS_MFR_READ(0xD0) + Address */
	u8 write_buf[] = {0xd0, 0x44, 0x00};
	u8 read_buf[2];
	int ret;

	struct i2c_msg msgs[2] = {
		{
			.addr = client->addr,
			.flags = 0,
			.buf = write_buf,
			.len = sizeof(write_buf),
		},
		{
			.addr = client->addr,
			.flags = I2C_M_RD,
			.buf = read_buf,
			.len = sizeof(read_buf),
		}
	};

	ret = i2c_transfer(client->adapter, msgs, 2);

	if (ret < 0) {
		dev_err(&client->dev, "%s:%d i2c_transfer failed. %d", __func__, 
__LINE__, ret);
		return ret;
	}
	/* 0x44[15] determines PMBus Operating Mode */
	return !!(read_buf[1] & BIT(7));
}

Based on svid_mode will init accordingly:
	if (!IS_ENABLED(CONFIG_SENSORS_TDA38640_REGULATOR) || !np || 
!svid_mode(client))
		return pmbus_do_probe(client, &data->info);

	dev_dbg(&client->dev, "SVID mode");

Regards,
Naresh
> 
> Guenter
> 
>> The workaround will map the PB_OPERATION_CONTROL_ON bit to the
>> PB_ON_OFF_CONFIG_EN_PIN_REQ bit of the ON_OFF_CONFIG register.
>> In combination with the fixed level on the ENABLE pin the regulator
>> can be controlled as expected.
>>
>> Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
>> Signed-off-by: Naresh Solanki <Naresh.Solanki@9elements.com>
>> ---
>>   drivers/hwmon/pmbus/tda38640.c | 95 +++++++++++++++++++++++++++++++++-
>>   1 file changed, 93 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/hwmon/pmbus/tda38640.c 
>> b/drivers/hwmon/pmbus/tda38640.c
>> index 450b0273fb59..9d3b89d9845c 100644
>> --- a/drivers/hwmon/pmbus/tda38640.c
>> +++ b/drivers/hwmon/pmbus/tda38640.c
>> @@ -18,6 +18,72 @@ static const struct regulator_desc __maybe_unused 
>> tda38640_reg_desc[] = {
>>       PMBUS_REGULATOR("vout", 0),
>>   };
>> +struct tda38640_data {
>> +    struct pmbus_driver_info info;
>> +    u32 en_pin_lvl;
>> +};
>> +
>> +#define to_tda38640_data(x)  container_of(x, struct tda38640_data, info)
>> +
>> +/*
>> + * Map PB_ON_OFF_CONFIG_POLARITY_HIGH to PB_OPERATION_CONTROL_ON.
>> + */
>> +static int tda38640_read_byte_data(struct i2c_client *client, int 
>> page, int reg)
>> +{
>> +    const struct pmbus_driver_info *info = 
>> pmbus_get_driver_info(client);
>> +    struct tda38640_data *data = to_tda38640_data(info);
>> +    int ret, on_off_config, enabled;
>> +
>> +    if (reg != PMBUS_OPERATION)
>> +        return -ENODATA;
>> +
>> +    ret = pmbus_read_byte_data(client, page, reg);
>> +    if (ret < 0)
>> +        return ret;
>> +
>> +    on_off_config = pmbus_read_byte_data(client, page,
>> +                         PMBUS_ON_OFF_CONFIG);
>> +    if (on_off_config < 0)
>> +        return on_off_config;
>> +
>> +    enabled = !!(on_off_config & PB_ON_OFF_CONFIG_POLARITY_HIGH);
>> +
>> +    enabled ^= data->en_pin_lvl;
>> +    if (enabled)
>> +        ret &= ~PB_OPERATION_CONTROL_ON;
>> +    else
>> +        ret |= PB_OPERATION_CONTROL_ON;
>> +
>> +    return ret;
>> +}
>> +
>> +/*
>> + * Map PB_OPERATION_CONTROL_ON to PB_ON_OFF_CONFIG_POLARITY_HIGH.
>> + */
>> +static int tda38640_write_byte_data(struct i2c_client *client, int page,
>> +                    int reg, u8 byte)
>> +{
>> +    const struct pmbus_driver_info *info = 
>> pmbus_get_driver_info(client);
>> +    struct tda38640_data *data = to_tda38640_data(info);
>> +    int enable, ret;
>> +
>> +    if (reg != PMBUS_OPERATION)
>> +        return -ENODATA;
>> +
>> +    enable = !!(byte & PB_OPERATION_CONTROL_ON);
>> +
>> +    byte &= ~PB_OPERATION_CONTROL_ON;
>> +    ret = pmbus_write_byte_data(client, page, reg, byte);
>> +    if (ret < 0)
>> +        return ret;
>> +
>> +    enable ^= data->en_pin_lvl;
>> +
>> +    return pmbus_update_byte_data(client, page, PMBUS_ON_OFF_CONFIG,
>> +                      PB_ON_OFF_CONFIG_POLARITY_HIGH,
>> +                      enable ? 0 : PB_ON_OFF_CONFIG_POLARITY_HIGH);
>> +}
>> +
>>   static struct pmbus_driver_info tda38640_info = {
>>       .pages = 1,
>>       .format[PSC_VOLTAGE_IN] = linear,
>> @@ -26,7 +92,6 @@ static struct pmbus_driver_info tda38640_info = {
>>       .format[PSC_CURRENT_IN] = linear,
>>       .format[PSC_POWER] = linear,
>>       .format[PSC_TEMPERATURE] = linear,
>> -
>>       .func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_STATUS_INPUT
>>           | PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP
>>           | PMBUS_HAVE_IIN
>> @@ -41,7 +106,33 @@ static struct pmbus_driver_info tda38640_info = {
>>   static int tda38640_probe(struct i2c_client *client)
>>   {
>> -    return pmbus_do_probe(client, &tda38640_info);
>> +    struct device *dev = &client->dev;
>> +    struct device_node *np = dev_of_node(dev);
>> +    struct tda38640_data *data;
>> +
>> +    data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
>> +    if (!data)
>> +        return -ENOMEM;
>> +    memcpy(&data->info, &tda38640_info, sizeof(tda38640_info));
>> +
>> +    if (!CONFIG_SENSORS_TDA38640_REGULATOR || !np ||
>> +        of_property_read_u32(np, "infineon,en-pin-fixed-level", 
>> &data->en_pin_lvl))
>> +        return pmbus_do_probe(client, &data->info);
>> +
>> +    /*
>> +     * Apply ON_OFF_CONFIG workaround as enabling the regulator using 
>> the
>> +     * OPERATION register doesn't work in SVID mode.
>> +     */
>> +    data->info.read_byte_data = tda38640_read_byte_data;
>> +    data->info.write_byte_data = tda38640_write_byte_data;
>> +    /*
>> +     * One should configure PMBUS_ON_OFF_CONFIG here, but
>> +     * PB_ON_OFF_CONFIG_POWERUP_CONTROL, PB_ON_OFF_CONFIG_EN_PIN_REQ and
>> +     * PB_ON_OFF_CONFIG_EN_PIN_REQ are ignored by the device.
>> +     * Only PB_ON_OFF_CONFIG_POLARITY_HIGH has an effect.
>> +     */
>> +
>> +    return pmbus_do_probe(client, &data->info);
>>   }
>>   static const struct i2c_device_id tda38640_id[] = {
>
Guenter Roeck July 26, 2023, 2:19 p.m. UTC | #5 
On 7/26/23 05:22, Naresh Solanki wrote:
> Hi Guenter,
> 
> On 25-07-2023 07:51 pm, Guenter Roeck wrote:
>> On 7/25/23 04:40, Naresh Solanki wrote:
>>> From: Patrick Rudolph <patrick.rudolph@9elements.com>
>>>
>>> The TDA38640 supports two operating modes to set the output voltage:
>>> - PMBUS
>>> - SVID
>>>
>>> Due to an undocumented bug the regulator cannot be enabled using BIT7
>>> of OPERATION(01h) register when in SVID mode.
>>> It works when in PMBUS mode. In SVID mode the regulator only cares
>>> about the ENABLE pin.
>>>
>>> Add a workaround that needs the ENABLE pin to be left floating or
>>> tied to a fixed level. The DT must contain the newly introduced
>>> property 'infineon,en-pin-fixed-level' to enable this workaround.
>>>
>>
>> Why is that property even needed ? Isn't the workaround always (and only)
>> required if the chip is in SVID mode ?
> Will add below function to detect SVID mode.
> static bool svid_mode(struct i2c_client *client)
> {
>      /* PMBUS_MFR_READ(0xD0) + Address */
>      u8 write_buf[] = {0xd0, 0x44, 0x00};
>      u8 read_buf[2];
>      int ret;
> 
>      struct i2c_msg msgs[2] = {
>          {
>              .addr = client->addr,
>              .flags = 0,
>              .buf = write_buf,
>              .len = sizeof(write_buf),
>          },
>          {
>              .addr = client->addr,
>              .flags = I2C_M_RD,
>              .buf = read_buf,
>              .len = sizeof(read_buf),
>          }
>      };
> 
>      ret = i2c_transfer(client->adapter, msgs, 2);
> 
drop empty line

>      if (ret < 0) {
>          dev_err(&client->dev, "%s:%d i2c_transfer failed. %d", __func__, __LINE__, ret);
>          return ret;

Return type is bool.

>      }
>      /* 0x44[15] determines PMBus Operating Mode */
>      return !!(read_buf[1] & BIT(7));
> }
> 

"The application note AN_2203_PL12_2204_210835 having information on the register map
  of TDA38640 is under review. The document will be uploaded to the Infineon website
  once the review is completed."

How annoying. Is that really the only way to get that information ?

> Based on svid_mode will init accordingly:
>      if (!IS_ENABLED(CONFIG_SENSORS_TDA38640_REGULATOR) || !np || !svid_mode(client))
>          return pmbus_do_probe(client, &data->info);
> 

This is unnecessary complexity. Just add the local read/write
commands and be done with it.

	if (svid_mode(client)) {
		data->info.read_byte_data = tda38640_read_byte_data;
	  	data->info.write_byte_data = tda38640_write_byte_data;
	}

though it would be useful to error check the return value.

	ret = svid_mode();
	if (ret < 0)
		return ret;
	if (ret) {
		/* consider adding comments here */
		data->info.read_byte_data = tda38640_read_byte_data;
	  	data->info.write_byte_data = tda38640_write_byte_data;
	}

Guenter

>      dev_dbg(&client->dev, "SVID mode");
> 
> Regards,
> Naresh
>>
>> Guenter
>>
>>> The workaround will map the PB_OPERATION_CONTROL_ON bit to the
>>> PB_ON_OFF_CONFIG_EN_PIN_REQ bit of the ON_OFF_CONFIG register.
>>> In combination with the fixed level on the ENABLE pin the regulator
>>> can be controlled as expected.
>>>
>>> Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
>>> Signed-off-by: Naresh Solanki <Naresh.Solanki@9elements.com>
>>> ---
>>>   drivers/hwmon/pmbus/tda38640.c | 95 +++++++++++++++++++++++++++++++++-
>>>   1 file changed, 93 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/drivers/hwmon/pmbus/tda38640.c b/drivers/hwmon/pmbus/tda38640.c
>>> index 450b0273fb59..9d3b89d9845c 100644
>>> --- a/drivers/hwmon/pmbus/tda38640.c
>>> +++ b/drivers/hwmon/pmbus/tda38640.c
>>> @@ -18,6 +18,72 @@ static const struct regulator_desc __maybe_unused tda38640_reg_desc[] = {
>>>       PMBUS_REGULATOR("vout", 0),
>>>   };
>>> +struct tda38640_data {
>>> +    struct pmbus_driver_info info;
>>> +    u32 en_pin_lvl;
>>> +};
>>> +
>>> +#define to_tda38640_data(x)  container_of(x, struct tda38640_data, info)
>>> +
>>> +/*
>>> + * Map PB_ON_OFF_CONFIG_POLARITY_HIGH to PB_OPERATION_CONTROL_ON.
>>> + */
>>> +static int tda38640_read_byte_data(struct i2c_client *client, int page, int reg)
>>> +{
>>> +    const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
>>> +    struct tda38640_data *data = to_tda38640_data(info);
>>> +    int ret, on_off_config, enabled;
>>> +
>>> +    if (reg != PMBUS_OPERATION)
>>> +        return -ENODATA;
>>> +
>>> +    ret = pmbus_read_byte_data(client, page, reg);
>>> +    if (ret < 0)
>>> +        return ret;
>>> +
>>> +    on_off_config = pmbus_read_byte_data(client, page,
>>> +                         PMBUS_ON_OFF_CONFIG);
>>> +    if (on_off_config < 0)
>>> +        return on_off_config;
>>> +
>>> +    enabled = !!(on_off_config & PB_ON_OFF_CONFIG_POLARITY_HIGH);
>>> +
>>> +    enabled ^= data->en_pin_lvl;
>>> +    if (enabled)
>>> +        ret &= ~PB_OPERATION_CONTROL_ON;
>>> +    else
>>> +        ret |= PB_OPERATION_CONTROL_ON;
>>> +
>>> +    return ret;
>>> +}
>>> +
>>> +/*
>>> + * Map PB_OPERATION_CONTROL_ON to PB_ON_OFF_CONFIG_POLARITY_HIGH.
>>> + */
>>> +static int tda38640_write_byte_data(struct i2c_client *client, int page,
>>> +                    int reg, u8 byte)
>>> +{
>>> +    const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
>>> +    struct tda38640_data *data = to_tda38640_data(info);
>>> +    int enable, ret;
>>> +
>>> +    if (reg != PMBUS_OPERATION)
>>> +        return -ENODATA;
>>> +
>>> +    enable = !!(byte & PB_OPERATION_CONTROL_ON);
>>> +
>>> +    byte &= ~PB_OPERATION_CONTROL_ON;
>>> +    ret = pmbus_write_byte_data(client, page, reg, byte);
>>> +    if (ret < 0)
>>> +        return ret;
>>> +
>>> +    enable ^= data->en_pin_lvl;
>>> +
>>> +    return pmbus_update_byte_data(client, page, PMBUS_ON_OFF_CONFIG,
>>> +                      PB_ON_OFF_CONFIG_POLARITY_HIGH,
>>> +                      enable ? 0 : PB_ON_OFF_CONFIG_POLARITY_HIGH);
>>> +}
>>> +
>>>   static struct pmbus_driver_info tda38640_info = {
>>>       .pages = 1,
>>>       .format[PSC_VOLTAGE_IN] = linear,
>>> @@ -26,7 +92,6 @@ static struct pmbus_driver_info tda38640_info = {
>>>       .format[PSC_CURRENT_IN] = linear,
>>>       .format[PSC_POWER] = linear,
>>>       .format[PSC_TEMPERATURE] = linear,
>>> -
>>>       .func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_STATUS_INPUT
>>>           | PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP
>>>           | PMBUS_HAVE_IIN
>>> @@ -41,7 +106,33 @@ static struct pmbus_driver_info tda38640_info = {
>>>   static int tda38640_probe(struct i2c_client *client)
>>>   {
>>> -    return pmbus_do_probe(client, &tda38640_info);
>>> +    struct device *dev = &client->dev;
>>> +    struct device_node *np = dev_of_node(dev);
>>> +    struct tda38640_data *data;
>>> +
>>> +    data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
>>> +    if (!data)
>>> +        return -ENOMEM;
>>> +    memcpy(&data->info, &tda38640_info, sizeof(tda38640_info));
>>> +
>>> +    if (!CONFIG_SENSORS_TDA38640_REGULATOR || !np ||
>>> +        of_property_read_u32(np, "infineon,en-pin-fixed-level", &data->en_pin_lvl))
>>> +        return pmbus_do_probe(client, &data->info);
>>> +
>>> +    /*
>>> +     * Apply ON_OFF_CONFIG workaround as enabling the regulator using the
>>> +     * OPERATION register doesn't work in SVID mode.
>>> +     */
>>> +    data->info.read_byte_data = tda38640_read_byte_data;
>>> +    data->info.write_byte_data = tda38640_write_byte_data;
>>> +    /*
>>> +     * One should configure PMBUS_ON_OFF_CONFIG here, but
>>> +     * PB_ON_OFF_CONFIG_POWERUP_CONTROL, PB_ON_OFF_CONFIG_EN_PIN_REQ and
>>> +     * PB_ON_OFF_CONFIG_EN_PIN_REQ are ignored by the device.
>>> +     * Only PB_ON_OFF_CONFIG_POLARITY_HIGH has an effect.
>>> +     */
>>> +
>>> +    return pmbus_do_probe(client, &data->info);
>>>   }
>>>   static const struct i2c_device_id tda38640_id[] = {
>>
Naresh Solanki July 27, 2023, 8:30 a.m. UTC | #6 
Hi Guenter,


On Wed, 26 Jul 2023 at 19:49, Guenter Roeck <linux@roeck-us.net> wrote:
>
> On 7/26/23 05:22, Naresh Solanki wrote:
> > Hi Guenter,
> >
> > On 25-07-2023 07:51 pm, Guenter Roeck wrote:
> >> On 7/25/23 04:40, Naresh Solanki wrote:
> >>> From: Patrick Rudolph <patrick.rudolph@9elements.com>
> >>>
> >>> The TDA38640 supports two operating modes to set the output voltage:
> >>> - PMBUS
> >>> - SVID
> >>>
> >>> Due to an undocumented bug the regulator cannot be enabled using BIT7
> >>> of OPERATION(01h) register when in SVID mode.
> >>> It works when in PMBUS mode. In SVID mode the regulator only cares
> >>> about the ENABLE pin.
> >>>
> >>> Add a workaround that needs the ENABLE pin to be left floating or
> >>> tied to a fixed level. The DT must contain the newly introduced
> >>> property 'infineon,en-pin-fixed-level' to enable this workaround.
> >>>
> >>
> >> Why is that property even needed ? Isn't the workaround always (and only)
> >> required if the chip is in SVID mode ?
> > Will add below function to detect SVID mode.
> > static bool svid_mode(struct i2c_client *client)
> > {
> >      /* PMBUS_MFR_READ(0xD0) + Address */
> >      u8 write_buf[] = {0xd0, 0x44, 0x00};
> >      u8 read_buf[2];
> >      int ret;
> >
> >      struct i2c_msg msgs[2] = {
> >          {
> >              .addr = client->addr,
> >              .flags = 0,
> >              .buf = write_buf,
> >              .len = sizeof(write_buf),
> >          },
> >          {
> >              .addr = client->addr,
> >              .flags = I2C_M_RD,
> >              .buf = read_buf,
> >              .len = sizeof(read_buf),
> >          }
> >      };
> >
> >      ret = i2c_transfer(client->adapter, msgs, 2);
> >
> drop empty line
Sure
>
> >      if (ret < 0) {
> >          dev_err(&client->dev, "%s:%d i2c_transfer failed. %d", __func__, __LINE__, ret);
> >          return ret;
>
> Return type is bool.
Yes. I've changed it to int so that return value can be validated.
>
> >      }
> >      /* 0x44[15] determines PMBus Operating Mode */
> >      return !!(read_buf[1] & BIT(7));
> > }
> >
>
> "The application note AN_2203_PL12_2204_210835 having information on the register map
>   of TDA38640 is under review. The document will be uploaded to the Infineon website
>   once the review is completed."
>
> How annoying. Is that really the only way to get that information ?
Datasheet does mention MTP register offset 0x44 bit 15 for PMBUS operating mode.
I validated those in my setup which has 4 tda38640 in SVID mode & 7 in
PMBUS mode.
>
> > Based on svid_mode will init accordingly:
> >      if (!IS_ENABLED(CONFIG_SENSORS_TDA38640_REGULATOR) || !np || !svid_mode(client))
> >          return pmbus_do_probe(client, &data->info);
> >
>
> This is unnecessary complexity. Just add the local read/write
> commands and be done with it.
>
>         if (svid_mode(client)) {
>                 data->info.read_byte_data = tda38640_read_byte_data;
>                 data->info.write_byte_data = tda38640_write_byte_data;
>         }
>
> though it would be useful to error check the return value.
>
>         ret = svid_mode();
>         if (ret < 0)
>                 return ret;
>         if (ret) {
>                 /* consider adding comments here */
>                 data->info.read_byte_data = tda38640_read_byte_data;
>                 data->info.write_byte_data = tda38640_write_byte_data;
>         }
Yes. I've updated accordingly.

Regards,
Naresh
>
> Guenter
>
> >      dev_dbg(&client->dev, "SVID mode");
> >
> > Regards,
> > Naresh
> >>
> >> Guenter
> >>
> >>> The workaround will map the PB_OPERATION_CONTROL_ON bit to the
> >>> PB_ON_OFF_CONFIG_EN_PIN_REQ bit of the ON_OFF_CONFIG register.
> >>> In combination with the fixed level on the ENABLE pin the regulator
> >>> can be controlled as expected.
> >>>
> >>> Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
> >>> Signed-off-by: Naresh Solanki <Naresh.Solanki@9elements.com>
> >>> ---
> >>>   drivers/hwmon/pmbus/tda38640.c | 95 +++++++++++++++++++++++++++++++++-
> >>>   1 file changed, 93 insertions(+), 2 deletions(-)
> >>>
> >>> diff --git a/drivers/hwmon/pmbus/tda38640.c b/drivers/hwmon/pmbus/tda38640.c
> >>> index 450b0273fb59..9d3b89d9845c 100644
> >>> --- a/drivers/hwmon/pmbus/tda38640.c
> >>> +++ b/drivers/hwmon/pmbus/tda38640.c
> >>> @@ -18,6 +18,72 @@ static const struct regulator_desc __maybe_unused tda38640_reg_desc[] = {
> >>>       PMBUS_REGULATOR("vout", 0),
> >>>   };
> >>> +struct tda38640_data {
> >>> +    struct pmbus_driver_info info;
> >>> +    u32 en_pin_lvl;
> >>> +};
> >>> +
> >>> +#define to_tda38640_data(x)  container_of(x, struct tda38640_data, info)
> >>> +
> >>> +/*
> >>> + * Map PB_ON_OFF_CONFIG_POLARITY_HIGH to PB_OPERATION_CONTROL_ON.
> >>> + */
> >>> +static int tda38640_read_byte_data(struct i2c_client *client, int page, int reg)
> >>> +{
> >>> +    const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
> >>> +    struct tda38640_data *data = to_tda38640_data(info);
> >>> +    int ret, on_off_config, enabled;
> >>> +
> >>> +    if (reg != PMBUS_OPERATION)
> >>> +        return -ENODATA;
> >>> +
> >>> +    ret = pmbus_read_byte_data(client, page, reg);
> >>> +    if (ret < 0)
> >>> +        return ret;
> >>> +
> >>> +    on_off_config = pmbus_read_byte_data(client, page,
> >>> +                         PMBUS_ON_OFF_CONFIG);
> >>> +    if (on_off_config < 0)
> >>> +        return on_off_config;
> >>> +
> >>> +    enabled = !!(on_off_config & PB_ON_OFF_CONFIG_POLARITY_HIGH);
> >>> +
> >>> +    enabled ^= data->en_pin_lvl;
> >>> +    if (enabled)
> >>> +        ret &= ~PB_OPERATION_CONTROL_ON;
> >>> +    else
> >>> +        ret |= PB_OPERATION_CONTROL_ON;
> >>> +
> >>> +    return ret;
> >>> +}
> >>> +
> >>> +/*
> >>> + * Map PB_OPERATION_CONTROL_ON to PB_ON_OFF_CONFIG_POLARITY_HIGH.
> >>> + */
> >>> +static int tda38640_write_byte_data(struct i2c_client *client, int page,
> >>> +                    int reg, u8 byte)
> >>> +{
> >>> +    const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
> >>> +    struct tda38640_data *data = to_tda38640_data(info);
> >>> +    int enable, ret;
> >>> +
> >>> +    if (reg != PMBUS_OPERATION)
> >>> +        return -ENODATA;
> >>> +
> >>> +    enable = !!(byte & PB_OPERATION_CONTROL_ON);
> >>> +
> >>> +    byte &= ~PB_OPERATION_CONTROL_ON;
> >>> +    ret = pmbus_write_byte_data(client, page, reg, byte);
> >>> +    if (ret < 0)
> >>> +        return ret;
> >>> +
> >>> +    enable ^= data->en_pin_lvl;
> >>> +
> >>> +    return pmbus_update_byte_data(client, page, PMBUS_ON_OFF_CONFIG,
> >>> +                      PB_ON_OFF_CONFIG_POLARITY_HIGH,
> >>> +                      enable ? 0 : PB_ON_OFF_CONFIG_POLARITY_HIGH);
> >>> +}
> >>> +
> >>>   static struct pmbus_driver_info tda38640_info = {
> >>>       .pages = 1,
> >>>       .format[PSC_VOLTAGE_IN] = linear,
> >>> @@ -26,7 +92,6 @@ static struct pmbus_driver_info tda38640_info = {
> >>>       .format[PSC_CURRENT_IN] = linear,
> >>>       .format[PSC_POWER] = linear,
> >>>       .format[PSC_TEMPERATURE] = linear,
> >>> -
> >>>       .func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_STATUS_INPUT
> >>>           | PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP
> >>>           | PMBUS_HAVE_IIN
> >>> @@ -41,7 +106,33 @@ static struct pmbus_driver_info tda38640_info = {
> >>>   static int tda38640_probe(struct i2c_client *client)
> >>>   {
> >>> -    return pmbus_do_probe(client, &tda38640_info);
> >>> +    struct device *dev = &client->dev;
> >>> +    struct device_node *np = dev_of_node(dev);
> >>> +    struct tda38640_data *data;
> >>> +
> >>> +    data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
> >>> +    if (!data)
> >>> +        return -ENOMEM;
> >>> +    memcpy(&data->info, &tda38640_info, sizeof(tda38640_info));
> >>> +
> >>> +    if (!CONFIG_SENSORS_TDA38640_REGULATOR || !np ||
> >>> +        of_property_read_u32(np, "infineon,en-pin-fixed-level", &data->en_pin_lvl))
> >>> +        return pmbus_do_probe(client, &data->info);
> >>> +
> >>> +    /*
> >>> +     * Apply ON_OFF_CONFIG workaround as enabling the regulator using the
> >>> +     * OPERATION register doesn't work in SVID mode.
> >>> +     */
> >>> +    data->info.read_byte_data = tda38640_read_byte_data;
> >>> +    data->info.write_byte_data = tda38640_write_byte_data;
> >>> +    /*
> >>> +     * One should configure PMBUS_ON_OFF_CONFIG here, but
> >>> +     * PB_ON_OFF_CONFIG_POWERUP_CONTROL, PB_ON_OFF_CONFIG_EN_PIN_REQ and
> >>> +     * PB_ON_OFF_CONFIG_EN_PIN_REQ are ignored by the device.
> >>> +     * Only PB_ON_OFF_CONFIG_POLARITY_HIGH has an effect.
> >>> +     */
> >>> +
> >>> +    return pmbus_do_probe(client, &data->info);
> >>>   }
> >>>   static const struct i2c_device_id tda38640_id[] = {
> >>
>
diff mbox series

Patch

diff --git a/drivers/hwmon/pmbus/tda38640.c b/drivers/hwmon/pmbus/tda38640.c
index 450b0273fb59..9d3b89d9845c 100644
--- a/drivers/hwmon/pmbus/tda38640.c
+++ b/drivers/hwmon/pmbus/tda38640.c
@@ -18,6 +18,72 @@  static const struct regulator_desc __maybe_unused tda38640_reg_desc[] = {
 	PMBUS_REGULATOR("vout", 0),
 };
 
+struct tda38640_data {
+	struct pmbus_driver_info info;
+	u32 en_pin_lvl;
+};
+
+#define to_tda38640_data(x)  container_of(x, struct tda38640_data, info)
+
+/*
+ * Map PB_ON_OFF_CONFIG_POLARITY_HIGH to PB_OPERATION_CONTROL_ON.
+ */
+static int tda38640_read_byte_data(struct i2c_client *client, int page, int reg)
+{
+	const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
+	struct tda38640_data *data = to_tda38640_data(info);
+	int ret, on_off_config, enabled;
+
+	if (reg != PMBUS_OPERATION)
+		return -ENODATA;
+
+	ret = pmbus_read_byte_data(client, page, reg);
+	if (ret < 0)
+		return ret;
+
+	on_off_config = pmbus_read_byte_data(client, page,
+					     PMBUS_ON_OFF_CONFIG);
+	if (on_off_config < 0)
+		return on_off_config;
+
+	enabled = !!(on_off_config & PB_ON_OFF_CONFIG_POLARITY_HIGH);
+
+	enabled ^= data->en_pin_lvl;
+	if (enabled)
+		ret &= ~PB_OPERATION_CONTROL_ON;
+	else
+		ret |= PB_OPERATION_CONTROL_ON;
+
+	return ret;
+}
+
+/*
+ * Map PB_OPERATION_CONTROL_ON to PB_ON_OFF_CONFIG_POLARITY_HIGH.
+ */
+static int tda38640_write_byte_data(struct i2c_client *client, int page,
+				    int reg, u8 byte)
+{
+	const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
+	struct tda38640_data *data = to_tda38640_data(info);
+	int enable, ret;
+
+	if (reg != PMBUS_OPERATION)
+		return -ENODATA;
+
+	enable = !!(byte & PB_OPERATION_CONTROL_ON);
+
+	byte &= ~PB_OPERATION_CONTROL_ON;
+	ret = pmbus_write_byte_data(client, page, reg, byte);
+	if (ret < 0)
+		return ret;
+
+	enable ^= data->en_pin_lvl;
+
+	return pmbus_update_byte_data(client, page, PMBUS_ON_OFF_CONFIG,
+				      PB_ON_OFF_CONFIG_POLARITY_HIGH,
+				      enable ? 0 : PB_ON_OFF_CONFIG_POLARITY_HIGH);
+}
+
 static struct pmbus_driver_info tda38640_info = {
 	.pages = 1,
 	.format[PSC_VOLTAGE_IN] = linear,
@@ -26,7 +92,6 @@  static struct pmbus_driver_info tda38640_info = {
 	.format[PSC_CURRENT_IN] = linear,
 	.format[PSC_POWER] = linear,
 	.format[PSC_TEMPERATURE] = linear,
-
 	.func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_STATUS_INPUT
 	    | PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP
 	    | PMBUS_HAVE_IIN
@@ -41,7 +106,33 @@  static struct pmbus_driver_info tda38640_info = {
 
 static int tda38640_probe(struct i2c_client *client)
 {
-	return pmbus_do_probe(client, &tda38640_info);
+	struct device *dev = &client->dev;
+	struct device_node *np = dev_of_node(dev);
+	struct tda38640_data *data;
+
+	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+	memcpy(&data->info, &tda38640_info, sizeof(tda38640_info));
+
+	if (!CONFIG_SENSORS_TDA38640_REGULATOR || !np ||
+	    of_property_read_u32(np, "infineon,en-pin-fixed-level", &data->en_pin_lvl))
+		return pmbus_do_probe(client, &data->info);
+
+	/*
+	 * Apply ON_OFF_CONFIG workaround as enabling the regulator using the
+	 * OPERATION register doesn't work in SVID mode.
+	 */
+	data->info.read_byte_data = tda38640_read_byte_data;
+	data->info.write_byte_data = tda38640_write_byte_data;
+	/*
+	 * One should configure PMBUS_ON_OFF_CONFIG here, but
+	 * PB_ON_OFF_CONFIG_POWERUP_CONTROL, PB_ON_OFF_CONFIG_EN_PIN_REQ and
+	 * PB_ON_OFF_CONFIG_EN_PIN_REQ are ignored by the device.
+	 * Only PB_ON_OFF_CONFIG_POLARITY_HIGH has an effect.
+	 */
+
+	return pmbus_do_probe(client, &data->info);
 }
 
 static const struct i2c_device_id tda38640_id[] = {