Message-ID: <2288d2ab-51c0-4e88-86e1-7a113ac67a16@linux.ibm.com>
Date: Mon, 16 Dec 2024 12:01:00 -0600
From: Ninad Palsule <ninad@...ux.ibm.com>
To: Guenter Roeck <linux@...ck-us.net>, robh@...nel.org, krzk+dt@...nel.org,
        conor+dt@...nel.org, eajames@...ux.ibm.com, jdelvare@...e.com,
        corbet@....net, joel@....id.au, andrew@...econstruct.com.au,
        Delphine_CC_Chiu@...ynn.com, broonie@...nel.org,
        peteryin.openbmc@...il.com, noahwang.wang@...look.com,
        naresh.solanki@...ements.com, lukas@...ner.de, jbrunet@...libre.com,
        patrick.rudolph@...ements.com, gregkh@...uxfoundation.org,
        peterz@...radead.org, pbiel7@...il.com, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-hwmon@...r.kernel.org,
        linux-doc@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-aspeed@...ts.ozlabs.org, linux-i2c@...r.kernel.org
Subject: Re: [PATCH v1 2/4] hwmon: (pmbus/crps) Add Intel CRPS185 power supply

Hi Guenter,

Thanks for the review!

On 12/12/24 19:29, Guenter Roeck wrote:
> On 12/12/24 13:49, Ninad Palsule wrote:
>> Add the driver to monitor Intel common redundant power supply (crps185)
>> with hwmon over pmbus.
>>
>> Signed-off-by: Ninad Palsule <ninad@...ux.ibm.com>
>> ---
>>   Documentation/hwmon/crps.rst |  95 +++++++++++
>
> Documentation/hwmon/index.rst needs to be updated.
Added the entry. Sorry for that.
>
>>   MAINTAINERS                  |   7 +
>>   drivers/hwmon/pmbus/Kconfig  |   9 ++
>>   drivers/hwmon/pmbus/Makefile |   1 +
>>   drivers/hwmon/pmbus/crps.c   | 299 +++++++++++++++++++++++++++++++++++
>>   5 files changed, 411 insertions(+)
>>   create mode 100644 Documentation/hwmon/crps.rst
>>   create mode 100644 drivers/hwmon/pmbus/crps.c
>>
>> diff --git a/Documentation/hwmon/crps.rst b/Documentation/hwmon/crps.rst
>> new file mode 100644
>> index 000000000000..81d5dfd68a46
>> --- /dev/null
>> +++ b/Documentation/hwmon/crps.rst
>> @@ -0,0 +1,95 @@
>> +.. SPDX-License-Identifier: GPL-2.0-or-later
>> +
>> +Kernel driver crps
>> +========================
>
> I am quite sure that this triggers a documentation warning.
Fixed it.
>
>> +
>> +Supported chips:
>> +
>> +  * Intel CRPS185
>> +
>> +    Prefix: 'crps185'
>> +
>> +    Addresses scanned: -
>> +
>> +Authors:
>> +    Ninad Palsule <ninad@...ux.ibm.com>
>> +
>> +
>
> Is the documentation available somewhere ?
> If yes, please add a reference. If not, add a comment explaining that
> it is not available to the public.
There is no public spec, added the comment
>
>> +Description
>> +-----------
>> +
>> +This driver implements support for Common Redundant Power supply 
>> with PMBus
>
> For _Intel_ ...
Updated.
>
>> +support.
>> +
>> +The driver is a client driver to the core PMBus driver.
>> +Please see Documentation/hwmon/pmbus.rst for details on PMBus client 
>> drivers.
>> +
>> +
>> +Usage Notes
>> +-----------
>> +
>> +This driver does not auto-detect devices. You will have to 
>> instantiate the
>> +devices explicitly. Please see 
>> Documentation/i2c/instantiating-devices.rst for
>> +details.
>> +
>> +
>> +Sysfs entries
>> +-------------
>> +
>> +======================= 
>> ======================================================
>> +curr1_label        "iin"
>> +curr1_input        Measured input current
>> +curr1_max        Maximum input current
>> +curr1_max_alarm         Input maximum current high alarm
>> +curr1_crit              Critial high input current
>> +curr1_crit_alarm        Input critical current high alarm
>> +curr1_rated_max        Maximum rated input current
>> +
>> +curr2_label        "iout1"
>> +curr2_input        Measured output current
>> +curr2_max        Maximum output current
>> +curr2_max_alarm         Output maximum current high alarm
>> +curr2_crit            Critial high output current
>> +curr2_crit_alarm        Output critical current high alarm
>> +curr2_rated_max        Maximum rated output current
>> +
>> +in1_label        "vin"
>> +in1_input        Measured input voltage
>> +in1_crit                Critical input over voltage
>> +in1_crit_alarm          Critical input over voltage alarm
>> +in1_max                 Maximum input over voltage
>> +in1_max_alarm           Maximum input over voltage alarm
>> +in1_rated_min        Minimum rated input voltage
>> +in1_rated_max        Maximum rated input voltage
>> +
>> +in2_label        "vout1"
>> +in2_input        Measured input voltage
>> +in2_crit                Critical input over voltage
>> +in2_crit_alarm          Critical input over voltage alarm
>> +in2_lcrit               Critical input under voltage fault
>> +in2_lcrit_alarm         Critical input under voltage fault alarm
>> +in2_max                 Maximum input over voltage
>> +in2_max_alarm           Maximum input over voltage alarm
>> +in2_min                 Minimum input under voltage warning
>> +in2_min_alarm           Minimum input under voltage warning alarm
>> +in2_rated_min        Minimum rated input voltage
>> +in2_rated_max        Maximum rated input voltage
>> +
>> +power1_label        "pin"
>> +power1_input        Measured input power
>> +power1_alarm        Input power high alarm
>> +power1_max          Maximum input power
>> +power1_rated_max        Maximum rated input power
>> +
>> +temp[1-2]_input        Measured temperature
>> +temp[1-2]_crit         Critical temperature
>> +temp[1-2]_crit_alarm    Critical temperature alarm
>> +temp[1-2]_max          Maximum temperature
>> +temp[1-2]_max_alarm     Maximum temperature alarm
>> +temp[1-2]_rated_max     Maximum rated temperature
>> +
>> +fan1_alarm        Fan 1 warning.
>> +fan1_fault        Fan 1 fault.
>> +fan1_input        Fan 1 speed in RPM.
>> +fan1_target             Fan 1 target.
>> +======================= 
>> ======================================================
>> diff --git a/MAINTAINERS b/MAINTAINERS
>> index 637ddd44245f..6b31d545f0f1 100644
>> --- a/MAINTAINERS
>> +++ b/MAINTAINERS
>> @@ -6100,6 +6100,13 @@ L:    linux-input@...r.kernel.org
>>   S:    Maintained
>>   F:    drivers/hid/hid-creative-sb0540.c
>>   +CRPS COMMON REDUNDANT PSU DRIVER
>
> This is _INTEL_ CRPS.
Updated.
>
>> +M:    Ninad Palsule <ninad@...ux.ibm.com>
>> +L:    linux-hwmon@...r.kernel.org
>> +S:    Maintained
>> +F:    Documentation/hwmon/crps.rst
>> +F:    drivers/hwmon/pmbus/crps.c
>> +
>>   CRYPTO API
>>   M:    Herbert Xu <herbert@...dor.apana.org.au>
>>   M:    "David S. Miller" <davem@...emloft.net>
>> diff --git a/drivers/hwmon/pmbus/Kconfig b/drivers/hwmon/pmbus/Kconfig
>> index 22418a05ced0..56c4eb4b846e 100644
>> --- a/drivers/hwmon/pmbus/Kconfig
>> +++ b/drivers/hwmon/pmbus/Kconfig
>> @@ -85,6 +85,15 @@ config SENSORS_BPA_RS600
>>         This driver can also be built as a module. If so, the module 
>> will
>>         be called bpa-rs600.
>>   +config SENSORS_CRPS
>> +    tristate "Common Redundant Power Supply"
>
> Again, this is an Intel product.
Fixed.
>
>> +    help
>> +      If you say yes here you get hardware monitoring support for 
>> the Common
>> +      Redundant Power Supply.
>> +
>> +      This driver can also be built as a module. If so, the module will
>> +      be called crps.
>> +
>>   config SENSORS_DELTA_AHE50DC_FAN
>>       tristate "Delta AHE-50DC fan control module"
>>       help
>> diff --git a/drivers/hwmon/pmbus/Makefile b/drivers/hwmon/pmbus/Makefile
>> index 3d3183f8d2a7..c7eb7739b7f8 100644
>> --- a/drivers/hwmon/pmbus/Makefile
>> +++ b/drivers/hwmon/pmbus/Makefile
>> @@ -62,3 +62,4 @@ obj-$(CONFIG_SENSORS_XDPE122)    += xdpe12284.o
>>   obj-$(CONFIG_SENSORS_XDPE152)    += xdpe152c4.o
>>   obj-$(CONFIG_SENSORS_ZL6100)    += zl6100.o
>>   obj-$(CONFIG_SENSORS_PIM4328)    += pim4328.o
>> +obj-$(CONFIG_SENSORS_CRPS)    += crps.o
>> diff --git a/drivers/hwmon/pmbus/crps.c b/drivers/hwmon/pmbus/crps.c
>> new file mode 100644
>> index 000000000000..44d309f81803
>> --- /dev/null
>> +++ b/drivers/hwmon/pmbus/crps.c
>> @@ -0,0 +1,299 @@
>> +// SPDX-License-Identifier: GPL-2.0-or-later
>> +/*
>> + * Copyright 2024 IBM Corp.
>> + */
>> +
>> +#include <linux/debugfs.h>
>> +#include <linux/i2c.h>
>> +#include <linux/of.h>
>> +#include <linux/pmbus.h>
>> +
>> +#include "pmbus.h"
>> +
>> +/* Intel crps185 specific commands. */
>> +#define CRPS185_MFR_IOUT_MAX        0xA6
>> +#define CRPS185_MFR_POUT_MAX        0xA7
>> +
>
> I fail to see the point in those defines, even more so since
> PMBUS_MFR_POUT_MAX and PMBUS_MFR_IOUT_MAX are used below.
Removed these defines.
>
>> +enum {
>> +    CRPS_DEBUGFS_PMBUS_REVISION = 0,
>> +    CRPS_DEBUGFS_MAX_POWER_OUT,
>> +    CRPS_DEBUGFS_MAX_CURRENT_OUT,
>> +    CRPS_DEBUGFS_NUM_ENTRIES
>> +};
>> +
>> +enum models { crps185 = 1, crps_unknown };
>
> Pointless enum. The driver only supports a single power supply.
Removed the enum.
>
>> +
>> +struct crps {
>> +    enum models version;
>> +    struct i2c_client *client;
>> +
>> +    int debugfs_entries[CRPS_DEBUGFS_NUM_ENTRIES];
>> +};
>> +
>> +#define to_psu(x, y) container_of((x), struct crps, 
>> debugfs_entries[(y)])
>> +
>> +static struct pmbus_platform_data crps_pdata = {
>> +    .flags = PMBUS_SKIP_STATUS_CHECK,
>> +};
>
> Did you confirm that it is needed ? If so, explain why it is needed.
I removed it and still driver is working. I added it because spec did 
not mention about PMBUS_STATUS_CML
>
>> +
>> +static const struct i2c_device_id crps_id[] = {
>> +    { "intel_crps185", crps185 },
>> +    {}
>> +};
>> +MODULE_DEVICE_TABLE(i2c, crps_id);
>> +
>> +/*
>> + * Convert linear format word to machine format. 11 LSB side bits 
>> are two's
>> + * complement integer mantissa and 5 MSB side bits are two's complement
>> + * exponent
>> + */
>> +static int crps_convert_linear(int rc)
>> +{
>> +    s16 exponent;
>> +    s32 mantissa;
>> +    s64 val;
>> +
>> +    exponent = ((s16)rc) >> 11;
>> +    mantissa = ((s16)((rc & 0x7ff) << 5)) >> 5;
>> +
>> +    val = mantissa;
>> +    if (exponent >= 0)
>> +        val <<= exponent;
>> +    else
>> +        val >>= -exponent;
>> +
>> +    return (int)val;
>> +}
>> +
>> +static ssize_t crps_debugfs_read(struct file *file, char __user *buf,
>> +                 size_t count, loff_t *ppos)
>> +{
>> +    int rc;
>> +    int *idxp = file->private_data;
>> +    int idx = *idxp;
>> +    struct crps *psu = to_psu(idxp, idx);
>> +    char data[2 * I2C_SMBUS_BLOCK_MAX] = { 0 };
>> +
>> +    rc = pmbus_lock_interruptible(psu->client);
>> +    if (rc)
>> +        return rc;
>> +
>> +    rc = pmbus_set_page(psu->client, 0, 0xff);
>> +    if (rc)
>> +        goto unlock;
>> +
>> +    switch (idx) {
>> +    case CRPS_DEBUGFS_PMBUS_REVISION:
>> +        rc = i2c_smbus_read_byte_data(psu->client, PMBUS_REVISION);
>> +        if (rc >= 0) {
>> +            if (psu->version == crps185) {
>> +                if (rc == 0)
>> +                    rc = sprintf(data, "%s", "1.0");
>> +                else if (rc == 0x11)
>> +                    rc = sprintf(data, "%s", "1.1");
>> +                else if (rc == 0x22)
>> +                    rc = sprintf(data, "%s", "1.2");
>> +                else
>> +                    rc = snprintf(data, 3, "0x%02x", rc);
>> +            } else {
>> +                rc = snprintf(data, 3, "%02x", rc);
>> +            }
>> +        }
>
> This attribute should be added into the PMBus core.

Moved the attribute in the core.


>
>> +        break;
>> +    case CRPS_DEBUGFS_MAX_POWER_OUT:
>> +        rc = i2c_smbus_read_word_data(psu->client, PMBUS_MFR_POUT_MAX);
>> +        if (rc >= 0) {
>> +            rc = crps_convert_linear(rc);
>> +            rc = snprintf(data, I2C_SMBUS_BLOCK_MAX, "%d", rc);
>> +        }
>> +        break;
>> +    case CRPS_DEBUGFS_MAX_CURRENT_OUT:
>> +        rc = i2c_smbus_read_word_data(psu->client, PMBUS_MFR_IOUT_MAX);
>> +        if (rc >= 0) {
>> +            rc = crps_convert_linear(rc);
>> +            rc = snprintf(data, I2C_SMBUS_BLOCK_MAX, "%d", rc);
>> +        }
>> +        break;
>
> What is the point of those two attributes ? There are already
> standard sysfs attributes reporting those values.
Removed debugfs
>
>> +    default:
>> +        rc = -EINVAL;
>> +        break;
>> +    }
>> +
>> +unlock:
>> +    pmbus_unlock(psu->client);
>> +    if (rc < 0)
>> +        return rc;
>> +
>> +    data[rc] = '\n';
>> +    rc += 2;
>> +
>> +    return simple_read_from_buffer(buf, count, ppos, data, rc);
>> +}
>> +
>> +static const struct file_operations crps_debugfs_fops = {
>> +    .llseek = noop_llseek,
>> +    .read = crps_debugfs_read,
>> +    .open = simple_open,
>> +};
>> +
>> +static int crps_read_word_data(struct i2c_client *client, int page,
>> +                int phase, int reg)
>> +{
>> +    int rc;
>> +
>> +    switch (reg) {
>> +    case PMBUS_STATUS_WORD:
>> +        rc = pmbus_read_word_data(client, page, phase, reg);
>> +        if (rc < 0)
>> +            return rc;
>> +        break;
>
> Why is this needed ?
You are right, removed it.
>
>> +    case PMBUS_OT_WARN_LIMIT:
>> +        rc = pmbus_read_word_data(client, page, phase,
>> +                      PMBUS_MFR_MAX_TEMP_1);
>> +        if (rc < 0)
>> +            return rc;
>> +        break;
>> +    case PMBUS_IOUT_OC_WARN_LIMIT:
>> +        rc = pmbus_read_word_data(client, page, phase,
>> +                      CRPS185_MFR_IOUT_MAX);
>> +        if (rc < 0)
>> +            return rc;
>> +        break;
>> +    case PMBUS_POUT_OP_WARN_LIMIT:
>> +        rc = pmbus_read_word_data(client, page, phase,
>> +                      CRPS185_MFR_POUT_MAX);
>> +        if (rc < 0)
>> +            return rc;
>> +        break;
>
> The above three values are more than odd. They duplicate the respective
> standard rated_max attributes as warning limits. Why ?
I realized that some of these registers exist. So removed it.
>
> On top of that, on writes, the actual warning limits are overwritten.
> That makes even less sense.
I have removed read function so now we don't need write too.
>
>> +    default:
>> +        rc = -ENODATA;
>> +        break;
>> +    }
>> +
>> +    return rc;
>> +}
>> +
>> +static struct pmbus_driver_info crps_info[] = {
>> +    [crps185] = {
>> +        .pages = 1,
>> +        /* PSU uses default linear data format. */
>> +        .func[0] = PMBUS_HAVE_PIN | PMBUS_HAVE_IOUT |
>> +            PMBUS_HAVE_STATUS_IOUT | PMBUS_HAVE_IIN |
>> +            PMBUS_HAVE_VIN | PMBUS_HAVE_STATUS_INPUT |
>> +            PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT |
>> +            PMBUS_HAVE_TEMP | PMBUS_HAVE_TEMP2 |
>> +            PMBUS_HAVE_STATUS_TEMP |
>> +            PMBUS_HAVE_FAN12 | PMBUS_HAVE_STATUS_FAN12,
>> +        .read_word_data = crps_read_word_data,
>> +    },
>> +};
>> +
>> +#define to_psu(x, y) container_of((x), struct crps, 
>> debugfs_entries[(y)])
>> +
>> +static void crps_init_debugfs(struct crps *psu)
>> +{
>> +    struct i2c_client *client = psu->client;
>> +    struct dentry *debugfs;
>> +    int i;
>> +
>> +    /* Don't fail the probe if we can't create debugfs */
>> +    debugfs = pmbus_get_debugfs_dir(client);
>> +    if (!debugfs)
>> +        return;
>> +
>> +    for (i = 0; i < CRPS_DEBUGFS_NUM_ENTRIES; ++i)
>> +        psu->debugfs_entries[i] = i;
>> +
>> +    debugfs_create_file("pmbus_revision", 0444, debugfs,
>> + &psu->debugfs_entries[CRPS_DEBUGFS_PMBUS_REVISION],
>> +                &crps_debugfs_fops);
>> +    debugfs_create_file("max_power_out", 0444, debugfs,
>> + &psu->debugfs_entries[CRPS_DEBUGFS_MAX_POWER_OUT],
>> +                &crps_debugfs_fops);
>> +    debugfs_create_file("max_current_out", 0444, debugfs,
>> + &psu->debugfs_entries[CRPS_DEBUGFS_MAX_CURRENT_OUT],
>> +                &crps_debugfs_fops);
>> +}
>> +
>> +static int crps_probe(struct i2c_client *client)
>> +{
>> +    int rc;
>> +    struct device *dev = &client->dev;
>> +    enum models vs = crps_unknown;
>> +    struct crps *psu;
>> +    const void *md = of_device_get_match_data(&client->dev);
>> +    const struct i2c_device_id *id = NULL;
>> +    char buf[I2C_SMBUS_BLOCK_MAX + 2] = { 0 };
>> +
>> +    if (md) {
>> +        vs = (uintptr_t)md;
>> +    } else {
>> +        id = i2c_match_id(crps_id, client);
>> +        if (id)
>> +            vs = (enum models)id->driver_data;
>> +    }
>> +
> Consider using i2c_get_match_data().
Removed this code.
>
>> +    if (!vs || vs >= crps_unknown) {
>> +        dev_err(dev, "Version %d not supported\n", vs);
>> +        return -EINVAL;
>> +    }
>
> This is very much pointless. The driver would not be instantiated 
> withut match.
Yes, removed it.
>
>> +
>> +    rc = i2c_smbus_read_block_data(client, PMBUS_MFR_MODEL, buf);
>> +    if (rc < 0) {
>> +        dev_err(dev, "Failed to read PMBUS_MFR_MODEL\n");
>> +        return rc;
>
> dev_err_probe().
Changed to use this function.
>
>> +    }
>> +    if (strncmp(buf, "03NK260", 7)) {
>
> This should also check and ensure that rc == 7.
Good idea, Added this check.
>
>> +        buf[rc] = '\0';
>> +        dev_err(dev, "Model '%s' not supported\n", buf);
>
> dev_err_probe()
Changed the function
>
>> +        return -ENODEV;
>> +    }
>> +
>> +    client->dev.platform_data = &crps_pdata;
>> +    rc = pmbus_do_probe(client, &crps_info[vs]);
>> +    if (rc) {
>> +        dev_err(dev, "Failed to probe %d\n", rc);
>> +        return rc;
>
> dev_err_probe().
Changed this function.
>
>> +    }
>> +
>> +    /*
>> +     * Don't fail the probe if there isn't enough memory for debugfs.
>> +     */
>> +    psu = devm_kzalloc(&client->dev, sizeof(*psu), GFP_KERNEL);
>> +    if (!psu) {
>> +        dev_warn(dev, "Failed to allocate memory. debugfs are not 
>> supported.\n");
>> +        return 0;
>> +    }
>> +
>> +    psu->version = vs;
>> +    psu->client = client;
>> +
>
> Drop all this. Add the PMBus version as standard debugfs attribute to 
> the PMBus core
> if needed/wanted. The rest is already provided as standard sysfs 
> attributes, and
> reporting the same value in debugfs files adds no value.
Yes, Removed debugfs.
>
>> +    crps_init_debugfs(psu);
>> +
>> +    return 0;
>> +}
>> +
>> +static const struct of_device_id crps_of_match[] = {
>> +    {
>> +        .compatible = "intel,crps185",
>> +        .data = (void *)crps185
>> +    },
>> +    {}
>> +};
>> +MODULE_DEVICE_TABLE(of, crps_of_match);
>> +
>> +static struct i2c_driver crps_driver = {
>> +    .driver = {
>> +        .name = "crps",
>> +        .of_match_table = crps_of_match,
>> +    },
>> +    .probe = crps_probe,
>> +    .id_table = crps_id,
>> +};
>> +
>> +module_i2c_driver(crps_driver);
>> +
>> +MODULE_AUTHOR("Ninad Palsule");
>> +MODULE_DESCRIPTION("PMBus driver for Common Redundant power supplies");
>
> Again, this is for _Intel_ power supplies.

Yes, Added Intel


Thanks and Regards,

Ninad Palsule

>
>> +MODULE_LICENSE("GPL");
>> +MODULE_IMPORT_NS("PMBUS");
>

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