On Wed, Jan 27, 2021 at 09:41:40AM +0100, Erik Rosen wrote:
> Add ST STPDDC60 pmbus client driver.
> 
> Signed-off-by: Erik Rosen <[email protected]>
> ---
>  Documentation/hwmon/index.rst    |   1 +
>  Documentation/hwmon/stpddc60.rst |  79 +++++++++++++
>  MAINTAINERS                      |   7 ++
>  drivers/hwmon/pmbus/Kconfig      |  10 ++
>  drivers/hwmon/pmbus/Makefile     |   2 +
>  drivers/hwmon/pmbus/stpddc60.c   | 188 +++++++++++++++++++++++++++++++
>  6 files changed, 287 insertions(+)
>  create mode 100644 Documentation/hwmon/stpddc60.rst
>  create mode 100644 drivers/hwmon/pmbus/stpddc60.c
> 
> diff --git a/Documentation/hwmon/index.rst b/Documentation/hwmon/index.rst
> index fcb870ce6286..94b4fcf182cd 100644
> --- a/Documentation/hwmon/index.rst
> +++ b/Documentation/hwmon/index.rst
> @@ -169,6 +169,7 @@ Hardware Monitoring Kernel Drivers
>     smsc47m192
>     smsc47m1
>     sparx5-temp
> +   stpddc60
>     tc654
>     tc74
>     thmc50
> diff --git a/Documentation/hwmon/stpddc60.rst 
> b/Documentation/hwmon/stpddc60.rst
> new file mode 100644
> index 000000000000..11d5a9977e80
> --- /dev/null
> +++ b/Documentation/hwmon/stpddc60.rst
> @@ -0,0 +1,79 @@
> +.. SPDX-License-Identifier: GPL-2.0
> +
> +Kernel driver stpddc60
> +======================
> +
> +Supported chips:
> +
> +  * ST STPDDC60
> +
> +    Prefix: 'stpddc60', 'bmr481'
> +
> +    Addresses scanned: -
> +
> +    Datasheet: https://flexpowermodules.com/documents/fpm-techspec-bmr481
> +
> +Author: Erik Rosen <[email protected]>
> +
> +
> +Description
> +-----------
> +
> +This driver supports hardware monitoring for ST STPDDC60 controller chip and
> +compatible modules.
> +
> +The driver is a client driver to the core PMBus driver. Please see
> +Documentation/hwmon/pmbus.rst and Documentation.hwmon/pmbus-core 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.
> +
> +The vout under- and over-voltage limits are read-only for this chip.
> +
> +
> +Platform data support
> +---------------------
> +
> +The driver supports standard PMBus driver platform data.
> +
> +
> +Sysfs entries
> +-------------
> +
> +The following attributes are supported. Vin, iout and temp limits
> +are read-write; all other attributes are read-only.
> +
> +======================= 
> ========================================================
> +in1_label            "vin"
> +in1_input            Measured input voltage.
> +in1_lcrit            Critical minimum input voltage.
> +in1_crit             Critical maximum input voltage.
> +in1_lcrit_alarm              Input voltage critical low alarm.
> +in1_crit_alarm               Input voltage critical high alarm.
> +
> +in2_label            "vout1"
> +in2_input            Measured output voltage.
> +in2_lcrit            Critical minimum output Voltage.
> +in2_crit             Critical maximum output voltage.
> +in2_lcrit_alarm              Critical output voltage critical low alarm.
> +in2_crit_alarm               Critical output voltage critical high alarm.
> +
> +curr1_label          "iout1"
> +curr1_input          Measured output current.
> +curr1_max            Maximum output current.
> +curr1_max_alarm              Output current high alarm.
> +curr1_crit           Critical maximum output current.
> +curr1_crit_alarm     Output current critical high alarm.
> +
> +temp1_input          Measured maximum temperature of all phases.
> +temp1_max            Maximum temperature limit.
> +temp1_max_alarm              High temperature alarm.
> +temp1_crit           Critical maximum temperature limit.
> +temp1_crit_alarm     Critical maximum temperature alarm.
> +======================= 
> ========================================================
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 992fe3b0900a..e4c696f8eabe 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -16819,6 +16819,13 @@ L:   [email protected]
>  S:   Maintained
>  F:   drivers/i2c/busses/i2c-stm32*
>  
> +ST STPDDC60 DRIVER
> +M:   Daniel Nilsson <[email protected]>
> +L:   [email protected]
> +S:   Maintained
> +F:   Documentation/hwmon/stpddc60.rst
> +F:   drivers/hwmon/pmbus/stpddc60.c
> +
>  ST VL53L0X ToF RANGER(I2C) IIO DRIVER
>  M:   Song Qiang <[email protected]>
>  L:   [email protected]
> diff --git a/drivers/hwmon/pmbus/Kconfig b/drivers/hwmon/pmbus/Kconfig
> index 03606d4298a4..b2becdd84b11 100644
> --- a/drivers/hwmon/pmbus/Kconfig
> +++ b/drivers/hwmon/pmbus/Kconfig
> @@ -247,6 +247,16 @@ config SENSORS_Q54SJ108A2
>         This driver can also be built as a module. If so, the module will
>         be called q54sj108a2.
>  
> +config SENSORS_STPDDC60
> +     tristate "ST STPDDC60"
> +     help
> +       If you say yes here you get hardware monitoring support for ST
> +       STPDDC60 Universal Digital Multicell Controller, as well as for
> +       Flex BMR481.
> +
> +       This driver can also be built as a module. If so, the module will
> +       be called stpddc60.
> +
>  config SENSORS_TPS40422
>       tristate "TI TPS40422"
>       help
> diff --git a/drivers/hwmon/pmbus/Makefile b/drivers/hwmon/pmbus/Makefile
> index 6a4ba0fdc1db..ef468806238c 100644
> --- a/drivers/hwmon/pmbus/Makefile
> +++ b/drivers/hwmon/pmbus/Makefile
> @@ -28,9 +28,11 @@ obj-$(CONFIG_SENSORS_MP2975)       += mp2975.o
>  obj-$(CONFIG_SENSORS_PM6764TR)       += pm6764tr.o
>  obj-$(CONFIG_SENSORS_PXE1610)        += pxe1610.o
>  obj-$(CONFIG_SENSORS_Q54SJ108A2)     += q54sj108a2.o
> +obj-$(CONFIG_SENSORS_STPDDC60)       += stpddc60.o
>  obj-$(CONFIG_SENSORS_TPS40422)       += tps40422.o
>  obj-$(CONFIG_SENSORS_TPS53679)       += tps53679.o
>  obj-$(CONFIG_SENSORS_UCD9000)        += ucd9000.o
>  obj-$(CONFIG_SENSORS_UCD9200)        += ucd9200.o
>  obj-$(CONFIG_SENSORS_XDPE122)        += xdpe12284.o
>  obj-$(CONFIG_SENSORS_ZL6100) += zl6100.o
> +
> diff --git a/drivers/hwmon/pmbus/stpddc60.c b/drivers/hwmon/pmbus/stpddc60.c
> new file mode 100644
> index 000000000000..4e3ab260a3c2
> --- /dev/null
> +++ b/drivers/hwmon/pmbus/stpddc60.c
> @@ -0,0 +1,188 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * Hardware monitoring driver for the STPDDC60 controller
> + *
> + * Copyright (c) 2021 Flextronics International Sweden AB.
> + */
> +
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/init.h>
> +#include <linux/err.h>
> +#include <linux/i2c.h>
> +#include <linux/pmbus.h>
> +#include "pmbus.h"
> +
> +enum chips { stpddc60 };

Seems pointless since it is not used.

> +
> +static const struct i2c_device_id stpddc60_id[] = {
> +     {"stpddc60", stpddc60},
> +     {"bmr481", stpddc60},
> +     {}
> +};
> +MODULE_DEVICE_TABLE(i2c, stpddc60_id);
> +
> +static struct pmbus_driver_info stpddc60_info = {
> +     .pages = 1,
> +     .func[0] = PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT
> +             | PMBUS_HAVE_VIN | PMBUS_HAVE_STATUS_INPUT
> +             | PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP
> +             | PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT
> +             | PMBUS_HAVE_POUT,
> +};
> +
> +/*
> + * Convert VID value to milli-volt
> + */
> +static long stpddc60_vid2mv(int val)
> +{
> +     long rv = 0;
> +
> +     if (val >= 0x01)
> +             rv = 250 + (val - 1) * 5;
> +
> +     return rv;
> +}
> +
> +/*
> + * Convert milli-volt to linear
> + */
> +static int stpddc60_mv2l(long mv)
> +{
> +     int rv;
> +
> +     rv = (mv << 8) / 1000;

DIV_ROUND_CLOSEST(), maybe ?

> +
> +     return rv;
> +}

Pleae combine those two functions into one to directly convert VID to
linear format. Having two functions is confusing and adds unnecessary
complexity.

> +
> +/*
> + * The VOUT_COMMAND register uses the VID format but the vout alarm limit
> + * registers use the linear format so we override VOUT_MODE here to force
> + * linear format for all registers.
> + */
> +static int stpddc60_read_byte_data(struct i2c_client *client, int page, int 
> reg)
> +{
> +     int ret;
> +
> +     if (page > 0)
> +             return -ENXIO;
> +
> +     switch (reg) {
> +     case PMBUS_VOUT_MODE:
> +             ret = 0x18;
> +             break;
> +     default:
> +             ret = -ENODATA;
> +             break;
> +     }
> +
> +     return ret;
> +}
> +
> +/*
> + * Do the necessary conversions between VID and linear data format.
> + */
> +static int stpddc60_read_word_data(struct i2c_client *client, int page,
> +                                int phase, int reg)
> +{
> +     int ret;
> +
> +     if (page > 0)
> +             return -ENXIO;
> +
> +     switch (reg) {
> +     case PMBUS_READ_VOUT:
> +             ret = pmbus_read_word_data(client, page, phase, reg);
> +             if (ret < 0)
> +                     return ret;
> +             ret = stpddc60_mv2l(stpddc60_vid2mv(ret));

It might possibly be simpler to just return the value reported
by MFR_READ_VOUT. 

> +             break;
> +     case PMBUS_VOUT_OV_FAULT_LIMIT:
> +     case PMBUS_VOUT_UV_FAULT_LIMIT:
> +             ret = pmbus_read_word_data(client, page, phase, reg);
> +             if (ret < 0)
> +                     return ret;
> +             ret &= 0x07ff;

This needs explanation. The BMR481 datasheet does not suggest that only
11 bits are valid.

> +             break;
> +     default:
> +             ret = -ENODATA;
> +             break;
> +     }
> +
> +     return ret;
> +}
> +
> +/*
> + * The vout under- and over-voltage limits are readonly for this chip.
> + */

Not really. The BMR481 datasheet suggests that the value can be changed
by writing to MFR_OV_LIMIT_OFFSET and MFR_UV_LIMIT_OFFSET.
I am not saying that you should implement that if you don't want to,
but I would suggest a better (more accurate) explanation.

> +static int stpddc60_write_word_data(struct i2c_client *client, int page,
> +                                 int reg, u16 word)
> +{
> +     int ret;
> +
> +     if (page > 0)
> +             return -ENXIO;
> +
> +     switch (reg) {
> +     case PMBUS_VOUT_OV_FAULT_LIMIT:
> +             ret = -EACCES;
> +             break;
> +     case PMBUS_VOUT_UV_FAULT_LIMIT:
> +             ret = -EACCES;
> +             break;
> +     default:
> +             ret = -ENODATA;
> +             break;
> +     }
> +
> +     return ret;
> +}
> +
> +static int stpddc60_probe(struct i2c_client *client,
> +                       const struct i2c_device_id *id)
> +{
> +     int status;
> +     u8 device_id[I2C_SMBUS_BLOCK_MAX + 1];
> +     const struct i2c_device_id *mid;
> +     struct pmbus_driver_info *info = &stpddc60_info;
> +
> +     if (!i2c_check_functionality(client->adapter,
> +                                  I2C_FUNC_SMBUS_READ_BYTE_DATA
> +                                  | I2C_FUNC_SMBUS_BLOCK_DATA))
> +             return -ENODEV;
> +
> +     status = i2c_smbus_read_block_data(client, PMBUS_MFR_MODEL, device_id);
> +     if (status < 0) {
> +             dev_err(&client->dev, "Failed to read Manufacturer Model\n");
> +             return status;
> +     }
> +     for (mid = stpddc60_id; mid->name[0]; mid++) {
> +             if (!strncasecmp(mid->name, device_id, strlen(mid->name)))
> +                     break;
> +     }
> +     if (!mid->name[0]) {
> +             dev_err(&client->dev, "Unsupported device\n");
> +             return -ENODEV;
> +     }
> +
> +     info->read_byte_data = stpddc60_read_byte_data;
> +     info->read_word_data = stpddc60_read_word_data;
> +     info->write_word_data = stpddc60_write_word_data;
> +
> +     return pmbus_do_probe(client, info);
> +}
> +
> +static struct i2c_driver stpddc60_driver = {
> +     .driver = {
> +                .name = "stpddc60",
> +                },
> +     .probe = stpddc60_probe,

Please use the probe_new function callback (no id parameter).

> +     .id_table = stpddc60_id,
> +};
> +
> +module_i2c_driver(stpddc60_driver);
> +
> +MODULE_AUTHOR("Erik Rosen <[email protected]>");
> +MODULE_DESCRIPTION("PMBus driver for ST STPDDC60");
> +MODULE_LICENSE("GPL");
> -- 
> 2.20.1
> 

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