Re: [PATCH 1/1] Add ST STPDDC60 pmbus driver

From: Guenter Roeck
Date: Wed Jan 27 2021 - 12:39:04 EST

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In reply to: Erik Rosen: "[PATCH 1/1] Add ST STPDDC60 pmbus driver"
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On Wed, Jan 27, 2021 at 09:41:40AM +0100, Erik Rosen wrote:
> Add ST STPDDC60 pmbus client driver.
>
> Signed-off-by: Erik Rosen <erik.rosen@xxxxxxxxxxxxx>
> ---
> 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 <erik.rosen@xxxxxxxxxxxxx>
> +
> +
> +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: linux-i2c@xxxxxxxxxxxxxxx
> S: Maintained
> F: drivers/i2c/busses/i2c-stm32*
>
> +ST STPDDC60 DRIVER
> +M: Daniel Nilsson <daniel.nilsson@xxxxxxxx>
> +L: linux-hwmon@xxxxxxxxxxxxxxx
> +S: Maintained
> +F: Documentation/hwmon/stpddc60.rst
> +F: drivers/hwmon/pmbus/stpddc60.c
> +
> ST VL53L0X ToF RANGER(I2C) IIO DRIVER
> M: Song Qiang <songqiang1304521@xxxxxxxxx>
> L: linux-iio@xxxxxxxxxxxxxxx
> 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 <erik.rosen@xxxxxxxxxxxxx>");
> +MODULE_DESCRIPTION("PMBus driver for ST STPDDC60");
> +MODULE_LICENSE("GPL");
> --
> 2.20.1
>

Next message: Rob Herring: "Re: [PATCH] PCI: xilinx-nwl: Enable coherenct PCIe traffic using CCI"
Previous message: Mark Brown: "Re: [PATCH] regulator: core: avoid error messages for deferred probing"
In reply to: Erik Rosen: "[PATCH 1/1] Add ST STPDDC60 pmbus driver"
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