On 26/11/22 18:50, Guenter Roeck wrote:
On 11/26/22 09:17, Saravanan Sekar wrote:
The MPQ7932 is a power management IC designed to operate from 5V buses to
power a variety of ADAS SOCs. Six integrated buck converters power a
variety of target rails configurable over PMBus interface.
Signed-off-by: Saravanan Sekar <saravanan@xxxxxxxxxxx>
Hello Guenter,
Thanks for your time to review.
I find no reference to this chip anywhere. Can you provide one ?
I have Preliminary specification under NDA, checking with manufactures
upload in public accessibility.
Also, please refrain from cryptic abbreviations. You may know what
ADAS means, but I have no idea.
Sure
---
drivers/hwmon/pmbus/Kconfig | 9 ++
drivers/hwmon/pmbus/Makefile | 1 +
drivers/hwmon/pmbus/mpq7932.c | 150 ++++++++++++++++++++++++++++++++++
3 files changed, 160 insertions(+)
create mode 100644 drivers/hwmon/pmbus/mpq7932.c
diff --git a/drivers/hwmon/pmbus/Kconfig b/drivers/hwmon/pmbus/Kconfig
index 89668af67206..5e938768bd77 100644
--- a/drivers/hwmon/pmbus/Kconfig
+++ b/drivers/hwmon/pmbus/Kconfig
@@ -317,6 +317,15 @@ config SENSORS_MP5023
This driver can also be built as a module. If so, the module will
be called mp5023.
+config SENSORS_MPQ7932_REGULATOR
Drop "_REGULATOR".
+ tristate "MPS MPQ7932 buck regulator"
+ help
+ If you say yes here you get six integrated buck converter
+ regulator support for power management IC MPS MPQ7932.
+
This primarily adds hardware monitoring support. Referring to it
only as regulator is misleading. Please also refer to hardware
monitoring functionality. More on that below.
okay
+ This driver can also be built as a module. If so, the module will
+ be called mpq7932.
+
config SENSORS_PIM4328
tristate "Flex PIM4328 and compatibles"
help
diff --git a/drivers/hwmon/pmbus/Makefile b/drivers/hwmon/pmbus/Makefile
index 0002dbe22d52..28a534629cc3 100644
--- a/drivers/hwmon/pmbus/Makefile
+++ b/drivers/hwmon/pmbus/Makefile
@@ -34,6 +34,7 @@ obj-$(CONFIG_SENSORS_MAX8688) += max8688.o
obj-$(CONFIG_SENSORS_MP2888) += mp2888.o
obj-$(CONFIG_SENSORS_MP2975) += mp2975.o
obj-$(CONFIG_SENSORS_MP5023) += mp5023.o
+obj-$(CONFIG_SENSORS_MPQ7932_REGULATOR) += mpq7932.o
obj-$(CONFIG_SENSORS_PLI1209BC) += pli1209bc.o
obj-$(CONFIG_SENSORS_PM6764TR) += pm6764tr.o
obj-$(CONFIG_SENSORS_PXE1610) += pxe1610.o
diff --git a/drivers/hwmon/pmbus/mpq7932.c
b/drivers/hwmon/pmbus/mpq7932.c
new file mode 100644
index 000000000000..23d3ccdaed1e
--- /dev/null
+++ b/drivers/hwmon/pmbus/mpq7932.c
@@ -0,0 +1,150 @@
+// SPDX-License-Identifier: GPL-2.0+
+//
+// mpq7932.c - regulator driver for mps mpq7932
+//
+// Copyright 2022 Monolithic Power Systems, Inc
+//
+// Author: Saravanan Sekar <saravanan@xxxxxxxxxxx>
+
No C++ comments in hwmon subsystem, please, unless mandated.
okay
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/err.h>
+#include <linux/of_device.h>
+#include <linux/pmbus.h>
+#include <linux/i2c.h>
Alphabetic include file order, please.
okay
+#include "pmbus.h"
+
+#define MPQ7932_BUCK_UV_MIN 206250
+#define MPQ7932_UV_STEP 6250
+#define MPQ7932_N_VOLTAGES 0xFF
+#define MPQ7932_NUM_PAGES 6
+
+#define MPQ7932_TON_DELAY 0x60
+#define MPQ7932_VOUT_STARTUP_SLEW 0xA3
+#define MPQ7932_VOUT_SHUTDOWN_SLEW 0xA5
+#define MPQ7932_VOUT_SLEW_MASK GENMASK(1, 0)
+#define MPQ7932_TON_DELAY_MASK GENMASK(4, 0)
+
+#define MPQ7932BUCK(_id) \
+ [_id] = { \
+ .id = _id, \
+ .name = ("buck" # _id), \
+ .of_match = of_match_ptr("buck" # _id), \
+ .regulators_node = "regulators", \
+ .ops = &pmbus_regulator_ops, \
+ .type = REGULATOR_VOLTAGE, \
+ .min_uV = MPQ7932_BUCK_UV_MIN, \
+ .uV_step = MPQ7932_UV_STEP, \
+ .n_voltages = MPQ7932_N_VOLTAGES, \
+ }
Why not use PMBUS_REGULATOR_STEP ?
MPQ7932 chip supports ramp delay and softstart which is not covered
by PMBUS_REGULATOR_STEP, I have incremental patch to address which
requires API's in pmbus_regulator_ops to be exported so chip driver
can extend/modifiy with reuse of pmbus_regulator api. Plan is to submit
1st set of minimal driver and create RFC.
I can replace PMBUS_REGULATOR_STEP for this series.
>> +
+struct mpq7932_data {
+ struct pmbus_driver_info info;
+ struct pmbus_platform_data pdata;
+};
+
+static struct regulator_desc mpq7932_regulators_desc[] = {
+ MPQ7932BUCK(0),
+ MPQ7932BUCK(1),
+ MPQ7932BUCK(2),
+ MPQ7932BUCK(3),
+ MPQ7932BUCK(4),
+ MPQ7932BUCK(5),
+};
+
+static int mpq7932_write_word_data(struct i2c_client *client, int
page, int reg,
+ u16 word)
+{
+
+ switch (reg) {
+ case PMBUS_VOUT_COMMAND:
+ return pmbus_write_byte_data(client, page, reg, (u8)word);
+
This needs explanation. VOUT_COMMAND directly sets a voltage, and the
provided
value is in ULINEAR16 format. Just using its lower 8 bits seems, at the
very
least, odd.
Indeed, unfortunately word_write results -EREMOTEIO and got clarified
with manufacture chip support only byte write except STATUS_WORD :(
+ default:
+ return -ENODATA;
+ }
+}
+
+static int mpq7932_read_word_data(struct i2c_client *client, int page,
+ int phase, int reg)
+{
+
+ switch (reg) {
+ case PMBUS_MFR_VOUT_MIN:
+ return 0;
+
+ case PMBUS_MFR_VOUT_MAX:
+ return MPQ7932_N_VOLTAGES;
+
This is not how this is intended to work. If the chip does not provide
those properties, they should not be faked.
Unfortunately, chip support neither
PMBUS_VOUT_MARGIN_HIGH = 0x25,
PMBUS_VOUT_MARGIN_LOW = 0x26,
nor
PMBUS_MFR_VOUT_MIN = 0xA4,
PMBUS_MFR_VOUT_MAX = 0xA5
as a result set voltage fails due to error in
pmbus_regulator_get_low_margin. I can understand these absolute
workaround, please suggest alternatives
+ case PMBUS_READ_VOUT:
+ return pmbus_read_byte_data(client, page, PMBUS_VOUT_COMMAND);
+
+ default:
+ return -ENODATA;
+ }
+}
+
+static int mpq7932_probe(struct i2c_client *client)
+{
+ struct mpq7932_data *data;
+ struct pmbus_driver_info *info;
+ struct device *dev = &client->dev;
+ int i;
+
+ if (!i2c_check_functionality(client->adapter,
+ I2C_FUNC_SMBUS_READ_WORD_DATA))
+ return -ENODEV;
+
+ data = devm_kzalloc(&client->dev, sizeof(struct mpq7932_data),
+ GFP_KERNEL);
+ if (!data)
+ return -ENOMEM;
+
+ info = &data->info;
+ info->pages = MPQ7932_NUM_PAGES;
+ info->num_regulators = ARRAY_SIZE(mpq7932_regulators_desc);
+ info->reg_desc = mpq7932_regulators_desc;
+ info->format[PSC_VOLTAGE_OUT] = direct;
+ info->m[PSC_VOLTAGE_OUT] = 160;
+ info->b[PSC_VOLTAGE_OUT] = -33;
+ for (i = 0; i < info->pages; i++) {
+ info->func[i] = PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT
+ | PMBUS_HAVE_STATUS_TEMP;
+ }
+
Is that really all the chip supports ? No input data, no current
or power measurements ?
Is this even a real PMBus chip, or a fake one which claims to support
PMBus but in reality doesn't ?
I would say this is PMIC buck regulator chip over PMBUS, I guess the
regulator support in pmbus shall be used without hardware monitor
support (though chip support temperature, error status, cml, status)
+ info->read_word_data = mpq7932_read_word_data;
+ info->write_word_data = mpq7932_write_word_data;
+
+ data->pdata.flags = PMBUS_NO_CAPABILITY;
+ dev->platform_data = &data->pdata;
+
+ return pmbus_do_probe(client, info);
+}
+
+static const struct of_device_id mpq7932_of_match[] = {
+ { .compatible = "mps,mpq7932"},
+ {},
+};
+MODULE_DEVICE_TABLE(of, mpq7932_of_match);
+
+static const struct i2c_device_id mpq7932_id[] = {
+ { "mpq7932", },
+ { },
+};
+MODULE_DEVICE_TABLE(i2c, mpq7932_id);
+
+static struct i2c_driver mpq7932_regulator_driver = {
PMBus drivers are not primarily regulator drivers. They
are hardware monitoring drivers. It is difficult for me to
determine, due to lack of information about this chip,
what it actually supports. If the chip is really a regulator
masquerading as PMBus chip, you might want to consider writing
a regulator driver for it.
I try to share datasheet once I got permission from manufacturer.
Sure, I consider to write regulator driver over pmbus (addnl helper
support on regulator subsystem like regmap) if we conclude should not be
part of hwmon.
Guenter
+ .driver = {
+ .name = "mpq7932",
+ .of_match_table = of_match_ptr(mpq7932_of_match),
+ },
+ .probe_new = mpq7932_probe,
+ .id_table = mpq7932_id,
+};
+module_i2c_driver(mpq7932_regulator_driver);
+
+MODULE_AUTHOR("Saravanan Sekar <saravanan@xxxxxxxxxxx>");
+MODULE_DESCRIPTION("MPQ7932 PMIC regulator driver");
+MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS(PMBUS);
Thanks,
Saravanan
