Messages in this thread | | | Date | Tue, 21 Nov 2023 08:13:42 -0800 | Subject | Re: [PATCH v6 2/2] hwmon: pmbus: Add ltc4286 driver | From | Guenter Roeck <> |
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On 11/20/23 21:07, Delphine CC Chiu wrote: > Add a driver to support ltc4286 chip > > Signed-off-by: Delphine CC Chiu <Delphine_CC_Chiu@Wiwynn.com> > --- > Changelog: > v6 - Check VRANGE_SELECT before driver loading > v5 - Check the overflow when reading rsense > - Set default rsense value > v4 - Add empty line before "config SENSORS_LTC4286" in Kconfig > - Add ltc4286 to Documentation/hwmon/index.rst > - Revise comment typo > - Use devm_kmemdup instead of memcpy > - Check MBR value before writting into > v3 - Use dev_err_probe() instead of dev_err() > - The VRANGE_SELECT bit only be written if it actually changed > - Avoid the info pointer being overwritten > - Check the MBR value range to avoid overflow > - Revise ltc4286.rst to corrcet description > v2 - Revise Linear Technologies LTC4286 to > Analog Devices LTC4286 in Kconfig > - Add more description for this driver in Kconfig > - Add some comments for MBR setting in ltc4286.c > - Add ltc4286.rst > --- > Documentation/hwmon/index.rst | 1 + > Documentation/hwmon/ltc4286.rst | 95 +++++++++++++++++ > drivers/hwmon/pmbus/Kconfig | 10 ++ > drivers/hwmon/pmbus/Makefile | 1 + > drivers/hwmon/pmbus/ltc4286.c | 183 ++++++++++++++++++++++++++++++++ > 5 files changed, 290 insertions(+) > create mode 100644 Documentation/hwmon/ltc4286.rst > create mode 100644 drivers/hwmon/pmbus/ltc4286.c > > diff --git a/Documentation/hwmon/index.rst b/Documentation/hwmon/index.rst > index 72f4e6065bae..080827cc4c34 100644 > --- a/Documentation/hwmon/index.rst > +++ b/Documentation/hwmon/index.rst > @@ -128,6 +128,7 @@ Hardware Monitoring Kernel Drivers > ltc4245 > ltc4260 > ltc4261 > + ltc4286 > max127 > max15301 > max16064 > diff --git a/Documentation/hwmon/ltc4286.rst b/Documentation/hwmon/ltc4286.rst > new file mode 100644 > index 000000000000..2cd149676d86 > --- /dev/null > +++ b/Documentation/hwmon/ltc4286.rst > @@ -0,0 +1,95 @@ > +.. SPDX-License-Identifier: GPL-2.0-or-later > + > +Kernel driver ltc4286 > +===================== > + > +Supported chips: > + > + * Analog Devices LTC4286 > + > + Prefix: 'ltc4286' > + > + Addresses scanned: - > + > + Datasheet: https://www.analog.com/media/en/technical-documentation/data-sheets/ltc4286.pdf > + > + * Analog Devices LTC4287 > + > + Prefix: 'ltc4287' > + > + Addresses scanned: - > + > + Datasheet: https://www.analog.com/media/en/technical-documentation/data-sheets/ltc4287.pdf > + > +Author: Delphine CC Chiu <Delphine_CC_Chiu@Wiwynn.com> > + > + > +Description > +----------- > + > +This driver supports hardware monitoring for Analog Devices LTC4286 > +and LTC4287 Hot-Swap Controller and Digital Power Monitors. > + > +LTC4286 and LTC4287 are hot-swap controllers that allow a circuit board > +to be removed from or inserted into a live backplane. They also feature > +current and voltage readback via an integrated 12 bit analog-to-digital > +converter (ADC), accessed using a PMBus interface. > + > +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. > + > +The shunt value in micro-ohms can be set via device tree at compile-time. Please > +refer to the Documentation/devicetree/bindings/hwmon/lltc,ltc4286.yaml for bindings > +if the device tree is used. > + > + > +Platform data support > +--------------------- > + > +The driver supports standard PMBus driver platform data. Please see > +Documentation/hwmon/pmbus.rst for details. > + > + > +Sysfs entries > +------------- > + > +The following attributes are supported. Limits are read-write, history reset > +attributes are write-only, all other attributes are read-only. > + > +======================= ======================================================= > +in1_label "vin" > +in1_input Measured voltage. > +in1_alarm Input voltage alarm. > +in1_min Minimum input voltage. > +in1_max Maximum input voltage. > + > +in2_label "vout1" > +in2_input Measured voltage. > +in2_alarm Output voltage alarm. > +in2_min Minimum output voltage. > +in2_max Maximum output voltage. > + > +curr1_label "iout1" > +curr1_input Measured current. > +curr1_alarm Output current alarm. > +curr1_max Maximum current. > + > +power1_label "pin" > +power1_input Input power. > +power1_alarm Input power alarm. > +power1_max Maximum poewr. > + > +temp1_input Chip temperature. > +temp1_min Minimum chip temperature. > +temp1_max Maximum chip temperature. > +temp1_crit Critical chip temperature. > +temp1_alarm Chip temperature alarm. > +======================= ======================================================= > diff --git a/drivers/hwmon/pmbus/Kconfig b/drivers/hwmon/pmbus/Kconfig > index b4e93bd5835e..2d4f972e5a65 100644 > --- a/drivers/hwmon/pmbus/Kconfig > +++ b/drivers/hwmon/pmbus/Kconfig > @@ -227,6 +227,16 @@ config SENSORS_LTC3815 > This driver can also be built as a module. If so, the module will > be called ltc3815. > > +config SENSORS_LTC4286 > + bool "Analog Devices LTC4286" > + help > + LTC4286 is an integrated solution for hot swap applications that > + allows a board to be safely inserted and removed from a live > + backplane. > + This chip could be used to monitor voltage, current, ...etc. > + If you say yes here you get hardware monitoring support for Analog > + Devices LTC4286. > + > config SENSORS_MAX15301 > tristate "Maxim MAX15301" > help > diff --git a/drivers/hwmon/pmbus/Makefile b/drivers/hwmon/pmbus/Makefile > index 84ee960a6c2d..94e28f6d6a61 100644 > --- a/drivers/hwmon/pmbus/Makefile > +++ b/drivers/hwmon/pmbus/Makefile > @@ -24,6 +24,7 @@ obj-$(CONFIG_SENSORS_LM25066) += lm25066.o > obj-$(CONFIG_SENSORS_LT7182S) += lt7182s.o > obj-$(CONFIG_SENSORS_LTC2978) += ltc2978.o > obj-$(CONFIG_SENSORS_LTC3815) += ltc3815.o > +obj-$(CONFIG_SENSORS_LTC4286) += ltc4286.o > obj-$(CONFIG_SENSORS_MAX15301) += max15301.o > obj-$(CONFIG_SENSORS_MAX16064) += max16064.o > obj-$(CONFIG_SENSORS_MAX16601) += max16601.o > diff --git a/drivers/hwmon/pmbus/ltc4286.c b/drivers/hwmon/pmbus/ltc4286.c > new file mode 100644 > index 000000000000..e43e05579be1 > --- /dev/null > +++ b/drivers/hwmon/pmbus/ltc4286.c > @@ -0,0 +1,183 @@ > +// SPDX-License-Identifier: GPL-2.0-or-later > + > +#include <linux/err.h> > +#include <linux/i2c.h> > +#include <linux/init.h> > +#include <linux/kernel.h> > +#include <linux/module.h> > +#include <linux/pmbus.h> > +#include "pmbus.h" > + > +/* LTC4286 register */ > +#define LTC4286_MFR_CONFIG1 0xF2 > + > +/* LTC4286 configuration */ > +#define VRANGE_SELECT_BIT BIT(1) > + > +#define LTC4286_MFR_ID_SIZE 3 > +#define VRANGE_102P4 1 > + > +/* > + * Initialize the MBR as default settings which is referred to LTC4286 datasheet > + * (March 22, 2022 version) table 3 page 16 > + */ > +static struct pmbus_driver_info ltc4286_info = { > + .pages = 1, > + .format[PSC_VOLTAGE_IN] = direct, > + .format[PSC_VOLTAGE_OUT] = direct, > + .format[PSC_CURRENT_OUT] = direct, > + .format[PSC_POWER] = direct, > + .format[PSC_TEMPERATURE] = direct, > + .m[PSC_VOLTAGE_IN] = 32, > + .b[PSC_VOLTAGE_IN] = 0, > + .R[PSC_VOLTAGE_IN] = 1, > + .m[PSC_VOLTAGE_OUT] = 32, > + .b[PSC_VOLTAGE_OUT] = 0, > + .R[PSC_VOLTAGE_OUT] = 1, > + .m[PSC_CURRENT_OUT] = 1024, > + .b[PSC_CURRENT_OUT] = 0, > + /* > + * The rsense value used in MBR formula in LTC4286 datasheet should be ohm unit. > + * However, the rsense value that user input is micro ohm. > + * Thus, the MBR setting which involves rsense should be shifted by 6 digits. > + */ > + .R[PSC_CURRENT_OUT] = 3 - 6, > + .m[PSC_POWER] = 1, > + .b[PSC_POWER] = 0, > + /* > + * The rsense value used in MBR formula in LTC4286 datasheet should be ohm unit. > + * However, the rsense value that user input is micro ohm. > + * Thus, the MBR setting which involves rsense should be shifted by 6 digits. > + */ > + .R[PSC_POWER] = 4 - 6, > + .m[PSC_TEMPERATURE] = 1, > + .b[PSC_TEMPERATURE] = 273, > + .R[PSC_TEMPERATURE] = 0, > + .func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_VOUT | PMBUS_HAVE_IOUT | > + PMBUS_HAVE_PIN | PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_VOUT | > + PMBUS_HAVE_STATUS_IOUT | PMBUS_HAVE_STATUS_TEMP, > +}; > + > +static const struct i2c_device_id ltc4286_id[] = { > + { "ltc4286", 0 }, > + { "ltc4287", 1 }, > + {} > +}; > +MODULE_DEVICE_TABLE(i2c, ltc4286_id); > + > +static int ltc4286_probe(struct i2c_client *client) > +{ > + int ret; > + const struct i2c_device_id *mid; > + u8 block_buffer[I2C_SMBUS_BLOCK_MAX + 1]; > + struct pmbus_driver_info *info; > + u32 rsense; > + > + ret = i2c_smbus_read_block_data(client, PMBUS_MFR_ID, block_buffer); > + if (ret < 0) { > + return dev_err_probe(&client->dev, ret, > + "Failed to read manufacturer id\n"); > + } > + > + /* > + * Refer to ltc4286 datasheet page 20 > + * the manufacturer id is LTC > + */ > + if (ret != LTC4286_MFR_ID_SIZE || > + strncmp(block_buffer, "LTC", LTC4286_MFR_ID_SIZE)) { > + return dev_err_probe(&client->dev, ret, > + "Manufacturer id mismatch\n"); > + } > + > + ret = i2c_smbus_read_block_data(client, PMBUS_MFR_MODEL, block_buffer); > + if (ret < 0) { > + return dev_err_probe(&client->dev, ret, > + "Failed to read manufacturer model\n"); > + } > + > + for (mid = ltc4286_id; mid->name[0]; mid++) { > + if (!strncasecmp(mid->name, block_buffer, strlen(mid->name))) > + break; > + } > + if (!mid->name[0]) > + return dev_err_probe(&client->dev, -ENODEV, > + "Unsupported device\n"); > + > + if (of_property_read_u32(client->dev.of_node, > + "shunt-resistor-micro-ohms", &rsense)) > + rsense = 300; /* 0.3 mOhm if not set via DT */ > + > + if (rsense == 0) > + return -EINVAL; > + > + /* Check for the latter MBR value won't overflow */ > + if (rsense > (INT_MAX / 1024)) > + return -EINVAL; > + > + info = devm_kmemdup(&client->dev, <c4286_info, sizeof(*info), > + GFP_KERNEL); > + if (!info) > + return -ENOMEM; > + > + /* Check MFR1 CONFIG register bit 1 VRANGE_SELECT before driver loading */ > + ret = i2c_smbus_read_word_data(client, LTC4286_MFR_CONFIG1); > + if (ret < 0) > + return dev_err_probe( > + &client->dev, ret, > + "Failed to read manufacturer configuration one\n"); > + > + if (device_property_read_bool(&client->dev, "adi,vrange-low-enable")) { > + /* The voltage range is 102.4 volts now */ > + if (ret == VRANGE_102P4) {
This has to check VRANGE_SELECT_BIT, not the entire register. Other register bit values are unknown.
if (ret & VRANGE_SELECT_BIT)
Alternatively, something like int new, orig; ... orig = i2c_smbus_read_word_data(client, LTC4286_MFR_CONFIG1); if (orig < 0) return dev_err_probe(...); new = orig; if (device_property_read_bool(&client->dev, "adi,vrange-low-enable")) { new &= ~VRANGE_SELECT_BIT; info->m[PSC_VOLTAGE_IN] = 128; info->m[PSC_VOLTAGE_OUT] = 128; info->m[PSC_POWER] = 4 * rsense; } else { new |= VRANGE_SELECT_BIT; info->m[PSC_POWER] = rsense; } if (new != orig) { ret = i2c_smbus_write_word_data(client, LTC4286_MFR_CONFIG1, new); if (ret) return dev_err_probe(...); }
seems cleaner to me, but that is your call.
Guenter
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