--- /dev/null
+.. SPDX-License-Identifier: GPL-2.0
+
+Kernel driver max15301
+======================
+
+Supported chips:
+
+ * Maxim MAX15301
+
+ Prefix: 'max15301', 'bmr461'
+
+ Addresses scanned: -
+
+ Datasheet: https://datasheets.maximintegrated.com/en/ds/MAX15301.pdf
+
+Author: Erik Rosen <erik.rosen@metormote.com>
+
+
+Description
+-----------
+
+This driver supports hardware monitoring for Maxim MAX15301 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.
+
+
+Platform data support
+---------------------
+
+The driver supports standard PMBus driver platform data.
+
+
+Module parameters
+-----------------
+
+delay
+-----
+
+The controller requires a minimum interval between I2C bus accesses.
+The default interval is set to 100 us. For manual override, the driver
+provides a writeable module parameter, 'delay', which can be used to
+set the interval to a value between 0 and 65,535 microseconds.
+
+
+Sysfs entries
+-------------
+
+The following attributes are supported. 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_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.
+======================= ========================================================
--- /dev/null
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Hardware monitoring driver for Maxim MAX15301
+ *
+ * Copyright (c) 2021 Flextronics International Sweden AB
+ *
+ * Even though the specification does not specifically mention it,
+ * extensive empirical testing has revealed that auto-detection of
+ * limit-registers will fail in a random fashion unless the delay
+ * parameter is set to above about 80us. The default delay is set
+ * to 100us to include some safety margin.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/err.h>
+#include <linux/slab.h>
+#include <linux/i2c.h>
+#include <linux/ktime.h>
+#include <linux/delay.h>
+#include <linux/pmbus.h>
+#include "pmbus.h"
+
+static const struct i2c_device_id max15301_id[] = {
+ {"bmr461", 0},
+ {"max15301", 0},
+ {}
+};
+MODULE_DEVICE_TABLE(i2c, max15301_id);
+
+struct max15301_data {
+ int id;
+ ktime_t access; /* Chip access time */
+ int delay; /* Delay between chip accesses in us */
+ struct pmbus_driver_info info;
+};
+
+#define to_max15301_data(x) container_of(x, struct max15301_data, info)
+
+#define MAX15301_WAIT_TIME 100 /* us */
+
+static ushort delay = MAX15301_WAIT_TIME;
+module_param(delay, ushort, 0644);
+MODULE_PARM_DESC(delay, "Delay between chip accesses in us");
+
+static struct max15301_data max15301_data = {
+ .info = {
+ .pages = 1,
+ .func[0] = PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT
+ | PMBUS_HAVE_VIN | PMBUS_HAVE_STATUS_INPUT
+ | PMBUS_HAVE_TEMP | PMBUS_HAVE_TEMP2
+ | PMBUS_HAVE_STATUS_TEMP
+ | PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT,
+ }
+};
+
+/* This chip needs a delay between accesses */
+static inline void max15301_wait(const struct max15301_data *data)
+{
+ if (data->delay) {
+ s64 delta = ktime_us_delta(ktime_get(), data->access);
+
+ if (delta < data->delay)
+ udelay(data->delay - delta);
+ }
+}
+
+static int max15301_read_word_data(struct i2c_client *client, int page,
+ int phase, int reg)
+{
+ const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
+ struct max15301_data *data = to_max15301_data(info);
+ int ret;
+
+ if (page > 0)
+ return -ENXIO;
+
+ if (reg >= PMBUS_VIRT_BASE)
+ return -ENXIO;
+
+ max15301_wait(data);
+ ret = pmbus_read_word_data(client, page, phase, reg);
+ data->access = ktime_get();
+
+ return ret;
+}
+
+static int max15301_read_byte_data(struct i2c_client *client, int page, int reg)
+{
+ const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
+ struct max15301_data *data = to_max15301_data(info);
+ int ret;
+
+ if (page > 0)
+ return -ENXIO;
+
+ max15301_wait(data);
+ ret = pmbus_read_byte_data(client, page, reg);
+ data->access = ktime_get();
+
+ return ret;
+}
+
+static int max15301_write_word_data(struct i2c_client *client, int page, int reg,
+ u16 word)
+{
+ const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
+ struct max15301_data *data = to_max15301_data(info);
+ int ret;
+
+ if (page > 0)
+ return -ENXIO;
+
+ if (reg >= PMBUS_VIRT_BASE)
+ return -ENXIO;
+
+ max15301_wait(data);
+ ret = pmbus_write_word_data(client, page, reg, word);
+ data->access = ktime_get();
+
+ return ret;
+}
+
+static int max15301_write_byte(struct i2c_client *client, int page, u8 value)
+{
+ const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
+ struct max15301_data *data = to_max15301_data(info);
+ int ret;
+
+ if (page > 0)
+ return -ENXIO;
+
+ max15301_wait(data);
+ ret = pmbus_write_byte(client, page, value);
+ data->access = ktime_get();
+
+ return ret;
+}
+
+static int max15301_probe(struct i2c_client *client)
+{
+ int status;
+ u8 device_id[I2C_SMBUS_BLOCK_MAX + 1];
+ const struct i2c_device_id *mid;
+ struct pmbus_driver_info *info = &max15301_data.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_IC_DEVICE_ID, device_id);
+ if (status < 0) {
+ dev_err(&client->dev, "Failed to read Device Id\n");
+ return status;
+ }
+ for (mid = max15301_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;
+ }
+
+ max15301_data.delay = delay;
+
+ info->read_byte_data = max15301_read_byte_data;
+ info->read_word_data = max15301_read_word_data;
+ info->write_byte = max15301_write_byte;
+ info->write_word_data = max15301_write_word_data;
+
+ return pmbus_do_probe(client, info);
+}
+
+static struct i2c_driver max15301_driver = {
+ .driver = {
+ .name = "max15301",
+ },
+ .probe_new = max15301_probe,
+ .id_table = max15301_id,
+};
+
+module_i2c_driver(max15301_driver);
+
+MODULE_AUTHOR("Erik Rosen <erik.rosen@metormote.com>");
+MODULE_DESCRIPTION("PMBus driver for Maxim MAX15301");
+MODULE_LICENSE("GPL");
projects / platform / kernel / linux-rpi.git / commitdiff