[RFC PATCH 4/4] pmbus: Add MAX31785 driver

From: Andrew Jeffery
Date: Mon Jul 10 2017 - 09:57:40 EST

Signed-off-by: Andrew Jeffery <andrew@xxxxxxxx>
---
drivers/hwmon/pmbus/Kconfig | 10 ++
drivers/hwmon/pmbus/Makefile | 1 +
drivers/hwmon/pmbus/max31785.c | 201 +++++++++++++++++++++++++++++++++++++++++
3 files changed, 212 insertions(+)
create mode 100644 drivers/hwmon/pmbus/max31785.c

diff --git a/drivers/hwmon/pmbus/Kconfig b/drivers/hwmon/pmbus/Kconfig
index cad1229b7e17..5f2f3c6c7499 100644
--- a/drivers/hwmon/pmbus/Kconfig
+++ b/drivers/hwmon/pmbus/Kconfig
@@ -95,6 +95,16 @@ config SENSORS_MAX20751
This driver can also be built as a module. If so, the module will
be called max20751.

+config SENSORS_MAX31785
+ tristate "Maxim MAX31785 and compatibles"
+ default n
+ help
+ If you say yes here you get hardware monitoring support for Maxim
+ MAX31785.
+
+ This driver can also be built as a module. If so, the module will
+ be called max31785.
+
config SENSORS_MAX34440
tristate "Maxim MAX34440 and compatibles"
default n
diff --git a/drivers/hwmon/pmbus/Makefile b/drivers/hwmon/pmbus/Makefile
index 24ff7ee7f8bb..acba1be0d9ad 100644
--- a/drivers/hwmon/pmbus/Makefile
+++ b/drivers/hwmon/pmbus/Makefile
@@ -10,6 +10,7 @@ obj-$(CONFIG_SENSORS_PMBUS) += pmbus.o
# obj-$(CONFIG_SENSORS_LTC3815) += ltc3815.o
# obj-$(CONFIG_SENSORS_MAX16064) += max16064.o
# obj-$(CONFIG_SENSORS_MAX20751) += max20751.o
+obj-$(CONFIG_SENSORS_MAX31785) += max31785.o
# obj-$(CONFIG_SENSORS_MAX34440) += max34440.o
# obj-$(CONFIG_SENSORS_MAX8688) += max8688.o
# obj-$(CONFIG_SENSORS_TPS40422) += tps40422.o
diff --git a/drivers/hwmon/pmbus/max31785.c b/drivers/hwmon/pmbus/max31785.c
new file mode 100644
index 000000000000..8432ed5a0ad6
--- /dev/null
+++ b/drivers/hwmon/pmbus/max31785.c
@@ -0,0 +1,201 @@
+/*
+ * Copyright (C) 2017 IBM Corp.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include "pmbus.h"
+
+enum max31785_regs {
+ PMBUS_MFR_FAN_CONFIG = 0xF1,
+ PMBUS_MFR_READ_FAN_PWM = 0xF3,
+ PMBUS_MFR_FAN_FAULT_LIMIT = 0xF5,
+ PMBUS_MFR_FAN_WARN_LIMIT = 0xF6,
+ PMBUS_MFR_FAN_PWM_AVG = 0xF8,
+};
+
+static const struct pmbus_coeffs fan_coeffs[] = {
+ [percent] = { .m = 1, .b = 0, .R = 2 },
+ [rpm] = { .m = 1, .b = 0, .R = 0 },
+};
+
+static const struct pmbus_coeffs *max31785_get_fan_coeffs(
+ const struct pmbus_driver_info *info, int index,
+ enum pmbus_fan_mode mode, int command)
+{
+ switch (command) {
+ case PMBUS_FAN_COMMAND_1:
+ case PMBUS_MFR_FAN_FAULT_LIMIT:
+ case PMBUS_MFR_FAN_WARN_LIMIT:
+ return &fan_coeffs[mode];
+ case PMBUS_READ_FAN_SPEED_1:
+ return &fan_coeffs[rpm];
+ case PMBUS_MFR_FAN_PWM_AVG:
+ return &fan_coeffs[percent];
+ default:
+ break;
+ }
+
+ return NULL;
+}
+
+static int max31785_get_pwm_mode(int id, u8 fan_config, u16 fan_command)
+{
+ enum pmbus_fan_mode mode;
+
+ /* MAX31785 only supports fan 1 on the fan pages */
+ if (WARN_ON(id > 0))
+ return -ENODEV;
+
+ mode = (fan_config & PB_FAN_1_RPM) ? rpm : percent;
+
+ switch (mode) {
+ case percent:
+ if (fan_command >= 0x8000)
+ return 2;
+ else if (fan_command >= 0x2711)
+ return 0;
+ else
+ return 1;
+ case rpm:
+ if (fan_command >= 0x8000)
+ return 2;
+ else
+ return 1;
+ break;
+ }
+
+ return 0;
+}
+
+static const int max31785_pwm_modes[] = { 0x7fff, 0x2710, 0xffff };
+
+int max31785_set_pwm_mode(int id, long mode, u8 *fan_config, u16 *fan_command)
+{
+ /* MAX31785 only supports fan 1 on the fan pages */
+ if (WARN_ON(id > 0))
+ return -ENODEV;
+
+ *fan_config &= ~PB_FAN_1_RPM;
+
+ if (mode >= ARRAY_SIZE(max31785_pwm_modes))
+ return -ENOTSUPP;
+
+ *fan_command = max31785_pwm_modes[mode];
+
+ return 0;
+}
+
+static struct pmbus_driver_info max31785_info = {
+ .pages = 23,
+
+ .get_fan_coeffs = max31785_get_fan_coeffs,
+ .get_pwm_mode = max31785_get_pwm_mode,
+ .set_pwm_mode = max31785_set_pwm_mode,
+
+ .format[PSC_FAN] = direct,
+ .func[0] = PMBUS_HAVE_FAN12 | PMBUS_HAVE_STATUS_FAN12,
+ .func[1] = PMBUS_HAVE_FAN12 | PMBUS_HAVE_STATUS_FAN12,
+ .func[2] = PMBUS_HAVE_FAN12 | PMBUS_HAVE_STATUS_FAN12,
+ .func[3] = PMBUS_HAVE_FAN12 | PMBUS_HAVE_STATUS_FAN12,
+ .func[4] = PMBUS_HAVE_FAN12 | PMBUS_HAVE_STATUS_FAN12,
+ .func[5] = PMBUS_HAVE_FAN12 | PMBUS_HAVE_STATUS_FAN12,
+
+ .format[PSC_TEMPERATURE] = direct,
+ .coeffs[PSC_TEMPERATURE].m = 1,
+ .coeffs[PSC_TEMPERATURE].b = 0,
+ .coeffs[PSC_TEMPERATURE].R = 2,
+ .func[6] = PMBUS_HAVE_STATUS_TEMP,
+ .func[7] = PMBUS_HAVE_STATUS_TEMP,
+ .func[8] = PMBUS_HAVE_STATUS_TEMP,
+ .func[9] = PMBUS_HAVE_STATUS_TEMP,
+ .func[10] = PMBUS_HAVE_STATUS_TEMP,
+ .func[11] = PMBUS_HAVE_STATUS_TEMP,
+ .func[12] = PMBUS_HAVE_STATUS_TEMP,
+ .func[13] = PMBUS_HAVE_STATUS_TEMP,
+ .func[14] = PMBUS_HAVE_STATUS_TEMP,
+ .func[15] = PMBUS_HAVE_STATUS_TEMP,
+ .func[16] = PMBUS_HAVE_STATUS_TEMP,
+
+ .format[PSC_VOLTAGE_OUT] = direct,
+ .coeffs[PSC_VOLTAGE_OUT].m = 1,
+ .coeffs[PSC_VOLTAGE_OUT].b = 0,
+ .coeffs[PSC_VOLTAGE_OUT].R = 0,
+ .func[17] = PMBUS_HAVE_STATUS_VOUT,
+ .func[18] = PMBUS_HAVE_STATUS_VOUT,
+ .func[19] = PMBUS_HAVE_STATUS_VOUT,
+ .func[20] = PMBUS_HAVE_STATUS_VOUT,
+ .func[21] = PMBUS_HAVE_STATUS_VOUT,
+ .func[22] = PMBUS_HAVE_STATUS_VOUT,
+};
+
+#define MFR_FAN_CONFIG_TSFO BIT(9)
+#define MFR_FAN_CONFIG_TACHO BIT(8)
+
+static int max31785_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ int rv;
+ int i;
+
+ rv = pmbus_do_probe(client, id, &max31785_info);
+ if (rv < 0)
+ return rv;
+
+ for (i = 0; i < max31785_info.pages; i++) {
+ int reg;
+
+ if (!(max31785_info.func[i] & (PMBUS_HAVE_FAN12)))
+ continue;
+
+ reg = pmbus_read_word_data(client, i, PMBUS_MFR_FAN_CONFIG);
+ if (reg < 0)
+ continue;
+
+ /*
+ * XXX: Purely for RFC/testing purposes, don't ramp fans on fan
+ * or temperature sensor fault, or a failure to write
+ * FAN_COMMAND_1 inside a 10s window (watchdog mode).
+ *
+ * The TSFO bit controls both ramping on temp sensor failure
+ * AND whether FAN_COMMAND_1 is in watchdog mode.
+ */
+ reg = (reg | MFR_FAN_CONFIG_TSFO | MFR_FAN_CONFIG_TACHO);
+ reg &= 0xffff;
+
+ rv = pmbus_write_word_data(client, i, PMBUS_MFR_FAN_CONFIG,
+ reg);
+ }
+
+ return 0;
+}
+
+static const struct i2c_device_id max31785_id[] = {
+ { "max31785", 0 },
+ { },
+};
+
+MODULE_DEVICE_TABLE(i2c, max31785_id);
+
+static struct i2c_driver max31785_driver = {
+ .driver = {
+ .name = "max31785",
+ },
+ .probe = max31785_probe,
+ .remove = pmbus_do_remove,
+ .id_table = max31785_id,
+};
+
+module_i2c_driver(max31785_driver);
+
+MODULE_AUTHOR("Andrew Jeffery <andrew@xxxxxxxx>");
+MODULE_DESCRIPTION("PMBus driver for the Maxim MAX31785");
+MODULE_LICENSE("GPL");
--
2.11.0