--- /dev/null
+Kernel driver ltc2978
+=====================
+
+Supported chips:
+ * Linear Technology LTC2978
+ Prefix: 'ltc2978'
+ Addresses scanned: -
+ Datasheet: http://cds.linear.com/docs/Datasheet/2978fa.pdf
+
+Author: Guenter Roeck <guenter.roeck@ericsson.com>
+
+
+Description
+-----------
+
+The LTC2978 is an octal power supply monitor, supervisor, sequencer and
+margin controller.
+
+
+Usage Notes
+-----------
+
+This driver does not probe for PMBus devices. You will have to instantiate
+devices explicitly.
+
+Example: the following commands will load the driver for an LTC2978 at address
+0x60 on I2C bus #1:
+
+# modprobe ltc2978
+# echo ltc2978 0x60 > /sys/bus/i2c/devices/i2c-1/new_device
+
+
+Sysfs attributes
+----------------
+
+in1_label "vin"
+in1_input Measured input voltage.
+in1_min Minimum input voltage.
+in1_max Maximum input voltage.
+in1_lcrit Critical minimum input voltage.
+in1_crit Critical maximum input voltage.
+in1_min_alarm Input voltage low alarm.
+in1_max_alarm Input voltage high alarm.
+in1_lcrit_alarm Input voltage critical low alarm.
+in1_crit_alarm Input voltage critical high alarm.
+in1_lowest Lowest input voltage.
+in1_highest Highest input voltage.
+in1_reset_history Reset history. Writing into this attribute will reset
+ history for all attributes.
+
+in[2-9]_label "vout[1-8]".
+in[2-9]_input Measured output voltage.
+in[2-9]_min Minimum output voltage.
+in[2-9]_max Maximum output voltage.
+in[2-9]_lcrit Critical minimum output voltage.
+in[2-9]_crit Critical maximum output voltage.
+in[2-9]_min_alarm Output voltage low alarm.
+in[2-9]_max_alarm Output voltage high alarm.
+in[2-9]_lcrit_alarm Output voltage critical low alarm.
+in[2-9]_crit_alarm Output voltage critical high alarm.
+in[2-9]_lowest Lowest output voltage.
+in[2-9]_highest Lowest output voltage.
+in[2-9]_reset_history Reset history. Writing into this attribute will reset
+ history for all attributes.
+
+temp1_input Measured temperature.
+temp1_min Mimimum temperature.
+temp1_max Maximum temperature.
+temp1_lcrit Critical low temperature.
+temp1_crit Critical high temperature.
+temp1_min_alarm Chip temperature low alarm.
+temp1_max_alarm Chip temperature high alarm.
+temp1_lcrit_alarm Chip temperature critical low alarm.
+temp1_crit_alarm Chip temperature critical high alarm.
+temp1_lowest Lowest measured temperature.
+temp1_highest Highest measured temperature.
+temp1_reset_history Reset history. Writing into this attribute will reset
+ history for all attributes.
--- /dev/null
+/*
+ * Hardware monitoring driver for LTC2978
+ *
+ * Copyright (c) 2011 Ericsson AB.
+ *
+ * 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.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#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 "pmbus.h"
+
+enum chips { ltc2978 };
+
+#define LTC2978_MFR_VOUT_PEAK 0xdd
+#define LTC2978_MFR_VIN_PEAK 0xde
+#define LTC2978_MFR_TEMPERATURE_PEAK 0xdf
+#define LTC2978_MFR_SPECIAL_ID 0xe7
+
+#define LTC2978_MFR_VOUT_MIN 0xfb
+#define LTC2978_MFR_VIN_MIN 0xfc
+#define LTC2978_MFR_TEMPERATURE_MIN 0xfd
+
+#define LTC2978_ID_REV1 0x0121
+#define LTC2978_ID_REV2 0x0122
+
+/*
+ * LTC2978 clears peak data whenever the CLEAR_FAULTS command is executed, which
+ * happens pretty much each time chip data is updated. Raw peak data therefore
+ * does not provide much value. To be able to provide useful peak data, keep an
+ * internal cache of measured peak data, which is only cleared if an explicit
+ * "clear peak" command is executed for the sensor in question.
+ */
+struct ltc2978_data {
+ enum chips id;
+ int vin_min, vin_max;
+ int temp_min, temp_max;
+ int vout_min[8], vout_max[8];
+ struct pmbus_driver_info info;
+};
+
+#define to_ltc2978_data(x) container_of(x, struct ltc2978_data, info)
+
+static inline int lin11_to_val(int data)
+{
+ s16 e = ((s16)data) >> 11;
+ s32 m = (((s16)(data << 5)) >> 5);
+
+ /*
+ * mantissa is 10 bit + sign, exponent adds up to 15 bit.
+ * Add 6 bit to exponent for maximum accuracy (10 + 15 + 6 = 31).
+ */
+ e += 6;
+ return (e < 0 ? m >> -e : m << e);
+}
+
+static int ltc2978_read_word_data(struct i2c_client *client, int page, int reg)
+{
+ const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
+ struct ltc2978_data *data = to_ltc2978_data(info);
+ int ret;
+
+ switch (reg) {
+ case PMBUS_VIRT_READ_VIN_MAX:
+ ret = pmbus_read_word_data(client, page, LTC2978_MFR_VIN_PEAK);
+ if (ret >= 0) {
+ if (lin11_to_val(ret) > lin11_to_val(data->vin_max))
+ data->vin_max = ret;
+ ret = data->vin_max;
+ }
+ break;
+ case PMBUS_VIRT_READ_VOUT_MAX:
+ ret = pmbus_read_word_data(client, page, LTC2978_MFR_VOUT_PEAK);
+ if (ret >= 0) {
+ /*
+ * VOUT is 16 bit unsigned with fixed exponent,
+ * so we can compare it directly
+ */
+ if (ret > data->vout_max[page])
+ data->vout_max[page] = ret;
+ ret = data->vout_max[page];
+ }
+ break;
+ case PMBUS_VIRT_READ_TEMP_MAX:
+ ret = pmbus_read_word_data(client, page,
+ LTC2978_MFR_TEMPERATURE_PEAK);
+ if (ret >= 0) {
+ if (lin11_to_val(ret) > lin11_to_val(data->temp_max))
+ data->temp_max = ret;
+ ret = data->temp_max;
+ }
+ break;
+ case PMBUS_VIRT_READ_VIN_MIN:
+ ret = pmbus_read_word_data(client, page, LTC2978_MFR_VIN_MIN);
+ if (ret >= 0) {
+ if (lin11_to_val(ret) < lin11_to_val(data->vin_min))
+ data->vin_min = ret;
+ ret = data->vin_min;
+ }
+ break;
+ case PMBUS_VIRT_READ_VOUT_MIN:
+ ret = pmbus_read_word_data(client, page, LTC2978_MFR_VOUT_MIN);
+ if (ret >= 0) {
+ /*
+ * VOUT_MIN is known to not be supported on some lots
+ * of LTC2978 revision 1, and will return the maximum
+ * possible voltage if read. If VOUT_MAX is valid and
+ * lower than the reading of VOUT_MIN, use it instead.
+ */
+ if (data->vout_max[page] && ret > data->vout_max[page])
+ ret = data->vout_max[page];
+ if (ret < data->vout_min[page])
+ data->vout_min[page] = ret;
+ ret = data->vout_min[page];
+ }
+ break;
+ case PMBUS_VIRT_READ_TEMP_MIN:
+ ret = pmbus_read_word_data(client, page,
+ LTC2978_MFR_TEMPERATURE_MIN);
+ if (ret >= 0) {
+ if (lin11_to_val(ret)
+ < lin11_to_val(data->temp_min))
+ data->temp_min = ret;
+ ret = data->temp_min;
+ }
+ break;
+ case PMBUS_VIRT_RESET_VOUT_HISTORY:
+ case PMBUS_VIRT_RESET_VIN_HISTORY:
+ case PMBUS_VIRT_RESET_TEMP_HISTORY:
+ ret = 0;
+ break;
+ default:
+ ret = -ENODATA;
+ break;
+ }
+ return ret;
+}
+
+static int ltc2978_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 ltc2978_data *data = to_ltc2978_data(info);
+ int ret;
+
+ switch (reg) {
+ case PMBUS_VIRT_RESET_VOUT_HISTORY:
+ data->vout_min[page] = 0xffff;
+ data->vout_max[page] = 0;
+ ret = pmbus_write_byte(client, page, PMBUS_CLEAR_FAULTS);
+ break;
+ case PMBUS_VIRT_RESET_VIN_HISTORY:
+ data->vin_min = 0x7bff;
+ data->vin_max = 0;
+ ret = pmbus_write_byte(client, page, PMBUS_CLEAR_FAULTS);
+ break;
+ case PMBUS_VIRT_RESET_TEMP_HISTORY:
+ data->temp_min = 0x7bff;
+ data->temp_max = 0x7fff;
+ ret = pmbus_write_byte(client, page, PMBUS_CLEAR_FAULTS);
+ break;
+ default:
+ ret = -ENODATA;
+ break;
+ }
+ return ret;
+}
+
+static const struct i2c_device_id ltc2978_id[] = {
+ {"ltc2978", ltc2978},
+ {}
+};
+MODULE_DEVICE_TABLE(i2c, ltc2978_id);
+
+static int ltc2978_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
+{
+ int chip_id, ret, i;
+ struct ltc2978_data *data;
+ struct pmbus_driver_info *info;
+
+ if (!i2c_check_functionality(client->adapter,
+ I2C_FUNC_SMBUS_READ_WORD_DATA))
+ return -ENODEV;
+
+ data = kzalloc(sizeof(struct ltc2978_data), GFP_KERNEL);
+ if (!data)
+ return -ENOMEM;
+
+ chip_id = i2c_smbus_read_word_data(client, LTC2978_MFR_SPECIAL_ID);
+ if (chip_id < 0) {
+ ret = chip_id;
+ goto err_mem;
+ }
+
+ if (chip_id == LTC2978_ID_REV1 || chip_id == LTC2978_ID_REV2) {
+ data->id = ltc2978;
+ } else {
+ dev_err(&client->dev, "Unsupported chip ID 0x%x\n", chip_id);
+ ret = -ENODEV;
+ goto err_mem;
+ }
+ if (data->id != id->driver_data)
+ dev_warn(&client->dev,
+ "Device mismatch: Configured %s, detected %s\n",
+ id->name,
+ ltc2978_id[data->id].name);
+
+ info = &data->info;
+ info->read_word_data = ltc2978_read_word_data;
+ info->write_word_data = ltc2978_write_word_data;
+
+ data->vout_min[0] = 0xffff;
+ data->vin_min = 0x7bff;
+ data->temp_min = 0x7bff;
+ data->temp_max = 0x7fff;
+
+ switch (id->driver_data) {
+ case ltc2978:
+ info->pages = 8;
+ info->func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_STATUS_INPUT
+ | PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT
+ | PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP;
+ for (i = 1; i < 8; i++) {
+ info->func[i] = PMBUS_HAVE_VOUT
+ | PMBUS_HAVE_STATUS_VOUT;
+ data->vout_min[i] = 0xffff;
+ }
+ break;
+ default:
+ ret = -ENODEV;
+ goto err_mem;
+ }
+
+ ret = pmbus_do_probe(client, id, info);
+ if (ret)
+ goto err_mem;
+ return 0;
+
+err_mem:
+ kfree(data);
+ return ret;
+}
+
+static int ltc2978_remove(struct i2c_client *client)
+{
+ const struct pmbus_driver_info *info = pmbus_get_driver_info(client);
+ const struct ltc2978_data *data = to_ltc2978_data(info);
+
+ pmbus_do_remove(client);
+ kfree(data);
+ return 0;
+}
+
+/* This is the driver that will be inserted */
+static struct i2c_driver ltc2978_driver = {
+ .driver = {
+ .name = "ltc2978",
+ },
+ .probe = ltc2978_probe,
+ .remove = ltc2978_remove,
+ .id_table = ltc2978_id,
+};
+
+static int __init ltc2978_init(void)
+{
+ return i2c_add_driver(<c2978_driver);
+}
+
+static void __exit ltc2978_exit(void)
+{
+ i2c_del_driver(<c2978_driver);
+}
+
+MODULE_AUTHOR("Guenter Roeck");
+MODULE_DESCRIPTION("PMBus driver for LTC2978");
+MODULE_LICENSE("GPL");
+module_init(ltc2978_init);
+module_exit(ltc2978_exit);
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