hwmon: (pmbus/ltc2978) Explicit driver for LTC2978
authorGuenter Roeck <guenter.roeck@ericsson.com>
Fri, 2 Sep 2011 16:58:37 +0000 (09:58 -0700)
committerGuenter Roeck <guenter.roeck@ericsson.com>
Mon, 24 Oct 2011 18:09:42 +0000 (11:09 -0700)
Provide explicit driver for LTC2978 to enable support for minimum and peak
attributes. Remove ltc2978 chip id from generic pmbus driver.

Signed-off-by: Guenter Roeck <guenter.roeck@ericsson.com>
Reviewed-by: Robert Coulson <robert.coulson@ericsson.com>
Documentation/hwmon/ltc2978 [new file with mode: 0644]
Documentation/hwmon/pmbus
drivers/hwmon/pmbus/Kconfig
drivers/hwmon/pmbus/Makefile
drivers/hwmon/pmbus/ltc2978.c [new file with mode: 0644]
drivers/hwmon/pmbus/pmbus.c

diff --git a/Documentation/hwmon/ltc2978 b/Documentation/hwmon/ltc2978
new file mode 100644 (file)
index 0000000..499129e
--- /dev/null
@@ -0,0 +1,78 @@
+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.
index c36c1c1a62bb3915ea47cb865c970720825d0ce3..ce02f5d9a6df8b5f530f47a900a2b6df4ce0206d 100644 (file)
@@ -8,11 +8,6 @@ Supported chips:
     Addresses scanned: -
     Datasheet:
  http://archive.ericsson.net/service/internet/picov/get?DocNo=28701-EN/LZT146395
-  * Linear Technology LTC2978
-    Octal PMBus Power Supply Monitor and Controller
-    Prefix: 'ltc2978'
-    Addresses scanned: -
-    Datasheet: http://cds.linear.com/docs/Datasheet/2978fa.pdf
   * ON Semiconductor ADP4000, NCP4200, NCP4208
     Prefixes: 'adp4000', 'ncp4200', 'ncp4208'
     Addresses scanned: -
index efaf340651a078a07a34bb7d5378efb5768e5d94..c4dcdca25555bb1468e745487a442d3aab19d621 100644 (file)
@@ -20,7 +20,7 @@ config SENSORS_PMBUS
        help
          If you say yes here you get hardware monitoring support for generic
          PMBus devices, including but not limited to ADP4000, BMR450, BMR451,
-         BMR453, BMR454, LTC2978, NCP4200, and NCP4208.
+         BMR453, BMR454, NCP4200, and NCP4208.
 
          This driver can also be built as a module. If so, the module will
          be called pmbus.
@@ -46,6 +46,16 @@ config SENSORS_LM25066
          This driver can also be built as a module. If so, the module will
          be called lm25066.
 
+config SENSORS_LTC2978
+       tristate "Linear Technologies LTC2978"
+       default n
+       help
+         If you say yes here you get hardware monitoring support for Linear
+         Technology LTC2978.
+
+         This driver can also be built as a module. If so, the module will
+         be called ltc2978.
+
 config SENSORS_MAX16064
        tristate "Maxim MAX16064"
        default n
index b9e4fb421f6c3bcd690d641d9ac12172851a6b24..789376c85dbb96f866d312e422c4eb67dec2ec23 100644 (file)
@@ -6,6 +6,7 @@ obj-$(CONFIG_PMBUS)             += pmbus_core.o
 obj-$(CONFIG_SENSORS_PMBUS)    += pmbus.o
 obj-$(CONFIG_SENSORS_ADM1275)  += adm1275.o
 obj-$(CONFIG_SENSORS_LM25066)  += lm25066.o
+obj-$(CONFIG_SENSORS_LTC2978)  += ltc2978.o
 obj-$(CONFIG_SENSORS_MAX16064) += max16064.o
 obj-$(CONFIG_SENSORS_MAX34440) += max34440.o
 obj-$(CONFIG_SENSORS_MAX8688)  += max8688.o
diff --git a/drivers/hwmon/pmbus/ltc2978.c b/drivers/hwmon/pmbus/ltc2978.c
new file mode 100644 (file)
index 0000000..02b2e49
--- /dev/null
@@ -0,0 +1,295 @@
+/*
+ * 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(&ltc2978_driver);
+}
+
+static void __exit ltc2978_exit(void)
+{
+       i2c_del_driver(&ltc2978_driver);
+}
+
+MODULE_AUTHOR("Guenter Roeck");
+MODULE_DESCRIPTION("PMBus driver for LTC2978");
+MODULE_LICENSE("GPL");
+module_init(ltc2978_init);
+module_exit(ltc2978_exit);
index 1dfba447749819c9fb674c6639ddd22c074e7ddb..ef5cc1eda0f6bac187c60ea22d83897fe3b76704 100644 (file)
@@ -204,7 +204,6 @@ static const struct i2c_device_id pmbus_id[] = {
        {"bmr451", 1},
        {"bmr453", 1},
        {"bmr454", 1},
-       {"ltc2978", 8},
        {"ncp4200", 1},
        {"ncp4208", 1},
        {"pmbus", 0},