hwmon: (pmbus/ltc2978) Add support for LTC3880 to LTC2978 driver

The LTC3880 PMBus command set is comparable to LTC2978. Add support for it
to the LTC2978 driver.

Signed-off-by: Guenter Roeck <guenter.roeck@ericsson.com>
Reviewed-by: Robert Coulson <robert.coulson@ericsson.com>

3 files changed, 168 insertions, 30 deletions

diff --git a/Documentation/hwmon/ltc2978 b/Documentation/hwmon/ltc2978
index 499129e11897..c365f9beb5dd 100644
--- a/Documentation/hwmon/ltc2978
+++ b/Documentation/hwmon/ltc2978
@@ -6,6 +6,10 @@ Supported chips:
     Prefix: 'ltc2978'
     Addresses scanned: -
     Datasheet: http://cds.linear.com/docs/Datasheet/2978fa.pdf
+  * Linear Technology LTC3880
+    Prefix: 'ltc3880'
+    Addresses scanned: -
+    Datasheet: http://cds.linear.com/docs/Datasheet/3880f.pdf
 
 Author: Guenter Roeck <guenter.roeck@ericsson.com>
 
@@ -14,7 +18,8 @@ Description
 -----------
 
 The LTC2978 is an octal power supply monitor, supervisor, sequencer and
-margin controller.
+margin controller. The LTC3880 is a dual, PolyPhase DC/DC synchronous
+step-down switching regulator controller.
 
 
 Usage Notes
@@ -43,12 +48,12 @@ 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_lowest              Lowest input voltage. LTC2978 only.
 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]_label           "vout[1-8]". Channels 3 to 9 on LTC2978 only.
 in[2-9]_input           Measured output voltage.
 in[2-9]_min             Minimum output voltage.
 in[2-9]_max             Maximum output voltage.
@@ -58,21 +63,41 @@ 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]_lowest          Lowest output voltage. LTC2978 only.
 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
+temp[1-3]_input         Measured temperature.
+                        On LTC2978, only one temperature measurement is
+                        supported and reflects the internal temperature.
+                        On LTC3880, temp1 and temp2 report external
+                        temperatures, and temp3 reports the internal
+                        temperature.
+temp[1-3]_min           Mimimum temperature.
+temp[1-3]_max           Maximum temperature.
+temp[1-3]_lcrit         Critical low temperature.
+temp[1-3]_crit          Critical high temperature.
+temp[1-3]_min_alarm     Chip temperature low alarm.
+temp[1-3]_max_alarm     Chip temperature high alarm.
+temp[1-3]_lcrit_alarm   Chip temperature critical low alarm.
+temp[1-3]_crit_alarm    Chip temperature critical high alarm.
+temp[1-3]_lowest        Lowest measured temperature. LTC2978 only.
+temp[1-3]_highest       Highest measured temperature.
+temp[1-3]_reset_history Reset history. Writing into this attribute will reset
                         history for all attributes.
+
+power[1-2]_label        "pout[1-2]". LTC3880 only.
+power[1-2]_input        Measured power.
+
+curr1_label             "iin". LTC3880 only.
+curr1_input             Measured input current.
+curr1_max               Maximum input current.
+curr1_max_alarm         Input current high alarm.
+
+curr[2-3]_label         "iout[1-2]". LTC3880 only.
+curr[2-3]_input         Measured input current.
+curr[2-3]_max           Maximum input current.
+curr[2-3]_crit          Critical input current.
+curr[2-3]_max_alarm     Input current high alarm.
+curr[2-3]_crit_alarm    Input current critical high alarm.
diff --git a/drivers/hwmon/pmbus/Kconfig b/drivers/hwmon/pmbus/Kconfig
index c4dcdca25555..4b26f51920ba 100644
--- a/drivers/hwmon/pmbus/Kconfig
+++ b/drivers/hwmon/pmbus/Kconfig
@@ -47,11 +47,11 @@ config SENSORS_LM25066
           be called lm25066.
 
 config SENSORS_LTC2978
-        tristate "Linear Technologies LTC2978"
+        tristate "Linear Technologies LTC2978 and LTC3880"
         default n
         help
           If you say yes here you get hardware monitoring support for Linear
-          Technology LTC2978.
+          Technology LTC2978 and LTC3880.
 
           This driver can also be built as a module. If so, the module will
           be called ltc2978.
diff --git a/drivers/hwmon/pmbus/ltc2978.c b/drivers/hwmon/pmbus/ltc2978.c
index 02b2e49adb31..820fff48910b 100644
--- a/drivers/hwmon/pmbus/ltc2978.c
+++ b/drivers/hwmon/pmbus/ltc2978.c
@@ -1,5 +1,5 @@
 /*
- * Hardware monitoring driver for LTC2978
+ * Hardware monitoring driver for LTC2978 and LTC3880
  *
  * Copyright (c) 2011 Ericsson AB.
  *
@@ -26,19 +26,28 @@
 #include <linux/i2c.h>
 #include "pmbus.h"
 
-enum chips { ltc2978 };
+enum chips { ltc2978, ltc3880 };
 
+/* LTC2978 and LTC3880 */
 #define LTC2978_MFR_VOUT_PEAK           0xdd
 #define LTC2978_MFR_VIN_PEAK            0xde
 #define LTC2978_MFR_TEMPERATURE_PEAK    0xdf
 #define LTC2978_MFR_SPECIAL_ID          0xe7
 
+/* LTC2978 only */
 #define LTC2978_MFR_VOUT_MIN            0xfb
 #define LTC2978_MFR_VIN_MIN             0xfc
 #define LTC2978_MFR_TEMPERATURE_MIN     0xfd
 
+/* LTC3880 only */
+#define LTC3880_MFR_IOUT_PEAK           0xd7
+#define LTC3880_MFR_CLEAR_PEAKS         0xe3
+#define LTC3880_MFR_TEMPERATURE2_PEAK   0xf4
+
 #define LTC2978_ID_REV1                 0x0121
 #define LTC2978_ID_REV2                 0x0122
+#define LTC3880_ID                      0x4000
+#define LTC3880_ID_MASK                 0xff00
 
 /*
  * LTC2978 clears peak data whenever the CLEAR_FAULTS command is executed, which
@@ -52,6 +61,8 @@ struct ltc2978_data {
         int vin_min, vin_max;
         int temp_min, temp_max;
         int vout_min[8], vout_max[8];
+        int iout_max[2];
+        int temp2_max[2];
         struct pmbus_driver_info info;
 };
 
@@ -70,7 +81,8 @@ static inline int lin11_to_val(int data)
         return (e < 0 ? m >> -e : m << e);
 }
 
-static int ltc2978_read_word_data(struct i2c_client *client, int page, int reg)
+static int ltc2978_read_word_data_common(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);
@@ -106,6 +118,25 @@ static int ltc2978_read_word_data(struct i2c_client *client, int page, int reg)
                         ret = data->temp_max;
                 }
                 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_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_MIN:
                 ret = pmbus_read_word_data(client, page, LTC2978_MFR_VIN_MIN);
                 if (ret >= 0) {
@@ -140,18 +171,74 @@ static int ltc2978_read_word_data(struct i2c_client *client, int page, int reg)
                         ret = data->temp_min;
                 }
                 break;
-        case PMBUS_VIRT_RESET_VOUT_HISTORY:
-        case PMBUS_VIRT_RESET_VIN_HISTORY:
-        case PMBUS_VIRT_RESET_TEMP_HISTORY:
+        case PMBUS_VIRT_READ_IOUT_MAX:
+        case PMBUS_VIRT_RESET_IOUT_HISTORY:
+        case PMBUS_VIRT_READ_TEMP2_MAX:
+        case PMBUS_VIRT_RESET_TEMP2_HISTORY:
+                ret = -ENXIO;
+                break;
+        default:
+                ret = ltc2978_read_word_data_common(client, page, reg);
+                break;
+        }
+        return ret;
+}
+
+static int ltc3880_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_IOUT_MAX:
+                ret = pmbus_read_word_data(client, page, LTC3880_MFR_IOUT_PEAK);
+                if (ret >= 0) {
+                        if (lin11_to_val(ret)
+                            > lin11_to_val(data->iout_max[page]))
+                                data->iout_max[page] = ret;
+                        ret = data->iout_max[page];
+                }
+                break;
+        case PMBUS_VIRT_READ_TEMP2_MAX:
+                ret = pmbus_read_word_data(client, page,
+                                           LTC3880_MFR_TEMPERATURE2_PEAK);
+                if (ret >= 0) {
+                        if (lin11_to_val(ret)
+                            > lin11_to_val(data->temp2_max[page]))
+                                data->temp2_max[page] = ret;
+                        ret = data->temp2_max[page];
+                }
+                break;
+        case PMBUS_VIRT_READ_VIN_MIN:
+        case PMBUS_VIRT_READ_VOUT_MIN:
+        case PMBUS_VIRT_READ_TEMP_MIN:
+                ret = -ENXIO;
+                break;
+        case PMBUS_VIRT_RESET_IOUT_HISTORY:
+        case PMBUS_VIRT_RESET_TEMP2_HISTORY:
                 ret = 0;
                 break;
         default:
-                ret = -ENODATA;
+                ret = ltc2978_read_word_data_common(client, page, reg);
                 break;
         }
         return ret;
 }
 
+static int ltc2978_clear_peaks(struct i2c_client *client, int page,
+                               enum chips id)
+{
+        int ret;
+
+        if (id == ltc2978)
+                ret = pmbus_write_byte(client, page, PMBUS_CLEAR_FAULTS);
+        else
+                ret = pmbus_write_byte(client, 0, LTC3880_MFR_CLEAR_PEAKS);
+
+        return ret;
+}
+
 static int ltc2978_write_word_data(struct i2c_client *client, int page,
                                     int reg, u16 word)
 {
@@ -160,20 +247,28 @@ static int ltc2978_write_word_data(struct i2c_client *client, int page,
         int ret;
 
         switch (reg) {
+        case PMBUS_VIRT_RESET_IOUT_HISTORY:
+                data->iout_max[page] = 0x7fff;
+                ret = ltc2978_clear_peaks(client, page, data->id);
+                break;
+        case PMBUS_VIRT_RESET_TEMP2_HISTORY:
+                data->temp2_max[page] = 0x7fff;
+                ret = ltc2978_clear_peaks(client, page, data->id);
+                break;
         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);
+                ret = ltc2978_clear_peaks(client, page, data->id);
                 break;
         case PMBUS_VIRT_RESET_VIN_HISTORY:
                 data->vin_min = 0x7bff;
                 data->vin_max = 0;
-                ret = pmbus_write_byte(client, page, PMBUS_CLEAR_FAULTS);
+                ret = ltc2978_clear_peaks(client, page, data->id);
                 break;
         case PMBUS_VIRT_RESET_TEMP_HISTORY:
                 data->temp_min = 0x7bff;
                 data->temp_max = 0x7fff;
-                ret = pmbus_write_byte(client, page, PMBUS_CLEAR_FAULTS);
+                ret = ltc2978_clear_peaks(client, page, data->id);
                 break;
         default:
                 ret = -ENODATA;
@@ -184,6 +279,7 @@ static int ltc2978_write_word_data(struct i2c_client *client, int page,
 
 static const struct i2c_device_id ltc2978_id[] = {
         {"ltc2978", ltc2978},
+        {"ltc3880", ltc3880},
         {}
 };
 MODULE_DEVICE_TABLE(i2c, ltc2978_id);
@@ -211,6 +307,8 @@ static int ltc2978_probe(struct i2c_client *client,
 
         if (chip_id == LTC2978_ID_REV1 || chip_id == LTC2978_ID_REV2) {
                 data->id = ltc2978;
+        } else if ((chip_id & LTC3880_ID_MASK) == LTC3880_ID) {
+                data->id = ltc3880;
         } else {
                 dev_err(&client->dev, "Unsupported chip ID 0x%x\n", chip_id);
                 ret = -ENODEV;
@@ -223,7 +321,6 @@ static int ltc2978_probe(struct i2c_client *client,
                          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;
@@ -233,6 +330,7 @@ static int ltc2978_probe(struct i2c_client *client,
 
         switch (id->driver_data) {
         case ltc2978:
+                info->read_word_data = ltc2978_read_word_data;
                 info->pages = 8;
                 info->func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_STATUS_INPUT
                   | PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT
@@ -243,6 +341,21 @@ static int ltc2978_probe(struct i2c_client *client,
                         data->vout_min[i] = 0xffff;
                 }
                 break;
+        case ltc3880:
+                info->read_word_data = ltc3880_read_word_data;
+                info->pages = 2;
+                info->func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_IIN
+                  | PMBUS_HAVE_STATUS_INPUT
+                  | PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT
+                  | PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT
+                  | PMBUS_HAVE_POUT | PMBUS_HAVE_TEMP
+                  | PMBUS_HAVE_TEMP2 | PMBUS_HAVE_STATUS_TEMP;
+                info->func[1] = PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT
+                  | PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT
+                  | PMBUS_HAVE_POUT
+                  | PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP;
+                data->vout_min[1] = 0xffff;
+                break;
         default:
                 ret = -ENODEV;
                 goto err_mem;
@@ -289,7 +402,7 @@ static void __exit ltc2978_exit(void)
 }
 
 MODULE_AUTHOR("Guenter Roeck");
-MODULE_DESCRIPTION("PMBus driver for LTC2978");
+MODULE_DESCRIPTION("PMBus driver for LTC2978 and LTC3880");
 MODULE_LICENSE("GPL");
 module_init(ltc2978_init);
 module_exit(ltc2978_exit);