hwmon: (ltc2978) Add support for LTC3882

LTC3882 is mostly compatible with LTC3880. Major differences are that it
does not measure the input current, and it no longer supports LTC's legacy
mechanism to identify the chip.

Signed-off-by: Guenter Roeck <linux@roeck-us.net>

1 files changed, 44 insertions, 6 deletions

diff --git a/drivers/hwmon/pmbus/ltc2978.c b/drivers/hwmon/pmbus/ltc2978.c
index 7e10fbf8e133..28e1e735b5c2 100644
--- a/drivers/hwmon/pmbus/ltc2978.c
+++ b/drivers/hwmon/pmbus/ltc2978.c
@@ -25,13 +25,13 @@
 #include <linux/regulator/driver.h>
 #include "pmbus.h"
 
-enum chips { ltc2974, ltc2977, ltc2978, ltc3880, ltc3883, ltm4676 };
+enum chips { ltc2974, ltc2977, ltc2978, ltc3880, ltc3882, ltc3883, ltm4676 };
 
 /* Common for all chips */
 #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_SPECIAL_ID          0xe7    /* Not on LTC3882 */
 
 /* LTC2974, LCT2977, and LTC2978 */
 #define LTC2978_MFR_VOUT_MIN            0xfb
@@ -42,7 +42,7 @@ enum chips { ltc2974, ltc2977, ltc2978, ltc3880, ltc3883, ltm4676 };
 #define LTC2974_MFR_IOUT_PEAK           0xd7
 #define LTC2974_MFR_IOUT_MIN            0xd8
 
-/* LTC3880, LTC3883, and LTM4676 */
+/* LTC3880, LTC3882, LTC3883, and LTM4676 */
 #define LTC3880_MFR_IOUT_PEAK           0xd7
 #define LTC3880_MFR_CLEAR_PEAKS         0xe3
 #define LTC3880_MFR_TEMPERATURE2_PEAK   0xf4
@@ -313,7 +313,7 @@ static int ltc2978_clear_peaks(struct i2c_client *client, int page,
 {
         int ret;
 
-        if (id == ltc3880 || id == ltc3883 || id == ltm4676)
+        if (id == ltc3880 || id == ltc3882 || id == ltc3883 || id == ltm4676)
                 ret = pmbus_write_byte(client, 0, LTC3880_MFR_CLEAR_PEAKS);
         else
                 ret = pmbus_write_byte(client, page, PMBUS_CLEAR_FAULTS);
@@ -369,6 +369,7 @@ static const struct i2c_device_id ltc2978_id[] = {
         {"ltc2977", ltc2977},
         {"ltc2978", ltc2978},
         {"ltc3880", ltc3880},
+        {"ltc3882", ltc3882},
         {"ltc3883", ltc3883},
         {"ltm4676", ltm4676},
         {}
@@ -393,8 +394,30 @@ static int ltc2978_get_id(struct i2c_client *client)
         int chip_id;
 
         chip_id = i2c_smbus_read_word_data(client, LTC2978_MFR_SPECIAL_ID);
-        if (chip_id < 0)
-                return chip_id;
+        if (chip_id < 0) {
+                const struct i2c_device_id *id;
+                u8 buf[I2C_SMBUS_BLOCK_MAX];
+                int ret;
+
+                if (!i2c_check_functionality(client->adapter,
+                                             I2C_FUNC_SMBUS_READ_BLOCK_DATA))
+                        return -ENODEV;
+
+                ret = i2c_smbus_read_block_data(client, PMBUS_MFR_ID, buf);
+                if (ret < 0)
+                        return ret;
+                if (ret < 3 || strncmp(buf, "LTC", 3))
+                        return -ENODEV;
+
+                ret = i2c_smbus_read_block_data(client, PMBUS_MFR_MODEL, buf);
+                if (ret < 0)
+                        return ret;
+                for (id = &ltc2978_id[0]; strlen(id->name); id++) {
+                        if (!strncasecmp(id->name, buf, strlen(id->name)))
+                                return (int)id->driver_data;
+                }
+                return -ENODEV;
+        }
 
         if (chip_id == LTC2974_ID_REV1 || chip_id == LTC2974_ID_REV2)
                 return ltc2974;
@@ -498,6 +521,20 @@ static int ltc2978_probe(struct i2c_client *client,
                   | PMBUS_HAVE_POUT
                   | PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP;
                 break;
+        case ltc3882:
+                info->read_word_data = ltc3880_read_word_data;
+                info->pages = LTC3880_NUM_PAGES;
+                info->func[0] = PMBUS_HAVE_VIN
+                  | 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;
+                break;
         case ltc3883:
                 info->read_word_data = ltc3883_read_word_data;
                 info->pages = LTC3883_NUM_PAGES;
@@ -530,6 +567,7 @@ static const struct of_device_id ltc2978_of_match[] = {
         { .compatible = "lltc,ltc2977" },
         { .compatible = "lltc,ltc2978" },
         { .compatible = "lltc,ltc3880" },
+        { .compatible = "lltc,ltc3882" },
         { .compatible = "lltc,ltc3883" },
         { .compatible = "lltc,ltm4676" },
         { }