iio: temperature: ltc2983: support more parts

Add support for the following parts:
 * LTC2984
 * LTC2986
 * LTM2985

The LTC2984 is a variant of the LTC2983 with EEPROM.
The LTC2986 is a variant of the LTC2983 with only 10 channels,
EEPROM and support for active analog temperature sensors.
The LTM2985 is software-compatible with the LTC2986.

Signed-off-by: Cosmin Tanislav <cosmin.tanislav@analog.com>
Link: https://lore.kernel.org/r/20221103130041.2153295-14-demonsingur@gmail.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

diff --git a/drivers/iio/temperature/ltc2983.c b/drivers/iio/temperature/ltc2983.c
index 1117991ca2ab618e8e226c5d99422723f9a16305..fcb96c44d9540793d20084579ab597155f3a3764 100644 (file)
--- a/drivers/iio/temperature/ltc2983.c
+++ b/drivers/iio/temperature/ltc2983.c
@@ -25,9 +25,12 @@
 #define LTC2983_STATUS_REG                     0x0000
 #define LTC2983_TEMP_RES_START_REG             0x0010
 #define LTC2983_TEMP_RES_END_REG               0x005F
+#define LTC2983_EEPROM_KEY_REG                 0x00B0
+#define LTC2983_EEPROM_READ_STATUS_REG         0x00D0
 #define LTC2983_GLOBAL_CONFIG_REG              0x00F0
 #define LTC2983_MULT_CHANNEL_START_REG         0x00F4
 #define LTC2983_MULT_CHANNEL_END_REG           0x00F7
+#define LTC2986_EEPROM_STATUS_REG              0x00F9
 #define LTC2983_MUX_CONFIG_REG                 0x00FF
 #define LTC2983_CHAN_ASSIGN_START_REG          0x0200
 #define LTC2983_CHAN_ASSIGN_END_REG            0x024F
@@ -35,13 +38,21 @@
 #define LTC2983_CUST_SENS_TBL_END_REG          0x03CF
 
 #define LTC2983_DIFFERENTIAL_CHAN_MIN          2
-#define LTC2983_MAX_CHANNELS_NR                        20
 #define LTC2983_MIN_CHANNELS_NR                        1
 #define LTC2983_SLEEP                          0x97
 #define LTC2983_CUSTOM_STEINHART_SIZE          24
 #define LTC2983_CUSTOM_SENSOR_ENTRY_SZ         6
 #define LTC2983_CUSTOM_STEINHART_ENTRY_SZ      4
 
+#define LTC2983_EEPROM_KEY                     0xA53C0F5A
+#define LTC2983_EEPROM_WRITE_CMD               0x15
+#define LTC2983_EEPROM_READ_CMD                        0x16
+#define LTC2983_EEPROM_STATUS_FAILURE_MASK     GENMASK(3, 1)
+#define LTC2983_EEPROM_READ_FAILURE_MASK       GENMASK(7, 0)
+
+#define LTC2983_EEPROM_WRITE_TIME_MS           2600
+#define LTC2983_EEPROM_READ_TIME_MS            20
+
 #define LTC2983_CHAN_START_ADDR(chan) \
                        (((chan - 1) * 4) + LTC2983_CHAN_ASSIGN_START_REG)
 #define LTC2983_CHAN_RES_ADDR(chan) \
@@ -171,6 +182,7 @@ enum {
        LTC2983_SENSOR_DIODE = 28,
        LTC2983_SENSOR_SENSE_RESISTOR = 29,
        LTC2983_SENSOR_DIRECT_ADC = 30,
+       LTC2983_SENSOR_ACTIVE_TEMP = 31,
 };
 
 #define to_thermocouple(_sensor) \
@@ -191,7 +203,17 @@ enum {
 #define to_adc(_sensor) \
                container_of(_sensor, struct ltc2983_adc, sensor)
 
+#define to_temp(_sensor) \
+               container_of(_sensor, struct ltc2983_temp, sensor)
+
+struct ltc2983_chip_info {
+       unsigned int max_channels_nr;
+       bool has_temp;
+       bool has_eeprom;
+};
+
 struct ltc2983_data {
+       const struct ltc2983_chip_info *info;
        struct regmap *regmap;
        struct spi_device *spi;
        struct mutex lock;
@@ -210,6 +232,7 @@ struct ltc2983_data {
         */
        __be32 temp __aligned(IIO_DMA_MINALIGN);
        __be32 chan_val;
+       __be32 eeprom_key;
 };
 
 struct ltc2983_sensor {
@@ -272,6 +295,12 @@ struct ltc2983_adc {
        bool single_ended;
 };
 
+struct ltc2983_temp {
+       struct ltc2983_sensor sensor;
+       struct ltc2983_custom_sensor *custom;
+       bool single_ended;
+};
+
 /*
  * Convert to Q format numbers. These number's are integers where
  * the number of integer and fractional bits are specified. The resolution
@@ -606,6 +635,22 @@ static int ltc2983_adc_assign_chan(struct ltc2983_data *st,
        return __ltc2983_chan_assign_common(st, sensor, chan_val);
 }
 
+static int ltc2983_temp_assign_chan(struct ltc2983_data *st,
+                                   const struct ltc2983_sensor *sensor)
+{
+       struct ltc2983_temp *temp = to_temp(sensor);
+       u32 chan_val;
+       int ret;
+
+       chan_val = LTC2983_ADC_SINGLE_ENDED(temp->single_ended);
+
+       ret = __ltc2983_chan_custom_sensor_assign(st, temp->custom, &chan_val);
+       if (ret)
+               return ret;
+
+       return __ltc2983_chan_assign_common(st, sensor, chan_val);
+}
+
 static struct ltc2983_sensor *
 ltc2983_thermocouple_new(const struct fwnode_handle *child, struct ltc2983_data *st,
                         const struct ltc2983_sensor *sensor)
@@ -771,10 +816,10 @@ ltc2983_rtd_new(const struct fwnode_handle *child, struct ltc2983_data *st,
        if (rtd->sensor_config & LTC2983_RTD_4_WIRE_MASK) {
                /* 4-wire */
                u8 min = LTC2983_DIFFERENTIAL_CHAN_MIN,
-                       max = LTC2983_MAX_CHANNELS_NR;
+                       max = st->info->max_channels_nr;
 
                if (rtd->sensor_config & LTC2983_RTD_ROTATION_MASK)
-                       max = LTC2983_MAX_CHANNELS_NR - 1;
+                       max = st->info->max_channels_nr - 1;
 
                if (((rtd->sensor_config & LTC2983_RTD_KELVIN_R_SENSE_MASK)
                     == LTC2983_RTD_KELVIN_R_SENSE_MASK) &&
@@ -1143,6 +1188,38 @@ static struct ltc2983_sensor *ltc2983_adc_new(struct fwnode_handle *child,
        return &adc->sensor;
 }
 
+static struct ltc2983_sensor *ltc2983_temp_new(struct fwnode_handle *child,
+                                              struct ltc2983_data *st,
+                                              const struct ltc2983_sensor *sensor)
+{
+       struct ltc2983_temp *temp;
+
+       temp = devm_kzalloc(&st->spi->dev, sizeof(*temp), GFP_KERNEL);
+       if (!temp)
+               return ERR_PTR(-ENOMEM);
+
+       if (fwnode_property_read_bool(child, "adi,single-ended"))
+               temp->single_ended = true;
+
+       if (!temp->single_ended &&
+           sensor->chan < LTC2983_DIFFERENTIAL_CHAN_MIN) {
+               dev_err(&st->spi->dev, "Invalid chan:%d for differential temp\n",
+                       sensor->chan);
+               return ERR_PTR(-EINVAL);
+       }
+
+       temp->custom = __ltc2983_custom_sensor_new(st, child, "adi,custom-temp",
+                                                  false, 4096, true);
+       if (IS_ERR(temp->custom))
+               return ERR_CAST(temp->custom);
+
+       /* set common parameters */
+       temp->sensor.assign_chan = ltc2983_temp_assign_chan;
+       temp->sensor.fault_handler = ltc2983_common_fault_handler;
+
+       return &temp->sensor;
+}
+
 static int ltc2983_chan_read(struct ltc2983_data *st,
                        const struct ltc2983_sensor *sensor, int *val)
 {
@@ -1302,10 +1379,10 @@ static int ltc2983_parse_dt(struct ltc2983_data *st)
 
                /* check if we have a valid channel */
                if (sensor.chan < LTC2983_MIN_CHANNELS_NR ||
-                   sensor.chan > LTC2983_MAX_CHANNELS_NR) {
+                   sensor.chan > st->info->max_channels_nr) {
                        ret = -EINVAL;
                        dev_err(dev, "chan:%d must be from %u to %u\n", sensor.chan,
-                               LTC2983_MIN_CHANNELS_NR, LTC2983_MAX_CHANNELS_NR);
+                               LTC2983_MIN_CHANNELS_NR, st->info->max_channels_nr);
                        goto put_child;
                } else if (channel_avail_mask & BIT(sensor.chan)) {
                        ret = -EINVAL;
@@ -1345,6 +1422,9 @@ static int ltc2983_parse_dt(struct ltc2983_data *st)
                        st->iio_channels--;
                } else if (sensor.type == LTC2983_SENSOR_DIRECT_ADC) {
                        st->sensors[chan] = ltc2983_adc_new(child, st, &sensor);
+               } else if (st->info->has_temp &&
+                          sensor.type == LTC2983_SENSOR_ACTIVE_TEMP) {
+                       st->sensors[chan] = ltc2983_temp_new(child, st, &sensor);
                } else {
                        dev_err(dev, "Unknown sensor type %d\n", sensor.type);
                        ret = -EINVAL;
@@ -1371,6 +1451,45 @@ put_child:
        return ret;
 }
 
+static int ltc2983_eeprom_cmd(struct ltc2983_data *st, unsigned int cmd,
+                             unsigned int wait_time, unsigned int status_reg,
+                             unsigned long status_fail_mask)
+{
+       unsigned long time;
+       unsigned int val;
+       int ret;
+
+       ret = regmap_bulk_write(st->regmap, LTC2983_EEPROM_KEY_REG,
+                               &st->eeprom_key, sizeof(st->eeprom_key));
+       if (ret)
+               return ret;
+
+       reinit_completion(&st->completion);
+
+       ret = regmap_write(st->regmap, LTC2983_STATUS_REG,
+                          LTC2983_STATUS_START(true) | cmd);
+       if (ret)
+               return ret;
+
+       time = wait_for_completion_timeout(&st->completion,
+                                          msecs_to_jiffies(wait_time));
+       if (!time) {
+               dev_err(&st->spi->dev, "EEPROM command timed out\n");
+               return -ETIMEDOUT;
+       }
+
+       ret = regmap_read(st->regmap, status_reg, &val);
+       if (ret)
+               return ret;
+
+       if (val & status_fail_mask) {
+               dev_err(&st->spi->dev, "EEPROM command failed: 0x%02X\n", val);
+               return -EINVAL;
+       }
+
+       return 0;
+}
+
 static int ltc2983_setup(struct ltc2983_data *st, bool assign_iio)
 {
        u32 iio_chan_t = 0, iio_chan_v = 0, chan, iio_idx = 0, status;
@@ -1396,6 +1515,15 @@ static int ltc2983_setup(struct ltc2983_data *st, bool assign_iio)
        if (ret)
                return ret;
 
+       if (st->info->has_eeprom && !assign_iio) {
+               ret = ltc2983_eeprom_cmd(st, LTC2983_EEPROM_READ_CMD,
+                                        LTC2983_EEPROM_READ_TIME_MS,
+                                        LTC2983_EEPROM_READ_STATUS_REG,
+                                        LTC2983_EEPROM_READ_FAILURE_MASK);
+               if (!ret)
+                       return 0;
+       }
+
        for (chan = 0; chan < st->num_channels; chan++) {
                u32 chan_type = 0, *iio_chan;
 
@@ -1435,9 +1563,13 @@ static int ltc2983_setup(struct ltc2983_data *st, bool assign_iio)
 static const struct regmap_range ltc2983_reg_ranges[] = {
        regmap_reg_range(LTC2983_STATUS_REG, LTC2983_STATUS_REG),
        regmap_reg_range(LTC2983_TEMP_RES_START_REG, LTC2983_TEMP_RES_END_REG),
+       regmap_reg_range(LTC2983_EEPROM_KEY_REG, LTC2983_EEPROM_KEY_REG),
+       regmap_reg_range(LTC2983_EEPROM_READ_STATUS_REG,
+                        LTC2983_EEPROM_READ_STATUS_REG),
        regmap_reg_range(LTC2983_GLOBAL_CONFIG_REG, LTC2983_GLOBAL_CONFIG_REG),
        regmap_reg_range(LTC2983_MULT_CHANNEL_START_REG,
                         LTC2983_MULT_CHANNEL_END_REG),
+       regmap_reg_range(LTC2986_EEPROM_STATUS_REG, LTC2986_EEPROM_STATUS_REG),
        regmap_reg_range(LTC2983_MUX_CONFIG_REG, LTC2983_MUX_CONFIG_REG),
        regmap_reg_range(LTC2983_CHAN_ASSIGN_START_REG,
                         LTC2983_CHAN_ASSIGN_END_REG),
@@ -1482,6 +1614,12 @@ static int ltc2983_probe(struct spi_device *spi)
 
        st = iio_priv(indio_dev);
 
+       st->info = device_get_match_data(&spi->dev);
+       if (!st->info)
+               st->info = (void *)spi_get_device_id(spi)->driver_data;
+       if (!st->info)
+               return -ENODEV;
+
        st->regmap = devm_regmap_init_spi(spi, &ltc2983_regmap_config);
        if (IS_ERR(st->regmap)) {
                dev_err(&spi->dev, "Failed to initialize regmap\n");
@@ -1491,6 +1629,7 @@ static int ltc2983_probe(struct spi_device *spi)
        mutex_init(&st->lock);
        init_completion(&st->completion);
        st->spi = spi;
+       st->eeprom_key = cpu_to_be32(LTC2983_EEPROM_KEY);
        spi_set_drvdata(spi, st);
 
        ret = ltc2983_parse_dt(st);
@@ -1524,6 +1663,15 @@ static int ltc2983_probe(struct spi_device *spi)
                return ret;
        }
 
+       if (st->info->has_eeprom) {
+               ret = ltc2983_eeprom_cmd(st, LTC2983_EEPROM_WRITE_CMD,
+                                        LTC2983_EEPROM_WRITE_TIME_MS,
+                                        LTC2986_EEPROM_STATUS_REG,
+                                        LTC2983_EEPROM_STATUS_FAILURE_MASK);
+               if (ret)
+                       return ret;
+       }
+
        indio_dev->name = name;
        indio_dev->num_channels = st->iio_channels;
        indio_dev->channels = st->iio_chan;
@@ -1554,14 +1702,35 @@ static int ltc2983_suspend(struct device *dev)
 static DEFINE_SIMPLE_DEV_PM_OPS(ltc2983_pm_ops, ltc2983_suspend,
                                ltc2983_resume);
 
+static const struct ltc2983_chip_info ltc2983_chip_info_data = {
+       .max_channels_nr = 20,
+};
+
+static const struct ltc2983_chip_info ltc2984_chip_info_data = {
+       .max_channels_nr = 20,
+       .has_eeprom = true,
+};
+
+static const struct ltc2983_chip_info ltc2986_chip_info_data = {
+       .max_channels_nr = 10,
+       .has_temp = true,
+       .has_eeprom = true,
+};
+
 static const struct spi_device_id ltc2983_id_table[] = {
-       { "ltc2983" },
+       { "ltc2983", (kernel_ulong_t)&ltc2983_chip_info_data },
+       { "ltc2984", (kernel_ulong_t)&ltc2984_chip_info_data },
+       { "ltc2986", (kernel_ulong_t)&ltc2986_chip_info_data },
+       { "ltm2985", (kernel_ulong_t)&ltc2986_chip_info_data },
        {},
 };
 MODULE_DEVICE_TABLE(spi, ltc2983_id_table);
 
 static const struct of_device_id ltc2983_of_match[] = {
-       { .compatible = "adi,ltc2983" },
+       { .compatible = "adi,ltc2983", .data = &ltc2983_chip_info_data },
+       { .compatible = "adi,ltc2984", .data = &ltc2984_chip_info_data },
+       { .compatible = "adi,ltc2986", .data = &ltc2986_chip_info_data },
+       { .compatible = "adi,ltm2985", .data = &ltc2986_chip_info_data },
        {},
 };
 MODULE_DEVICE_TABLE(of, ltc2983_of_match);