[PATCH v3 4/4] iio: temperature: ltc2983: support more parts

From: Cosmin Tanislav
Date: Tue Oct 25 2022 - 04:19:36 EST

From: Cosmin Tanislav <cosmin.tanislav@xxxxxxxxxx>

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@xxxxxxxxxx>
Reviewed-by: Nuno Sá <nuno.sa@xxxxxxxxxx>
---
drivers/iio/temperature/ltc2983.c | 183 ++++++++++++++++++++++++++++--
1 file changed, 176 insertions(+), 7 deletions(-)

diff --git a/drivers/iio/temperature/ltc2983.c b/drivers/iio/temperature/ltc2983.c
index ca1bb5f48988..72c052e4c7bc 100644
--- 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 @@ static int ltc2983_parse_dt(struct ltc2983_data *st)
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;
@@ -1403,6 +1522,15 @@ 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;

@@ -1442,9 +1570,13 @@ 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),
@@ -1489,6 +1621,12 @@ 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");
@@ -1498,6 +1636,7 @@ 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);
@@ -1525,6 +1664,15 @@ 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;
@@ -1555,14 +1703,35 @@ 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);
--
2.38.1