Add tsys01 meas-spec driver support
authorLudovic Tancerel <ludovic.tancerel@maplehightech.com>
Thu, 1 Oct 2015 14:13:37 +0000 (16:13 +0200)
committerJonathan Cameron <jic23@kernel.org>
Sun, 4 Oct 2015 14:02:28 +0000 (15:02 +0100)
Support for TSYS01 temperature sensor

Signed-off-by: Ludovic Tancerel <ludovic.tancerel@maplehightech.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
drivers/iio/temperature/Kconfig
drivers/iio/temperature/Makefile
drivers/iio/temperature/tsys01.c [new file with mode: 0644]

index 21feaa4661b4672425fad790b1d64af61fa084d2..35712032b4b994427482a930aee7db65adfc8bca 100644 (file)
@@ -23,4 +23,15 @@ config TMP006
          This driver can also be built as a module. If so, the module will
          be called tmp006.
 
+config TSYS01
+       tristate "Measurement Specialties TSYS01 temperature sensor using I2C bus connection"
+       depends on I2C
+       select IIO_MS_SENSORS_I2C
+       help
+         If you say yes here you get support for the Measurement Specialties
+         TSYS01 I2C temperature sensor.
+
+         This driver can also be built as a module. If so, the module will
+         be called tsys01.
+
 endmenu
index 40710a81158e1c770cf05f00546093fd5cdbef9f..368a2a2ffe520cc5eb9c9444c08991ca73afc671 100644 (file)
@@ -4,3 +4,4 @@
 
 obj-$(CONFIG_MLX90614) += mlx90614.o
 obj-$(CONFIG_TMP006) += tmp006.o
+obj-$(CONFIG_TSYS01) += tsys01.o
diff --git a/drivers/iio/temperature/tsys01.c b/drivers/iio/temperature/tsys01.c
new file mode 100644 (file)
index 0000000..05c1206
--- /dev/null
@@ -0,0 +1,230 @@
+/*
+ * tsys01.c - Support for Measurement-Specialties tsys01 temperature sensor
+ *
+ * Copyright (c) 2015 Measurement-Specialties
+ *
+ * Licensed under the GPL-2.
+ *
+ * Datasheet:
+ *  http://www.meas-spec.com/downloads/TSYS01_Digital_Temperature_Sensor.pdf
+ */
+
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+#include <linux/device.h>
+#include <linux/mutex.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/stat.h>
+#include "../common/ms_sensors/ms_sensors_i2c.h"
+
+/* TSYS01 Commands */
+#define TSYS01_RESET                           0x1E
+#define TSYS01_CONVERSION_START                        0x48
+#define TSYS01_ADC_READ                                0x00
+#define TSYS01_PROM_READ                       0xA0
+
+#define TSYS01_PROM_WORDS_NB                   8
+
+struct tsys01_dev {
+       void *client;
+       struct mutex lock; /* lock during conversion */
+
+       int (*reset)(void *cli, u8 cmd, unsigned int delay);
+       int (*convert_and_read)(void *cli, u8 conv, u8 rd,
+                               unsigned int delay, u32 *adc);
+       int (*read_prom_word)(void *cli, int cmd, u16 *word);
+
+       u16 prom[TSYS01_PROM_WORDS_NB];
+};
+
+/* Multiplication coefficients for temperature computation */
+static const int coeff_mul[] = { -1500000, 1000000, -2000000,
+                                4000000, -2000000 };
+
+static int tsys01_read_temperature(struct iio_dev *indio_dev,
+                                  s32 *temperature)
+{
+       int ret, i;
+       u32 adc;
+       s64 temp = 0;
+       struct tsys01_dev *dev_data = iio_priv(indio_dev);
+
+       mutex_lock(&dev_data->lock);
+       ret = dev_data->convert_and_read(dev_data->client,
+                                        TSYS01_CONVERSION_START,
+                                        TSYS01_ADC_READ, 9000, &adc);
+       mutex_unlock(&dev_data->lock);
+       if (ret)
+               return ret;
+
+       adc >>= 8;
+
+       /* Temperature algorithm */
+       for (i = 4; i > 0; i--) {
+               temp += coeff_mul[i] *
+                       (s64)dev_data->prom[5 - i];
+               temp *= (s64)adc;
+               temp = div64_s64(temp, 100000);
+       }
+       temp *= 10;
+       temp += coeff_mul[0] * (s64)dev_data->prom[5];
+       temp = div64_s64(temp, 100000);
+
+       *temperature = temp;
+
+       return 0;
+}
+
+static int tsys01_read_raw(struct iio_dev *indio_dev,
+                          struct iio_chan_spec const *channel, int *val,
+                          int *val2, long mask)
+{
+       int ret;
+       s32 temperature;
+
+       switch (mask) {
+       case IIO_CHAN_INFO_PROCESSED:
+               switch (channel->type) {
+               case IIO_TEMP:  /* in milli °C */
+                       ret = tsys01_read_temperature(indio_dev, &temperature);
+                       if (ret)
+                               return ret;
+                       *val = temperature;
+
+                       return IIO_VAL_INT;
+               default:
+                       return -EINVAL;
+               }
+       default:
+               return -EINVAL;
+       }
+}
+
+static const struct iio_chan_spec tsys01_channels[] = {
+       {
+               .type = IIO_TEMP,
+               .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_PROCESSED),
+       }
+};
+
+static const struct iio_info tsys01_info = {
+       .read_raw = tsys01_read_raw,
+       .driver_module = THIS_MODULE,
+};
+
+static bool tsys01_crc_valid(u16 *n_prom)
+{
+       u8 cnt;
+       u8 sum = 0;
+
+       for (cnt = 0; cnt < TSYS01_PROM_WORDS_NB; cnt++)
+               sum += ((n_prom[0] >> 8) + (n_prom[0] & 0xFF));
+
+       return (sum == 0);
+}
+
+static int tsys01_read_prom(struct iio_dev *indio_dev)
+{
+       int i, ret;
+       struct tsys01_dev *dev_data = iio_priv(indio_dev);
+       char buf[7 * TSYS01_PROM_WORDS_NB + 1];
+       char *ptr = buf;
+
+       for (i = 0; i < TSYS01_PROM_WORDS_NB; i++) {
+               ret = dev_data->read_prom_word(dev_data->client,
+                                              TSYS01_PROM_READ + (i << 1),
+                                              &dev_data->prom[i]);
+               if (ret)
+                       return ret;
+
+               ret = sprintf(ptr, "0x%04x ", dev_data->prom[i]);
+               ptr += ret;
+       }
+
+       if (!tsys01_crc_valid(dev_data->prom)) {
+               dev_err(&indio_dev->dev, "prom crc check error\n");
+               return -ENODEV;
+       }
+       *ptr = 0;
+       dev_info(&indio_dev->dev, "PROM coefficients : %s\n", buf);
+
+       return 0;
+}
+
+static int tsys01_probe(struct iio_dev *indio_dev, struct device *dev)
+{
+       int ret;
+       struct tsys01_dev *dev_data = iio_priv(indio_dev);
+
+       mutex_init(&dev_data->lock);
+
+       indio_dev->info = &tsys01_info;
+       indio_dev->name = dev->driver->name;
+       indio_dev->dev.parent = dev;
+       indio_dev->modes = INDIO_DIRECT_MODE;
+       indio_dev->channels = tsys01_channels;
+       indio_dev->num_channels = ARRAY_SIZE(tsys01_channels);
+
+       ret = dev_data->reset(dev_data->client, TSYS01_RESET, 3000);
+       if (ret)
+               return ret;
+
+       ret = tsys01_read_prom(indio_dev);
+       if (ret)
+               return ret;
+
+       return devm_iio_device_register(dev, indio_dev);
+}
+
+static int tsys01_i2c_probe(struct i2c_client *client,
+                           const struct i2c_device_id *id)
+{
+       struct tsys01_dev *dev_data;
+       struct iio_dev *indio_dev;
+
+       if (!i2c_check_functionality(client->adapter,
+                                    I2C_FUNC_SMBUS_WORD_DATA |
+                                    I2C_FUNC_SMBUS_WRITE_BYTE |
+                                    I2C_FUNC_SMBUS_READ_I2C_BLOCK)) {
+               dev_err(&client->dev,
+                       "Adapter does not support some i2c transaction\n");
+               return -ENODEV;
+       }
+
+       indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*dev_data));
+       if (!indio_dev)
+               return -ENOMEM;
+
+       dev_data = iio_priv(indio_dev);
+       dev_data->client = client;
+       dev_data->reset = ms_sensors_reset;
+       dev_data->read_prom_word = ms_sensors_read_prom_word;
+       dev_data->convert_and_read = ms_sensors_convert_and_read;
+
+       i2c_set_clientdata(client, indio_dev);
+
+       return tsys01_probe(indio_dev, &client->dev);
+}
+
+static const struct i2c_device_id tsys01_id[] = {
+       {"tsys01", 0},
+       {}
+};
+MODULE_DEVICE_TABLE(i2c, tsys01_id);
+
+static struct i2c_driver tsys01_driver = {
+       .probe = tsys01_i2c_probe,
+       .id_table = tsys01_id,
+       .driver = {
+                  .name = "tsys01",
+                  },
+};
+
+module_i2c_driver(tsys01_driver);
+
+MODULE_DESCRIPTION("Measurement-Specialties tsys01 temperature driver");
+MODULE_AUTHOR("William Markezana <william.markezana@meas-spec.com>");
+MODULE_AUTHOR("Ludovic Tancerel <ludovic.tancerel@maplehightech.com>");
+MODULE_LICENSE("GPL v2");