iio: mlx90614: Add MLX90615 support

Add support for MLX90615 Infra Red Thermometer, which seems to be
the predecesor of MLX90614 . There are significant differences in
the register layout compared to MLX90614, but the functionality
of the device is virtually identical.

The following differences have been identified:
- RAM/EEPROM/SLEEP access opcodes are different
- RAM/EEPROM registers are at different offsets
- EEPROM emissivity and configuration registers are at different offsets
- EEPROM configuration register bits are shuffled around
- EEPROM emissivity settings are 14 bit on MLX90615 , 16 bit on MLX90614
- MLX90615 can only ever support one sensor, MLX90614 could support two
- FIR filter is set to fixed settings on MLX90615
- IIR filter coefficients are different

This patch fills in the MLX90615 specific description and quirk handling.

The IIR filter coefficients were provided by Melexis as follows:
0b0000 - Forbidden value
0b0001 - 100% - settling time = refresh rate = 205ms (around 5Hz)
0b0010 - 50% - settling time = 2050ms (around 0.5Hz)
0b0011 - 33% - settling time = 36900ms (around 0.3Hz)
0b0100 - 25% - settling time = 5125ms (around 0.2Hz)
0b0101 - 20% - settling time = 6355ms (around 0.15Hz)
0b0110 - 17% - settling time = 7790ms (around 0.13Hz)
0b0111 - 14% - settling time = 9225ms (around 0.1Hz)

Signed-off-by: Marek Vasut <marex@denx.de>
Acked-by: Crt Mori <cmo@melexis.com>
Link: https://lore.kernel.org/r/20230510102251.10118-6-marex@denx.de
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

diff --git a/drivers/iio/temperature/mlx90614.c b/drivers/iio/temperature/mlx90614.c
index ab83e97594bdada3f7303d7cf06ed1719befe582..676dc870192443e023c4d6596c127b380687fd30 100644 (file)
--- a/drivers/iio/temperature/mlx90614.c
+++ b/drivers/iio/temperature/mlx90614.c
@@ -1,12 +1,15 @@
 // SPDX-License-Identifier: GPL-2.0-only
 /*
- * mlx90614.c - Support for Melexis MLX90614 contactless IR temperature sensor
+ * mlx90614.c - Support for Melexis MLX90614/MLX90615 contactless IR temperature sensor
  *
  * Copyright (c) 2014 Peter Meerwald <pmeerw@pmeerw.net>
  * Copyright (c) 2015 Essensium NV
  * Copyright (c) 2015 Melexis
  *
- * Driver for the Melexis MLX90614 I2C 16-bit IR thermopile sensor
+ * Driver for the Melexis MLX90614/MLX90615 I2C 16-bit IR thermopile sensor
+ *
+ * MLX90614 - 17-bit ADC + MLX90302 DSP
+ * MLX90615 - 16-bit ADC + MLX90325 DSP
  *
  * (7-bit I2C slave address 0x5a, 100KHz bus speed only!)
  *
@@ -35,6 +38,10 @@
 #define MLX90614_OP_EEPROM     0x20
 #define MLX90614_OP_SLEEP      0xff
 
+#define MLX90615_OP_EEPROM     0x10
+#define MLX90615_OP_RAM                0x20
+#define MLX90615_OP_SLEEP      0xc6
+
 /* Control bits in configuration register */
 #define MLX90614_CONFIG_IIR_SHIFT 0 /* IIR coefficient */
 #define MLX90614_CONFIG_IIR_MASK (0x7 << MLX90614_CONFIG_IIR_SHIFT)
@@ -43,11 +50,16 @@
 #define MLX90614_CONFIG_FIR_SHIFT 8 /* FIR coefficient */
 #define MLX90614_CONFIG_FIR_MASK (0x7 << MLX90614_CONFIG_FIR_SHIFT)
 
+#define MLX90615_CONFIG_IIR_SHIFT 12 /* IIR coefficient */
+#define MLX90615_CONFIG_IIR_MASK (0x7 << MLX90615_CONFIG_IIR_SHIFT)
+
 /* Timings (in ms) */
 #define MLX90614_TIMING_EEPROM 20 /* time for EEPROM write/erase to complete */
 #define MLX90614_TIMING_WAKEUP 34 /* time to hold SDA low for wake-up */
 #define MLX90614_TIMING_STARTUP 250 /* time before first data after wake-up */
 
+#define MLX90615_TIMING_WAKEUP 22 /* time to hold SCL low for wake-up */
+
 #define MLX90614_AUTOSLEEP_DELAY 5000 /* default autosleep delay */
 
 /* Magic constants */
@@ -305,8 +317,8 @@ static int mlx90614_read_raw(struct iio_dev *indio_dev,
                        *val2 = ret * NSEC_PER_SEC / chip_info->emissivity_max;
                }
                return IIO_VAL_INT_PLUS_NANO;
-       case IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY: /* IIR setting with
-                                                            FIR = 1024 */
+       /* IIR setting with FIR=1024 (MLX90614) or FIR=65536 (MLX90615) */
+       case IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY:
                ret = mlx90614_power_get(data, false);
                if (ret < 0)
                        return ret;
@@ -664,14 +676,42 @@ static const struct mlx_chip_info mlx90614_chip_info = {
        },
 };
 
+static const struct mlx_chip_info mlx90615_chip_info = {
+       .op_eeprom_emissivity           = MLX90615_OP_EEPROM | 0x03,
+       .op_eeprom_config1              = MLX90615_OP_EEPROM | 0x02,
+       .op_ram_ta                      = MLX90615_OP_RAM | 0x06,
+       .op_ram_tobj1                   = MLX90615_OP_RAM | 0x07,
+       .op_ram_tobj2                   = MLX90615_OP_RAM | 0x08,
+       .op_sleep                       = MLX90615_OP_SLEEP,
+       .dual_channel                   = false,
+       .wakeup_delay_ms                = MLX90615_TIMING_WAKEUP,
+       .emissivity_max                 = 16383,
+       .fir_config_mask                = 0,    /* MLX90615 FIR is fixed */
+       .iir_config_mask                = MLX90615_CONFIG_IIR_MASK,
+       /* IIR value 0 is FORBIDDEN COMBINATION on MLX90615 */
+       .iir_valid_offset               = 1,
+       .iir_values                     = { 500, 50, 30, 20, 15, 13, 10 },
+       .iir_freqs                      = {
+               { 0, 100000 },  /* 14% ~= 0.10 Hz */
+               { 0, 130000 },  /* 17% ~= 0.13 Hz */
+               { 0, 150000 },  /* 20% ~= 0.15 Hz */
+               { 0, 200000 },  /* 25% ~= 0.20 Hz */
+               { 0, 300000 },  /* 33% ~= 0.30 Hz */
+               { 0, 500000 },  /* 50% ~= 0.50 Hz */
+               { 5, 000000 },  /* 100% ~= 5.00 Hz */
+       },
+};
+
 static const struct i2c_device_id mlx90614_id[] = {
        { "mlx90614", .driver_data = (kernel_ulong_t)&mlx90614_chip_info },
+       { "mlx90615", .driver_data = (kernel_ulong_t)&mlx90615_chip_info },
        { }
 };
 MODULE_DEVICE_TABLE(i2c, mlx90614_id);
 
 static const struct of_device_id mlx90614_of_match[] = {
        { .compatible = "melexis,mlx90614", .data = &mlx90614_chip_info },
+       { .compatible = "melexis,mlx90615", .data = &mlx90615_chip_info },
        { }
 };
 MODULE_DEVICE_TABLE(of, mlx90614_of_match);