iio: chemical: vz89x: add support for VZ89TE part

Add support the VZ89TE variant which removes the voc_short channel,
and has CRC check for data transactions.

Signed-off-by: Matt Ranostay <mranostay@gmail.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

diff --git a/drivers/iio/chemical/vz89x.c b/drivers/iio/chemical/vz89x.c
index aa6ebc084e1919d9a94c09406e77eb34254b24a8..289d2919deeaee8897629284dbb46e2f250938ee 100644 (file)
--- a/drivers/iio/chemical/vz89x.c
+++ b/drivers/iio/chemical/vz89x.c
@@ -34,8 +34,17 @@
 #define VZ89X_VOC_TVOC_IDX             2
 #define VZ89X_VOC_RESISTANCE_IDX       3
 
+#define VZ89TE_REG_MEASUREMENT         0x0c
+#define VZ89TE_REG_MEASUREMENT_RD_SIZE 7
+#define VZ89TE_REG_MEASUREMENT_WR_SIZE 6
+
+#define VZ89TE_VOC_TVOC_IDX            0
+#define VZ89TE_VOC_CO2_IDX             1
+#define VZ89TE_VOC_RESISTANCE_IDX      2
+
 enum {
        VZ89X,
+       VZ89TE,
 };
 
 struct vz89x_chip_data;
@@ -47,7 +56,7 @@ struct vz89x_data {
        int (*xfer)(struct vz89x_data *data, u8 cmd);
 
        unsigned long last_update;
-       u8 buffer[VZ89X_REG_MEASUREMENT_RD_SIZE];
+       u8 buffer[VZ89TE_REG_MEASUREMENT_RD_SIZE];
 };
 
 struct vz89x_chip_data {
@@ -90,6 +99,40 @@ static const struct iio_chan_spec vz89x_channels[] = {
                .info_mask_separate =
                        BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE),
                .address = VZ89X_VOC_RESISTANCE_IDX,
+               .scan_index = -1,
+               .scan_type = {
+                       .endianness = IIO_LE,
+               },
+       },
+};
+
+static const struct iio_chan_spec vz89te_channels[] = {
+       {
+               .type = IIO_CONCENTRATION,
+               .channel2 = IIO_MOD_VOC,
+               .modified = 1,
+               .info_mask_separate =
+                       BIT(IIO_CHAN_INFO_OFFSET) | BIT(IIO_CHAN_INFO_RAW),
+               .address = VZ89TE_VOC_TVOC_IDX,
+       },
+
+       {
+               .type = IIO_CONCENTRATION,
+               .channel2 = IIO_MOD_CO2,
+               .modified = 1,
+               .info_mask_separate =
+                       BIT(IIO_CHAN_INFO_OFFSET) | BIT(IIO_CHAN_INFO_RAW),
+               .address = VZ89TE_VOC_CO2_IDX,
+       },
+       {
+               .type = IIO_RESISTANCE,
+               .info_mask_separate =
+                       BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE),
+               .address = VZ89TE_VOC_RESISTANCE_IDX,
+               .scan_index = -1,
+               .scan_type = {
+                       .endianness = IIO_BE,
+               },
        },
 };
 
@@ -121,13 +164,28 @@ static bool vz89x_measurement_is_valid(struct vz89x_data *data)
        return !!(data->buffer[data->chip->read_size - 1] > 0);
 }
 
+/* VZ89TE device has a modified CRC-8 two complement check */
+static bool vz89te_measurement_is_valid(struct vz89x_data *data)
+{
+       u8 crc = 0;
+       int i, sum = 0;
+
+       for (i = 0; i < (data->chip->read_size - 1); i++) {
+               sum = crc + data->buffer[i];
+               crc = sum;
+               crc += sum / 256;
+       }
+
+       return !((0xff - crc) == data->buffer[data->chip->read_size - 1]);
+}
+
 static int vz89x_i2c_xfer(struct vz89x_data *data, u8 cmd)
 {
        const struct vz89x_chip_data *chip = data->chip;
        struct i2c_client *client = data->client;
        struct i2c_msg msg[2];
        int ret;
-       u8 buf[3] = { cmd, 0, 0};
+       u8 buf[6] = { cmd, 0, 0, 0, 0, 0xf3 };
 
        msg[0].addr = client->addr;
        msg[0].flags = client->flags;
@@ -186,11 +244,24 @@ static int vz89x_get_measurement(struct vz89x_data *data)
        return 0;
 }
 
-static int vz89x_get_resistance_reading(struct vz89x_data *data)
+static int vz89x_get_resistance_reading(struct vz89x_data *data,
+                                       struct iio_chan_spec const *chan,
+                                       int *val)
 {
-       u8 *buf = &data->buffer[VZ89X_VOC_RESISTANCE_IDX];
+       u8 *tmp = (u8 *) &data->buffer[chan->address];
 
-       return buf[0] | (buf[1] << 8);
+       switch (chan->scan_type.endianness) {
+       case IIO_LE:
+               *val = le32_to_cpup((__le32 *) tmp) & GENMASK(23, 0);
+               break;
+       case IIO_BE:
+               *val = be32_to_cpup((__be32 *) tmp) >> 8;
+               break;
+       default:
+               return -EINVAL;
+       }
+
+       return 0;
 }
 
 static int vz89x_read_raw(struct iio_dev *indio_dev,
@@ -209,15 +280,15 @@ static int vz89x_read_raw(struct iio_dev *indio_dev,
                if (ret)
                        return ret;
 
-               switch (chan->address) {
-               case VZ89X_VOC_CO2_IDX:
-               case VZ89X_VOC_SHORT_IDX:
-               case VZ89X_VOC_TVOC_IDX:
+               switch (chan->type) {
+               case IIO_CONCENTRATION:
                        *val = data->buffer[chan->address];
                        return IIO_VAL_INT;
-               case VZ89X_VOC_RESISTANCE_IDX:
-                       *val = vz89x_get_resistance_reading(data);
-                       return IIO_VAL_INT;
+               case IIO_RESISTANCE:
+                       ret = vz89x_get_resistance_reading(data, chan, val);
+                       if (!ret)
+                               return IIO_VAL_INT;
+                       break;
                default:
                        return -EINVAL;
                }
@@ -232,12 +303,12 @@ static int vz89x_read_raw(struct iio_dev *indio_dev,
                }
                break;
        case IIO_CHAN_INFO_OFFSET:
-               switch (chan->address) {
-               case VZ89X_VOC_CO2_IDX:
+               switch (chan->channel2) {
+               case IIO_MOD_CO2:
                        *val = 44;
                        *val2 = 250000;
                        return IIO_VAL_INT_PLUS_MICRO;
-               case VZ89X_VOC_TVOC_IDX:
+               case IIO_MOD_VOC:
                        *val = -13;
                        return IIO_VAL_INT;
                default:
@@ -265,10 +336,21 @@ static const struct vz89x_chip_data vz89x_chips[] = {
                .channels = vz89x_channels,
                .num_channels = ARRAY_SIZE(vz89x_channels),
        },
+       {
+               .valid = vz89te_measurement_is_valid,
+
+               .cmd = VZ89TE_REG_MEASUREMENT,
+               .read_size = VZ89TE_REG_MEASUREMENT_RD_SIZE,
+               .write_size = VZ89TE_REG_MEASUREMENT_WR_SIZE,
+
+               .channels = vz89te_channels,
+               .num_channels = ARRAY_SIZE(vz89te_channels),
+       },
 };
 
 static const struct of_device_id vz89x_dt_ids[] = {
        { .compatible = "sgx,vz89x", .data = (void *) VZ89X },
+       { .compatible = "sgx,vz89te", .data = (void *) VZ89TE },
        { }
 };
 MODULE_DEVICE_TABLE(of, vz89x_dt_ids);
@@ -319,6 +401,7 @@ static int vz89x_probe(struct i2c_client *client,
 
 static const struct i2c_device_id vz89x_id[] = {
        { "vz89x", VZ89X },
+       { "vz89te", VZ89TE },
        { }
 };
 MODULE_DEVICE_TABLE(i2c, vz89x_id);