iio: adc: mcp320x. Add support for more ADCs

Signed-off-by: Soeren Andersen <san at rosetechnology.dk>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

1 files changed, 187 insertions, 35 deletions

diff --git a/drivers/iio/adc/mcp320x.c b/drivers/iio/adc/mcp320x.c
index 28a086e48776..efbfd12a4bfd 100644
--- a/drivers/iio/adc/mcp320x.c
+++ b/drivers/iio/adc/mcp320x.c
@@ -1,9 +1,30 @@
 /*
  * Copyright (C) 2013 Oskar Andero <oskar.andero@gmail.com>
+ * Copyright (C) 2014 Rose Technology
+ *         Allan Bendorff Jensen <abj@rosetechnology.dk>
+ *         Soren Andersen <san@rosetechnology.dk>
+ *
+ * Driver for following ADC chips from Microchip Technology's:
+ * 10 Bit converter
+ * MCP3001
+ * MCP3002
+ * MCP3004
+ * MCP3008
+ * ------------
+ * 12 bit converter
+ * MCP3201
+ * MCP3202
+ * MCP3204
+ * MCP3208
+ * ------------
  *
- * Driver for Microchip Technology's MCP3204 and MCP3208 ADC chips.
  * Datasheet can be found here:
- * http://ww1.microchip.com/downloads/en/devicedoc/21298c.pdf
+ * http://ww1.microchip.com/downloads/en/DeviceDoc/21293C.pdf  mcp3001
+ * http://ww1.microchip.com/downloads/en/DeviceDoc/21294E.pdf  mcp3002
+ * http://ww1.microchip.com/downloads/en/DeviceDoc/21295d.pdf  mcp3004/08
+ * http://ww1.microchip.com/downloads/en/DeviceDoc/21290D.pdf  mcp3201
+ * http://ww1.microchip.com/downloads/en/DeviceDoc/21034D.pdf  mcp3202
+ * http://ww1.microchip.com/downloads/en/DeviceDoc/21298c.pdf  mcp3204/08
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
@@ -11,19 +32,29 @@
  */
 
 #include <linux/err.h>
+#include <linux/delay.h>
 #include <linux/spi/spi.h>
 #include <linux/module.h>
 #include <linux/iio/iio.h>
 #include <linux/regulator/consumer.h>
 
-#define MCP_SINGLE_ENDED        (1 << 3)
-#define MCP_START_BIT           (1 << 4)
-
 enum {
+        mcp3001,
+        mcp3002,
+        mcp3004,
+        mcp3008,
+        mcp3201,
+        mcp3202,
         mcp3204,
         mcp3208,
 };
 
+struct mcp320x_chip_info {
+        const struct iio_chan_spec *channels;
+        unsigned int num_channels;
+        unsigned int resolution;
+};
+
 struct mcp320x {
         struct spi_device *spi;
         struct spi_message msg;
@@ -34,19 +65,69 @@ struct mcp320x {
 
         struct regulator *reg;
         struct mutex lock;
+        const struct mcp320x_chip_info *chip_info;
 };
 
-static int mcp320x_adc_conversion(struct mcp320x *adc, u8 msg)
+static int mcp320x_channel_to_tx_data(int device_index,
+                        const unsigned int channel, bool differential)
+{
+        int start_bit = 1;
+
+        switch (device_index) {
+        case mcp3001:
+        case mcp3201:
+                return 0;
+        case mcp3002:
+        case mcp3202:
+                return ((start_bit << 4) | (!differential << 3) |
+                                                        (channel << 2));
+        case mcp3004:
+        case mcp3204:
+        case mcp3008:
+        case mcp3208:
+                return ((start_bit << 6) | (!differential << 5) |
+                                                        (channel << 2));
+        default:
+                return -EINVAL;
+        }
+}
+
+static int mcp320x_adc_conversion(struct mcp320x *adc, u8 channel,
+                                  bool differential, int device_index)
 {
         int ret;
 
-        adc->tx_buf = msg;
-        ret = spi_sync(adc->spi, &adc->msg);
-        if (ret < 0)
-                return ret;
+        adc->rx_buf[0] = 0;
+        adc->rx_buf[1] = 0;
+        adc->tx_buf = mcp320x_channel_to_tx_data(device_index,
+                                                channel, differential);
+
+        if (device_index != mcp3001 && device_index != mcp3201) {
+                ret = spi_sync(adc->spi, &adc->msg);
+                if (ret < 0)
+                        return ret;
+        } else {
+                ret = spi_read(adc->spi, &adc->rx_buf, sizeof(adc->rx_buf));
+                if (ret < 0)
+                        return ret;
+        }
 
-        return ((adc->rx_buf[0] & 0x3f) << 6)  |
-                (adc->rx_buf[1] >> 2);
+        switch (device_index) {
+        case mcp3001:
+                return (adc->rx_buf[0] << 5 | adc->rx_buf[1] >> 3);
+        case mcp3002:
+        case mcp3004:
+        case mcp3008:
+                return (adc->rx_buf[0] << 2 | adc->rx_buf[1] >> 6);
+        case mcp3201:
+                return (adc->rx_buf[0] << 7 | adc->rx_buf[1] >> 1);
+        case mcp3202:
+        case mcp3204:
+        case mcp3208:
+                return (adc->rx_buf[0] << 4 | adc->rx_buf[1] >> 4);
+        default:
+                return -EINVAL;
+        }
 }
 
 static int mcp320x_read_raw(struct iio_dev *indio_dev,
@@ -55,18 +136,17 @@ static int mcp320x_read_raw(struct iio_dev *indio_dev,
 {
         struct mcp320x *adc = iio_priv(indio_dev);
         int ret = -EINVAL;
+        int device_index = 0;
 
         mutex_lock(&adc->lock);
 
+        device_index = spi_get_device_id(adc->spi)->driver_data;
+
         switch (mask) {
         case IIO_CHAN_INFO_RAW:
-                if (channel->differential)
-                        ret = mcp320x_adc_conversion(adc,
-                                MCP_START_BIT | channel->address);
-                else
-                        ret = mcp320x_adc_conversion(adc,
-                                MCP_START_BIT | MCP_SINGLE_ENDED |
-                                channel->address);
+                ret = mcp320x_adc_conversion(adc, channel->address,
+                        channel->differential, device_index);
+
                 if (ret < 0)
                         goto out;
 
@@ -75,18 +155,15 @@ static int mcp320x_read_raw(struct iio_dev *indio_dev,
                 break;
 
         case IIO_CHAN_INFO_SCALE:
-                /* Digital output code = (4096 * Vin) / Vref */
                 ret = regulator_get_voltage(adc->reg);
                 if (ret < 0)
                         goto out;
 
+                /* convert regulator output voltage to mV */
                 *val = ret / 1000;
-                *val2 = 12;
+                *val2 = adc->chip_info->resolution;
                 ret = IIO_VAL_FRACTIONAL_LOG2;
                 break;
-
-        default:
-                break;
         }
 
 out:
@@ -117,6 +194,16 @@ out:
                 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) \
         }
 
+static const struct iio_chan_spec mcp3201_channels[] = {
+        MCP320X_VOLTAGE_CHANNEL_DIFF(0),
+};
+
+static const struct iio_chan_spec mcp3202_channels[] = {
+        MCP320X_VOLTAGE_CHANNEL(0),
+        MCP320X_VOLTAGE_CHANNEL(1),
+        MCP320X_VOLTAGE_CHANNEL_DIFF(0),
+};
+
 static const struct iio_chan_spec mcp3204_channels[] = {
         MCP320X_VOLTAGE_CHANNEL(0),
         MCP320X_VOLTAGE_CHANNEL(1),
@@ -146,19 +233,46 @@ static const struct iio_info mcp320x_info = {
         .driver_module = THIS_MODULE,
 };
 
-struct mcp3208_chip_info {
-        const struct iio_chan_spec *channels;
-        unsigned int num_channels;
-};
-
-static const struct mcp3208_chip_info mcp3208_chip_infos[] = {
+static const struct mcp320x_chip_info mcp320x_chip_infos[] = {
+        [mcp3001] = {
+                .channels = mcp3201_channels,
+                .num_channels = ARRAY_SIZE(mcp3201_channels),
+                .resolution = 10
+        },
+        [mcp3002] = {
+                .channels = mcp3202_channels,
+                .num_channels = ARRAY_SIZE(mcp3202_channels),
+                .resolution = 10
+        },
+        [mcp3004] = {
+                .channels = mcp3204_channels,
+                .num_channels = ARRAY_SIZE(mcp3204_channels),
+                .resolution = 10
+        },
+        [mcp3008] = {
+                .channels = mcp3208_channels,
+                .num_channels = ARRAY_SIZE(mcp3208_channels),
+                .resolution = 10
+        },
+        [mcp3201] = {
+                .channels = mcp3201_channels,
+                .num_channels = ARRAY_SIZE(mcp3201_channels),
+                .resolution = 12
+        },
+        [mcp3202] = {
+                .channels = mcp3202_channels,
+                .num_channels = ARRAY_SIZE(mcp3202_channels),
+                .resolution = 12
+        },
         [mcp3204] = {
                 .channels = mcp3204_channels,
-                .num_channels = ARRAY_SIZE(mcp3204_channels)
+                .num_channels = ARRAY_SIZE(mcp3204_channels),
+                .resolution = 12
         },
         [mcp3208] = {
                 .channels = mcp3208_channels,
-                .num_channels = ARRAY_SIZE(mcp3208_channels)
+                .num_channels = ARRAY_SIZE(mcp3208_channels),
+                .resolution = 12
         },
 };
 
@@ -166,7 +280,7 @@ static int mcp320x_probe(struct spi_device *spi)
 {
         struct iio_dev *indio_dev;
         struct mcp320x *adc;
-        const struct mcp3208_chip_info *chip_info;
+        const struct mcp320x_chip_info *chip_info;
         int ret;
 
         indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*adc));
@@ -181,7 +295,7 @@ static int mcp320x_probe(struct spi_device *spi)
         indio_dev->modes = INDIO_DIRECT_MODE;
         indio_dev->info = &mcp320x_info;
 
-        chip_info = &mcp3208_chip_infos[spi_get_device_id(spi)->driver_data];
+        chip_info = &mcp320x_chip_infos[spi_get_device_id(spi)->driver_data];
         indio_dev->channels = chip_info->channels;
         indio_dev->num_channels = chip_info->num_channels;
 
@@ -226,7 +340,45 @@ static int mcp320x_remove(struct spi_device *spi)
         return 0;
 }
 
+#if defined(CONFIG_OF)
+static const struct of_device_id mcp320x_dt_ids[] = {
+        {
+                .compatible = "mcp3001",
+                .data = &mcp320x_chip_infos[mcp3001],
+        }, {
+                .compatible = "mcp3002",
+                .data = &mcp320x_chip_infos[mcp3002],
+        }, {
+                .compatible = "mcp3004",
+                .data = &mcp320x_chip_infos[mcp3004],
+        }, {
+                .compatible = "mcp3008",
+                .data = &mcp320x_chip_infos[mcp3008],
+        }, {
+                .compatible = "mcp3201",
+                .data = &mcp320x_chip_infos[mcp3201],
+        }, {
+                .compatible = "mcp3202",
+                .data = &mcp320x_chip_infos[mcp3202],
+        }, {
+                .compatible = "mcp3204",
+                .data = &mcp320x_chip_infos[mcp3204],
+        }, {
+                .compatible = "mcp3208",
+                .data = &mcp320x_chip_infos[mcp3208],
+        }, {
+        }
+};
+MODULE_DEVICE_TABLE(of, mcp320x_dt_ids);
+#endif
+
 static const struct spi_device_id mcp320x_id[] = {
+        { "mcp3001", mcp3001 },
+        { "mcp3002", mcp3002 },
+        { "mcp3004", mcp3004 },
+        { "mcp3008", mcp3008 },
+        { "mcp3201", mcp3201 },
+        { "mcp3202", mcp3202 },
         { "mcp3204", mcp3204 },
         { "mcp3208", mcp3208 },
         { }
@@ -245,5 +397,5 @@ static struct spi_driver mcp320x_driver = {
 module_spi_driver(mcp320x_driver);
 
 MODULE_AUTHOR("Oskar Andero <oskar.andero@gmail.com>");
-MODULE_DESCRIPTION("Microchip Technology MCP3204/08");
+MODULE_DESCRIPTION("Microchip Technology MCP3x01/02/04/08");
 MODULE_LICENSE("GPL v2");