iio: adc: add driver for the ti-adc084s021 chip
authorMårten Lindahl <martenli@axis.com>
Tue, 9 May 2017 16:05:01 +0000 (18:05 +0200)
committerJonathan Cameron <jic23@kernel.org>
Sun, 14 May 2017 15:34:11 +0000 (16:34 +0100)
This adds support for the Texas Instruments ADC084S021 ADC chip.

Signed-off-by: Mårten Lindahl <martenli@axis.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
drivers/iio/adc/Kconfig
drivers/iio/adc/Makefile
drivers/iio/adc/ti-adc084s021.c [new file with mode: 0644]

index 0b8915298bf1ff8d663b6d66e4c0af7d5ea57d30..9e08b8afccc6eac31bb7f2f695ed3743fe2b8b3a 100644 (file)
@@ -670,6 +670,18 @@ config TI_ADC0832
          This driver can also be built as a module. If so, the module will be
          called ti-adc0832.
 
+config TI_ADC084S021
+       tristate "Texas Instruments ADC084S021"
+       depends on SPI
+       select IIO_BUFFER
+       select IIO_TRIGGERED_BUFFER
+       help
+         If you say yes here you get support for Texas Instruments ADC084S021
+         chips.
+
+         This driver can also be built as a module. If so, the module will be
+         called ti-adc084s021.
+
 config TI_ADC12138
        tristate "Texas Instruments ADC12130/ADC12132/ADC12138"
        depends on SPI
index 56e5fabece4ce12d54a3ca9ce8fbb651cf913a29..ed8e8e220dbbad765edca77ad77745f6d5043563 100644 (file)
@@ -61,6 +61,7 @@ obj-$(CONFIG_STM32_ADC_CORE) += stm32-adc-core.o
 obj-$(CONFIG_STM32_ADC) += stm32-adc.o
 obj-$(CONFIG_TI_ADC081C) += ti-adc081c.o
 obj-$(CONFIG_TI_ADC0832) += ti-adc0832.o
+obj-$(CONFIG_TI_ADC084S021) += ti-adc084s021.o
 obj-$(CONFIG_TI_ADC12138) += ti-adc12138.o
 obj-$(CONFIG_TI_ADC128S052) += ti-adc128s052.o
 obj-$(CONFIG_TI_ADC161S626) += ti-adc161s626.o
diff --git a/drivers/iio/adc/ti-adc084s021.c b/drivers/iio/adc/ti-adc084s021.c
new file mode 100644 (file)
index 0000000..a355121
--- /dev/null
@@ -0,0 +1,275 @@
+/**
+ * Copyright (C) 2017 Axis Communications AB
+ *
+ * Driver for Texas Instruments' ADC084S021 ADC chip.
+ * Datasheets can be found here:
+ * http://www.ti.com/lit/ds/symlink/adc084s021.pdf
+ *
+ * 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
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/err.h>
+#include <linux/spi/spi.h>
+#include <linux/module.h>
+#include <linux/interrupt.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/buffer.h>
+#include <linux/iio/triggered_buffer.h>
+#include <linux/iio/trigger_consumer.h>
+#include <linux/regulator/consumer.h>
+
+#define ADC084S021_DRIVER_NAME "adc084s021"
+
+struct adc084s021 {
+       struct spi_device *spi;
+       struct spi_message message;
+       struct spi_transfer spi_trans;
+       struct regulator *reg;
+       struct mutex lock;
+       /*
+        * DMA (thus cache coherency maintenance) requires the
+        * transfer buffers to live in their own cache line.
+        */
+       u16 tx_buf[4] ____cacheline_aligned;
+       __be16 rx_buf[5]; /* First 16-bits are trash */
+};
+
+#define ADC084S021_VOLTAGE_CHANNEL(num)                  \
+       {                                                      \
+               .type = IIO_VOLTAGE,                                 \
+               .channel = (num),                                    \
+               .indexed = 1,                                        \
+               .scan_index = (num),                                 \
+               .scan_type = {                                       \
+                       .sign = 'u',                                       \
+                       .realbits = 8,                                     \
+                       .storagebits = 16,                                 \
+                       .shift = 4,                                        \
+                       .endianness = IIO_BE,                              \
+               },                                                   \
+               .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),        \
+               .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),\
+       }
+
+static const struct iio_chan_spec adc084s021_channels[] = {
+       ADC084S021_VOLTAGE_CHANNEL(0),
+       ADC084S021_VOLTAGE_CHANNEL(1),
+       ADC084S021_VOLTAGE_CHANNEL(2),
+       ADC084S021_VOLTAGE_CHANNEL(3),
+       IIO_CHAN_SOFT_TIMESTAMP(4),
+};
+
+/**
+ * Read an ADC channel and return its value.
+ *
+ * @adc: The ADC SPI data.
+ * @data: Buffer for converted data.
+ */
+static int adc084s021_adc_conversion(struct adc084s021 *adc, void *data)
+{
+       int n_words = (adc->spi_trans.len >> 1) - 1; /* Discard first word */
+       int ret, i = 0;
+       u16 *p = data;
+
+       /* Do the transfer */
+       ret = spi_sync(adc->spi, &adc->message);
+       if (ret < 0)
+               return ret;
+
+       for (; i < n_words; i++)
+               *(p + i) = adc->rx_buf[i + 1];
+
+       return ret;
+}
+
+static int adc084s021_read_raw(struct iio_dev *indio_dev,
+                          struct iio_chan_spec const *channel, int *val,
+                          int *val2, long mask)
+{
+       struct adc084s021 *adc = iio_priv(indio_dev);
+       int ret;
+
+       switch (mask) {
+       case IIO_CHAN_INFO_RAW:
+               ret = iio_device_claim_direct_mode(indio_dev);
+               if (ret < 0)
+                       return ret;
+
+               ret = regulator_enable(adc->reg);
+               if (ret) {
+                       iio_device_release_direct_mode(indio_dev);
+                       return ret;
+               }
+
+               adc->tx_buf[0] = channel->channel << 3;
+               ret = adc084s021_adc_conversion(adc, val);
+               iio_device_release_direct_mode(indio_dev);
+               regulator_disable(adc->reg);
+               if (ret < 0)
+                       return ret;
+
+               *val = be16_to_cpu(*val);
+               *val = (*val >> channel->scan_type.shift) & 0xff;
+
+               return IIO_VAL_INT;
+       case IIO_CHAN_INFO_SCALE:
+               ret = regulator_enable(adc->reg);
+               if (ret)
+                       return ret;
+
+               ret = regulator_get_voltage(adc->reg);
+               regulator_disable(adc->reg);
+               if (ret < 0)
+                       return ret;
+
+               *val = ret / 1000;
+
+               return IIO_VAL_INT;
+       default:
+               return -EINVAL;
+       }
+}
+
+/**
+ * Read enabled ADC channels and push data to the buffer.
+ *
+ * @irq: The interrupt number (not used).
+ * @pollfunc: Pointer to the poll func.
+ */
+static irqreturn_t adc084s021_buffer_trigger_handler(int irq, void *pollfunc)
+{
+       struct iio_poll_func *pf = pollfunc;
+       struct iio_dev *indio_dev = pf->indio_dev;
+       struct adc084s021 *adc = iio_priv(indio_dev);
+       __be16 data[8] = {0}; /* 4 * 16-bit words of data + 8 bytes timestamp */
+
+       mutex_lock(&adc->lock);
+
+       if (adc084s021_adc_conversion(adc, &data) < 0)
+               dev_err(&adc->spi->dev, "Failed to read data\n");
+
+       iio_push_to_buffers_with_timestamp(indio_dev, data,
+                                          iio_get_time_ns(indio_dev));
+       mutex_unlock(&adc->lock);
+       iio_trigger_notify_done(indio_dev->trig);
+
+       return IRQ_HANDLED;
+}
+
+static int adc084s021_buffer_preenable(struct iio_dev *indio_dev)
+{
+       struct adc084s021 *adc = iio_priv(indio_dev);
+       int scan_index;
+       int i = 0;
+
+       for_each_set_bit(scan_index, indio_dev->active_scan_mask,
+                        indio_dev->masklength) {
+               const struct iio_chan_spec *channel =
+                       &indio_dev->channels[scan_index];
+               adc->tx_buf[i++] = channel->channel << 3;
+       }
+       adc->spi_trans.len = 2 + (i * sizeof(__be16)); /* Trash + channels */
+
+       return regulator_enable(adc->reg);
+}
+
+static int adc084s021_buffer_postdisable(struct iio_dev *indio_dev)
+{
+       struct adc084s021 *adc = iio_priv(indio_dev);
+
+       adc->spi_trans.len = 4; /* Trash + single channel */
+
+       return regulator_disable(adc->reg);
+}
+
+static const struct iio_info adc084s021_info = {
+       .read_raw = adc084s021_read_raw,
+       .driver_module = THIS_MODULE,
+};
+
+static const struct iio_buffer_setup_ops adc084s021_buffer_setup_ops = {
+       .preenable = adc084s021_buffer_preenable,
+       .postenable = iio_triggered_buffer_postenable,
+       .predisable = iio_triggered_buffer_predisable,
+       .postdisable = adc084s021_buffer_postdisable,
+};
+
+static int adc084s021_probe(struct spi_device *spi)
+{
+       struct iio_dev *indio_dev;
+       struct adc084s021 *adc;
+       int ret;
+
+       indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*adc));
+       if (!indio_dev) {
+               dev_err(&spi->dev, "Failed to allocate IIO device\n");
+               return -ENOMEM;
+       }
+
+       adc = iio_priv(indio_dev);
+       adc->spi = spi;
+
+       /* Connect the SPI device and the iio dev */
+       spi_set_drvdata(spi, indio_dev);
+
+       /* Initiate the Industrial I/O device */
+       indio_dev->dev.parent = &spi->dev;
+       indio_dev->dev.of_node = spi->dev.of_node;
+       indio_dev->name = spi_get_device_id(spi)->name;
+       indio_dev->modes = INDIO_DIRECT_MODE;
+       indio_dev->info = &adc084s021_info;
+       indio_dev->channels = adc084s021_channels;
+       indio_dev->num_channels = ARRAY_SIZE(adc084s021_channels);
+
+       /* Create SPI transfer for channel reads */
+       adc->spi_trans.tx_buf = adc->tx_buf;
+       adc->spi_trans.rx_buf = adc->rx_buf;
+       adc->spi_trans.len = 4; /* Trash + single channel */
+       spi_message_init_with_transfers(&adc->message, &adc->spi_trans, 1);
+
+       adc->reg = devm_regulator_get(&spi->dev, "vref");
+       if (IS_ERR(adc->reg))
+               return PTR_ERR(adc->reg);
+
+       mutex_init(&adc->lock);
+
+       /* Setup triggered buffer with pollfunction */
+       ret = devm_iio_triggered_buffer_setup(&spi->dev, indio_dev, NULL,
+                                           adc084s021_buffer_trigger_handler,
+                                           &adc084s021_buffer_setup_ops);
+       if (ret) {
+               dev_err(&spi->dev, "Failed to setup triggered buffer\n");
+               return ret;
+       }
+
+       return devm_iio_device_register(&spi->dev, indio_dev);
+}
+
+static const struct of_device_id adc084s021_of_match[] = {
+       { .compatible = "ti,adc084s021", },
+       {},
+};
+MODULE_DEVICE_TABLE(of, adc084s021_of_match);
+
+static const struct spi_device_id adc084s021_id[] = {
+       { ADC084S021_DRIVER_NAME, 0},
+       {}
+};
+MODULE_DEVICE_TABLE(spi, adc084s021_id);
+
+static struct spi_driver adc084s021_driver = {
+       .driver = {
+               .name = ADC084S021_DRIVER_NAME,
+               .of_match_table = of_match_ptr(adc084s021_of_match),
+       },
+       .probe = adc084s021_probe,
+       .id_table = adc084s021_id,
+};
+module_spi_driver(adc084s021_driver);
+
+MODULE_AUTHOR("Mårten Lindahl <martenli@axis.com>");
+MODULE_DESCRIPTION("Texas Instruments ADC084S021");
+MODULE_LICENSE("GPL v2");
+MODULE_VERSION("1.0");