This adds Texas Instruments' ADC12130/ADC12132/ADC12138 12-bit plus
sign ADC driver. I have tested with the ADC12138. The ADC12130 and
ADC12132 are not tested but these are similar to ADC12138 except that
the mode programming instruction is a bit different.
Signed-off-by: Akinobu Mita <akinobu.mita@xxxxxxxxx>
Acked-by: Rob Herring <robh@xxxxxxxxxx>
Cc: Jonathan Cameron <jic23@xxxxxxxxxx>
Cc: Hartmut Knaack <knaack.h@xxxxxx>
Cc: Lars-Peter Clausen <lars@xxxxxxxxxx>
Cc: Peter Meerwald <pmeerw@xxxxxxxxxx>
---
* Changes from v3
- rename acquisition-time DT property to ti,acquisition-time
- add explanation for ti,acquisition-time DT property
- add a note for vref-n-supply in the device tree document
- change parameter for ADC12138_VOLTAGE_CHANNEL_DIFF
- handle defer probing for vref-n optional regulator
.../devicetree/bindings/iio/adc/ti-adc12138.txt | 37 ++
drivers/iio/adc/Kconfig | 12 +
drivers/iio/adc/Makefile | 1 +
drivers/iio/adc/ti-adc12138.c | 551 +++++++++++++++++++++
4 files changed, 601 insertions(+)
create mode 100644 Documentation/devicetree/bindings/iio/adc/ti-adc12138.txt
create mode 100644 drivers/iio/adc/ti-adc12138.c
diff --git a/Documentation/devicetree/bindings/iio/adc/ti-adc12138.txt b/Documentation/devicetree/bindings/iio/adc/ti-adc12138.txt
new file mode 100644
index 0000000..049a1d3
--- /dev/null
+++ b/Documentation/devicetree/bindings/iio/adc/ti-adc12138.txt
@@ -0,0 +1,37 @@
+* Texas Instruments' ADC12130/ADC12132/ADC12138
+
+Required properties:
+ - compatible: Should be one of
+ * "ti,adc12130"
+ * "ti,adc12132"
+ * "ti,adc12138"
+ - reg: SPI chip select number for the device
+ - interrupts: Should contain interrupt for EOC (end of conversion)
+ - clocks: phandle to conversion clock input
+ - spi-max-frequency: Definision as per
+ Documentation/devicetree/bindings/spi/spi-bus.txt
+ - vref-p-supply: The regulator supply for positive analog voltage reference
+
+Optional properties:
+ - vref-n-supply: The regulator supply for negative analog voltage reference
+ (Note that this must not go below GND or exceed vref-p)
+ If not specified, this is assumed to be analog ground.
+ - ti,acquisition-time: The number of conversion clock periods for the S/H's
+ acquisition time. Should be one of 6, 10, 18, 34. If not specified,
+ default value of 10 is used.
+ For high source impedances, this value can be increased to 18 or 34.
+ For less ADC accuracy and/or slower CCLK frequencies this value may be
+ decreased to 6. See section 6.0 INPUT SOURCE RESISTANCE in the
+ datasheet for details.
+
+Example:
+adc@0 {
+ compatible = "ti,adc12138";
+ reg = <0>;
+ interrupts = <28 IRQ_TYPE_EDGE_RISING>;
+ interrupt-parent = <&gpio1>;
+ clocks = <&cclk>;
+ vref-p-supply = <&ldo4_reg>;
+ spi-max-frequency = <5000000>;
+ ti,acquisition-time = <6>;
+};
diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index fa0ff29..87ed82d 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -414,6 +414,18 @@ config TI_ADC0832
This driver can also be built as a module. If so, the module will be
called ti-adc0832.
+config TI_ADC12138
+ tristate "Texas Instruments ADC12130/ADC12132/ADC12138"
+ depends on SPI
+ select IIO_BUFFER
+ select IIO_TRIGGERED_BUFFER
+ help
+ If you say yes here you get support for Texas Instruments ADC12130,
+ ADC12132 and ADC12138 chips.
+
+ This driver can also be built as a module. If so, the module will be
+ called ti-adc12138.
+
config TI_ADC128S052
tristate "Texas Instruments ADC128S052/ADC122S021/ADC124S021"
depends on SPI
diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
index 599714b..3ae4ae3 100644
--- a/drivers/iio/adc/Makefile
+++ b/drivers/iio/adc/Makefile
@@ -40,6 +40,7 @@ obj-$(CONFIG_QCOM_SPMI_VADC) += qcom-spmi-vadc.o
obj-$(CONFIG_ROCKCHIP_SARADC) += rockchip_saradc.o
obj-$(CONFIG_TI_ADC081C) += ti-adc081c.o
obj-$(CONFIG_TI_ADC0832) += ti-adc0832.o
+obj-$(CONFIG_TI_ADC12138) += ti-adc12138.o
obj-$(CONFIG_TI_ADC128S052) += ti-adc128s052.o
obj-$(CONFIG_TI_ADS1015) += ti-ads1015.o
obj-$(CONFIG_TI_ADS8688) += ti-ads8688.o
diff --git a/drivers/iio/adc/ti-adc12138.c b/drivers/iio/adc/ti-adc12138.c
new file mode 100644
index 0000000..908b8b5
--- /dev/null
+++ b/drivers/iio/adc/ti-adc12138.c
@@ -0,0 +1,551 @@
+/*
+ * ADC12130/ADC12132/ADC12138 12-bit plus sign ADC driver
+ *
+ * Copyright (c) 2016 Akinobu Mita <akinobu.mita@xxxxxxxxx>
+ *
+ * This file is subject to the terms and conditions of version 2 of
+ * the GNU General Public License. See the file COPYING in the main
+ * directory of this archive for more details.
+ *
+ * Datasheet: http://www.ti.com/lit/ds/symlink/adc12138.pdf
+ */
+
+#include <linux/module.h>
+#include <linux/interrupt.h>
+#include <linux/completion.h>
+#include <linux/clk.h>
+#include <linux/spi/spi.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/buffer.h>
+#include <linux/iio/trigger.h>
+#include <linux/iio/triggered_buffer.h>
+#include <linux/iio/trigger_consumer.h>
+#include <linux/regulator/consumer.h>
+
+#define ADC12138_MODE_AUTO_CAL 0x08
+#define ADC12138_MODE_READ_STATUS 0x0c
+#define ADC12138_MODE_ACQUISITION_TIME_6 0x0e
+#define ADC12138_MODE_ACQUISITION_TIME_10 0x4e
+#define ADC12138_MODE_ACQUISITION_TIME_18 0x8e
+#define ADC12138_MODE_ACQUISITION_TIME_34 0xce
+
+#define ADC12138_STATUS_CAL BIT(6)
+
+enum {
+ adc12130,
+ adc12132,
+ adc12138,
+};
+
+struct adc12138 {
+ struct spi_device *spi;
+ unsigned int id;
+ /* conversion clock */
+ struct clk *cclk;
+ /* positive analog voltage reference */
+ struct regulator *vref_p;
+ /* negative analog voltage reference */
+ struct regulator *vref_n;
+ struct mutex lock;
+ struct completion complete;
+ /* The number of cclk periods for the S/H's acquisition time */
+ unsigned int acquisition_time;
+
+ u8 tx_buf[2] ____cacheline_aligned;
+ u8 rx_buf[2];
+};
+
+#define ADC12138_VOLTAGE_CHANNEL(chan) \
+ { \
+ .type = IIO_VOLTAGE, \
+ .indexed = 1, \
+ .channel = chan, \
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
+ .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) \
+ | BIT(IIO_CHAN_INFO_OFFSET), \
+ .scan_index = chan, \
+ .scan_type = { \
+ .sign = 's', \
+ .realbits = 13, \
+ .storagebits = 16, \
+ .shift = 3, \
+ .endianness = IIO_BE, \
+ }, \
+ }
+
+#define ADC12138_VOLTAGE_CHANNEL_DIFF(chan1, chan2, si) \
+ { \
+ .type = IIO_VOLTAGE, \
+ .indexed = 1, \
+ .channel = (chan1), \
+ .channel2 = (chan2), \
+ .differential = 1, \
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
+ .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) \
+ | BIT(IIO_CHAN_INFO_OFFSET), \
+ .scan_index = si, \
+ .scan_type = { \
+ .sign = 's', \
+ .realbits = 13, \
+ .storagebits = 16, \
+ .shift = 3, \
+ .endianness = IIO_BE, \
+ }, \
+ }
+
+static const struct iio_chan_spec adc12132_channels[] = {
+ ADC12138_VOLTAGE_CHANNEL(0),
+ ADC12138_VOLTAGE_CHANNEL(1),
+ ADC12138_VOLTAGE_CHANNEL_DIFF(0, 1, 2),
+ ADC12138_VOLTAGE_CHANNEL_DIFF(1, 0, 3),
+ IIO_CHAN_SOFT_TIMESTAMP(4),
+};
+
+static const struct iio_chan_spec adc12138_channels[] = {
+ ADC12138_VOLTAGE_CHANNEL(0),
+ ADC12138_VOLTAGE_CHANNEL(1),
+ ADC12138_VOLTAGE_CHANNEL(2),
+ ADC12138_VOLTAGE_CHANNEL(3),
+ ADC12138_VOLTAGE_CHANNEL(4),
+ ADC12138_VOLTAGE_CHANNEL(5),
+ ADC12138_VOLTAGE_CHANNEL(6),
+ ADC12138_VOLTAGE_CHANNEL(7),
+ ADC12138_VOLTAGE_CHANNEL_DIFF(0, 1, 8),
+ ADC12138_VOLTAGE_CHANNEL_DIFF(1, 0, 9),
+ ADC12138_VOLTAGE_CHANNEL_DIFF(2, 3, 10),
+ ADC12138_VOLTAGE_CHANNEL_DIFF(3, 2, 11),
+ ADC12138_VOLTAGE_CHANNEL_DIFF(4, 5, 12),
+ ADC12138_VOLTAGE_CHANNEL_DIFF(5, 4, 13),
+ ADC12138_VOLTAGE_CHANNEL_DIFF(6, 7, 14),
+ ADC12138_VOLTAGE_CHANNEL_DIFF(7, 6, 15),
+ IIO_CHAN_SOFT_TIMESTAMP(16),
+};
+
+static int adc12138_mode_programming(struct adc12138 *adc, u8 mode,
+ void *rx_buf, int len)
+{
+ struct spi_transfer xfer = {
+ .tx_buf = adc->tx_buf,
+ .rx_buf = adc->rx_buf,
+ .len = len,
+ };
+ int ret;
+
+ /* Skip unused bits for ADC12130 and ADC12132 */
+ if (adc->id != adc12138)
+ mode = (mode & 0xc0) | ((mode & 0x0f) << 2);
+
+ adc->tx_buf[0] = mode;
+
+ ret = spi_sync_transfer(adc->spi, &xfer, 1);
+ if (ret)
+ return ret;
+
+ memcpy(rx_buf, adc->rx_buf, len);
+
+ return 0;
+}
+
+static int adc12138_read_status(struct adc12138 *adc)
+{
+ u8 rx_buf[2];
+ int ret;
+
+ ret = adc12138_mode_programming(adc, ADC12138_MODE_READ_STATUS,
+ rx_buf, 2);
+ if (ret)
+ return ret;
+
+ return (rx_buf[0] << 1) | (rx_buf[1] >> 7);
+}
+
+static int __adc12138_start_conv(struct adc12138 *adc,
+ struct iio_chan_spec const *channel,
+ void *data, int len)
+
+{
+ const u8 ch_to_mux[] = { 0, 4, 1, 5, 2, 6, 3, 7 };
+ u8 mode = (ch_to_mux[channel->channel] << 4) |
+ (channel->differential ? 0 : 0x80);
+
+ return adc12138_mode_programming(adc, mode, data, len);
+}
+
+static int adc12138_start_conv(struct adc12138 *adc,
+ struct iio_chan_spec const *channel)
+{
+ u8 trash;
+
+ return __adc12138_start_conv(adc, channel, &trash, 1);
+}
+
+static int adc12138_start_and_read_conv(struct adc12138 *adc,
+ struct iio_chan_spec const *channel,
+ __be16 *data)
+{
+ return __adc12138_start_conv(adc, channel, data, 2);
+}
+
+static int adc12138_read_conv_data(struct adc12138 *adc, __be16 *value)
+{
+ /* Issue a read status instruction and read previous conversion data */
+ return adc12138_mode_programming(adc, ADC12138_MODE_READ_STATUS,
+ value, sizeof(*value));
+}
+
+static int adc12138_wait_eoc(struct adc12138 *adc, unsigned long timeout)
+{
+ if (!wait_for_completion_timeout(&adc->complete, timeout))
+ return -ETIMEDOUT;
+
+ return 0;
+}
+
+static int adc12138_adc_conversion(struct adc12138 *adc,
+ struct iio_chan_spec const *channel,
+ __be16 *value)
+{
+ int ret;
+
+ reinit_completion(&adc->complete);
+
+ ret = adc12138_start_conv(adc, channel);
+ if (ret)
+ return ret;
+
+ ret = adc12138_wait_eoc(adc, msecs_to_jiffies(100));
+ if (ret)
+ return ret;
+
+ return adc12138_read_conv_data(adc, value);
+}
+
+static int adc12138_read_raw(struct iio_dev *iio,
+ struct iio_chan_spec const *channel, int *value,
+ int *shift, long mask)
+{
+ struct adc12138 *adc = iio_priv(iio);
+ int ret;
+ __be16 data;
+
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW:
+ mutex_lock(&adc->lock);
+ ret = adc12138_adc_conversion(adc, channel, &data);
+ mutex_unlock(&adc->lock);
+ if (ret)
+ return ret;
+
+ *value = sign_extend32(be16_to_cpu(data) >> 3, 12);
+
+ return IIO_VAL_INT;
+ case IIO_CHAN_INFO_SCALE:
+ ret = regulator_get_voltage(adc->vref_p);
+ if (ret < 0)
+ return ret;
+ *value = ret;
+
+ if (!IS_ERR(adc->vref_n)) {
+ ret = regulator_get_voltage(adc->vref_n);
+ if (ret < 0)
+ return ret;
+ *value -= ret;
+ }
+
+ /* convert regulator output voltage to mV */
+ *value /= 1000;
+ *shift = channel->scan_type.realbits - 1;
+
+ return IIO_VAL_FRACTIONAL_LOG2;
+ case IIO_CHAN_INFO_OFFSET:
+ if (!IS_ERR(adc->vref_n)) {
+ *value = regulator_get_voltage(adc->vref_n);
+ if (*value < 0)
+ return *value;
+ } else {
+ *value = 0;
+ }
+
+ /* convert regulator output voltage to mV */
+ *value /= 1000;
+
+ return IIO_VAL_INT;
+ }
+
+ return -EINVAL;
+}
+
+static const struct iio_info adc12138_info = {
+ .read_raw = adc12138_read_raw,
+ .driver_module = THIS_MODULE,
+};
+
+static int adc12138_init(struct adc12138 *adc)
+{
+ int ret;
+ int status;
+ u8 mode;
+ u8 trash;
+
+ reinit_completion(&adc->complete);
+
+ ret = adc12138_mode_programming(adc, ADC12138_MODE_AUTO_CAL, &trash, 1);
+ if (ret)
+ return ret;
+
+ /* data output at this time has no significance */
+ status = adc12138_read_status(adc);
+ if (status < 0)
+ return status;
+
+ adc12138_wait_eoc(adc, msecs_to_jiffies(100));
+
+ status = adc12138_read_status(adc);
+ if (status & ADC12138_STATUS_CAL) {
+ dev_warn(&adc->spi->dev,
+ "Auto Cal sequence is still in progress: %#x\n",
+ status);
+ return -EIO;
+ }
+
+ switch (adc->acquisition_time) {
+ case 6:
+ mode = ADC12138_MODE_ACQUISITION_TIME_6;
+ break;
+ case 10:
+ mode = ADC12138_MODE_ACQUISITION_TIME_10;
+ break;
+ case 18:
+ mode = ADC12138_MODE_ACQUISITION_TIME_18;
+ break;
+ case 34:
+ mode = ADC12138_MODE_ACQUISITION_TIME_34;
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ return adc12138_mode_programming(adc, mode, &trash, 1);
+}
+
+static irqreturn_t adc12138_trigger_handler(int irq, void *p)
+{
+ struct iio_poll_func *pf = p;
+ struct iio_dev *indio_dev = pf->indio_dev;
+ struct adc12138 *adc = iio_priv(indio_dev);
+ __be16 data[20] = { }; /* 16x 2 bytes ADC data + 8 bytes timestamp */
+ __be16 trash;
+ int ret;
+ int scan_index;
+ int i = 0;
+
+ mutex_lock(&adc->lock);
+
+ for_each_set_bit(scan_index, indio_dev->active_scan_mask,
+ indio_dev->masklength) {
+ const struct iio_chan_spec *scan_chan =
+ &indio_dev->channels[scan_index];
+
+ reinit_completion(&adc->complete);
+
+ ret = adc12138_start_and_read_conv(adc, scan_chan,
+ i ? &data[i - 1] : &trash);
+ if (ret) {
+ dev_warn(&adc->spi->dev,
+ "failed to start conversion\n");
+ goto out;
+ }
+
+ ret = adc12138_wait_eoc(adc, msecs_to_jiffies(100));
+ if (ret) {
+ dev_warn(&adc->spi->dev, "wait eoc timeout\n");
+ goto out;
+ }
+
+ i++;
+ }
+
+ if (i) {
+ ret = adc12138_read_conv_data(adc, &data[i - 1]);
+ if (ret) {
+ dev_warn(&adc->spi->dev,
+ "failed to get conversion data\n");
+ goto out;
+ }
+ }
+
+ iio_push_to_buffers_with_timestamp(indio_dev, data, iio_get_time_ns());
+out:
+ mutex_unlock(&adc->lock);
+
+ iio_trigger_notify_done(indio_dev->trig);
+
+ return IRQ_HANDLED;
+}
+
+static irqreturn_t adc12138_eoc_handler(int irq, void *p)
+{
+ struct iio_dev *indio_dev = p;
+ struct adc12138 *adc = iio_priv(indio_dev);
+
+ complete(&adc->complete);
+
+ return IRQ_HANDLED;
+}
+
+static int adc12138_probe(struct spi_device *spi)
+{
+ struct iio_dev *indio_dev;
+ struct adc12138 *adc;
+ int ret;
+
+ indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*adc));
+ if (!indio_dev)
+ return -ENOMEM;
+
+ adc = iio_priv(indio_dev);
+ adc->spi = spi;
+ adc->id = spi_get_device_id(spi)->driver_data;
+ mutex_init(&adc->lock);
+ init_completion(&adc->complete);
+
+ indio_dev->name = spi_get_device_id(spi)->name;
+ indio_dev->dev.parent = &spi->dev;
+ indio_dev->info = &adc12138_info;
+ indio_dev->modes = INDIO_DIRECT_MODE;
+
+ switch (adc->id) {
+ case adc12130:
+ case adc12132:
+ indio_dev->channels = adc12132_channels;
+ indio_dev->num_channels = ARRAY_SIZE(adc12132_channels);
+ break;
+ case adc12138:
+ indio_dev->channels = adc12138_channels;
+ indio_dev->num_channels = ARRAY_SIZE(adc12138_channels);
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ ret = of_property_read_u32(spi->dev.of_node, "ti,acquisition-time",
+ &adc->acquisition_time);
+ if (ret)
+ adc->acquisition_time = 10;
+
+ adc->cclk = devm_clk_get(&spi->dev, NULL);
+ if (IS_ERR(adc->cclk))
+ return PTR_ERR(adc->cclk);
+
+ adc->vref_p = devm_regulator_get(&spi->dev, "vref-p");
+ if (IS_ERR(adc->vref_p))
+ return PTR_ERR(adc->vref_p);
+
+ adc->vref_n = devm_regulator_get_optional(&spi->dev, "vref-n");
+ if (IS_ERR(adc->vref_n)) {
+ /*
+ * Assume vref_n is 0V if an optional regulator is not
+ * specified, otherwise return the error code.
+ */
+ ret = PTR_ERR(adc->vref_n);
+ if (ret != -ENODEV)
+ return ret;
+ }
+
+ ret = devm_request_irq(&spi->dev, spi->irq, adc12138_eoc_handler,
+ IRQF_TRIGGER_RISING, indio_dev->name, indio_dev);
+ if (ret)
+ return ret;
+
+ ret = clk_prepare_enable(adc->cclk);
+ if (ret)
+ return ret;
+
+ ret = regulator_enable(adc->vref_p);
+ if (ret)
+ goto err_clk_disable;
+
+ if (!IS_ERR(adc->vref_n)) {
+ ret = regulator_enable(adc->vref_n);
+ if (ret)
+ goto err_vref_p_disable;
+ }
+
+ ret = adc12138_init(adc);
+ if (ret)
+ goto err_vref_n_disable;
+
+ spi_set_drvdata(spi, indio_dev);
+
+ ret = iio_triggered_buffer_setup(indio_dev, NULL,
+ adc12138_trigger_handler, NULL);
+ if (ret)
+ goto err_vref_n_disable;
+
+ ret = iio_device_register(indio_dev);
+ if (ret)
+ goto err_buffer_cleanup;
+
+ return 0;
+err_buffer_cleanup:
+ iio_triggered_buffer_cleanup(indio_dev);
+err_vref_n_disable:
+ if (!IS_ERR(adc->vref_n))
+ regulator_disable(adc->vref_n);
+err_vref_p_disable:
+ regulator_disable(adc->vref_p);
+err_clk_disable:
+ clk_disable_unprepare(adc->cclk);
+
+ return ret;
+}
+
+static int adc12138_remove(struct spi_device *spi)
+{
+ struct iio_dev *indio_dev = spi_get_drvdata(spi);
+ struct adc12138 *adc = iio_priv(indio_dev);
+
+ iio_device_unregister(indio_dev);
+ iio_triggered_buffer_cleanup(indio_dev);
+ if (!IS_ERR(adc->vref_n))
+ regulator_disable(adc->vref_n);
+ regulator_disable(adc->vref_p);
+ clk_disable_unprepare(adc->cclk);
+
+ return 0;
+}
+
+#ifdef CONFIG_OF
+
+static const struct of_device_id adc12138_dt_ids[] = {
+ { .compatible = "ti,adc12130", },
+ { .compatible = "ti,adc12132", },
+ { .compatible = "ti,adc12138", },
+ {}
+};
+MODULE_DEVICE_TABLE(of, adc12138_dt_ids);
+
+#endif
+
+static const struct spi_device_id adc12138_id[] = {
+ { "adc12130", adc12130 },
+ { "adc12132", adc12132 },
+ { "adc12138", adc12138 },
+ {}
+};
+MODULE_DEVICE_TABLE(spi, adc12138_id);
+
+static struct spi_driver adc12138_driver = {
+ .driver = {
+ .name = "adc12138",
+ .of_match_table = of_match_ptr(adc12138_dt_ids),
+ },
+ .probe = adc12138_probe,
+ .remove = adc12138_remove,
+ .id_table = adc12138_id,
+};
+module_spi_driver(adc12138_driver);
+
+MODULE_AUTHOR("Akinobu Mita <akinobu.mita@xxxxxxxxx>");
+MODULE_DESCRIPTION("ADC12130/ADC12132/ADC12138 driver");
+MODULE_LICENSE("GPL v2");
--
2.7.4
--
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