--- /dev/null
+/*
+ * AD7766/AD7767 SPI ADC driver
+ *
+ * Copyright 2016 Analog Devices Inc.
+ *
+ * Licensed under the GPL-2 or later.
+ */
+
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/gpio/consumer.h>
+#include <linux/module.h>
+#include <linux/regulator/consumer.h>
+#include <linux/slab.h>
+#include <linux/spi/spi.h>
+
+#include <linux/iio/iio.h>
+#include <linux/iio/buffer.h>
+#include <linux/iio/trigger.h>
+#include <linux/iio/trigger_consumer.h>
+#include <linux/iio/triggered_buffer.h>
+
+struct ad7766_chip_info {
+ unsigned int decimation_factor;
+};
+
+enum {
+ AD7766_SUPPLY_AVDD = 0,
+ AD7766_SUPPLY_DVDD = 1,
+ AD7766_SUPPLY_VREF = 2,
+ AD7766_NUM_SUPPLIES = 3
+};
+
+struct ad7766 {
+ const struct ad7766_chip_info *chip_info;
+ struct spi_device *spi;
+ struct clk *mclk;
+ struct gpio_desc *pd_gpio;
+ struct regulator_bulk_data reg[AD7766_NUM_SUPPLIES];
+
+ struct iio_trigger *trig;
+
+ struct spi_transfer xfer;
+ struct spi_message msg;
+
+ /*
+ * DMA (thus cache coherency maintenance) requires the
+ * transfer buffers to live in their own cache lines.
+ * Make the buffer large enough for one 24 bit sample and one 64 bit
+ * aligned 64 bit timestamp.
+ */
+ unsigned char data[ALIGN(3, sizeof(s64)) + sizeof(s64)]
+ ____cacheline_aligned;
+};
+
+/*
+ * AD7766 and AD7767 variations are interface compatible, the main difference is
+ * analog performance. Both parts will use the same ID.
+ */
+enum ad7766_device_ids {
+ ID_AD7766,
+ ID_AD7766_1,
+ ID_AD7766_2,
+};
+
+static irqreturn_t ad7766_trigger_handler(int irq, void *p)
+{
+ struct iio_poll_func *pf = p;
+ struct iio_dev *indio_dev = pf->indio_dev;
+ struct ad7766 *ad7766 = iio_priv(indio_dev);
+ int ret;
+
+ ret = spi_sync(ad7766->spi, &ad7766->msg);
+ if (ret < 0)
+ goto done;
+
+ iio_push_to_buffers_with_timestamp(indio_dev, ad7766->data,
+ pf->timestamp);
+done:
+ iio_trigger_notify_done(indio_dev->trig);
+
+ return IRQ_HANDLED;
+}
+
+static int ad7766_preenable(struct iio_dev *indio_dev)
+{
+ struct ad7766 *ad7766 = iio_priv(indio_dev);
+ int ret;
+
+ ret = regulator_bulk_enable(ARRAY_SIZE(ad7766->reg), ad7766->reg);
+ if (ret < 0) {
+ dev_err(&ad7766->spi->dev, "Failed to enable supplies: %d\n",
+ ret);
+ return ret;
+ }
+
+ ret = clk_prepare_enable(ad7766->mclk);
+ if (ret < 0) {
+ dev_err(&ad7766->spi->dev, "Failed to enable MCLK: %d\n", ret);
+ regulator_bulk_disable(ARRAY_SIZE(ad7766->reg), ad7766->reg);
+ return ret;
+ }
+
+ if (ad7766->pd_gpio)
+ gpiod_set_value(ad7766->pd_gpio, 0);
+
+ return 0;
+}
+
+static int ad7766_postdisable(struct iio_dev *indio_dev)
+{
+ struct ad7766 *ad7766 = iio_priv(indio_dev);
+
+ if (ad7766->pd_gpio)
+ gpiod_set_value(ad7766->pd_gpio, 1);
+
+ /*
+ * The PD pin is synchronous to the clock, so give it some time to
+ * notice the change before we disable the clock.
+ */
+ msleep(20);
+
+ clk_disable_unprepare(ad7766->mclk);
+ regulator_bulk_disable(ARRAY_SIZE(ad7766->reg), ad7766->reg);
+
+ return 0;
+}
+
+static int ad7766_read_raw(struct iio_dev *indio_dev,
+ const struct iio_chan_spec *chan, int *val, int *val2, long info)
+{
+ struct ad7766 *ad7766 = iio_priv(indio_dev);
+ struct regulator *vref = ad7766->reg[AD7766_SUPPLY_VREF].consumer;
+ int scale_uv;
+
+ switch (info) {
+ case IIO_CHAN_INFO_SCALE:
+ scale_uv = regulator_get_voltage(vref);
+ if (scale_uv < 0)
+ return scale_uv;
+ *val = scale_uv / 1000;
+ *val2 = chan->scan_type.realbits;
+ return IIO_VAL_FRACTIONAL_LOG2;
+ case IIO_CHAN_INFO_SAMP_FREQ:
+ *val = clk_get_rate(ad7766->mclk) /
+ ad7766->chip_info->decimation_factor;
+ return IIO_VAL_INT;
+ }
+ return -EINVAL;
+}
+
+static const struct iio_chan_spec ad7766_channels[] = {
+ {
+ .type = IIO_VOLTAGE,
+ .indexed = 1,
+ .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
+ .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),
+ .scan_type = {
+ .sign = 's',
+ .realbits = 24,
+ .storagebits = 32,
+ .endianness = IIO_BE,
+ },
+ },
+ IIO_CHAN_SOFT_TIMESTAMP(1),
+};
+
+static const struct ad7766_chip_info ad7766_chip_info[] = {
+ [ID_AD7766] = {
+ .decimation_factor = 8,
+ },
+ [ID_AD7766_1] = {
+ .decimation_factor = 16,
+ },
+ [ID_AD7766_2] = {
+ .decimation_factor = 32,
+ },
+};
+
+static const struct iio_buffer_setup_ops ad7766_buffer_setup_ops = {
+ .preenable = &ad7766_preenable,
+ .postenable = &iio_triggered_buffer_postenable,
+ .predisable = &iio_triggered_buffer_predisable,
+ .postdisable = &ad7766_postdisable,
+};
+
+static const struct iio_info ad7766_info = {
+ .driver_module = THIS_MODULE,
+ .read_raw = &ad7766_read_raw,
+};
+
+static irqreturn_t ad7766_irq(int irq, void *private)
+{
+ iio_trigger_poll(private);
+ return IRQ_HANDLED;
+}
+
+static int ad7766_set_trigger_state(struct iio_trigger *trig, bool enable)
+{
+ struct ad7766 *ad7766 = iio_trigger_get_drvdata(trig);
+
+ if (enable)
+ enable_irq(ad7766->spi->irq);
+ else
+ disable_irq(ad7766->spi->irq);
+
+ return 0;
+}
+
+static const struct iio_trigger_ops ad7766_trigger_ops = {
+ .owner = THIS_MODULE,
+ .set_trigger_state = ad7766_set_trigger_state,
+ .validate_device = iio_trigger_validate_own_device,
+};
+
+static int ad7766_probe(struct spi_device *spi)
+{
+ const struct spi_device_id *id = spi_get_device_id(spi);
+ struct iio_dev *indio_dev;
+ struct ad7766 *ad7766;
+ int ret;
+
+ indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*ad7766));
+ if (!indio_dev)
+ return -ENOMEM;
+
+ ad7766 = iio_priv(indio_dev);
+ ad7766->chip_info = &ad7766_chip_info[id->driver_data];
+
+ ad7766->mclk = devm_clk_get(&spi->dev, "mclk");
+ if (IS_ERR(ad7766->mclk))
+ return PTR_ERR(ad7766->mclk);
+
+ ad7766->reg[AD7766_SUPPLY_AVDD].supply = "avdd";
+ ad7766->reg[AD7766_SUPPLY_DVDD].supply = "dvdd";
+ ad7766->reg[AD7766_SUPPLY_VREF].supply = "vref";
+
+ ret = devm_regulator_bulk_get(&spi->dev, ARRAY_SIZE(ad7766->reg),
+ ad7766->reg);
+ if (IS_ERR(ad7766->reg))
+ return PTR_ERR(ad7766->reg);
+
+ ad7766->pd_gpio = devm_gpiod_get_optional(&spi->dev, "powerdown",
+ GPIOD_OUT_HIGH);
+ if (IS_ERR(ad7766->pd_gpio))
+ return PTR_ERR(ad7766->pd_gpio);
+
+ indio_dev->dev.parent = &spi->dev;
+ indio_dev->name = spi_get_device_id(spi)->name;
+ indio_dev->modes = INDIO_DIRECT_MODE;
+ indio_dev->channels = ad7766_channels;
+ indio_dev->num_channels = ARRAY_SIZE(ad7766_channels);
+ indio_dev->info = &ad7766_info;
+
+ if (spi->irq > 0) {
+ ad7766->trig = devm_iio_trigger_alloc(&spi->dev, "%s-dev%d",
+ indio_dev->name, indio_dev->id);
+ if (!ad7766->trig)
+ return -ENOMEM;
+
+ ad7766->trig->ops = &ad7766_trigger_ops;
+ ad7766->trig->dev.parent = &spi->dev;
+ iio_trigger_set_drvdata(ad7766->trig, ad7766);
+
+ ret = devm_request_irq(&spi->dev, spi->irq, ad7766_irq,
+ IRQF_TRIGGER_FALLING, dev_name(&spi->dev),
+ ad7766->trig);
+ if (ret < 0)
+ return ret;
+
+ /*
+ * The device generates interrupts as long as it is powered up.
+ * Some platforms might not allow the option to power it down so
+ * disable the interrupt to avoid extra load on the system
+ */
+ disable_irq(spi->irq);
+
+ ret = devm_iio_trigger_register(&spi->dev, ad7766->trig);
+ if (ret)
+ return ret;
+ }
+
+ spi_set_drvdata(spi, indio_dev);
+
+ ad7766->spi = spi;
+
+ /* First byte always 0 */
+ ad7766->xfer.rx_buf = &ad7766->data[1];
+ ad7766->xfer.len = 3;
+
+ spi_message_init(&ad7766->msg);
+ spi_message_add_tail(&ad7766->xfer, &ad7766->msg);
+
+ ret = devm_iio_triggered_buffer_setup(&spi->dev, indio_dev,
+ &iio_pollfunc_store_time, &ad7766_trigger_handler,
+ &ad7766_buffer_setup_ops);
+ if (ret)
+ return ret;
+
+ ret = devm_iio_device_register(&spi->dev, indio_dev);
+ if (ret)
+ return ret;
+ return 0;
+}
+
+static const struct spi_device_id ad7766_id[] = {
+ {"ad7766", ID_AD7766},
+ {"ad7766-1", ID_AD7766_1},
+ {"ad7766-2", ID_AD7766_2},
+ {"ad7767", ID_AD7766},
+ {"ad7767-1", ID_AD7766_1},
+ {"ad7767-2", ID_AD7766_2},
+ {}
+};
+MODULE_DEVICE_TABLE(spi, ad7766_id);
+
+static struct spi_driver ad7766_driver = {
+ .driver = {
+ .name = "ad7766",
+ },
+ .probe = ad7766_probe,
+ .id_table = ad7766_id,
+};
+module_spi_driver(ad7766_driver);
+
+MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
+MODULE_DESCRIPTION("Analog Devices AD7766 and AD7767 ADCs driver support");
+MODULE_LICENSE("GPL v2");
projects / platform / kernel / linux-exynos.git / commitdiff