On 06/11/2013 05:56 PM, Lars-Peter Clausen wrote:
> This patch adds support for the AD7303. The AD7303 is a simple 2 channel 8 bit
> DAC with an SPI interface.
>
Do we need an explicit, 'Use the reference regulator' element in device tree
/platform data? (I know this is done in existing drivers) Or would a simple
lack of having one specified be sufficient? Are there real cases where
a board is designed with one, but we want to not use it (other than bugs
of course ;) Doesn't seem to be documented.
Otherwise, whether you put a blank line before return statements is a bit
random in this driver.
Rest is fine and I'm only bring the above up because its that sort of an evening ;)
> Signed-off-by: Lars-Peter Clausen <lars@xxxxxxxxxx>
> ---
> .../devicetree/bindings/iio/dac/ad7303.txt | 23 ++
> drivers/iio/dac/Kconfig | 10 +
> drivers/iio/dac/Makefile | 1 +
> drivers/iio/dac/ad7303.c | 315 +++++++++++++++++++++
> include/linux/platform_data/ad7303.h | 21 ++
> 5 files changed, 370 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/iio/dac/ad7303.txt
> create mode 100644 drivers/iio/dac/ad7303.c
> create mode 100644 include/linux/platform_data/ad7303.h
>
> diff --git a/Documentation/devicetree/bindings/iio/dac/ad7303.txt b/Documentation/devicetree/bindings/iio/dac/ad7303.txt
> new file mode 100644
> index 0000000..914610f
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/iio/dac/ad7303.txt
> @@ -0,0 +1,23 @@
> +Analog Devices AD7303 DAC device driver
> +
> +Required properties:
> + - compatible: Must be "adi,ad7303"
> + - reg: SPI chip select number for the device
> + - spi-max-frequency: Max SPI frequency to use (< 30000000)
> + - Vdd-supply: Phandle to the Vdd power supply
> +
> +Optional properties:
> + - REF-supply: Phandle to the external reference voltage supply. This should
> + only be set if there is an external reference voltage connected to the REF
> + pin. If the property is not set Vdd/2 is used as the reference voltage.
> +
> +Example:
> +
> + ad7303@4 {
> + compatible = "adi,ad7303";
> + reg = <4>;
> + spi-max-frequency = <10000000>;
> + Vdd-supply = <&vdd_supply>;
> + adi,use-external-reference;
above is a I think undocumented?
> + REF-supply = <&vref_supply>;
> + };
> diff --git a/drivers/iio/dac/Kconfig b/drivers/iio/dac/Kconfig
> index b61160b..c9c33ce 100644
> --- a/drivers/iio/dac/Kconfig
> +++ b/drivers/iio/dac/Kconfig
> @@ -130,6 +130,16 @@ config AD5686
> To compile this driver as a module, choose M here: the
> module will be called ad5686.
>
> +config AD7303
> + tristate "Analog Devices Analog Devices AD7303 DAC driver"
> + depends on SPI
> + help
> + Say yes here to build support for Analog Devices AD7303 Digital to Analog
> + Converters (DAC).
> +
> + To compile this driver as module choose M here: the module will be called
> + ad7303.
> +
> config MAX517
> tristate "Maxim MAX517/518/519 DAC driver"
> depends on I2C
> diff --git a/drivers/iio/dac/Makefile b/drivers/iio/dac/Makefile
> index 5b528eb..c8d7ab6 100644
> --- a/drivers/iio/dac/Makefile
> +++ b/drivers/iio/dac/Makefile
> @@ -14,5 +14,6 @@ obj-$(CONFIG_AD5755) += ad5755.o
> obj-$(CONFIG_AD5764) += ad5764.o
> obj-$(CONFIG_AD5791) += ad5791.o
> obj-$(CONFIG_AD5686) += ad5686.o
> +obj-$(CONFIG_AD7303) += ad7303.o
> obj-$(CONFIG_MAX517) += max517.o
> obj-$(CONFIG_MCP4725) += mcp4725.o
> diff --git a/drivers/iio/dac/ad7303.c b/drivers/iio/dac/ad7303.c
> new file mode 100644
> index 0000000..85aeef6
> --- /dev/null
> +++ b/drivers/iio/dac/ad7303.c
> @@ -0,0 +1,315 @@
> +/*
> + * AD7303 Digital to analog converters driver
> + *
> + * Copyright 2013 Analog Devices Inc.
> + *
> + * Licensed under the GPL-2.
> + */
> +
> +#include <linux/err.h>
> +#include <linux/module.h>
> +#include <linux/kernel.h>
> +#include <linux/spi/spi.h>
> +#include <linux/slab.h>
> +#include <linux/sysfs.h>
> +#include <linux/regulator/consumer.h>
> +#include <linux/of.h>
> +
> +#include <linux/iio/iio.h>
> +#include <linux/iio/sysfs.h>
> +
> +#include <linux/platform_data/ad7303.h>
> +
> +#define AD7303_CFG_EXTERNAL_VREF BIT(15)
> +#define AD7303_CFG_POWER_DOWN(ch) BIT(11 + (ch))
> +#define AD7303_CFG_ADDR_OFFSET 10
> +
> +#define AD7303_CMD_UPDATE_DAC (0x3 << 8)
> +
> +/**
> + * struct ad7303_state - driver instance specific data
> + * @spi: the device for this driver instance
> + * @config: cached config register value
> + * @dac_cache: current DAC raw value (chip does not support readback)
> + * @data: spi transfer buffer
> + */
> +
> +struct ad7303_state {
> + struct spi_device *spi;
> + uint16_t config;
> + uint8_t dac_cache[2];
> +
> + struct regulator *vdd_reg;
> + struct regulator *vref_reg;
> +
> + /*
> + * DMA (thus cache coherency maintenance) requires the
> + * transfer buffers to live in their own cache lines.
> + */
> + __be16 data ____cacheline_aligned;
> +};
> +
> +static int ad7303_write(struct ad7303_state *st, unsigned int chan,
> + uint8_t val)
> +{
> + st->data = cpu_to_be16(AD7303_CMD_UPDATE_DAC |
> + (chan << AD7303_CFG_ADDR_OFFSET) |
> + st->config | val);
> +
> + return spi_write(st->spi, &st->data, sizeof(st->data));
> +}
> +
> +static ssize_t ad7303_read_dac_powerdown(struct iio_dev *indio_dev,
> + uintptr_t private, const struct iio_chan_spec *chan, char *buf)
> +{
> + struct ad7303_state *st = iio_priv(indio_dev);
> +
> + return sprintf(buf, "%d\n", (bool)(st->config &
> + AD7303_CFG_POWER_DOWN(chan->channel)));
> +}
> +
> +static ssize_t ad7303_write_dac_powerdown(struct iio_dev *indio_dev,
> + uintptr_t private, const struct iio_chan_spec *chan, const char *buf,
> + size_t len)
> +{
> + struct ad7303_state *st = iio_priv(indio_dev);
> + bool pwr_down;
> + int ret;
> +
> + ret = strtobool(buf, &pwr_down);
> + if (ret)
> + return ret;
> +
> + mutex_lock(&indio_dev->mlock);
> +
> + if (pwr_down)
> + st->config |= AD7303_CFG_POWER_DOWN(chan->channel);
> + else
> + st->config &= ~AD7303_CFG_POWER_DOWN(chan->channel);
> +
> + /* There is no noop cmd which allows us to only update the powerdown
> + * mode, so just write one of the DAC channels again */
> + ad7303_write(st, chan->channel, st->dac_cache[chan->channel]);
> +
> + mutex_unlock(&indio_dev->mlock);
> + return ret ? ret : len;
> +}
> +
> +static int ad7303_get_vref(struct ad7303_state *st,
> + struct iio_chan_spec const *chan)
> +{
> + int ret;
> +
> + if (st->config & AD7303_CFG_EXTERNAL_VREF)
> + return regulator_get_voltage(st->vref_reg);
> +
> + ret = regulator_get_voltage(st->vdd_reg);
> + if (ret < 0)
> + return ret;
> + return ret / 2;
> +}
> +
> +static int ad7303_read_raw(struct iio_dev *indio_dev,
> + struct iio_chan_spec const *chan, int *val, int *val2, long info)
> +{
> + struct ad7303_state *st = iio_priv(indio_dev);
> + int vref_uv;
> +
> + switch (info) {
> + case IIO_CHAN_INFO_RAW:
> + *val = st->dac_cache[chan->channel];
> + return IIO_VAL_INT;
> + case IIO_CHAN_INFO_SCALE:
> + vref_uv = ad7303_get_vref(st, chan);
> + if (vref_uv < 0)
> + return vref_uv;
> +
> + *val = 2 * vref_uv / 1000;
> + *val2 = chan->scan_type.realbits;
> +
> + return IIO_VAL_FRACTIONAL_LOG2;
> + default:
> + break;
> + }
> + return -EINVAL;
> +}
> +
> +static int ad7303_write_raw(struct iio_dev *indio_dev,
> + struct iio_chan_spec const *chan, int val, int val2, long mask)
> +{
> + struct ad7303_state *st = iio_priv(indio_dev);
> + int ret;
> +
> + switch (mask) {
> + case IIO_CHAN_INFO_RAW:
> + if (val >= (1 << chan->scan_type.realbits) || val < 0)
> + return -EINVAL;
> +
> + mutex_lock(&indio_dev->mlock);
> + ret = ad7303_write(st, chan->address, val);
> + if (ret == 0)
> + st->dac_cache[chan->channel] = val;
> + mutex_unlock(&indio_dev->mlock);
> + break;
> + default:
> + ret = -EINVAL;
> + }
> +
> + return ret;
> +}
> +
> +static const struct iio_info ad7303_info = {
> + .read_raw = ad7303_read_raw,
> + .write_raw = ad7303_write_raw,
> + .driver_module = THIS_MODULE,
> +};
> +
> +static const struct iio_chan_spec_ext_info ad7303_ext_info[] = {
> + {
> + .name = "powerdown",
> + .read = ad7303_read_dac_powerdown,
> + .write = ad7303_write_dac_powerdown,
> + },
> + { },
> +};
> +
> +#define AD7303_CHANNEL(chan) { \
> + .type = IIO_VOLTAGE, \
> + .indexed = 1, \
> + .output = 1, \
> + .channel = (chan), \
> + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
> + .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
> + .address = (chan), \
> + .scan_type = { \
> + .sign = 'u', \
> + .realbits = '8', \
> + .storagebits = '8', \
> + .shift = '0', \
> + }, \
> + .ext_info = ad7303_ext_info, \
> +}
> +
> +static const struct iio_chan_spec ad7303_channels[] = {
> + AD7303_CHANNEL(0),
> + AD7303_CHANNEL(1),
> +};
> +
> +static int ad7303_probe(struct spi_device *spi)
> +{
> + const struct spi_device_id *id = spi_get_device_id(spi);
> + struct iio_dev *indio_dev;
> + struct ad7303_state *st;
> + bool ext_ref;
> + int ret;
> +
> + indio_dev = iio_device_alloc(sizeof(*st));
> + if (indio_dev == NULL)
> + return -ENOMEM;
> +
> + st = iio_priv(indio_dev);
> + spi_set_drvdata(spi, indio_dev);
> +
> + st->spi = spi;
> +
> + st->vdd_reg = regulator_get(&spi->dev, "Vdd");
> + if (IS_ERR(st->vdd_reg)) {
> + ret = PTR_ERR(st->vdd_reg);
> + goto err_free;
> + }
> +
> + ret = regulator_enable(st->vdd_reg);
> + if (ret)
> + goto err_put_vdd_reg;
> +
> + if (spi->dev.of_node) {
> + ext_ref = of_property_read_bool(spi->dev.of_node,
> + "REF-supply");
> + } else {
> + struct ad7303_platform_data *pdata = spi->dev.platform_data;
> + if (pdata && pdata->use_external_ref)
> + ext_ref = true;
> + else
> + ext_ref = false;
> + }
> +
> + if (ext_ref) {
> + st->vref_reg = regulator_get(&spi->dev, "REF");
> + if (IS_ERR(st->vref_reg))
> + goto err_disable_vdd_reg;
> +
> + ret = regulator_enable(st->vref_reg);
> + if (ret)
> + goto err_put_vref_reg;
> +
> + st->config |= AD7303_CFG_EXTERNAL_VREF;
> + }
> +
> + indio_dev->dev.parent = &spi->dev;
> + indio_dev->name = id->name;
> + indio_dev->info = &ad7303_info;
> + indio_dev->modes = INDIO_DIRECT_MODE;
> + indio_dev->channels = ad7303_channels;
> + indio_dev->num_channels = ARRAY_SIZE(ad7303_channels);
> +
> + ret = iio_device_register(indio_dev);
> + if (ret)
> + goto err_disable_vref_reg;
> +
> + return 0;
> +
> +err_disable_vref_reg:
> + if (st->vref_reg)
> + regulator_disable(st->vref_reg);
> +err_put_vref_reg:
> + if (st->vref_reg)
> + regulator_put(st->vref_reg);
> +err_disable_vdd_reg:
> + regulator_disable(st->vdd_reg);
> +err_put_vdd_reg:
> + regulator_put(st->vdd_reg);
> +err_free:
> + iio_device_free(indio_dev);
> +
> + return ret;
> +}
> +
> +static int ad7303_remove(struct spi_device *spi)
> +{
> + struct iio_dev *indio_dev = spi_get_drvdata(spi);
> + struct ad7303_state *st = iio_priv(indio_dev);
> +
> + iio_device_unregister(indio_dev);
> +
> + if (st->vref_reg) {
> + regulator_disable(st->vref_reg);
> + regulator_put(st->vref_reg);
> + }
> + regulator_disable(st->vdd_reg);
> + regulator_put(st->vdd_reg);
> +
> + iio_device_free(indio_dev);
> +
> + return 0;
> +}
> +
> +static const struct spi_device_id ad7303_spi_ids[] = {
> + { "ad7303", 0 },
> + {}
> +};
> +MODULE_DEVICE_TABLE(spi, ad7303_spi_ids);
> +
> +static struct spi_driver ad7303_driver = {
> + .driver = {
> + .name = "ad7303",
> + .owner = THIS_MODULE,
> + },
> + .probe = ad7303_probe,
> + .remove = ad7303_remove,
> + .id_table = ad7303_spi_ids,
> +};
> +module_spi_driver(ad7303_driver);
> +
> +MODULE_AUTHOR("Lars-Peter Clausen <lars@xxxxxxxxxx>");
> +MODULE_DESCRIPTION("Analog Devices AD7303 DAC driver");
> +MODULE_LICENSE("GPL v2");
> diff --git a/include/linux/platform_data/ad7303.h b/include/linux/platform_data/ad7303.h
> new file mode 100644
> index 0000000..de6a7a6
> --- /dev/null
> +++ b/include/linux/platform_data/ad7303.h
> @@ -0,0 +1,21 @@
> +/*
> + * Analog Devices AD7303 DAC driver
> + *
> + * Copyright 2013 Analog Devices Inc.
> + *
> + * Licensed under the GPL-2.
> + */
> +
> +#ifndef __IIO_ADC_AD7303_H__
> +#define __IIO_ADC_AD7303_H__
> +
> +/**
> + * struct ad7303_platform_data - AD7303 platform data
> + * @use_external_ref: If set to true use an external voltage reference connected
> + * to the REF pin, otherwise use the internal reference derived from Vdd.
> + */
> +struct ad7303_platform_data {
> + bool use_external_ref;
> +};
> +
> +#endif
>
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