On 06/11/2013 07:28 PM, Lars-Peter Clausen wrote:
> On 06/11/2013 08:16 PM, Jonathan Cameron wrote:
>> 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?
>
> Yes, the problem is that if the regulator framework is disabled or
> CONFIG_REGULATOR_DUMMY is set regulator_get() returns a valid (dummy)
> regulator. So we can't distinguish between whether a regulator is present or
> not in that case. But we need to configure the device according to whether
> there is an external ref or not. Of course scale reporting won't work if the
> regulator framework is disabled, but at least the device works still fine
> otherwise.
>
>> 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.
>
> No, if you don't want to use it even though it is on the board just don't
> specify it. E.g. in the devicetree case we use the presence of the property
> whether to use the internal or external reference.
>
Fair enough and thanks for clarifying this.
>>
>> 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>
Applied to the togreg branch of iio.git
Thanks,
>>> ---
>>> .../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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