Re: [PATCH v2] iio: adc: Add Texas Instruments ADC081C021/027 support

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On 11/24/2012 03:54 PM, Lars-Peter Clausen wrote:
> On 11/24/2012 11:54 AM, Jonathan Cameron wrote:
>> On 11/23/2012 03:13 PM, Thierry Reding wrote:
>>> Add support for reading conversion results from the ADC and provide them
>>> through a single IIO channel. A proper scaling factor is also exported
>>> based on the reference voltage provided by a regulator.
>>>
>>> Signed-off-by: Thierry Reding <thierry.reding@xxxxxxxxxxxxxxxxx>
>>
>> Looks good to me.  I think timing is against you (depending on what Linus
>> says with his next rc).  IIO patches are routed through Greg KH. His cut
>> off is 1 week before the merge window opens.  Mine tends to as a result
>> be a few days before that.  Linus stated in last rc message that the one he'll
>> do today or tomorrow will be the last for this cycle (and hence merge window
>> will open in a week from now). Hence this will probably hit linux next after
>> the merge window closes and merge in the 3.9 cycle.
>>
>> Shall I add a reviewed by from you Lars? Looks like Thierry has directly
>> addressed all your comments (thanks for doing the review by the way!)
> 
> Yes, Reviewed-by: Lars-Peter Clausen <lars@xxxxxxxxxx>
Added to togreg branch of iio.git.

Note this was a little interesting as the patch was (I guess) generated against
linux next.  The am35xx driver is coming in via a different tree so the context was
wrong.  I've fixed up for iio.git but it'll cause trouble the other way around
at some point...
> 
>>
>>> ---
>>> Changes in v2:
>>> - use the more common IIO_VAL_FRACTIONAL_LOG2 instead of IIO_VAL_INT_PLUS_MICRO
>>>   for the ADC scale factor
>>> - make the channel specification static const since it is the same for
>>>   all devices
>>> - convert the scale factor such that the result of multiplying the raw
>>>   value with the scale factor yields a voltage in millivolts
>>>
>>>  drivers/iio/adc/Kconfig      |  10 +++
>>>  drivers/iio/adc/Makefile     |   1 +
>>>  drivers/iio/adc/ti-adc081c.c | 161 +++++++++++++++++++++++++++++++++++++++++++
>>>  3 files changed, 172 insertions(+)
>>>  create mode 100644 drivers/iio/adc/ti-adc081c.c
>>>
>>> diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
>>> index b719f3b..e8be025 100644
>>> --- a/drivers/iio/adc/Kconfig
>>> +++ b/drivers/iio/adc/Kconfig
>>> @@ -91,6 +91,16 @@ config MAX1363
>>>  	  max11646, max11647) Provides direct access via sysfs and buffered
>>>  	  data via the iio dev interface.
>>>
>>> +config TI_ADC081C
>>> +	tristate "Texas Instruments ADC081C021/027"
>>> +	depends on I2C
>>> +	help
>>> +	  If you say yes here you get support for Texas Instruments ADC081C021
>>> +	  and ADC081C027 ADC chips.
>>> +
>>> +	  This driver can also be built as a module. If so, the module will be
>>> +	  called ti-adc081c.
>>> +
>>>  config TI_AM335X_ADC
>>>  	tristate "TI's ADC driver"
>>>  	depends on MFD_TI_AM335X_TSCADC
>>> diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
>>> index 19d709c..6ad20aa 100644
>>> --- a/drivers/iio/adc/Makefile
>>> +++ b/drivers/iio/adc/Makefile
>>> @@ -10,4 +10,5 @@ obj-$(CONFIG_AD7887) += ad7887.o
>>>  obj-$(CONFIG_AT91_ADC) += at91_adc.o
>>>  obj-$(CONFIG_LP8788_ADC) += lp8788_adc.o
>>>  obj-$(CONFIG_MAX1363) += max1363.o
>>> +obj-$(CONFIG_TI_ADC081C) += ti-adc081c.o
>>>  obj-$(CONFIG_TI_AM335X_ADC) += ti_am335x_adc.o
>>> diff --git a/drivers/iio/adc/ti-adc081c.c b/drivers/iio/adc/ti-adc081c.c
>>> new file mode 100644
>>> index 0000000..f4a46dd
>>> --- /dev/null
>>> +++ b/drivers/iio/adc/ti-adc081c.c
>>> @@ -0,0 +1,161 @@
>>> +/*
>>> + * Copyright (C) 2012 Avionic Design GmbH
>>> + *
>>> + * 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/i2c.h>
>>> +#include <linux/module.h>
>>> +
>>> +#include <linux/iio/iio.h>
>>> +#include <linux/regulator/consumer.h>
>>> +
>>> +struct adc081c {
>>> +	struct i2c_client *i2c;
>>> +	struct regulator *ref;
>>> +};
>>> +
>>> +#define REG_CONV_RES 0x00
>>> +
>>> +static int adc081c_read_raw(struct iio_dev *iio,
>>> +			    struct iio_chan_spec const *channel, int *value,
>>> +			    int *shift, long mask)
>>> +{
>>> +	struct adc081c *adc = iio_priv(iio);
>>> +	int err;
>>> +
>>> +	switch (mask) {
>>> +	case IIO_CHAN_INFO_RAW:
>>> +		err = i2c_smbus_read_word_swapped(adc->i2c, REG_CONV_RES);
>>> +		if (err < 0)
>>> +			return err;
>>> +
>>> +		*value = (err >> 4) & 0xff;
>>> +		return IIO_VAL_INT;
>>> +
>>> +	case IIO_CHAN_INFO_SCALE:
>>> +		err = regulator_get_voltage(adc->ref);
>>> +		if (err < 0)
>>> +			return err;
>>> +
>>> +		*value = err / 1000;
>>> +		*shift = 8;
>>> +
>>> +		return IIO_VAL_FRACTIONAL_LOG2;
>>> +
>>> +	default:
>>> +		break;
>>> +	}
>>> +
>>> +	return -EINVAL;
>>> +}
>>> +
>>> +static const struct iio_chan_spec adc081c_channel = {
>>> +	.type = IIO_VOLTAGE,
>>> +	.info_mask = IIO_CHAN_INFO_SCALE_SHARED_BIT |
>>> +		     IIO_CHAN_INFO_RAW_SEPARATE_BIT,
>>> +};
>>> +
>>> +static const struct iio_info adc081c_info = {
>>> +	.read_raw = adc081c_read_raw,
>>> +	.driver_module = THIS_MODULE,
>>> +};
>>> +
>>> +static int adc081c_probe(struct i2c_client *client,
>>> +			 const struct i2c_device_id *id)
>>> +{
>>> +	struct iio_dev *iio;
>>> +	struct adc081c *adc;
>>> +	int err;
>>> +
>>> +	if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_WORD_DATA))
>>> +		return -ENODEV;
>>> +
>>> +	iio = iio_device_alloc(sizeof(*adc));
>>> +	if (!iio)
>>> +		return -ENOMEM;
>>> +
>>> +	adc = iio_priv(iio);
>>> +	adc->i2c = client;
>>> +
>>> +	adc->ref = regulator_get(&client->dev, "vref");
>>> +	if (IS_ERR(adc->ref)) {
>>> +		err = PTR_ERR(adc->ref);
>>> +		goto iio_free;
>>> +	}
>>> +
>>> +	err = regulator_enable(adc->ref);
>>> +	if (err < 0)
>>> +		goto regulator_put;
>>> +
>>> +	iio->dev.parent = &client->dev;
>>> +	iio->name = dev_name(&client->dev);
>>> +	iio->modes = INDIO_DIRECT_MODE;
>>> +	iio->info = &adc081c_info;
>>> +
>>> +	iio->channels = &adc081c_channel;
>>> +	iio->num_channels = 1;
>>> +
>>> +	err = iio_device_register(iio);
>>> +	if (err < 0)
>>> +		goto regulator_disable;
>>> +
>>> +	i2c_set_clientdata(client, iio);
>>> +
>>> +	return 0;
>>> +
>>> +regulator_disable:
>>> +	regulator_disable(adc->ref);
>>> +regulator_put:
>>> +	regulator_put(adc->ref);
>>> +iio_free:
>>> +	iio_device_free(iio);
>>> +
>>> +	return err;
>>> +}
>>> +
>>> +static int adc081c_remove(struct i2c_client *client)
>>> +{
>>> +	struct iio_dev *iio = i2c_get_clientdata(client);
>>> +	struct adc081c *adc = iio_priv(iio);
>>> +
>>> +	iio_device_unregister(iio);
>>> +	regulator_disable(adc->ref);
>>> +	regulator_put(adc->ref);
>>> +	iio_device_free(iio);
>>> +
>>> +	return 0;
>>> +}
>>> +
>>> +static const struct i2c_device_id adc081c_id[] = {
>>> +	{ "adc081c", 0 },
>>> +	{ }
>>> +};
>>> +MODULE_DEVICE_TABLE(i2c, adc081c_id);
>>> +
>>> +#ifdef CONFIG_OF
>>> +static const struct of_device_id adc081c_of_match[] = {
>>> +	{ .compatible = "ti,adc081c" },
>>> +	{ }
>>> +};
>>> +MODULE_DEVICE_TABLE(of, adc081c_of_match);
>>> +#endif
>>> +
>>> +static struct i2c_driver adc081c_driver = {
>>> +	.driver = {
>>> +		.name = "adc081c",
>>> +		.owner = THIS_MODULE,
>>> +		.of_match_table = of_match_ptr(adc081c_of_match),
>>> +	},
>>> +	.probe = adc081c_probe,
>>> +	.remove = adc081c_remove,
>>> +	.id_table = adc081c_id,
>>> +};
>>> +module_i2c_driver(adc081c_driver);
>>> +
>>> +MODULE_AUTHOR("Thierry Reding <thierry.reding@xxxxxxxxxxxxxxxxx>");
>>> +MODULE_DESCRIPTION("Texas Instruments ADC081C021/027 driver");
>>> +MODULE_LICENSE("GPL v2");
>>>
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