Date:	Sat, 24 Nov 2012 10:54:03 +0000
From:	Jonathan Cameron <jic23@...nel.org>
To:	Thierry Reding <thierry.reding@...onic-design.de>
CC:	Jonathan Cameron <jic23@....ac.uk>,
	Lars-Peter Clausen <lars@...afoo.de>,
	linux-iio@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] iio: adc: Add Texas Instruments ADC081C021/027 support

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@...onic-design.de>

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!)

> ---
> 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@...onic-design.de>");
> +MODULE_DESCRIPTION("Texas Instruments ADC081C021/027 driver");
> +MODULE_LICENSE("GPL v2");
>
--
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