Date:   Mon, 5 Aug 2019 16:57:27 +0100
From:   Jonathan Cameron <jic23@...nel.org>
To:     Martyn Welch <martyn.welch@...labora.com>
Cc:     Mark Rutland <mark.rutland@....com>,
        Hartmut Knaack <knaack.h@....de>,
        Lars-Peter Clausen <lars@...afoo.de>,
        Peter Meerwald-Stadler <pmeerw@...erw.net>,
        linux-iio@...r.kernel.org, linux-kernel@...r.kernel.org,
        kernel@...ts.collabora.co.uk, devicetree@...r.kernel.org,
        Sergei M <fizik1@...dex.com>
Subject: Re: [PATCH v4 2/2] iio: light: noa1305: Add support for NOA1305

On Fri,  2 Aug 2019 12:42:28 +0100
Martyn Welch <martyn.welch@...labora.com> wrote:

> This driver adds the initial support for the ON Semiconductor
> NOA1305 Ambient Light Sensor.
> 
> Originally written by Sergei Miroshnichenko. Found here:
>   https://github.com/EmcraftSystems/linux-upstream/commit/196d6cf897e632d2cb82d45484bd7a1bfdd5b6d9
> 
> Signed-off-by: Sergei M <fizik1@...dex.com>
> Signed-off-by: Martyn Welch <martyn.welch@...labora.com>

One minor thing I'll fix up whilst applying.

Applied to the togreg branch of iio.git and pushed out as testing
to see if we missed anything!

Thanks,

Jonathan

> ---
> 
> Changes:
> v2:
>  - Correcting authorship and SOB.
> v3:
>  - Improve register define naming.
>  - Follow IIO convention of interleaving register bit definitions with
>    register defintions.
>  - Use proper endian swapping.
>  - Process raw sensor count into Lux.
>  - Avoid setting variables to zero when not needed.
>  - Check return value of i2c writes.
>  - Implement disabling of regulator as a devm action.
>  - Remove excessive white spacing.
> v4:
>  - Clean up returns
>  - Remove redundant noa1305_remove()
>  - Remove redundant interrupt configuration/disabling
>  - Return raw value and scaling
> 
> Note: Scaling added for all possible interation times to ensure the
>       mechanism utilised would allow this, though chip currently
>       statically configured to 800mS.
> 
>  drivers/iio/light/Kconfig   |  10 ++
>  drivers/iio/light/Makefile  |   1 +
>  drivers/iio/light/noa1305.c | 312 ++++++++++++++++++++++++++++++++++++
>  3 files changed, 323 insertions(+)
>  create mode 100644 drivers/iio/light/noa1305.c
> 
> diff --git a/drivers/iio/light/Kconfig b/drivers/iio/light/Kconfig
> index 954c958cfc43..d1db0ec0d0f5 100644
> --- a/drivers/iio/light/Kconfig
> +++ b/drivers/iio/light/Kconfig
> @@ -309,6 +309,16 @@ config MAX44009
>  	 To compile this driver as a module, choose M here:
>  	 the module will be called max44009.
>  
> +config NOA1305
> +	tristate "ON Semiconductor NOA1305 ambient light sensor"
> +	depends on I2C

Needs to select REGMAP_I2C I think. I'll add that if it's all I find.

> +	help
> +	 Say Y here if you want to build support for the ON Semiconductor
> +	 NOA1305 ambient light sensor.
> +
> +	 To compile this driver as a module, choose M here:
> +	 The module will be called noa1305.
> +
>  config OPT3001
>  	tristate "Texas Instruments OPT3001 Light Sensor"
>  	depends on I2C
> diff --git a/drivers/iio/light/Makefile b/drivers/iio/light/Makefile
> index e40794fbb435..00d1f9b98f39 100644
> --- a/drivers/iio/light/Makefile
> +++ b/drivers/iio/light/Makefile
> @@ -29,6 +29,7 @@ obj-$(CONFIG_LTR501)		+= ltr501.o
>  obj-$(CONFIG_LV0104CS)		+= lv0104cs.o
>  obj-$(CONFIG_MAX44000)		+= max44000.o
>  obj-$(CONFIG_MAX44009)		+= max44009.o
> +obj-$(CONFIG_NOA1305)		+= noa1305.o
>  obj-$(CONFIG_OPT3001)		+= opt3001.o
>  obj-$(CONFIG_PA12203001)	+= pa12203001.o
>  obj-$(CONFIG_RPR0521)		+= rpr0521.o
> diff --git a/drivers/iio/light/noa1305.c b/drivers/iio/light/noa1305.c
> new file mode 100644
> index 000000000000..b8758aa7b32a
> --- /dev/null
> +++ b/drivers/iio/light/noa1305.c
> @@ -0,0 +1,312 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Support for ON Semiconductor NOA1305 ambient light sensor
> + *
> + * Copyright (C) 2016 Emcraft Systems
> + * Copyright (C) 2019 Collabora Ltd.
> + */
> +
> +#include <linux/delay.h>
> +#include <linux/err.h>
> +#include <linux/i2c.h>
> +#include <linux/iio/iio.h>
> +#include <linux/iio/sysfs.h>
> +#include <linux/module.h>
> +#include <linux/regmap.h>
> +#include <linux/regulator/consumer.h>
> +
> +#define NOA1305_REG_POWER_CONTROL	0x0
> +#define   NOA1305_POWER_CONTROL_DOWN	0x00
> +#define   NOA1305_POWER_CONTROL_ON	0x08
> +#define NOA1305_REG_RESET		0x1
> +#define   NOA1305_RESET_RESET		0x10
> +#define NOA1305_REG_INTEGRATION_TIME	0x2
> +#define   NOA1305_INTEGR_TIME_800MS	0x00
> +#define   NOA1305_INTEGR_TIME_400MS	0x01
> +#define   NOA1305_INTEGR_TIME_200MS	0x02
> +#define   NOA1305_INTEGR_TIME_100MS	0x03
> +#define   NOA1305_INTEGR_TIME_50MS	0x04
> +#define   NOA1305_INTEGR_TIME_25MS	0x05
> +#define   NOA1305_INTEGR_TIME_12_5MS	0x06
> +#define   NOA1305_INTEGR_TIME_6_25MS	0x07
> +#define NOA1305_REG_INT_SELECT		0x3
> +#define   NOA1305_INT_SEL_ACTIVE_HIGH	0x01
> +#define   NOA1305_INT_SEL_ACTIVE_LOW	0x02
> +#define   NOA1305_INT_SEL_INACTIVE	0x03
> +#define NOA1305_REG_INT_THRESH_LSB	0x4
> +#define NOA1305_REG_INT_THRESH_MSB	0x5
> +#define NOA1305_REG_ALS_DATA_LSB	0x6
> +#define NOA1305_REG_ALS_DATA_MSB	0x7
> +#define NOA1305_REG_DEVICE_ID_LSB	0x8
> +#define NOA1305_REG_DEVICE_ID_MSB	0x9
> +
> +#define NOA1305_DEVICE_ID	0x0519
> +#define NOA1305_DRIVER_NAME	"noa1305"
> +
> +struct noa1305_priv {
> +	struct i2c_client *client;
> +	struct regmap *regmap;
> +	struct regulator *vin_reg;
> +};
> +
> +static int noa1305_measure(struct noa1305_priv *priv)
> +{
> +	__le16 data;
> +	int ret;
> +
> +	ret = regmap_bulk_read(priv->regmap, NOA1305_REG_ALS_DATA_LSB, &data,
> +			       2);
> +	if (ret < 0)
> +		return ret;
> +
> +	return le16_to_cpu(data);
> +}
> +
> +static int noa1305_scale(struct noa1305_priv *priv, int *val, int *val2)
> +{
> +	int data;
> +	int ret;
> +
> +	ret = regmap_read(priv->regmap, NOA1305_REG_INTEGRATION_TIME, &data);
> +	if (ret < 0)
> +		return ret;
> +
> +	/*
> +	 * Lux = count / (<Integration Constant> * <Integration Time>)
> +	 *
> +	 * Integration Constant = 7.7
> +	 * Integration Time in Seconds
> +	 */
> +	switch (data) {
> +	case NOA1305_INTEGR_TIME_800MS:
> +		*val = 100;
> +		*val2 = 77 * 8;
> +		break;
> +	case NOA1305_INTEGR_TIME_400MS:
> +		*val = 100;
> +		*val2 = 77 * 4;
> +	case NOA1305_INTEGR_TIME_200MS:
> +		*val = 100;
> +		*val2 = 77 * 2;
> +		break;
> +	case NOA1305_INTEGR_TIME_100MS:
> +		*val = 100;
> +		*val2 = 77;
> +		break;
> +	case NOA1305_INTEGR_TIME_50MS:
> +		*val = 1000;
> +		*val2 = 77 * 5;
> +		break;
> +	case NOA1305_INTEGR_TIME_25MS:
> +		*val = 10000;
> +		*val2 = 77 * 25;
> +		break;
> +	case NOA1305_INTEGR_TIME_12_5MS:
> +		*val = 100000;
> +		*val2 = 77 * 125;
> +		break;
> +	case NOA1305_INTEGR_TIME_6_25MS:
> +		*val = 1000000;
> +		*val2 = 77 * 625;
> +		break;
> +	default:
> +		return -EINVAL;
> +	}
> +
> +	return IIO_VAL_FRACTIONAL;
> +}
> +
> +static const struct iio_chan_spec noa1305_channels[] = {
> +	{
> +		.type = IIO_LIGHT,
> +		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
> +		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
> +	}
> +};
> +
> +static int noa1305_read_raw(struct iio_dev *indio_dev,
> +				struct iio_chan_spec const *chan,
> +				int *val, int *val2, long mask)
> +{
> +	int ret = -EINVAL;
> +	struct noa1305_priv *priv = iio_priv(indio_dev);
> +
> +	switch (mask) {
> +	case IIO_CHAN_INFO_RAW:
> +		switch (chan->type) {
> +		case IIO_LIGHT:
> +			ret = noa1305_measure(priv);
> +			if (ret < 0)
> +				return ret;
> +			*val = ret;
> +			return IIO_VAL_INT;
> +		default:
> +			break;
> +		}
> +		break;
> +	case IIO_CHAN_INFO_SCALE:
> +		switch (chan->type) {
> +		case IIO_LIGHT:
> +			return noa1305_scale(priv, val, val2);
> +		default:
> +			break;
> +		}
> +		break;
> +	default:
> +		break;
> +	}
> +
> +	return ret;
> +}
> +
> +static const struct iio_info noa1305_info = {
> +	.read_raw = noa1305_read_raw,
> +};
> +
> +static bool noa1305_writable_reg(struct device *dev, unsigned int reg)
> +{
> +	switch (reg) {
> +	case NOA1305_REG_POWER_CONTROL:
> +	case NOA1305_REG_RESET:
> +	case NOA1305_REG_INTEGRATION_TIME:
> +	case NOA1305_REG_INT_SELECT:
> +	case NOA1305_REG_INT_THRESH_LSB:
> +	case NOA1305_REG_INT_THRESH_MSB:
> +		return true;
> +	default:
> +		return false;
> +	}
> +}
> +
> +static const struct regmap_config noa1305_regmap_config = {
> +	.name = NOA1305_DRIVER_NAME,
> +	.reg_bits = 8,
> +	.val_bits = 8,
> +	.max_register = NOA1305_REG_DEVICE_ID_MSB,
> +	.writeable_reg = noa1305_writable_reg,
> +};
> +
> +static void noa1305_reg_remove(void *data)
> +{
> +	struct noa1305_priv *priv = data;
> +
> +	regulator_disable(priv->vin_reg);
> +}
> +
> +static int noa1305_probe(struct i2c_client *client,
> +			 const struct i2c_device_id *id)
> +{
> +	struct noa1305_priv *priv;
> +	struct iio_dev *indio_dev;
> +	struct regmap *regmap;
> +	__le16 data;
> +	unsigned int dev_id;
> +	int ret;
> +
> +	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*priv));
> +	if (!indio_dev)
> +		return -ENOMEM;
> +
> +	regmap = devm_regmap_init_i2c(client, &noa1305_regmap_config);
> +	if (IS_ERR(regmap)) {
> +		dev_err(&client->dev, "Regmap initialization failed.\n");
> +		return PTR_ERR(regmap);
> +	}
> +
> +	priv = iio_priv(indio_dev);
> +
> +	priv->vin_reg = devm_regulator_get(&client->dev, "vin");
> +	if (IS_ERR(priv->vin_reg)) {
> +		dev_err(&client->dev, "get regulator vin failed\n");
> +		return PTR_ERR(priv->vin_reg);
> +	}
> +
> +	ret = regulator_enable(priv->vin_reg);
> +	if (ret) {
> +		dev_err(&client->dev, "enable regulator vin failed\n");
> +		return ret;
> +	}
> +
> +	ret = devm_add_action_or_reset(&client->dev, noa1305_reg_remove, priv);
> +	if (ret) {
> +		dev_err(&client->dev, "addition of devm action failed\n");
> +		return ret;
> +	}
> +
> +	i2c_set_clientdata(client, indio_dev);
> +	priv->client = client;
> +	priv->regmap = regmap;
> +
> +	ret = regmap_bulk_read(regmap, NOA1305_REG_DEVICE_ID_LSB, &data, 2);
> +	if (ret < 0) {
> +		dev_err(&client->dev, "ID reading failed: %d\n", ret);
> +		return ret;
> +	}
> +
> +	dev_id = le16_to_cpu(data);
> +	if (dev_id != NOA1305_DEVICE_ID) {
> +		dev_err(&client->dev, "Unknown device ID: 0x%x\n", dev_id);
> +		return -ENODEV;
> +	}
> +
> +	ret = regmap_write(regmap, NOA1305_REG_POWER_CONTROL,
> +			   NOA1305_POWER_CONTROL_ON);
> +	if (ret < 0) {
> +		dev_err(&client->dev, "Enabling power control failed\n");
> +		return ret;
> +	}
> +
> +	ret = regmap_write(regmap, NOA1305_REG_RESET, NOA1305_RESET_RESET);
> +	if (ret < 0) {
> +		dev_err(&client->dev, "Device reset failed\n");
> +		return ret;
> +	}
> +
> +	ret = regmap_write(regmap, NOA1305_REG_INTEGRATION_TIME,
> +			   NOA1305_INTEGR_TIME_800MS);
> +	if (ret < 0) {
> +		dev_err(&client->dev, "Setting integration time failed\n");
> +		return ret;
> +	}
> +
> +	indio_dev->dev.parent = &client->dev;
> +	indio_dev->info = &noa1305_info;
> +	indio_dev->channels = noa1305_channels;
> +	indio_dev->num_channels = ARRAY_SIZE(noa1305_channels);
> +	indio_dev->name = NOA1305_DRIVER_NAME;
> +	indio_dev->modes = INDIO_DIRECT_MODE;
> +
> +	ret = devm_iio_device_register(&client->dev, indio_dev);
> +	if (ret)
> +		dev_err(&client->dev, "registering device failed\n");
> +
> +	return ret;
> +}
> +
> +static const struct of_device_id noa1305_of_match[] = {
> +	{ .compatible = "onnn,noa1305" },
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(of, noa1305_of_match);
> +
> +static const struct i2c_device_id noa1305_ids[] = {
> +	{ "noa1305", 0 },
> +	{ }
> +};
> +MODULE_DEVICE_TABLE(i2c, noa1305_id);
> +
> +static struct i2c_driver noa1305_driver = {
> +	.driver = {
> +		.name		= NOA1305_DRIVER_NAME,
> +		.of_match_table	= noa1305_of_match,
> +	},
> +	.probe		= noa1305_probe,
> +	.id_table	= noa1305_ids,
> +};
> +
> +module_i2c_driver(noa1305_driver);
> +
> +MODULE_AUTHOR("Sergei Miroshnichenko <sergeimir@...raft.com>");
> +MODULE_AUTHOR("Martyn Welch <martyn.welch@...labora.com");
> +MODULE_DESCRIPTION("ON Semiconductor NOA1305 ambient light sensor");
> +MODULE_LICENSE("GPL");

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