Date:	Tue, 4 Aug 2015 16:40:33 +0200 (CEST)
From:	Peter Meerwald <pmeerw@...erw.net>
To:	Adriana Reus <adriana.reus@...el.com>
cc:	jic23@...nel.org, linux-iio@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] iio: light: Add support for UPISEMI uS5182d als and
 proximity sensor

On Tue, 4 Aug 2015, Adriana Reus wrote:

> Add support for UPISEMI us5182d als and proximity sensor.
> Supports raw readings.
> Data sheet for this device can be found here:
> http://www.upi-semi.com/temp/uS5182D-DS-P0103-temp.pdf

comments below
 
> Signed-off-by: Adriana Reus <adriana.reus@...el.com>
> ---
>  Changes since v1: added data-sheet link to commit message
>  drivers/iio/light/Kconfig   |  10 +
>  drivers/iio/light/Makefile  |   1 +
>  drivers/iio/light/us5182d.c | 539 ++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 550 insertions(+)
>  create mode 100644 drivers/iio/light/us5182d.c
> 
> diff --git a/drivers/iio/light/Kconfig b/drivers/iio/light/Kconfig
> index a459341..0aa819d 100644
> --- a/drivers/iio/light/Kconfig
> +++ b/drivers/iio/light/Kconfig
> @@ -285,6 +285,16 @@ config TSL4531
>  	 To compile this driver as a module, choose M here: the
>  	 module will be called tsl4531.
>  
> +config US5182D
> +	tristate "UPISEMI light and proximity sensor"
> +	depends on I2C
> +	help
> +	 If you say yes here you get support for the UPISEMI US5182D
> +	 ambient light and proximity sensor.
> +
> +	 This driver can also be built as a module.  If so, the module
> +	 will be called us5182d.
> +
>  config VCNL4000
>  	tristate "VCNL4000 combined ALS and proximity sensor"
>  	depends on I2C
> diff --git a/drivers/iio/light/Makefile b/drivers/iio/light/Makefile
> index 91c74c0..528cc8f 100644
> --- a/drivers/iio/light/Makefile
> +++ b/drivers/iio/light/Makefile
> @@ -27,4 +27,5 @@ obj-$(CONFIG_STK3310)          += stk3310.o
>  obj-$(CONFIG_TCS3414)		+= tcs3414.o
>  obj-$(CONFIG_TCS3472)		+= tcs3472.o
>  obj-$(CONFIG_TSL4531)		+= tsl4531.o
> +obj-$(CONFIG_US5182D)		+= us5182d.o
>  obj-$(CONFIG_VCNL4000)		+= vcnl4000.o
> diff --git a/drivers/iio/light/us5182d.c b/drivers/iio/light/us5182d.c
> new file mode 100644
> index 0000000..6654bb0
> --- /dev/null
> +++ b/drivers/iio/light/us5182d.c
> @@ -0,0 +1,539 @@
> +/*
> + * Copyright (c) 2015 Intel Corporation
> + *
> + * Driver for UPISEMI us5182d Proximity and Ambient Light Sensor.
> + *
> + * 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.
> + *
> + * This program is distributed in the hope it will be useful, but WITHOUT
> + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
> + * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
> + * more details.
> + *
> + * To do: Interrupt support.
> + */
> +
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/acpi.h>
> +#include <linux/delay.h>
> +#include <linux/i2c.h>
> +#include <linux/iio/iio.h>
> +#include <linux/iio/sysfs.h>
> +#include <linux/mutex.h>
> +
> +#define US5182D_REG_CFG0		0x00
> +#define US5182D_REG_CFG1		0x01
> +#define US5182D_REG_CFG2		0x02
> +#define US5182D_REG_CFG3		0x03
> +#define US5182D_REG_CFG4		0x10
> +
> +/*
> + * Registers for tuning the auto dark current cancelling feature.
> + * DARK_TH(reg 0x27,0x28) - threshold (counts) for auto dark cancelling.
> + * when ALS  > DARK_TH --> ALS_Code = ALS - Upper(0x2A) * Dark
> + * when ALS < DARK_TH --> ALS_Code = ALS - Lower(0x29) * Dark
> + */
> +#define US5182D_REG_UDARK_TH			0x27
> +#define US5182D_REG_DARK_AUTO_EN		0x2b
> +#define US5182D_REG_AUTO_LDARK_TH		0x29
> +#define US5182D_REG_AUTO_HDARK_TH		0x2a
> +
> +/*
> + * power-mode - oneshot, non-interrupt, word mode access for
> + * als code, th registers.
> + */
> +#define US5182D_REG_CFG0_DEFAULT		0x81
> +
> +/*
> + * no als fault queue, 16 bit als resolution (supports 12 and 14 also),
> + * max-range 12354.
> + */
> +#define US5182D_REG_CFG1_DEFAULT		0x10
> +
> +/*
> + * 16 bit resolution for PX, x16 sensing amplifier for px
> + * supports [x1 x2 x4 x8 x16 x32 x64 x128]
> + */
> +#define US5182D_REG_CFG2_DEFAULT		0x14
> +
> +/*
> + * led current : 100mA, supports [12.5 25 50 100] mA,
> + * interrupt source selection "px approach",
> + * [als or ps, als only, ps only, ps approach]
> + */
> +#define US5182D_REG_CFG3_DEFAULT		0x3C
> +
> +/*
> + * led frequency ADC Clock/2 from [ADC Clock/2, /4, /8, /10]
> + * automatic 50/60 Hz ripple rejection disabled.
> + */
> +#define US5182D_REG_CFG4_DEFAULT		0x00
> +
> +#define US5182D_REG_DARK_AUTO_EN_DEFAULT	0x80
> +#define US5182D_REG_AUTO_LDARK_TH_DEFAULT	0x16
> +#define US5182D_REG_AUTO_HDARK_TH_DEFAULT	0x00
> +
> +#define US5182D_REG_ADL			0x0c
> +#define US5182D_REG_PDL			0x0e
> +
> +#define US5182D_REG_MODE_STORE		0x21
> +#define US5182D_STORE_MODE		0x01
> +
> +#define US5182D_REG_CHIPID		0xb2
> +
> +#define US5182D_ONESHOT_EN_MASK		BIT(6)
> +#define US5182D_SHUTDOWN_EN_MASK	BIT(7)
> +#define US5182D_OPMODE_MASK		GENMASK(5, 4)
> +#define US5182D_AGAIN_MASK		0x07
> +#define US5182D_OPMODE_ALS		0x01
> +#define US5182D_OPMODE_PX		0x02
> +#define US5182D_OPMODE_SHIFT		4
> +#define US5182D_RESET_CHIP		0x01
> +
> +#define US5182D_CHIPID			0x26
> +#define US5182D_DRV_NAME		"us5182d"
> +
> +#define US5182D_GA_RESOLUTION		1000
> +
> +#define READ_BYTE		1

US5128D_ prefix?!

> +#define READ_WORD		2
> +#define OPSTORE_SLEEP_TIME	20 /* ms */
> +
> +/* available ranges: [12354, 7065, 3998, 2202, 1285, 498, 256, 138] lux*/

space before */

> +static const int us5182d_scales[] = {188500, 107800, 61000, 33600, 19600, 7600,
> +				     3900, 2100};
> +
> +/*
> + * experimental th's that work with US5182D sensor on evaluation board
> + * roughly between 12-32 lux
> + */
> +static u16 us5182d_dark_ths_vals[] = {170, 200, 512, 512, 800, 2000, 4000,

const int

is 2x 512 correct?

> +				      8000};
> +
> +enum mode {
> +	ALS_PX,

US5128D_ prefix

> +	ALS_ONLY,
> +	PX_ONLY
> +};
> +
> +struct us5182d_data {
> +	struct i2c_client *client;
> +	/* protect opmode */
> +	struct mutex lock;
> +
> +	/* Glass attenuation factor */
> +	u32 ga;
> +
> +	/* Dark gain tuning */
> +	u16 lower_dark_th;
> +	u16 upper_dark_th;
> +	u16 *us5182d_dark_ths;
> +
> +	u8 opmode;
> +};
> +
> +static IIO_CONST_ATTR(in_illuminance_scale_available,
> +		      "0.0021 0.0039 0.0076 0.0196 0.0336 0.061 0.1078 0.1885");
> +
> +static struct attribute *us5182d_attrs[] = {
> +	&iio_const_attr_in_illuminance_scale_available.dev_attr.attr,
> +	NULL
> +};
> +
> +static const struct attribute_group us5182d_attr_group = {
> +	.attrs = us5182d_attrs,
> +};
> +
> +static const struct {
> +	u8 reg;
> +	u8 val;
> +} us5182d_regvals[] = {
> +	{US5182D_REG_CFG0, US5182D_REG_CFG0_DEFAULT},
> +	{US5182D_REG_CFG1, US5182D_REG_CFG1_DEFAULT},
> +	{US5182D_REG_CFG2, US5182D_REG_CFG2_DEFAULT},
> +	{US5182D_REG_CFG3, US5182D_REG_CFG3_DEFAULT},
> +	{US5182D_REG_MODE_STORE, US5182D_STORE_MODE},
> +	{US5182D_REG_CFG4, US5182D_REG_CFG4_DEFAULT},
> +};
> +
> +static const struct iio_chan_spec us5182d_channels[] = {
> +	{
> +		.type = IIO_LIGHT,
> +		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
> +				      BIT(IIO_CHAN_INFO_SCALE),
> +	},
> +	{
> +		.type = IIO_PROXIMITY,
> +		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
> +	}
> +};
> +
> +static int us5182d_read(struct i2c_client *client, u8 reg, int len, u8 *val)
> +{
> +	struct i2c_msg msg[2] = {
> +		{
> +			/* Write - use repeated start */
> +			.addr = client->addr,
> +			.flags = I2C_M_NOSTART,
> +			.len = 1,
> +			.buf = &reg
> +		},
> +		{
> +			.addr = client->addr,
> +			.flags = I2C_M_RD,
> +			.len = len,
> +			.buf = val
> +		}
> +	};
> +
> +	return i2c_transfer(client->adapter, msg, 2);
> +}
> +
> +static int us5182d_read_byte_data(struct i2c_client *client, u8 reg)
> +{
> +	u8 val[1];
> +	int ret;
> +
> +	ret = us5182d_read(client, reg, READ_BYTE, val);
> +	return (ret < 0) ? ret : val[0];
> +}
> +
> +static int us5182d_read_word_data(struct i2c_client *client, u8 reg)
> +{
> +	u8 val[2];
> +	int ret;
> +
> +	ret = us5182d_read(client, reg, READ_WORD, val);

use le16_to_cpu()

> +	return (ret < 0) ? ret : (val[0] | (val[1] << 8));
> +}
> +
> +static int us5182d_get_als(struct us5182d_data *data)
> +{
> +	int ret;
> +	unsigned long result;
> +
> +	ret = us5182d_read_word_data(data->client,
> +				     US5182D_REG_ADL);
> +	if (ret < 0)
> +		return ret;
> +
> +	result = ret * data->ga / US5182D_GA_RESOLUTION;
> +	if (result > 0xffff)
> +		result = 0xffff;
> +
> +	return result;
> +}
> +
> +static int us5182d_set_opmode(struct us5182d_data *data, u8 mode)
> +{
> +	int ret;
> +
> +	ret = us5182d_read_byte_data(data->client, US5182D_REG_CFG0);
> +	if (ret < 0)
> +		return ret;
> +
> +	ret = ret | US5182D_ONESHOT_EN_MASK;
> +
> +	/* update mode */
> +	ret = ret & ~US5182D_OPMODE_MASK;
> +	ret = ret | (mode << US5182D_OPMODE_SHIFT);
> +
> +	ret = i2c_smbus_write_byte_data(data->client, US5182D_REG_CFG0, ret);
> +	if (ret < 0)
> +		return ret;
> +
> +	if (mode == data->opmode)
> +		return 0;
> +
> +	data->opmode = mode;
> +	ret = i2c_smbus_write_byte_data(data->client, US5182D_REG_MODE_STORE,
> +					US5182D_STORE_MODE);
> +	if (ret < 0)
> +		return ret;
> +	msleep(OPSTORE_SLEEP_TIME);
> +
> +	return 0;
> +}
> +
> +static int us5182d_read_raw(struct iio_dev *indio_dev,
> +			    struct iio_chan_spec const *chan, int *val,
> +			    int *val2, long mask)
> +{
> +	struct us5182d_data *data = iio_priv(indio_dev);
> +	int ret;
> +
> +	switch (mask) {
> +	case IIO_CHAN_INFO_RAW:
> +		switch (chan->type) {
> +		case IIO_LIGHT:
> +			mutex_lock(&data->lock);
> +			ret = us5182d_set_opmode(data, US5182D_OPMODE_ALS);
> +			if (ret < 0)
> +				goto out_err;
> +
> +			ret = us5182d_get_als(data);
> +			if (ret < 0)
> +				goto out_err;
> +			mutex_unlock(&data->lock);
> +			*val = ret;
> +			*val2 = 0;

no need to set val2

> +			return IIO_VAL_INT;
> +		case IIO_PROXIMITY:
> +			mutex_lock(&data->lock);
> +			ret = us5182d_set_opmode(data, US5182D_OPMODE_PX);
> +			if (ret < 0)
> +				goto out_err;
> +
> +			ret = us5182d_read_word_data(data->client,
> +						     US5182D_REG_PDL);
> +			if (ret < 0)
> +				goto out_err;
> +			mutex_unlock(&data->lock);
> +			*val = ret;
> +			*val2 = 0;
> +			return  IIO_VAL_INT;
> +		default:
> +			break;

return -EINVAL; directly

> +		}
> +
> +	case IIO_CHAN_INFO_SCALE:
> +		ret = us5182d_read_byte_data(data->client, US5182D_REG_CFG1);
> +		if (ret < 0)
> +			return ret;
> +		*val = 0;
> +		ret = (ret & US5182D_AGAIN_MASK);
> +		*val2 = us5182d_scales[ret];
> +		return IIO_VAL_INT_PLUS_MICRO;
> +	default:
> +		return -EINVAL;
> +	}
> +
> +	return -EINVAL;
> +out_err:
> +	mutex_unlock(&data->lock);
> +	return ret;
> +}
> +
> +static int us5182d_update_dark_th(struct us5182d_data *data, int index)
> +{
> +	__be16 dark_th = cpu_to_be16(data->us5182d_dark_ths[index]);

really? 
in us5182d_read_word_data() it appears that the sensor wants little endian

> +	u8 *bytes = (u8 *)&dark_th;
> +	int ret;
> +
> +	/* Registers Dark_Th (0x27 0x28) don't work in word mode accessing */
> +	ret = i2c_smbus_write_byte_data(data->client, US5182D_REG_UDARK_TH,
> +					bytes[0]);
> +	if (ret < 0)
> +		return ret;
> +
> +	return i2c_smbus_write_byte_data(data->client, US5182D_REG_UDARK_TH + 1,
> +					bytes[1]);
> +}
> +
> +static int us5182d_apply_scale(struct us5182d_data *data, int index)
> +{
> +	int ret;
> +
> +	ret = us5182d_read_byte_data(data->client, US5182D_REG_CFG1);
> +	if (ret < 0)
> +		return ret;
> +
> +	ret = ret & (~US5182D_AGAIN_MASK);
> +	ret |= index;
> +
> +	ret = i2c_smbus_write_byte_data(data->client, US5182D_REG_CFG1, ret);
> +	if (ret < 0)
> +		return ret;
> +
> +	return us5182d_update_dark_th(data, index);
> +}
> +
> +static int us5182d_write_raw(struct iio_dev *indio_dev,
> +			     struct iio_chan_spec const *chan, int val,
> +			     int val2, long mask)
> +{
> +	struct us5182d_data *data = iio_priv(indio_dev);
> +	int i;
> +
> +	switch (mask) {
> +	case IIO_CHAN_INFO_SCALE:
> +		if (val != 0)
> +			return -EINVAL;
> +		for (i = 0; i < ARRAY_SIZE(us5182d_scales); i++)
> +			if (val2 == us5182d_scales[i])
> +				return us5182d_apply_scale(data, i);

I guess we want locking since two i2c operations are involved

> +		break;
> +	default:
> +		break;
> +	}
> +
> +	return -EINVAL;
> +}
> +
> +static const struct iio_info us5182d_info = {
> +	.driver_module	= THIS_MODULE,
> +	.read_raw = us5182d_read_raw,
> +	.write_raw = us5182d_write_raw,
> +	.attrs = &us5182d_attr_group,
> +};
> +
> +static int us5182d_reset(struct iio_dev *indio_dev)
> +{
> +	struct us5182d_data *data = iio_priv(indio_dev);
> +	int ret;
> +
> +	ret = i2c_smbus_write_byte_data(data->client, US5182D_REG_CFG3,
> +					US5182D_RESET_CHIP);

return i2c_smbus_write_byte_data(..);
directly

> +	if (ret < 0)
> +		return ret;
> +
> +	return 0;
> +}
> +
> +static int us5182d_init(struct iio_dev *indio_dev)
> +{
> +	struct us5182d_data *data = iio_priv(indio_dev);
> +	int i, ret;
> +
> +	ret = us5182d_reset(indio_dev);
> +	if (ret < 0)
> +		return ret;
> +
> +	data->opmode = 0;
> +	for (i = 0; i < ARRAY_SIZE(us5182d_regvals); i++) {
> +		ret = i2c_smbus_write_byte_data(data->client,
> +						us5182d_regvals[i].reg,
> +						us5182d_regvals[i].val);
> +		if (ret < 0)
> +			return ret;
> +	}
> +
> +	return 0;
> +}
> +
> +static void us5182d_get_platform_data(struct iio_dev *indio_dev)
> +{
> +	struct us5182d_data *data = iio_priv(indio_dev);
> +
> +	if (device_property_read_u32(&data->client->dev, "upisemi,glass-coef",
> +				     &data->ga))
> +		data->ga = US5182D_GA_RESOLUTION;
> +	if (device_property_read_u16_array(&data->client->dev,
> +					   "upisemi,dark-ths",
> +					   data->us5182d_dark_ths,
> +					   ARRAY_SIZE(us5182d_dark_ths_vals)))
> +		data->us5182d_dark_ths = us5182d_dark_ths_vals;
> +	if (device_property_read_u16(&data->client->dev,
> +				     "upisemi,upper-dark-gain",
> +				     &data->upper_dark_th))
> +		data->upper_dark_th = US5182D_REG_AUTO_HDARK_TH_DEFAULT;
> +	if (device_property_read_u16(&data->client->dev,
> +				     "upisemi,lower-dark-gain",
> +				     &data->lower_dark_th))
> +		data->lower_dark_th = US5182D_REG_AUTO_LDARK_TH_DEFAULT;
> +}
> +
> +static int  us5182d_dark_gain_config(struct iio_dev *indio_dev)
> +{
> +	struct us5182d_data *data = iio_priv(indio_dev);
> +	u8 index = US5182D_REG_CFG1_DEFAULT & US5182D_AGAIN_MASK;
> +	int ret;
> +
> +	ret = us5182d_update_dark_th(data, index);
> +	if (ret < 0)
> +		return ret;
> +
> +	ret = i2c_smbus_write_byte_data(data->client, US5182D_REG_AUTO_LDARK_TH,
> +					data->lower_dark_th);
> +	if (ret < 0)
> +		return ret;
> +
> +	ret = i2c_smbus_write_byte_data(data->client, US5182D_REG_AUTO_HDARK_TH,
> +					data->upper_dark_th);
> +	if (ret < 0)
> +		return ret;
> +
> +	return i2c_smbus_write_byte_data(data->client, US5182D_REG_DARK_AUTO_EN,
> +					US5182D_REG_DARK_AUTO_EN_DEFAULT);
> +}
> +
> +static int us5182d_probe(struct i2c_client *client,
> +			 const struct i2c_device_id *id)
> +{
> +	struct us5182d_data *data;
> +	struct iio_dev *indio_dev;
> +	int ret;
> +
> +	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
> +	if (!indio_dev)
> +		return -ENOMEM;
> +
> +	data = iio_priv(indio_dev);
> +	i2c_set_clientdata(client, indio_dev);
> +	data->client = client;
> +
> +	mutex_init(&data->lock);
> +
> +	indio_dev->dev.parent = &client->dev;
> +	indio_dev->info = &us5182d_info;
> +	indio_dev->name = US5182D_DRV_NAME;
> +	indio_dev->channels = us5182d_channels;
> +	indio_dev->num_channels = ARRAY_SIZE(us5182d_channels);
> +	indio_dev->modes = INDIO_DIRECT_MODE;
> +
> +	ret = us5182d_read_byte_data(data->client, US5182D_REG_CHIPID);
> +	if (ret != US5182D_CHIPID)
> +		dev_warn(&data->client->dev,
> +			 "Failed to detect US5182 light chip\n");
> +
> +	us5182d_get_platform_data(indio_dev);
> +	ret = us5182d_init(indio_dev);
> +	if (ret < 0)
> +		return ret;
> +
> +	ret = us5182d_dark_gain_config(indio_dev);
> +	if (ret < 0)
> +		return ret;
> +
> +	return iio_device_register(indio_dev);
> +}
> +
> +static int us5182d_remove(struct i2c_client *client)
> +{
> +	iio_device_unregister(i2c_get_clientdata(client));
> +	return i2c_smbus_write_byte_data(client, US5182D_REG_CFG0,
> +					 US5182D_REG_CFG0_DEFAULT);
> +}
> +
> +static const struct acpi_device_id us5182d_acpi_match[] = {
> +	{ "USD5182", 0},
> +	{}
> +};
> +
> +MODULE_DEVICE_TABLE(acpi, us5182d_acpi_match);
> +
> +static const struct i2c_device_id us5182d_id[] = {
> +		{"usd5182", 0},
> +		{}
> +};
> +
> +MODULE_DEVICE_TABLE(i2c, us5182d_id);
> +
> +static struct i2c_driver us5182d_driver = {
> +	.driver = {
> +		.name = US5182D_DRV_NAME,
> +		.acpi_match_table = ACPI_PTR(us5182d_acpi_match),
> +	},
> +	.probe = us5182d_probe,
> +	.remove = us5182d_remove,
> +	.id_table = us5182d_id,
> +
> +};
> +module_i2c_driver(us5182d_driver);
> +
> +MODULE_AUTHOR("Adriana Reus <adriana.reus@...el.com>");
> +MODULE_DESCRIPTION("Driver for us5182d Proximity and Light Sensor");
> +MODULE_LICENSE("GPL v2");
> 

-- 

Peter Meerwald
+43-664-2444418 (mobile)
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