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SubjectRe: [PATCH v4] iio: add LM3533 ambient-light-sensor driver
On 05/18/2012 02:07 PM, Johan Hovold wrote:
> Add sub-driver for the ambient-light-sensor interface on National
> Semiconductor / TI LM3533 lighting power chips.
>
> The sensor interface can be used to control the LEDs and backlights of
> the chip through defining five light zones and three sets of
> corresponding brightness target levels.
>
> The driver provides raw and mean adc readings along with the current
> light zone through sysfs. A threshold event can be generated on zone
> changes.

Hi Johan,

I hate to be a pain with this one, but it's a complex beast and I'd
really like to get the interface right first time - particularly as
you are going in after the move out of staging.


Queries for you.
1) Ordering in the probe function. Normally expect iio_device_register
to be the last call. Why not here?
2) Worth combining enable / disable into one as very similar functions?
3) Suspicious code in als_set_input_mode

Naming of the target values. I think we can make the naming of these
fit in much better with the normal abi which is going to be all for the
good in the long run. They are basically current output channels
with a controllable set of steps (where we don't have direct control
of which one we are in). This is very similar to the frequency controls
on some of Analog's dds that we have a well defined interface for.

More detail below, but in summary.

out_currentX_currentY_raw for channel X value for zone Y.

Jonathan
>
> Signed-off-by: Johan Hovold <jhovold@gmail.com>
> ---
>
> Note that addition of r_select to the platform data probably needs to go
> in via mfd.
>
>
> v2:
> - reimplement using iio
> - add sysfs-ABI documentation
> v3
> - use indexed channel
> - fix sysfs-ABI documentation typo and style
> - replace gain attribute with in_illuminance0_calibscale
> - add calibscale to platform data
> - fix adc register definitions
> - replace to_lm3533_dev_attr macro with inline function
> - fix device used for error reporting at irq allocation
> - use iio device for error reporting during setup/enable
> - rebase on staging-next
> - fix header include paths
> - use dev_to_iio_dev
> - add IIO_CHAN_INFO_RAW to info mask
> - use iio_device_{alloc,free}
> v4
> - move to driver/iio/light
> - add events/in_illuminance0_threshY_hysteresis attributes
> - fix device zone-boundary quirkiness
> - clean up attribute handling
> - replace calibscale with device-specific r_select attribute
>
>
> .../ABI/testing/sysfs-bus-iio-light-lm3533-als | 64 ++
> drivers/iio/Kconfig | 1 +
> drivers/iio/Makefile | 1 +
> drivers/iio/light/Kconfig | 22 +
> drivers/iio/light/Makefile | 5 +
> drivers/iio/light/lm3533-als.c | 941 ++++++++++++++++++++
> include/linux/mfd/lm3533.h | 1 +
> 7 files changed, 1035 insertions(+), 0 deletions(-)
> create mode 100644 Documentation/ABI/testing/sysfs-bus-iio-light-lm3533-als
> create mode 100644 drivers/iio/light/Kconfig
> create mode 100644 drivers/iio/light/Makefile
> create mode 100644 drivers/iio/light/lm3533-als.c
>
> diff --git a/Documentation/ABI/testing/sysfs-bus-iio-light-lm3533-als b/Documentation/ABI/testing/sysfs-bus-iio-light-lm3533-als
> new file mode 100644
> index 0000000..7ea1770
> --- /dev/null
> +++ b/Documentation/ABI/testing/sysfs-bus-iio-light-lm3533-als
> @@ -0,0 +1,64 @@
> +What: /sys/bus/iio/devices/iio:deviceX/r_select
> +Date: April 2012
> +KernelVersion: 3.5
> +Contact: Johan Hovold <jhovold@gmail.com>
> +Description:
> + Set the ALS internal pull-down resistor for analog input mode
> + (1..127), such that,
> +
> + R_als = 200000 / r_select (ohm)
> +
> + This setting is ignored in PWM-mode (input is always high
> + impedance in PWM-mode).
> +
> +What: /sys/.../events/in_illuminance0_thresh_either_en
> +Date: April 2012
> +KernelVersion: 3.5
> +Contact: Johan Hovold <jhovold@gmail.com>
> +Description:
> + Event generated when channel passes one of the four thresholds
> + in each direction (rising|falling) and a zone change occurs.
> + The corresponding light zone can be read from
> + in_illuminance0_zone.
> +
> +What: /sys/.../events/in_illuminance0_threshY_hysteresis
> +Date: May 2012
> +KernelVersion: 3.5
> +Contact: Johan Hovold <jhovold@gmail.com>
> +Description:
> + Get the hysteresis for thresholds Y, that is,
> +
> + threshY_hysteresis = threshY_raising - threshY_falling
> +
> +What: /sys/.../events/illuminance_threshY_falling_value
> +What: /sys/.../events/illuminance_threshY_raising_value
> +Date: April 2012
> +KernelVersion: 3.5
> +Contact: Johan Hovold <jhovold@gmail.com>
> +Description:
> + Specifies the value of threshold that the device is
> + comparing against for the events enabled by
> + in_illuminance0_thresh_either_en, where Y in 0..3.
> +
> + Note that threshY_falling must be less than or equal to
> + threshY_raising.
> +
> + These thresholds correspond to the eight zone-boundary
> + registers (boundaryY_{low,high}) and defines the five light
> + zones.
> +
> +What: /sys/bus/iio/devices/iio:deviceX/in_illuminance0_zone
> +Date: April 2012
> +KernelVersion: 3.5
> +Contact: Johan Hovold <jhovold@gmail.com>
> +Description:
> + Get the current light zone (0..4) as defined by the
> + in_illuminance0_threshY_{falling,rising} thresholds.
> +
> +What: /sys/bus/iio/devices/iio:deviceX/targetY_Z
> +Date: April 2012
> +KernelVersion: 3.5
> +Contact: Johan Hovold <jhovold@gmail.com>
> +Description:
> + Set the target brightness for ALS-mapper Y in light zone Z
> + (0..255), where Y in 1..3 and Z in 0..4.

What are the units of this? Also arguably is it not the als that this
is related to, but rather the light source? A quick datasheet browse says
that these are current targets? If so I wonder if we can make that
explicit... Could treat them as 3 output channels and have indexed values
like we do for frequencies in dds devices (where external hardware is
controlling them.

Hmm. lets see.

out_currentX_currentY_raw
(the double naming is a bit clunky but corresponds to frequency devices
where we have
out_altvoltageX_frequencyY_raw

Hence we'd treat you 3 mapers as indexed channels 0,1,2 and the zones
as indexed values they can take 0,1,2,3,4
out_currentX_raw is not read only and gives you the current for whichever
zone the device is currently in.

This may seem convoluted but I'd really rather have something generalizable
for this if we possibly can. We'd still need documentation to say what is
controlling these, but at least they'd fit within our more general abi.

What do you think?

> diff --git a/drivers/iio/Kconfig b/drivers/iio/Kconfig
> index 56eecef..cacc74d 100644
> --- a/drivers/iio/Kconfig
> +++ b/drivers/iio/Kconfig
> @@ -50,5 +50,6 @@ config IIO_CONSUMERS_PER_TRIGGER
>
> source "drivers/iio/adc/Kconfig"
> source "drivers/iio/amplifiers/Kconfig"
> +source "drivers/iio/light/Kconfig"
>
> endif # IIO
> diff --git a/drivers/iio/Makefile b/drivers/iio/Makefile
> index e425afd..060b674 100644
> --- a/drivers/iio/Makefile
> +++ b/drivers/iio/Makefile
> @@ -11,3 +11,4 @@ obj-$(CONFIG_IIO_KFIFO_BUF) += kfifo_buf.o
>
> obj-y += adc/
> obj-y += amplifiers/
> +obj-y += light/
> diff --git a/drivers/iio/light/Kconfig b/drivers/iio/light/Kconfig
> new file mode 100644
> index 0000000..7738a58
> --- /dev/null
> +++ b/drivers/iio/light/Kconfig
> @@ -0,0 +1,22 @@
> +#
> +# Light sensors
> +#
> +menu "Light sensors"
> +
> +config SENSORS_LM3533
> + tristate "LM3533 ambient light sensor"
> + depends on MFD_LM3533
> + help
> + If you say yes here you get support for the ambient light sensor
> + interface on National Semiconductor / TI LM3533 Lighting Power
> + chips.
> +
> + The sensor interface can be used to control the LEDs and backlights
> + of the chip through defining five light zones and three sets of
> + corresponding brightness target levels.
> +
> + The driver provides raw and mean adc readings along with the current
> + light zone through sysfs. A threshold event can be generated on zone
> + changes.
> +
> +endmenu
> diff --git a/drivers/iio/light/Makefile b/drivers/iio/light/Makefile
> new file mode 100644
> index 0000000..c1c23a0
> --- /dev/null
> +++ b/drivers/iio/light/Makefile
> @@ -0,0 +1,5 @@
> +#
> +# Makefile for IIO Light sensors
> +#
> +
> +obj-$(CONFIG_SENSORS_LM3533) += lm3533-als.o
> diff --git a/drivers/iio/light/lm3533-als.c b/drivers/iio/light/lm3533-als.c
> new file mode 100644
> index 0000000..5944ac1
> --- /dev/null
> +++ b/drivers/iio/light/lm3533-als.c
> @@ -0,0 +1,941 @@
> +/*
> + * lm3533-als.c -- LM3533 Ambient Light Sensor driver
> + *
> + * Copyright (C) 2011-2012 Texas Instruments
> + *
> + * Author: Johan Hovold <jhovold@gmail.com>
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms of the GNU General Public License as published by the
> + * Free Software Foundation; either version 2 of the License, or (at your
> + * option) any later version.
> + */
> +
> +#include <linux/atomic.h>
> +#include <linux/fs.h>
> +#include <linux/interrupt.h>
> +#include <linux/io.h>
> +#include <linux/iio/events.h>
> +#include <linux/iio/iio.h>
> +#include <linux/module.h>
> +#include <linux/mutex.h>
> +#include <linux/mfd/core.h>
> +#include <linux/platform_device.h>
> +#include <linux/slab.h>
> +#include <linux/uaccess.h>
> +
> +#include <linux/mfd/lm3533.h>
> +
> +
> +#define LM3533_ALS_RESISTOR_MIN 1
> +#define LM3533_ALS_RESISTOR_MAX 127
> +#define LM3533_ALS_MAPPER_MIN 1
> +#define LM3533_ALS_MAPPER_MAX 3
> +#define LM3533_ALS_THRESH_MAX 3
> +#define LM3533_ALS_ZONE_MAX 4
> +
> +#define LM3533_REG_ALS_RESISTOR_SELECT 0x30
> +#define LM3533_REG_ALS_CONF 0x31
> +#define LM3533_REG_ALS_ZONE_INFO 0x34
> +#define LM3533_REG_ALS_READ_ADC_RAW 0x37
> +#define LM3533_REG_ALS_READ_ADC_AVERAGE 0x38
> +#define LM3533_REG_ALS_BOUNDARY_BASE 0x50
> +#define LM3533_REG_ALS_TARGET_BASE 0x60
> +
> +#define LM3533_ALS_ENABLE_MASK 0x01
> +#define LM3533_ALS_INPUT_MODE_MASK 0x02
> +#define LM3533_ALS_INT_ENABLE_MASK 0x01
> +
> +#define LM3533_ALS_ZONE_SHIFT 2
> +#define LM3533_ALS_ZONE_MASK 0x1c
> +
> +#define LM3533_ALS_FLAG_INT_ENABLED 1
> +
> +
> +struct lm3533_als {
> + struct lm3533 *lm3533;
> +
> + unsigned long flags;
> + int irq;
> +
Boolean might be better as it's not a though this will save
space!
> + int pwm_mode:1;
> +
> + atomic_t zone;
> + struct mutex thresh_mutex;
> +};
Rarely a reason for more than one blank line in my opinion...
> +
> +
May be roll this into it's one call site. will make for marginally
less code I think..
> +static int lm3533_als_get_adc(struct iio_dev *indio_dev, bool average,
> + int *adc)
> +{
> + struct lm3533_als *als = iio_priv(indio_dev);
> + u8 reg;
> + u8 val;
> + int ret;
> +
> + if (average)
> + reg = LM3533_REG_ALS_READ_ADC_AVERAGE;
> + else
> + reg = LM3533_REG_ALS_READ_ADC_RAW;
> +
> + ret = lm3533_read(als->lm3533, reg, &val);
> + if (ret) {
> + dev_err(&indio_dev->dev, "failed to read adc\n");
> + return ret;
> + }
> +
> + *adc = val;
> +
> + return 0;
> +}
> +
> +static int lm3533_als_read_raw(struct iio_dev *indio_dev,
> + struct iio_chan_spec const *chan,
> + int *val, int *val2, long mask)
> +{
> + int ret;
> +
> + switch (mask) {
> + case 0:
> + ret = lm3533_als_get_adc(indio_dev, false, val);
> + break;
> + case IIO_CHAN_INFO_AVERAGE_RAW:
> + ret = lm3533_als_get_adc(indio_dev, true, val);
> + break;
> + default:
> + return -EINVAL;
> + }
> +
> + if (ret)
> + return ret;
> +
> + return IIO_VAL_INT;
> +}
> +
Why have an array? Just use the address and set the num_channels = 1;
> +static const struct iio_chan_spec lm3533_als_channels[] = {
> + {
> + .type = IIO_LIGHT,
> + .channel = 0,
> + .indexed = 1,
> + .info_mask = (IIO_CHAN_INFO_AVERAGE_RAW_SEPARATE_BIT |
> + IIO_CHAN_INFO_RAW_SEPARATE_BIT),
> + }
> +};
> +
> +static int lm3533_als_get_zone(struct iio_dev *indio_dev, u8 *zone)
> +{
> + struct lm3533_als *als = iio_priv(indio_dev);
> + u8 val;
> + int ret;
> +
> + ret = lm3533_read(als->lm3533, LM3533_REG_ALS_ZONE_INFO, &val);
> + if (ret) {
> + dev_err(&indio_dev->dev, "failed to read zone\n");
> + return ret;
> + }
> +
> + val = (val & LM3533_ALS_ZONE_MASK) >> LM3533_ALS_ZONE_SHIFT;
> + *zone = min_t(u8, val, LM3533_ALS_ZONE_MAX);
> +
> + return 0;
> +}
> +
> +static irqreturn_t lm3533_als_isr(int irq, void *dev_id)
> +{
> +
> + struct iio_dev *indio_dev = dev_id;
> + struct lm3533_als *als = iio_priv(indio_dev);
> + u8 zone;
> + int ret;
> +
> + /* Clear interrupt by reading the ALS zone register. */
> + ret = lm3533_als_get_zone(indio_dev, &zone);
> + if (ret)
> + goto out;
> +
> + atomic_set(&als->zone, zone);
> +
> + iio_push_event(indio_dev,
> + IIO_UNMOD_EVENT_CODE(IIO_LIGHT,
> + 0,
> + IIO_EV_TYPE_THRESH,
> + IIO_EV_DIR_EITHER),
> + iio_get_time_ns());
> +out:
> + return IRQ_HANDLED;
> +}
> +
could just roll this into the one call point, it's not exactly complex.
> +static int lm3533_als_set_int_mode(struct iio_dev *indio_dev, int enable)
> +{
> + struct lm3533_als *als = iio_priv(indio_dev);
> + u8 mask = LM3533_ALS_INT_ENABLE_MASK;
> + u8 val;
> + int ret;
> +
> + if (enable)
> + val = mask;
> + else
> + val = 0;
> +
> + ret = lm3533_update(als->lm3533, LM3533_REG_ALS_ZONE_INFO, val, mask);
> + if (ret) {
> + dev_err(&indio_dev->dev, "failed to set int mode %d\n",
> + enable);
> + return ret;
> + }
> +
> + return 0;
> +}
> +
> +static int lm3533_als_get_int_mode(struct iio_dev *indio_dev, int *enable)
> +{
> + struct lm3533_als *als = iio_priv(indio_dev);
> + u8 mask = LM3533_ALS_INT_ENABLE_MASK;
> + u8 val;
> + int ret;
> +
> + ret = lm3533_read(als->lm3533, LM3533_REG_ALS_ZONE_INFO, &val);
> + if (ret) {
> + dev_err(&indio_dev->dev, "failed to get int mode\n");
> + return ret;
> + }
> +
> + *enable = !!(val & mask);
> +
> + return 0;
> +}
> +
Given only accessed from one place, why not just roll it in there?
> +static int lm3533_als_get_resistor(struct iio_dev *indio_dev, u8 *val)
> +{
> + struct lm3533_als *als = iio_priv(indio_dev);
> + int ret;
> +
> + if (als->pwm_mode) {
> + *val = 0; /* always high impedance */
> + return 0;
> + }
> +
> + ret = lm3533_read(als->lm3533, LM3533_REG_ALS_RESISTOR_SELECT, val);
> + if (ret) {
> + dev_err(&indio_dev->dev, "failed to get resistor\n");
> + return ret;
> + }
> +
> + return 0;
> +}
> +
> +static int lm3533_als_set_resistor(struct iio_dev *indio_dev, u8 val)
> +{
> + struct lm3533_als *als = iio_priv(indio_dev);
> + int ret;
> +
> + if (als->pwm_mode)
> + return -EPERM; /* always high impedance */
> +
> + if (val < LM3533_ALS_RESISTOR_MIN || val > LM3533_ALS_RESISTOR_MAX)
> + return -EINVAL;
> +
> + ret = lm3533_write(als->lm3533, LM3533_REG_ALS_RESISTOR_SELECT, val);
> + if (ret) {
> + dev_err(&indio_dev->dev, "failed to set resistor\n");
> + return ret;
> + }
> +
> + return 0;
> +}
> +
> +/*
> + * nr -- als mapper 1..3
> + * zone -- als zone 0..4
> + */
> +static inline u8 lm3533_als_get_target_reg(unsigned nr, unsigned zone)
> +{
> + return LM3533_REG_ALS_TARGET_BASE + 5 * (nr - 1) + zone;
> +}
> +
> +static int lm3533_als_get_target(struct iio_dev *indio_dev, unsigned nr,
> + unsigned zone, u8 *val)
> +{
> + struct lm3533_als *als = iio_priv(indio_dev);
> + u8 reg;
> + int ret;
> +
> + if (nr < LM3533_ALS_MAPPER_MIN || nr > LM3533_ALS_MAPPER_MAX)
> + return -EINVAL;
> +
> + if (zone > LM3533_ALS_ZONE_MAX)
> + return -EINVAL;
> +
> + reg = lm3533_als_get_target_reg(nr, zone);
> + ret = lm3533_read(als->lm3533, reg, val);
> + if (ret)
> + dev_err(&indio_dev->dev, "failed to get target brightness\n");
> +
> + return ret;
> +}
> +
> +static int lm3533_als_set_target(struct iio_dev *indio_dev, unsigned nr,
> + unsigned zone, u8 val)
> +{
> + struct lm3533_als *als = iio_priv(indio_dev);
> + u8 reg;
> + int ret;
> +
> + if (nr < LM3533_ALS_MAPPER_MIN || nr > LM3533_ALS_MAPPER_MAX)
> + return -EINVAL;
> +
> + if (zone > LM3533_ALS_ZONE_MAX)
> + return -EINVAL;
> +
> + reg = lm3533_als_get_target_reg(nr, zone);
> + ret = lm3533_write(als->lm3533, reg, val);
I wouldn't bother with the intermediate but up to you...

ret = lm3533_write(als->lm3533, lm3533_als_get_target_reg(nr, zone), val);

> + if (ret)
> + dev_err(&indio_dev->dev, "failed to set target brightness\n");
> +
> + return ret;
> +}
> +
> +static inline u8 lm3533_als_get_threshold_reg(unsigned nr, bool raising)
> +{
> + u8 offset;
> +
offset = !raising;

> + if (raising)
> + offset = 0;
> + else
> + offset = 1;
> +
> + return LM3533_REG_ALS_BOUNDARY_BASE + 2 * nr + offset;
> +}
> +
> +static int lm3533_als_get_threshold(struct iio_dev *indio_dev, unsigned nr,
> + bool raising, u8 *val)
> +{
> + struct lm3533_als *als = iio_priv(indio_dev);
> + u8 reg;
> + int ret;
> +
> + if (nr > LM3533_ALS_THRESH_MAX)
> + return -EINVAL;
> +
> + reg = lm3533_als_get_threshold_reg(nr, raising);
> + ret = lm3533_read(als->lm3533, reg, val);
> + if (ret)
> + dev_err(&indio_dev->dev, "failed to get threshold\n");
> +
> + return ret;
> +}
> +
> +static int lm3533_als_set_threshold(struct iio_dev *indio_dev, unsigned nr,
> + bool raising, u8 val)
> +{
> + struct lm3533_als *als = iio_priv(indio_dev);
> + u8 val2;
> + u8 reg;
> + u8 reg2;
u8 val2, reg, reg2; Shorter and still obvious.
> + int ret;
> +
> + if (nr > LM3533_ALS_THRESH_MAX)
> + return -EINVAL;
> +
> + reg = lm3533_als_get_threshold_reg(nr, raising);
> + reg2 = lm3533_als_get_threshold_reg(nr, !raising);
> +
> + mutex_lock(&als->thresh_mutex);
> + ret = lm3533_read(als->lm3533, reg2, &val2);
> + if (ret) {
> + dev_err(&indio_dev->dev, "failed to get threshold\n");
> + goto out;
> + }
> + /*
> + * This device does not allow negative hysteresis (in fact, it uses
> + * whichever value is smaller as the lower bound) so we need to make
> + * sure that thresh_falling <= thresh_raising.
> + */
> + if ((raising && (val < val2)) || (!raising && (val > val2))) {
> + ret = -EINVAL;
> + goto out;
> + }
> +
> + ret = lm3533_write(als->lm3533, reg, val);
> + if (ret) {
> + dev_err(&indio_dev->dev, "failed to set threshold\n");
> + goto out;
> + }
> +out:
> + mutex_unlock(&als->thresh_mutex);
> +
> + return ret;
> +}
> +
> +static int lm3533_als_get_hysteresis(struct iio_dev *indio_dev, unsigned nr,
> + u8 *val)
> +{
> + struct lm3533_als *als = iio_priv(indio_dev);
> + u8 falling;
> + u8 raising;
> + int ret;
> +
> + if (nr > LM3533_ALS_THRESH_MAX)
> + return -EINVAL;
> +
> + mutex_lock(&als->thresh_mutex);
> + ret = lm3533_als_get_threshold(indio_dev, nr, false, &falling);
> + if (ret)
> + goto out;
> + ret = lm3533_als_get_threshold(indio_dev, nr, true, &raising);
> + if (ret)
> + goto out;
> +
> + *val = raising - falling;
> +out:
> + mutex_unlock(&als->thresh_mutex);
> +
> + return ret;
> +}
> +
> +static int show_thresh_either_en(struct device *dev,
> + struct device_attribute *attr,
> + char *buf)
> +{
> + struct iio_dev *indio_dev = dev_to_iio_dev(dev);
> + struct lm3533_als *als = iio_priv(indio_dev);
> + int enable;
> + int ret;
> +
> + if (als->irq) {
> + ret = lm3533_als_get_int_mode(indio_dev, &enable);
> + if (ret)
> + return ret;
> + } else {
> + enable = 0;
> + }
> +
> + return scnprintf(buf, PAGE_SIZE, "%u\n", enable);
> +}
> +
> +static int store_thresh_either_en(struct device *dev,
> + struct device_attribute *attr,
> + const char *buf, size_t len)
> +{
> + struct iio_dev *indio_dev = dev_to_iio_dev(dev);
> + struct lm3533_als *als = iio_priv(indio_dev);
> + unsigned long enable;
> + bool int_enabled;
> + u8 zone;
> + int ret;
> +
> + if (!als->irq)
> + return -EBUSY;
> +
> + if (kstrtoul(buf, 0, &enable))
> + return -EINVAL;
> +
> + int_enabled = test_bit(LM3533_ALS_FLAG_INT_ENABLED, &als->flags);
> +
> + if (enable && !int_enabled) {
> + ret = lm3533_als_get_zone(indio_dev, &zone);
> + if (ret)
> + return ret;
> +
> + atomic_set(&als->zone, zone);
> +
> + set_bit(LM3533_ALS_FLAG_INT_ENABLED, &als->flags);
> + }
> +
> + ret = lm3533_als_set_int_mode(indio_dev, enable);
> + if (ret) {
> + if (!int_enabled)
> + clear_bit(LM3533_ALS_FLAG_INT_ENABLED, &als->flags);
> +
> + return ret;
> + }
> +
> + if (!enable)
> + clear_bit(LM3533_ALS_FLAG_INT_ENABLED, &als->flags);
> +
> + return len;
> +}
> +
> +static ssize_t show_zone(struct device *dev,
> + struct device_attribute *attr, char *buf)
> +{
> + struct iio_dev *indio_dev = dev_to_iio_dev(dev);
> + struct lm3533_als *als = iio_priv(indio_dev);
> + u8 zone;
> + int ret;
> +
> + if (test_bit(LM3533_ALS_FLAG_INT_ENABLED, &als->flags)) {
> + zone = atomic_read(&als->zone);
> + } else {
> + ret = lm3533_als_get_zone(indio_dev, &zone);
> + if (ret)
> + return ret;
> + }
> +
> + return scnprintf(buf, PAGE_SIZE, "%u\n", zone);
> +}
> +
> +static ssize_t show_r_select(struct device *dev,
> + struct device_attribute *attr, char *buf)
> +{
> + struct iio_dev *indio_dev = dev_to_iio_dev(dev);
> + u8 r_select;
> + int ret;
> +
> + ret = lm3533_als_get_resistor(indio_dev, &r_select);
> + if (ret)
> + return ret;
> +
> + return scnprintf(buf, PAGE_SIZE, "%u\n", r_select);
> +}
> +
> +static int store_r_select(struct device *dev,
> + struct device_attribute *attr,
> + const char *buf, size_t len)
> +{
> + struct iio_dev *indio_dev = dev_to_iio_dev(dev);
> + unsigned long r_select;
> + int ret;
> +
> + if (kstrtoul(buf, 0, &r_select))
> + return -EINVAL;
> +
> + ret = lm3533_als_set_resistor(indio_dev, r_select);
> + if (ret)
> + return ret;
> +
> + return len;
> +}
> +
> +enum lm3533_als_attribute_type {
> + LM3533_ATTR_TYPE_HYSTERESIS,
> + LM3533_ATTR_TYPE_TARGET,
> + LM3533_ATTR_TYPE_THRESH_FALLING,
> + LM3533_ATTR_TYPE_THRESH_RAISING,
> +};
> +
> +struct lm3533_als_attribute {
> + struct device_attribute dev_attr;
> + enum lm3533_als_attribute_type type;
> + u8 val1;
> + u8 val2;
> +};
> +
> +static inline struct lm3533_als_attribute *
> +to_lm3533_als_attr(struct device_attribute *attr)
> +{
> + return container_of(attr, struct lm3533_als_attribute, dev_attr);
> +}
> +
> +static ssize_t show_als_attr(struct device *dev,
> + struct device_attribute *attr,
> + char *buf)
> +{
> + struct iio_dev *indio_dev = dev_to_iio_dev(dev);
> + struct lm3533_als_attribute *als_attr = to_lm3533_als_attr(attr);
> + u8 val;
> + int ret;
> +
> + switch (als_attr->type) {
> + case LM3533_ATTR_TYPE_HYSTERESIS:
> + ret = lm3533_als_get_hysteresis(indio_dev, als_attr->val1,
> + &val);
> + break;
> + case LM3533_ATTR_TYPE_TARGET:
> + ret = lm3533_als_get_target(indio_dev, als_attr->val1,
> + als_attr->val2, &val);
> + break;
> + case LM3533_ATTR_TYPE_THRESH_FALLING:
> + ret = lm3533_als_get_threshold(indio_dev, als_attr->val1,
> + false, &val);
> + break;
> + case LM3533_ATTR_TYPE_THRESH_RAISING:
> + ret = lm3533_als_get_threshold(indio_dev, als_attr->val1,
> + true, &val);
> + break;
> + default:
> + WARN(1, "%s - bad attribute type %d\n", __func__,
> + als_attr->type);
> + ret = -ENXIO;
> + }
> +
> + if (ret)
> + return ret;
> +
> + return scnprintf(buf, PAGE_SIZE, "%u\n", val);
> +}
> +
> +static ssize_t store_als_attr(struct device *dev,
> + struct device_attribute *attr,
> + const char *buf, size_t len)
> +{
> + struct iio_dev *indio_dev = dev_to_iio_dev(dev);
> + struct lm3533_als_attribute *als_attr = to_lm3533_als_attr(attr);
> + u8 val;
> + int ret;
> +
> + if (kstrtou8(buf, 0, &val))
> + return -EINVAL;
> +
> + switch (als_attr->type) {
> + case LM3533_ATTR_TYPE_TARGET:
> + ret = lm3533_als_set_target(indio_dev, als_attr->val1,
> + als_attr->val2, val);
> + break;
> + case LM3533_ATTR_TYPE_THRESH_FALLING:
> + ret = lm3533_als_set_threshold(indio_dev, als_attr->val1,
> + false, val);
> + break;
> + case LM3533_ATTR_TYPE_THRESH_RAISING:
> + ret = lm3533_als_set_threshold(indio_dev, als_attr->val1,
> + true, val);
> + break;
> + default:
I'd be tempted to drop this. It is easy to verify whether it will occur.
> + WARN(1, "%s - bad attribute type %d\n", __func__,
> + als_attr->type);
> + ret = -ENXIO;
> + }
> +
> + if (ret)
> + return ret;
> +
> + return len;
> +}
> +
> +#define ALS_ATTR(_name, _mode, _show, _store, _type, _val1, _val2) \
> + { .dev_attr = __ATTR(_name, _mode, _show, _store), \
> + .type = _type, \
> + .val1 = _val1, \
> + .val2 = _val2 }
> +
> +#define LM3533_ALS_ATTR(_name, _mode, _show, _store, _type, _val1, _val2) \
> + struct lm3533_als_attribute lm3533_als_attr_##_name = \
> + ALS_ATTR(_name, _mode, _show, _store, _type, _val1, _val2)
> +
> +#define ALS_TARGET_ATTR_RW(_nr, _zone) \
> + LM3533_ALS_ATTR(target##_nr##_##_zone, S_IRUGO | S_IWUSR, \
> + show_als_attr, store_als_attr, \
> + LM3533_ATTR_TYPE_TARGET, _nr, _zone)
> +/*
> + * ALS Mapper targets
> + *
> + * target[1-3]_[0-4] 0-255
> + */
> +static ALS_TARGET_ATTR_RW(1, 0);
> +static ALS_TARGET_ATTR_RW(1, 1);
> +static ALS_TARGET_ATTR_RW(1, 2);
> +static ALS_TARGET_ATTR_RW(1, 3);
> +static ALS_TARGET_ATTR_RW(1, 4);
> +
> +static ALS_TARGET_ATTR_RW(2, 0);
> +static ALS_TARGET_ATTR_RW(2, 1);
> +static ALS_TARGET_ATTR_RW(2, 2);
> +static ALS_TARGET_ATTR_RW(2, 3);
> +static ALS_TARGET_ATTR_RW(2, 4);
> +
> +static ALS_TARGET_ATTR_RW(3, 0);
> +static ALS_TARGET_ATTR_RW(3, 1);
> +static ALS_TARGET_ATTR_RW(3, 2);
> +static ALS_TARGET_ATTR_RW(3, 3);
> +static ALS_TARGET_ATTR_RW(3, 4);
> +
> +#define ALS_THRESH_FALLING_ATTR_RW(_nr) \
> + LM3533_ALS_ATTR(in_illuminance0_thresh##_nr##_falling_value, \
> + S_IRUGO | S_IWUSR, \
> + show_als_attr, store_als_attr, \
> + LM3533_ATTR_TYPE_THRESH_FALLING, _nr, 0)
> +
> +#define ALS_THRESH_RAISING_ATTR_RW(_nr) \
> + LM3533_ALS_ATTR(in_illuminance0_thresh##_nr##_raising_value, \
> + S_IRUGO | S_IWUSR, \
> + show_als_attr, store_als_attr, \
> + LM3533_ATTR_TYPE_THRESH_RAISING, _nr, 0)
> +/*
> + * ALS Zone thresholds (boundaries)
> + *
> + * in_illuminance0_thresh[0-3]_falling_value 0-255
> + * in_illuminance0_thresh[0-3]_raising_value 0-255
> + */
> +static ALS_THRESH_FALLING_ATTR_RW(0);
> +static ALS_THRESH_FALLING_ATTR_RW(1);
> +static ALS_THRESH_FALLING_ATTR_RW(2);
> +static ALS_THRESH_FALLING_ATTR_RW(3);
> +
> +static ALS_THRESH_RAISING_ATTR_RW(0);
> +static ALS_THRESH_RAISING_ATTR_RW(1);
> +static ALS_THRESH_RAISING_ATTR_RW(2);
> +static ALS_THRESH_RAISING_ATTR_RW(3);
> +
> +#define ALS_HYSTERESIS_ATTR_RO(_nr) \
> + LM3533_ALS_ATTR(in_illuminance0_thresh##_nr##_hysteresis, \
> + S_IRUGO, show_als_attr, NULL, \
> + LM3533_ATTR_TYPE_HYSTERESIS, _nr, 0)
> +/*
> + * ALS Zone threshold hysteresis
> + *
> + * threshY_hysteresis = threshY_raising - threshY_falling
> + *
> + * in_illuminance0_thresh[0-3]_hysteresis 0-255
> + * in_illuminance0_thresh[0-3]_hysteresis 0-255
> + */
> +static ALS_HYSTERESIS_ATTR_RO(0);
> +static ALS_HYSTERESIS_ATTR_RO(1);
> +static ALS_HYSTERESIS_ATTR_RO(2);
> +static ALS_HYSTERESIS_ATTR_RO(3);
> +
> +#define ILLUMINANCE_ATTR_RO(_name) \
> + DEVICE_ATTR(in_illuminance0_##_name, S_IRUGO, show_##_name, NULL)
> +#define ILLUMINANCE_ATTR_RW(_name) \
> + DEVICE_ATTR(in_illuminance0_##_name, S_IRUGO | S_IWUSR , \
> + show_##_name, store_##_name)
> +/*
> + * ALS Zone threshold-event enable
> + *
> + * in_illuminance0_thresh_either_en 0,1
> + */
> +static ILLUMINANCE_ATTR_RW(thresh_either_en);
> +
> +/*
> + * ALS Current Zone
> + *
> + * in_illuminance0_zone 0-4
> + */
> +static ILLUMINANCE_ATTR_RO(zone);
> +
> +/*
> + * ALS internal pull-down resistor select (analog mode)
> + *
> + * r_select 1-127
> + *
> + * R_als = 200000 / r_select (ohm)
> + */
> +static LM3533_ATTR_RW(r_select);
> +
> +static struct attribute *lm3533_als_event_attributes[] = {
> + &dev_attr_in_illuminance0_thresh_either_en.attr,
> + &lm3533_als_attr_in_illuminance0_thresh0_falling_value.dev_attr.attr,
> + &lm3533_als_attr_in_illuminance0_thresh0_hysteresis.dev_attr.attr,
Just to verify the hysteresis applies to bother thresh0_falling and
thresh0_rising?
> + &lm3533_als_attr_in_illuminance0_thresh0_raising_value.dev_attr.attr,
> + &lm3533_als_attr_in_illuminance0_thresh1_falling_value.dev_attr.attr,
> + &lm3533_als_attr_in_illuminance0_thresh1_hysteresis.dev_attr.attr,
> + &lm3533_als_attr_in_illuminance0_thresh1_raising_value.dev_attr.attr,
> + &lm3533_als_attr_in_illuminance0_thresh2_falling_value.dev_attr.attr,
> + &lm3533_als_attr_in_illuminance0_thresh2_hysteresis.dev_attr.attr,
> + &lm3533_als_attr_in_illuminance0_thresh2_raising_value.dev_attr.attr,
> + &lm3533_als_attr_in_illuminance0_thresh3_falling_value.dev_attr.attr,
> + &lm3533_als_attr_in_illuminance0_thresh3_hysteresis.dev_attr.attr,
> + &lm3533_als_attr_in_illuminance0_thresh3_raising_value.dev_attr.attr,
> + NULL
> +};
> +
> +static struct attribute_group lm3533_als_event_attribute_group = {
> + .attrs = lm3533_als_event_attributes
> +};
> +
> +static struct attribute *lm3533_als_attributes[] = {
> + &dev_attr_r_select.attr,
Just to keep info in one place. We agreed in other branch
of thread that r_select would be done with platform data.

I wonder if we can make the naming a little clearer for these.. hmm.
> + &lm3533_als_attr_target1_0.dev_attr.attr,
> + &lm3533_als_attr_target1_1.dev_attr.attr,
> + &lm3533_als_attr_target1_2.dev_attr.attr,
> + &lm3533_als_attr_target1_3.dev_attr.attr,
> + &lm3533_als_attr_target1_4.dev_attr.attr,
> + &lm3533_als_attr_target2_0.dev_attr.attr,
> + &lm3533_als_attr_target2_1.dev_attr.attr,
> + &lm3533_als_attr_target2_2.dev_attr.attr,
> + &lm3533_als_attr_target2_3.dev_attr.attr,
> + &lm3533_als_attr_target2_4.dev_attr.attr,
> + &lm3533_als_attr_target3_0.dev_attr.attr,
> + &lm3533_als_attr_target3_1.dev_attr.attr,
> + &lm3533_als_attr_target3_2.dev_attr.attr,
> + &lm3533_als_attr_target3_3.dev_attr.attr,
> + &lm3533_als_attr_target3_4.dev_attr.attr,
> + &dev_attr_in_illuminance0_zone.attr,
> + NULL
> +};
> +
> +static struct attribute_group lm3533_als_attribute_group = {
> + .attrs = lm3533_als_attributes
> +};
> +
> +static int __devinit lm3533_als_set_input_mode(struct iio_dev *indio_dev,
> + int pwm_mode)
> +{
> + struct lm3533_als *als = iio_priv(indio_dev);
> + u8 mask = LM3533_ALS_INPUT_MODE_MASK;
> + u8 val;
Just use mask directly, why introduce val as well
(particularly as you don't use it ;)
> + int ret;
> +
> + if (pwm_mode)
> + val = mask; /* pwm input */
> + else
> + val = 0; /* analog input */
> +
Why have val?
> + ret = lm3533_update(als->lm3533, LM3533_REG_ALS_CONF, mask, mask);
> + if (ret) {
> + dev_err(&indio_dev->dev,
> + "failed to set input mode %d\n", pwm_mode);
> + }
> +
> + return ret;
> +}
> +
> +static int __devinit lm3533_als_setup(struct iio_dev *indio_dev,
> + struct lm3533_als_platform_data *pdata)
> +{
> + int ret;
> +
> + ret = lm3533_als_set_input_mode(indio_dev, pdata->pwm_mode);
> + if (ret)
> + return ret;
> +
> + /* ALS input is always high impedance in PWM-mode. */
> + if (!pdata->pwm_mode) {
> + ret = lm3533_als_set_resistor(indio_dev, pdata->r_select);
> + if (ret)
> + return ret;
> + }
> +
> + return 0;
> +}
> +
This enable / disable pair does rather look like it could
be combined into one function and save a few lines of repeated
code
> +static int __devinit lm3533_als_enable(struct iio_dev *indio_dev)
> +{
> + struct lm3533_als *als = iio_priv(indio_dev);
> + u8 mask = LM3533_ALS_ENABLE_MASK;
> + int ret;
> +
> + ret = lm3533_update(als->lm3533, LM3533_REG_ALS_CONF, mask, mask);
> + if (ret)
> + dev_err(&indio_dev->dev, "failed to enable ALS\n");
> +
> + return ret;
> +}
> +
> +static int __devexit lm3533_als_disable(struct iio_dev *indio_dev)
> +{
> + struct lm3533_als *als = iio_priv(indio_dev);
> + u8 mask = LM3533_ALS_ENABLE_MASK;
> + int ret;
> +
> + ret = lm3533_update(als->lm3533, LM3533_REG_ALS_CONF, 0, mask);
> + if (ret)
> + dev_err(&indio_dev->dev, "failed to disable ALS\n");
> +
> + return ret;
> +}
> +
> +static const struct iio_info lm3533_als_info = {
> + .attrs = &lm3533_als_attribute_group,
> + .event_attrs = &lm3533_als_event_attribute_group,
> + .driver_module = THIS_MODULE,
> + .read_raw = &lm3533_als_read_raw,
> +};
> +
> +static int __devinit lm3533_als_probe(struct platform_device *pdev)
> +{
> + struct lm3533 *lm3533;
> + struct lm3533_als_platform_data *pdata;
> + struct lm3533_als *als;
> + struct iio_dev *indio_dev;
> + int ret;
> +
> + dev_dbg(&pdev->dev, "%s\n", __func__);
> +
> + lm3533 = dev_get_drvdata(pdev->dev.parent);
> + if (!lm3533)
> + return -EINVAL;
> +
> + pdata = pdev->dev.platform_data;
> + if (!pdata) {
> + dev_err(&pdev->dev, "no platform data\n");
> + return -EINVAL;
> + }
> +
> + indio_dev = iio_device_alloc(sizeof(*als));
> + if (!indio_dev)
> + return -ENOMEM;
> +
> + indio_dev->info = &lm3533_als_info;
> + indio_dev->channels = lm3533_als_channels;
> + indio_dev->num_channels = ARRAY_SIZE(lm3533_als_channels);
> + indio_dev->name = "lm3533-als";
> + indio_dev->dev.parent = pdev->dev.parent;
> + indio_dev->modes = INDIO_DIRECT_MODE;
> +
> + als = iio_priv(indio_dev);
> + als->lm3533 = lm3533;
> + als->irq = lm3533->irq;
> + als->pwm_mode = pdata->pwm_mode;
> + atomic_set(&als->zone, 0);
> + mutex_init(&als->thresh_mutex);
> +
> + if (als->irq) {
> + ret = request_threaded_irq(als->irq, NULL, lm3533_als_isr,
> + IRQF_TRIGGER_LOW | IRQF_ONESHOT,
> + indio_dev->name, indio_dev);
> + if (ret) {
> + dev_err(&pdev->dev, "failed to request irq %d\n",
> + als->irq);
> + goto err_free_dev;
> + }
> + }
> +
> + platform_set_drvdata(pdev, indio_dev);
> +
amongst other things this register does the creation of the
sysfs attributes. Is there a race here if a read on one of
those occurs before the setup stuff below?

Normally I'd expect this call to the last one in the probe
function. Why did you chose this ordering?
> + ret = iio_device_register(indio_dev);
> + if (ret) {
> + dev_err(&pdev->dev, "failed to register ALS\n");
> + goto err_free_irq;
> + }
> +
> + ret = lm3533_als_setup(indio_dev, pdata);
> + if (ret)
> + goto err_unregister;
> +
> + ret = lm3533_als_enable(indio_dev);
> + if (ret)
> + goto err_unregister;
> +
> + return 0;
> +
> +err_unregister:
> + iio_device_unregister(indio_dev);
> +err_free_irq:
> + if (als->irq)
> + free_irq(als->irq, indio_dev);
> +err_free_dev:
> + iio_device_free(indio_dev);
> +
> + return ret;
> +}
> +
> +static int __devexit lm3533_als_remove(struct platform_device *pdev)
> +{
> + struct iio_dev *indio_dev = platform_get_drvdata(pdev);
> + struct lm3533_als *als = iio_priv(indio_dev);
> +
> + dev_dbg(&pdev->dev, "%s\n", __func__);
> +
> + lm3533_als_disable(indio_dev);
> + iio_device_unregister(indio_dev);
> + if (als->irq)
> + free_irq(als->irq, indio_dev);
> + iio_device_free(indio_dev);
> +
> + return 0;
> +}
> +
> +static struct platform_driver lm3533_als_driver = {
> + .driver = {
> + .name = "lm3533-als",
> + .owner = THIS_MODULE,
> + },
> + .probe = lm3533_als_probe,
> + .remove = __devexit_p(lm3533_als_remove),
> +};
> +module_platform_driver(lm3533_als_driver);
> +
> +MODULE_AUTHOR("Johan Hovold <jhovold@gmail.com>");
> +MODULE_DESCRIPTION("LM3533 Ambient Light Sensor driver");
> +MODULE_LICENSE("GPL");
> +MODULE_ALIAS("platform:lm3533-als");
> diff --git a/include/linux/mfd/lm3533.h b/include/linux/mfd/lm3533.h
> index 9660feb..594bc59 100644
> --- a/include/linux/mfd/lm3533.h
> +++ b/include/linux/mfd/lm3533.h
> @@ -43,6 +43,7 @@ struct lm3533_ctrlbank {
>
> struct lm3533_als_platform_data {
> unsigned pwm_mode:1; /* PWM input mode (default analog) */
> + u8 r_select; /* 1 - 127 (ignored in PWM-mode) */
> };
>
> struct lm3533_bl_platform_data {



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