Re: [PATCH v6 2/2] iio: light: ROHM BH1745 colour sensor

Matti Vaittinen
2024-07-01T11:32:58Z

On 6/26/24 01:03, Mudit Sharma wrote:
> Add support for BH1745, which is an I2C colour sensor with red, green,
> blue and clear channels. It has a programmable active low interrupt
> pin. Interrupt occurs when the signal from the selected interrupt
> source channel crosses set interrupt threshold high or low level.
>
> Interrupt source for the device can be configured by enabling the
> corresponding event. Interrupt latch is always enabled when setting
> up interrupt.
>
> Add myself as the maintainer for this driver in MAINTAINERS.
>
> Signed-off-by: Mudit Sharma <muditsharma.info@gmail.com>
> Reviewed-by: Ivan Orlov <ivan.orlov0322@gmail.com>
> Reviewed-by: Javier Carrasco <javier.carrasco.cruz@gmail.com>
> ---
> v5->v6:
> - Fix typo
> - Fix Indentation
> - Drop read in bh1745_set_trigger_state() as configuring all the value
> v4->v5:
> - Provide scale instead of HW gain
> - Use GTS helpers
> - Code style fixes
> - Add check for part ID during probe
> - Always enable latch when enabling interrupt
> - Use devm_add_action_or_reset() and drop bh1745_remove() function
> - Drop custom DEVICE_ATTR and provide related read_avail and setup
> interrupt source with event_config
> - Make buffer support independent of IRQ
> - Add power regulator handing with devm_regulator_get_enable()
> - Drop read and write wrappers and use regmap functions directly
> - Add MODULE_DEVICE_TABLE for of_device_id
> v3->v4:
> - Fix formatting:
> - Remove redundant new line
> - Use '0x' rather than '0X'
> v2->v3:
> - Squash commit for addition to MAINTAINERS
> - Fix code style for consistency:
> - New line before last 'return'
> - Use variable name 'value' instead of 'val' in
> 'bh1745_set_trigger_state()'
> - Align function parameters to match parenthesis
> - Avoid use of magic number
> - Use named enum instead of anonymous enum
> - Use 'guard(mutex)(&data->lock)' instead of 'mutex_lock()'
> 'mutex_unlock()'
> - Only initialize 'ret' and 'value' when necessary
> - Fix and optimize logic for `in_interrupt_latch_store()`
> - Fix error handling in irq , trigger handlers and dev attribute for
> latch
> v1->v2:
> - No changes
>
> MAINTAINERS | 6 +
> drivers/iio/light/Kconfig | 13 +
> drivers/iio/light/Makefile | 1 +
> drivers/iio/light/bh1745.c | 931 +++++++++++++++++++++++++++++++++++++
> 4 files changed, 951 insertions(+)
> create mode 100644 drivers/iio/light/bh1745.c
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 2ca8f35dfe03..e9ff6f465e7f 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -19404,6 +19404,12 @@ S: Supported
> F: drivers/power/supply/bd99954-charger.c
> F: drivers/power/supply/bd99954-charger.h
>
> +ROHM BH1745 COLOUR SENSOR
> +M: Mudit Sharma <muditsharma.info@gmail.com>
> +L: linux-iio@vger.kernel.org
> +S: Maintained
> +F: drivers/iio/light/bh1745.c
> +
> ROHM BH1750 AMBIENT LIGHT SENSOR DRIVER
> M: Tomasz Duszynski <tduszyns@gmail.com>
> S: Maintained
> diff --git a/drivers/iio/light/Kconfig b/drivers/iio/light/Kconfig
> index 9a587d403118..6cde702fa78d 100644
> --- a/drivers/iio/light/Kconfig
> +++ b/drivers/iio/light/Kconfig
> @@ -114,6 +114,19 @@ config AS73211
> This driver can also be built as a module. If so, the module
> will be called as73211.
>
> +config BH1745
> + tristate "ROHM BH1745 colour sensor"
> + depends on I2C
> + select REGMAP_I2C
> + select IIO_BUFFER
> + select IIO_TRIGGERED_BUFFER
> + select IIO_GTS_HELPER
> + help
> + Say Y here to build support for the ROHM bh1745 colour sensor.
> +
> + To compile this driver as a module, choose M here: the module will
> + be called bh1745.
> +
> config BH1750
> tristate "ROHM BH1750 ambient light sensor"
> depends on I2C
> diff --git a/drivers/iio/light/Makefile b/drivers/iio/light/Makefile
> index a30f906e91ba..939a701a06ac 100644
> --- a/drivers/iio/light/Makefile
> +++ b/drivers/iio/light/Makefile
> @@ -13,6 +13,7 @@ obj-$(CONFIG_APDS9300) += apds9300.o
> obj-$(CONFIG_APDS9306) += apds9306.o
> obj-$(CONFIG_APDS9960) += apds9960.o
> obj-$(CONFIG_AS73211) += as73211.o
> +obj-$(CONFIG_BH1745) += bh1745.o
> obj-$(CONFIG_BH1750) += bh1750.o
> obj-$(CONFIG_BH1780) += bh1780.o
> obj-$(CONFIG_CM32181) += cm32181.o
> diff --git a/drivers/iio/light/bh1745.c b/drivers/iio/light/bh1745.c
> new file mode 100644
> index 000000000000..8412d5da3019
> --- /dev/null
> +++ b/drivers/iio/light/bh1745.c
> @@ -0,0 +1,931 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * ROHM BH1745 digital colour sensor driver
> + *
> + * Copyright (C) Mudit Sharma <muditsharma.info@gmail.com>
> + *
> + * 7-bit I2C slave addresses:
> + * 0x38 (ADDR pin low)
> + * 0x39 (ADDR pin high)
> + */
> +
> +#include <linux/i2c.h>
> +#include <linux/mutex.h>
> +#include <linux/util_macros.h>
> +#include <linux/iio/events.h>
> +#include <linux/regmap.h>
> +#include <linux/bits.h>
> +#include <linux/bitfield.h>
> +
> +#include <linux/iio/iio.h>
> +#include <linux/iio/sysfs.h>
> +#include <linux/iio/trigger.h>
> +#include <linux/iio/trigger_consumer.h>
> +#include <linux/iio/triggered_buffer.h>
> +#include <linux/iio/iio-gts-helper.h>
> +
> +/* BH1745 config regs */
> +#define BH1745_SYS_CTRL 0x40
> +
> +#define BH1745_MODE_CTRL_1 0x41
> +#define BH1745_MODE_CTRL_2 0x42
> +#define BH1745_MODE_CTRL_3 0x44
> +
> +#define BH1745_INTR 0x60
> +#define BH1745_INTR_STATUS BIT(7)
> +
> +#define BH1745_PERSISTENCE 0x61
> +
> +#define BH1745_TH_LSB 0x62
> +#define BH1745_TH_MSB 0x63
> +
> +#define BH1745_TL_LSB 0x64
> +#define BH1745_TL_MSB 0x65
> +
> +#define BH1745_MANU_ID 0x92
> +
> +/* BH1745 output regs */
> +#define BH1745_RED_LSB 0x50
> +#define BH1745_RED_MSB 0x51
> +#define BH1745_GREEN_LSB 0x52
> +#define BH1745_GREEN_MSB 0x53
> +#define BH1745_BLUE_LSB 0x54
> +#define BH1745_BLUE_MSB 0x55
> +#define BH1745_CLEAR_LSB 0x56
> +#define BH1745_CLEAR_MSB 0x57
> +
> +#define BH1745_SW_RESET BIT(7)
> +#define BH1745_INT_RESET BIT(6)
> +
> +#define BH1745_MEASUREMENT_TIME_MASK GENMASK(2, 0)
> +
> +#define BH1745_RGBC_EN BIT(4)
> +
> +#define BH1745_ADC_GAIN_MASK GENMASK(1, 0)
> +
> +#define BH1745_INT_ENABLE BIT(0)
> +#define BH1745_INT_SIGNAL_ACTIVE BIT(7)
> +
> +#define BH1745_INT_SIGNAL_LATCHED BIT(4)
> +
> +#define BH1745_INT_SOURCE_MASK GENMASK(3, 2)
> +
> +#define BH1745_PART_ID 0x0B
> +#define BH1745_PART_ID_MASK GENMASK(5, 0)
> +
> +// From 16x max HW gain and 32x max integration time
> +#define BH1745_MAX_GAIN 512
> +
> +static const int bh1745_int_time[][2] = {
> + { 0, 160000 }, /* 160 ms */
> + { 0, 320000 }, /* 320 ms */
> + { 0, 640000 }, /* 640 ms */
> + { 1, 280000 }, /* 1280 ms */
> + { 2, 560000 }, /* 2560 ms */
> + { 5, 120000 }, /* 5120 ms */
> +};
> +
> +static const u8 bh1745_gain_factor[] = { 1, 2, 16 };
> +
> +static const int bh1745_int_time_us[] = { 160000, 320000, 640000,
> + 1280000, 2560000, 5120000 };

I am not sure why you need these tables above? Can't the iio_gts do all
the conversions from register-value to int time/gain and int-time/gain
to register value, as well as the checks for supported values? Ideally,
you would not need anything else but the bh1745_itimes and the
bh1745_gain tables below - they should contain all the same information.

> +
> +enum bh1745_int_source {
> + BH1745_INT_SOURCE_RED,
> + BH1745_INT_SOURCE_GREEN,
> + BH1745_INT_SOURCE_BLUE,
> + BH1745_INT_SOURCE_CLEAR,
> +};
> +
> +enum bh1745_gain {
> + BH1745_ADC_GAIN_1X,
> + BH1745_ADC_GAIN_2X,
> + BH1745_ADC_GAIN_16X,
> +};
> +
> +enum bh1745_measurement_time {
> + BH1745_MEASUREMENT_TIME_160MS,
> + BH1745_MEASUREMENT_TIME_320MS,
> + BH1745_MEASUREMENT_TIME_640MS,
> + BH1745_MEASUREMENT_TIME_1280MS,
> + BH1745_MEASUREMENT_TIME_2560MS,
> + BH1745_MEASUREMENT_TIME_5120MS,
> +};
> +
> +enum bh1745_presistence_value {
> + BH1745_PRESISTENCE_UPDATE_TOGGLE,
> + BH1745_PRESISTENCE_UPDATE_EACH_MEASUREMENT,
> + BH1745_PRESISTENCE_UPDATE_FOUR_MEASUREMENT,
> + BH1745_PRESISTENCE_UPDATE_EIGHT_MEASUREMENT,
> +};
> +
> +static const struct iio_gain_sel_pair bh1745_gain[] = {
> + GAIN_SCALE_GAIN(1, BH1745_ADC_GAIN_1X),
> + GAIN_SCALE_GAIN(2, BH1745_ADC_GAIN_2X),
> + GAIN_SCALE_GAIN(16, BH1745_ADC_GAIN_16X),
> +};
> +
> +static const struct iio_itime_sel_mul bh1745_itimes[] = {
> + GAIN_SCALE_ITIME_US(5120000, BH1745_MEASUREMENT_TIME_5120MS, 32),
> + GAIN_SCALE_ITIME_US(2560000, BH1745_MEASUREMENT_TIME_2560MS, 16),
> + GAIN_SCALE_ITIME_US(1280000, BH1745_MEASUREMENT_TIME_1280MS, 8),
> + GAIN_SCALE_ITIME_US(640000, BH1745_MEASUREMENT_TIME_640MS, 4),
> + GAIN_SCALE_ITIME_US(320000, BH1745_MEASUREMENT_TIME_320MS, 2),
> + GAIN_SCALE_ITIME_US(160000, BH1745_MEASUREMENT_TIME_160MS, 1),
> +};
> +
> +struct bh1745_data {
> + /*
> + * Lock to prevent device setting update or read before related
> + * calculations or event push are completed
> + */
> + struct mutex lock;
> + struct regmap *regmap;
> + struct i2c_client *client;
> + struct iio_trigger *trig;
> + struct iio_gts gts;
> + u8 int_src;
> +};
> +
> +static const struct regmap_range bh1745_volatile_ranges[] = {
> + regmap_reg_range(BH1745_MODE_CTRL_2, BH1745_MODE_CTRL_2), /* VALID */
> + regmap_reg_range(BH1745_RED_LSB, BH1745_CLEAR_MSB), /* Data */
> + regmap_reg_range(BH1745_INTR, BH1745_INTR), /* Interrupt */
> +};
> +
> +static const struct regmap_access_table bh1745_volatile_regs = {
> + .yes_ranges = bh1745_volatile_ranges,
> + .n_yes_ranges = ARRAY_SIZE(bh1745_volatile_ranges),
> +};
> +
> +static const struct regmap_range bh1745_read_ranges[] = {
> + regmap_reg_range(BH1745_SYS_CTRL, BH1745_MODE_CTRL_2),
> + regmap_reg_range(BH1745_RED_LSB, BH1745_CLEAR_MSB),
> + regmap_reg_range(BH1745_INTR, BH1745_INTR),
> + regmap_reg_range(BH1745_PERSISTENCE, BH1745_TL_MSB),
> + regmap_reg_range(BH1745_MANU_ID, BH1745_MANU_ID),
> +};
> +
> +static const struct regmap_access_table bh1745_ro_regs = {
> + .yes_ranges = bh1745_read_ranges,
> + .n_yes_ranges = ARRAY_SIZE(bh1745_read_ranges),
> +};
> +
> +static const struct regmap_range bh1745_writable_ranges[] = {
> + regmap_reg_range(BH1745_SYS_CTRL, BH1745_MODE_CTRL_2),
> + regmap_reg_range(BH1745_INTR, BH1745_INTR),
> + regmap_reg_range(BH1745_PERSISTENCE, BH1745_TL_MSB),
> +};
> +
> +static const struct regmap_access_table bh1745_wr_regs = {
> + .yes_ranges = bh1745_writable_ranges,
> + .n_yes_ranges = ARRAY_SIZE(bh1745_writable_ranges),
> +};
> +
> +static const struct regmap_config bh1745_regmap = {
> + .reg_bits = 8,
> + .val_bits = 8,
> + .max_register = BH1745_MANU_ID,
> + .cache_type = REGCACHE_RBTREE,
> + .volatile_table = &bh1745_volatile_regs,
> + .wr_table = &bh1745_wr_regs,
> + .rd_table = &bh1745_ro_regs,

I am not 100% sure what this does. (Let's say it is just my ignorance
:)). Does the 'ro' in 'bh1745_ro_regs' stand for read-only?

If so, shouldn't the read-inly registers be marked as "not writable",
which would be adding them in .wr_table in 'no_ranges'? Also, what is
the idea of the 'wr_regs'?

> +};
> +
> +static const struct iio_event_spec bh1745_event_spec[] = {
> + {
> + .type = IIO_EV_TYPE_THRESH,
> + .dir = IIO_EV_DIR_RISING,
> + .mask_shared_by_type = BIT(IIO_EV_INFO_VALUE),
> + },
> + {
> + .type = IIO_EV_TYPE_THRESH,
> + .dir = IIO_EV_DIR_FALLING,
> + .mask_shared_by_type = BIT(IIO_EV_INFO_VALUE),
> + },
> + {
> + .type = IIO_EV_TYPE_THRESH,
> + .dir = IIO_EV_DIR_EITHER,
> + .mask_shared_by_type = BIT(IIO_EV_INFO_PERIOD),
> + .mask_separate = BIT(IIO_EV_INFO_ENABLE),
> + },
> +};
> +
> +#define BH1745_CHANNEL(_colour, _si, _addr) \
> + { \
> + .type = IIO_INTENSITY, .modified = 1, \
> + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
> + .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SCALE) | \
> + BIT(IIO_CHAN_INFO_INT_TIME), \
> + .info_mask_shared_by_all_available = \
> + BIT(IIO_CHAN_INFO_SCALE) | \
> + BIT(IIO_CHAN_INFO_INT_TIME), \
> + .event_spec = bh1745_event_spec, \
> + .num_event_specs = ARRAY_SIZE(bh1745_event_spec), \
> + .channel2 = IIO_MOD_LIGHT_##_colour, .address = _addr, \
> + .scan_index = _si, \
> + .scan_type = { \
> + .sign = 'u', \
> + .realbits = 16, \
> + .storagebits = 16, \
> + .endianness = IIO_CPU, \
> + }, \
> + }
> +
> +static const struct iio_chan_spec bh1745_channels[] = {
> + BH1745_CHANNEL(RED, 0, BH1745_RED_LSB),
> + BH1745_CHANNEL(GREEN, 1, BH1745_GREEN_LSB),
> + BH1745_CHANNEL(BLUE, 2, BH1745_BLUE_LSB),
> + BH1745_CHANNEL(CLEAR, 3, BH1745_CLEAR_LSB),
> + IIO_CHAN_SOFT_TIMESTAMP(4),
> +};
> +
> +static int bh1745_reset(struct bh1745_data *data)
> +{
> + int ret;
> + int value;
> +
> + ret = regmap_read(data->regmap, BH1745_SYS_CTRL, &value);
> + if (ret)
> + return ret;
> +
> + value |= (BH1745_SW_RESET | BH1745_INT_RESET);
> +
> + return regmap_write(data->regmap, BH1745_SYS_CTRL, value);

Would it work if you used regmap_write_bits() instead?

... Sorry, my reviewing time is out :/ I may continue later but no need
to wait for my comments if I am not responding. I've too much stuff
piling on :(

Yours,
-- Matti

--
Matti Vaittinen
Linux kernel developer at ROHM Semiconductors
Oulu Finland

~~ When things go utterly wrong vim users can always type :help! ~~