Re: [PATCH v2 2/3] iio: light: ROHM BH1745 colour sensor

Mudit Sharma
2024-06-04T14:24:39Z

On 04/06/2024 00:10, Javier Carrasco wrote:
> On 03/06/2024 18:21, 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.
>>
>> This driver includes device attributes to configure the following:
>> - Interrupt pin latch: The interrupt pin can be configured to
>> be latched (until interrupt register (0x60) is read or initialized)
>> or update after each measurement.
>> - Interrupt source: The colour channel that will cause the interrupt
>> when channel will cross the set threshold high or low level.
>>
>> This driver also includes device attributes to present valid
>> configuration options/values for:
>> - Integration time
>> - Interrupt colour source
>> - Hardware gain
>>
>> Signed-off-by: Mudit Sharma <muditsharma.info@gmail.com>
>
> Hi Mudit,
>
> a few minor comments inline.
>
>> ---
>> v1->v2:
>> - No changes
>>
>> drivers/iio/light/Kconfig | 12 +
>> drivers/iio/light/Makefile | 1 +
>> drivers/iio/light/bh1745.c | 879 +++++++++++++++++++++++++++++++++++++
>> 3 files changed, 892 insertions(+)
>> create mode 100644 drivers/iio/light/bh1745.c
>>
>> diff --git a/drivers/iio/light/Kconfig b/drivers/iio/light/Kconfig
>> index 9a587d403118..6e0bd2addf9e 100644
>> --- a/drivers/iio/light/Kconfig
>> +++ b/drivers/iio/light/Kconfig
>> @@ -114,6 +114,18 @@ 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
>> + 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..a7b660a1bdc8
>> --- /dev/null
>> +++ b/drivers/iio/light/bh1745.c
>> @@ -0,0 +1,879 @@
>> +// 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/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>
>> +
>> +#define BH1745_MOD_NAME "bh1745"
>
> Given that this define is only used in one place, using the string
> directly is common practice in iio.
>
>> +
>> +/* 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_THRESHOLD_MAX 0xFFFF
>> +#define BH1745_THRESHOLD_MIN 0x0
>> +
>> +#define BH1745_MANU_ID 0X92
>> +
>> +/* BH1745 output regs */
>> +#define BH1745_R_LSB 0x50
>> +#define BH1745_R_MSB 0x51
>> +#define BH1745_G_LSB 0x52
>> +#define BH1745_G_MSB 0x53
>> +#define BH1745_B_LSB 0x54
>> +#define BH1745_B_MSB 0x55
>> +#define BH1745_CLR_LSB 0x56
>> +#define BH1745_CLR_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_SIGNAL_LATCH_OFFSET 4
>> +
>> +#define BH1745_INT_SOURCE_MASK GENMASK(3, 2)
>> +#define BH1745_INT_SOURCE_OFFSET 2
>> +
>> +#define BH1745_INT_TIME_AVAILABLE "0.16 0.32 0.64 1.28 2.56 5.12"
>> +#define BH1745_HARDWAREGAIN_AVAILABLE "1 2 16"
>> +#define BH1745_INT_COLOUR_CHANNEL_AVAILABLE \
>> + "0 (Red Channel) 1 (Green Channel) 2 (Blue channel) 3 (Clear channel)"
>> +
>> +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 };
>> +
>> +enum {
>> + BH1745_INT_SOURCE_RED,
>> + BH1745_INT_SOURCE_GREEN,
>> + BH1745_INT_SOURCE_BLUE,
>> + BH1745_INT_SOURCE_CLEAR,
>> +} bh1745_int_source;
>> +
>> +enum {
>> + BH1745_ADC_GAIN_1X,
>> + BH1745_ADC_GAIN_2X,
>> + BH1745_ADC_GAIN_16X,
>> +} bh1745_gain;
>> +
>> +enum {
>> + BH1745_MEASUREMENT_TIME_160MS,
>> + BH1745_MEASUREMENT_TIME_320MS,
>> + BH1745_MEASUREMENT_TIME_640MS,
>> + BH1745_MEASUREMENT_TIME_1280MS,
>> + BH1745_MEASUREMENT_TIME_2560MS,
>> + BH1745_MEASUREMENT_TIME_5120MS,
>> +} bh1745_measurement_time;
>> +
>> +enum {
>> + BH1745_PRESISTENCE_UPDATE_TOGGLE,
>> + BH1745_PRESISTENCE_UPDATE_EACH_MEASUREMENT,
>> + BH1745_PRESISTENCE_UPDATE_FOUR_MEASUREMENT,
>> + BH1745_PRESISTENCE_UPDATE_EIGHT_MEASUREMENT,
>> +} bh1745_presistence_value;
>> +
>> +struct bh1745_data {
>> + struct mutex lock;
>> + struct regmap *regmap;
>> + struct i2c_client *client;
>> + struct iio_trigger *trig;
>> + u8 mode_ctrl1;
>> + u8 mode_ctrl2;
>> + u8 int_src;
>> + u8 int_latch;
>> + u8 interrupt;
>> +};
>> +
>> +static const struct regmap_range bh1745_volatile_ranges[] = {
>> + regmap_reg_range(BH1745_MODE_CTRL_2, BH1745_MODE_CTRL_2), /* VALID */
>> + regmap_reg_range(BH1745_R_LSB, BH1745_CLR_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_R_LSB, BH1745_CLR_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_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,
>> +};
>> +
>> +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),
>> + },
>> +};
>> +
>> +#define BH1745_CHANNEL(_colour, _si, _addr) \
>> + { \
>> + .type = IIO_INTENSITY, .modified = 1, \
>> + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
>> + .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_HARDWAREGAIN) | \
>> + 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_R_LSB),
>> + BH1745_CHANNEL(GREEN, 1, BH1745_G_LSB),
>> + BH1745_CHANNEL(BLUE, 2, BH1745_B_LSB),
>> + BH1745_CHANNEL(CLEAR, 3, BH1745_CLR_LSB),
>> + IIO_CHAN_SOFT_TIMESTAMP(4),
>> +};
>> +
>> +static int bh1745_write_value(struct bh1745_data *data, u8 reg, void *value,
>> + size_t len)
>> +{
>
> The initial assignment is unnecessary, as a new assignment is made
> immediately. This applies to several declarations of ret in this driver,
> but not always (e.g. bh1745_setup_trigger()).
>
>> + int ret = 0;
>> +
>> + ret = regmap_bulk_write(data->regmap, reg, value, len);
>> + if (ret < 0) {
>> + dev_err(&data->client->dev,
>> + "Failed to write to sensor. Reg: 0x%x\n", reg);
>> + return ret;
>> + }
>
> Nit: black line before return (it applies to several functions in this
> driver, but again, not in all of them).

Hi Javier,

Thank you for the review on this.

Can you please point me to resource/section of code style guide for
reference which talks about new line before 'return'.

Best regards,
Mudit Sharma