Re: [PATCH v4 02/12] hwmon: Add Qualcomm PMIC BCL driver

[Daniel Lezcano <daniel.lezcano@oss.qualcomm.com>]

Hi Manaf,

On 10/5/26 14:24, Manaf Meethalavalappu Pallikunhi wrote:
> Add driver for Qualcomm SPMI PMIC Battery Current Limiting (BCL)
> hardware monitor. The driver exposes battery voltage and current
> monitoring through hwmon interface.
> 
> The BCL driver provides
> - Real-time voltage and current readings
> - Configurable threshold-based alarms
> - Interrupt-driven notifications when thresholds are exceeded
> - Automatic threshold management with polling-based recovery
> - Hardware-specific scaling factors and threshold representations
> 
> Signed-off-by: Manaf Meethalavalappu Pallikunhi <manaf.pallikunhi@oss.qualcomm.com>
> ---

There are a couple of issues in sashiko related to this patch (devres 
LIFO issue and 6 bits encoding value too short for the represented value).

[ ... ]

> +/**
> + * struct bcl_channel_cfg - BCL channel related configuration
> + * @default_scale_nu:  Default scaling factor in nano unit
> + * @base_mu: Base threshold value in milli unit
> + * @max_mu: Maximum threshold value in milli unit
> + * @step_mu: step increment value between two indexed threshold value in milli unit
> + * @thresh_type: Array specifying threshold representation type for each alarm level
> + *
> + * Contains hardware-specific configuration and scaling parameters for different
> + * channels (voltage and current).
> + */
> +struct bcl_channel_cfg {
> +	u32 default_scale_nu;
> +	u32 base_mu;
> +	u32 max_mu;
> +	u32 step_mu;
> +	u8 thresh_type[BCL_LIMIT_ALARM_MAX];
> +};
> +
> +/**
> + * struct bcl_desc - BCL device descriptor
> + * @reg_fields: Array of register field definitions for this device variant
> + * @channel_cfg: Array of channel configurations indexed by battery config
> + *               PMICs without battery detection: only [BCL_BATT_1S] is defined
> + *               PMICs with battery detection: [BCL_BATT_2S], [BCL_BATT_3S]
> + * @battery_config_field: Register field for battery configuration detection
> + *                        NOTE: This is an ABSOLUTE address, not relative to BCL base
> + *                        Set to REG_FIELD(0, 0, 0) if not used
> + * @num_reg_fields: Number of register field definitions for this device variant
> + * @data_field_bits_size: data read register bit size
> + * @thresh_field_bits_size: lsb bit size those are not included in threshold register
> + * @in_mon_enabled: Voltage monitoring enabled at boot
> + * @in_input_enabled: Voltage input reading enabled at boot
> + * @curr_mon_enabled: Current monitoring enabled at boot
> + *
> + * Contains hardware-specific configuration and scaling parameters for different
> + * BCL variants. Each PMIC model may have different register layouts and
> + * conversion factors.
> + */
> +struct bcl_desc {
> +	const struct reg_field *reg_fields;
> +	struct bcl_channel_cfg channel_cfg[BCL_BATT_3S + 1][CHANNEL_MAX];
> +	const struct reg_field battery_config_field;
> +	u8 num_reg_fields;
> +	u8 data_field_bits_size;
> +	u8 thresh_field_bits_size;
> +	bool in_mon_enabled;
> +	bool in_input_enabled;
> +	bool curr_mon_enabled;
> +};

It is your call but I suggest to use a single variable:

eg. u8 features

and use masks

	features = IN_MON | IN_INPUT;

that will reduce the declaration size below.

> +/**
> + * struct bcl_alarm_data - BCL alarm interrupt data
> + * @irq: IRQ number assigned to this alarm
> + * @irq_enabled: Flag indicating if IRQ is enabled
> + * @irq_wake_enabled: Flag indicating if IRQ wake is enabled
> + * @shutting_down: Flag preventing work from re-enabling IRQ during teardown
> + * @type: Alarm level type (LVL0, or LVL1)
> + * @device: Pointer to parent BCL device structure
> + * @a_lock: Mutex for protecting alarm state
> + * @alarm_poll_work: delayed_work to poll alarm status
> + *
> + * Stores interrupt-related information for each alarm threshold level.
> + * Used by the IRQ handler to identify which alarm triggered.
> + */
> +struct bcl_alarm_data {
> +	int			irq;
> +	bool			irq_enabled;
> +	bool			irq_wake_enabled;
> +	bool			shutting_down;

Same suggestion

> +	enum bcl_limit_alarm	type;
> +	void			*device;
> +	/* Protects alarm IRQ enable/disable state */
> +	struct mutex		a_lock;
> +	struct delayed_work	alarm_poll_work;
> +};
> +
> +/**
> + * struct bcl_device - Main BCL device structure
> + * @dev: Pointer to device structure
> + * @regmap: Regmap for accessing PMIC registers
> + * @base: the BCL regbase offset from regmap
> + * @fields: Array of regmap fields for register access
> + * @bcl_alarms: Array of alarm data structures for each threshold level
> + * @lock: Mutex for protecting concurrent hardware access
> + * @last_in_input: Last valid voltage input reading in millivolts
> + * @last_curr_input: Last valid current input reading in milliamps
> + * @last_in_updated: Timestamp of last voltage input update
> + * @last_curr_updated: Timestamp of last current input update
> + * @desc: Pointer to device descriptor with hardware-specific parameters
> + * @hwmon_dev: Pointer to registered hwmon device
> + * @hwmon_name: Sanitized name for hwmon device
> + * @batt_config: Detected battery configuration (only for SMB2360/2370)
> + * @batt_config_regfield: Regmap field for battery configuration register
> + *
> + * Main driver structure containing all state and configuration for a BCL
> + * monitoring instance. Manages voltage and current monitoring, thresholds,
> + * and alarm handling.
> + */
> +struct bcl_device {
> +	struct device		*dev;
> +	struct regmap		*regmap;
> +	u16			base;
> +	struct regmap_field	*fields[F_MAX_FIELDS];
> +	struct bcl_alarm_data	bcl_alarms[BCL_LIMIT_ALARM_MAX];
> +	/* Protects hardware register access and device state */
> +	struct mutex		lock;
> +	u32			last_in_input;
> +	s32			last_curr_input;
> +	unsigned long		last_in_updated;
> +	unsigned long		last_curr_updated;
> +	const struct bcl_desc	*desc;
> +	struct device		*hwmon_dev;
> +	char			*hwmon_name;
> +	enum bcl_battery_config	batt_config;
> +	struct regmap_field	*batt_config_regfield;
> +};
> +
> +static const u8 in_attr_to_lvl_map[] = {
> +	[hwmon_in_min] = BCL_LIMIT_ALARM_LVL0,
> +	[hwmon_in_lcrit] = BCL_LIMIT_ALARM_LVL1,
> +	[hwmon_in_lemergency] = BCL_LIMIT_ALARM_LVL2,
> +	[hwmon_in_min_alarm] = BCL_LIMIT_ALARM_LVL0,
> +	[hwmon_in_lcrit_alarm] = BCL_LIMIT_ALARM_LVL1,
> +	[hwmon_in_lemergency_alarm] = BCL_LIMIT_ALARM_LVL2,
> +};
> +
> +static const u8 in_lvl_to_attr_map[BCL_LIMIT_ALARM_MAX] = {
> +	[BCL_LIMIT_ALARM_LVL0] = hwmon_in_min_alarm,
> +	[BCL_LIMIT_ALARM_LVL1] = hwmon_in_lcrit_alarm,
> +	[BCL_LIMIT_ALARM_LVL2] = hwmon_in_lemergency_alarm,
> +};
> +
> +static const u8 curr_attr_to_lvl_map[] = {
> +	[hwmon_curr_max] = BCL_LIMIT_ALARM_LVL0,
> +	[hwmon_curr_crit] = BCL_LIMIT_ALARM_LVL1,
> +	[hwmon_curr_max_alarm] = BCL_LIMIT_ALARM_LVL0,
> +	[hwmon_curr_crit_alarm] = BCL_LIMIT_ALARM_LVL1,
> +	[hwmon_curr_emergency_alarm] = BCL_LIMIT_ALARM_LVL2,
> +};
> +
> +static const u8 curr_lvl_to_attr_map[BCL_LIMIT_ALARM_MAX] = {
> +	[BCL_LIMIT_ALARM_LVL0] = hwmon_curr_max_alarm,
> +	[BCL_LIMIT_ALARM_LVL1] = hwmon_curr_crit_alarm,
> +	[BCL_LIMIT_ALARM_LVL2] = hwmon_curr_emergency_alarm,
> +};
> +
> +/* Interrupt names for each alarm level */
> +static const char * const bcl_int_names[BCL_LIMIT_ALARM_MAX] = {
> +	[BCL_LIMIT_ALARM_LVL0] = "max-min",
> +	[BCL_LIMIT_ALARM_LVL1] = "critical",
> +	[BCL_LIMIT_ALARM_LVL2] = "emergency",
> +};

why not fold the structures into a single one?

eg.

struct attr_lvl_map {
	const int level;
	const int attr;
	const char *name;
};

const curr_attr_lvl_map[] = {
	{
	  .level = BCL_LIMIT_ALARM_LVL0,
	  .attr = hwmon_curr_max_alarm,
	  .name = "max-min"
	}
	...
};

And a function lvl_to_attr() / attr_to_lvl()

?


[ ... ]

Thanks

   -- Daniel