adding support for Microchip PAC194X Power Monitor

From: Marius Cristea <[email protected]>

This is the device tree schema for iio driver for Microchip PAC194X and PAC195X series of Power Monitors with Accumulator.
The PAC194X family supports 9V Full-Scale Range and the PAC195X supports 32V Full-Scale Range.
There are two versions of the PAC194X/5X: the PAC194X/5X-1 devices are for high-side current sensing and the PAC194X/5X-2 devices are for low-side current sensing or floating VBUS applications.
The PAC194X/5X-1 is named shortly PAC194X/5X.

Signed-off-by Marius Cristea <[email protected]>

---
 .../bindings/iio/adc/microchip,pac1944.yaml   | 195 ++++++++++++++++++
 1 file changed, 195 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/iio/adc/microchip,pac1944.yaml

From: Marius Cristea <[email protected]>

This is the device tree schema for iio driver for Microchip PAC194X and PAC195X series of Power Monitors with Accumulator.

The PAC194X family supports 9V Full-Scale Range and the PAC195X supports 32V Full-Scale Range.
There are two versions of the PAC194X/5X: the PAC194X/5X-1 devices are for high-side current sensing and the PAC194X/5X-2 devices are for low-side current sensing or floating VBUS applications.
The PAC194X/5X-1 is named shortly PAC194X/5X.

Signed-off-by Marius Cristea <[email protected]>

---
 .../bindings/iio/adc/microchip,pac1944.yaml   | 195 ++++++++++++++++++
 1 file changed, 195 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/iio/adc/microchip,pac1944.yaml

Documentation/devicetree/bindings/iio/adc/microchip,pac1944.yaml new file +9 -0

new file mode 100644
index 000000000000..1997e889e3f6
 
+
+      microchip,vbus-mode:
+        $ref: /schemas/types.yaml#/definitions/uint32
+        description:
+          In order to increase measurement resolution and keeping the same
+          number the of bits the device has a configurable VBUS full range
+          scale (FSR). The range should be set by hardware design and it should
+          not be changed during runtime. The bipolar capability for VBUS enables
+          accurate offset measurement and correction.

Documentation/devicetree/bindings/iio/adc/microchip,pac1944.yaml new file +4 -0

+
+      microchip,vsense-mode:
+        $ref: /schemas/types.yaml#/definitions/uint32
+        description:

Documentation/devicetree/bindings/iio/adc/microchip,pac1944.yaml new file +11 -0

+
+      microchip,accumulation-mode:
+        $ref: /schemas/types.yaml#/definitions/uint32
+        description:
+          The Hardware Accumulator may be used to accumulate VPOWER, VSENSE or
+          VBUS values for any channel. By setting the accumulator for a channel
+          to accumulate the VPOWER values gives a measure of accumulated power
+          into a time period, which is equivalent to energy. Setting the
+          accumulator for a channel to accumulate VSENSE values gives a measure
+          of accumulated current, which is equivalent to charge. This allows the
+          accumulator to be used as a coulomb counter. For either VSENSE or

From: Marius Cristea <[email protected]>

This is the iio driver for Microchip PAC194X and PAC195X series of Power Monitors with Accumulator.
The PAC194X family supports 9V Full-Scale Range and the PAC195X supports 32V Full-Scale Range.
There are two versions of the PAC194X/5X: the PAC194X/5X-1 devices are for high-side current sensing and the PAC194X/5X-2 devices are for low-side current sensing or floating VBUS applications.
The PAC194X/5X-1 is named shortly PAC194X/5X.

Signed-off-by Marius Cristea <[email protected]>

---
 .../ABI/testing/sysfs-bus-iio-adc-pac1944     |  118 +
 MAINTAINERS                                   |    7 +
 drivers/iio/adc/Kconfig                       |   12 +
 drivers/iio/adc/Makefile                      |    1 +
 drivers/iio/adc/pac1944.c                     | 3314 +++++++++++++++++
 5 files changed, 3452 insertions(+)
 create mode 100644 Documentation/ABI/testing/sysfs-bus-iio-adc-pac1944
 create mode 100644 drivers/iio/adc/pac1944.c

Documentation/ABI/testing/sysfs-bus-iio-adc-pac1944 new file +0 -0

new file mode 100644
index 000000000000..e4122f58fe39

Documentation/ABI/testing/sysfs-bus-iio-adc-pac1944 new file +5 -0

+KernelVersion:	6.13
+Contact:	[email protected]
+Description:
+		The value of the shunt resistor may be known only at runtime
+		and set by a client application. This attribute allows to

Documentation/ABI/testing/sysfs-bus-iio-adc-pac1944 new file +6 -0

+KernelVersion:	6.13
+Contact:	[email protected]
+Description:
+		Number of consecutive samples exceeding the undercurrent limit
+		that are required to trigger the ALERT function for
+		channel Y. Consecutive sample count to trigger could be:

Documentation/ABI/testing/sysfs-bus-iio-adc-pac1944 new file +10 -0

+KernelVersion:	6.13
+Contact:	[email protected]
+Description:
+		Number of consecutive samples exceeding the undervoltage limit
+		that are required to trigger the ALERT function for channel Y.
+		Consecutive sample count to trigger could be:
+			- 1 sample (default),
+			- 4 samples,
+			- 8 samples,
+			- 16 samples.

Documentation/ABI/testing/sysfs-bus-iio-adc-pac1944 new file +4 -0

+		The fullness limit could be set to:
+			- full,
+			- 15/16 full (default),
+			- 7/8 full,

drivers/iio/adc/pac1944.c new file +3 -0

new file mode 100644
index 000000000000..b6f93d21b86b
@@ -0,0 +1,3314 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * IIO driver for PAC194X and PAC195X series chips

drivers/iio/adc/pac1944.c new file +19 -0

+
+static int pac1944_disable_alert_reg(struct device *dev, u32 mask, u8 *status)
+{
+	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+	struct pac1944_chip_info *info = iio_priv(indio_dev);
+	struct i2c_client *client = info->client;
+	int ret;
+	u32 val;
+	u8 buf[PAC1944_ALERT_ENABLE_REG_LEN];
+
+	ret = i2c_smbus_read_i2c_block_data(client,
+					    PAC1944_ALERT_ENABLE_REG_ADDR,
+					    PAC1944_ALERT_ENABLE_REG_LEN,
+					    status);
+	if (ret < 0) {
+		dev_err(dev, "failing %s\n", __func__);
+		return ret;
+	}
+

drivers/iio/adc/pac1944.c new file +13 -0

+}
 
+
+static ssize_t pac1944_alert_status_show(struct device *dev,
+					 struct device_attribute *attr,
+					 char *buf)
+{
+	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+	struct pac1944_chip_info *info = iio_priv(indio_dev);
+	struct i2c_client *client = info->client;
+	int ret;
+	u32 tmp;
+	u8 status[3];
+

drivers/iio/adc/pac1944.c new file +11 -0

+static int pac1944_reg_snapshot(struct pac1944_chip_info *info,
+				bool do_refresh, u8 refresh_cmd, u32 wait_time)
+{
+	struct i2c_client *client = info->client;
+	u8 shift, idx;
+	u8 *offset_reg_data_p;
+	int cnt, ret;
+	u32 count, inc_count;
+	u32 fs = 0;
+	s64 stored_value, tmp_s64;
+	s64 inc = 0;

drivers/iio/adc/pac1944.c new file +3 -0

+			return ret;
+		}
+	}

drivers/iio/adc/pac1944.c new file +51 -0

+
+		offset_reg_data_p += PAC1944_VBUS_SENSE_REG_LEN;
+	}
+
+	for_each_set_bit(cnt, &info->active_channels_mask, info->phys_channels) {
+		info->chip_reg_data.vsense[cnt] = get_unaligned_be16(offset_reg_data_p);
+
+		if (info->chip_reg_data.vsense_mode[cnt] != PAC1944_UNIPOLAR_FSR_CFG)
+			info->chip_reg_data.vsense[cnt] =
+			sign_extend32(info->chip_reg_data.vsense[cnt], 15);
+
+		offset_reg_data_p += PAC1944_VBUS_SENSE_REG_LEN;
+	}
+
+	for_each_set_bit(cnt, &info->active_channels_mask, info->phys_channels) {
+		info->chip_reg_data.vbus_avg[cnt] = get_unaligned_be16(offset_reg_data_p);
+
+		if (info->chip_reg_data.vbus_mode[cnt] != PAC1944_UNIPOLAR_FSR_CFG)
+			info->chip_reg_data.vbus_avg[cnt] =
+			sign_extend32(info->chip_reg_data.vbus_avg[cnt], 15);
+
+		offset_reg_data_p += PAC1944_VBUS_SENSE_REG_LEN;
+	}
+
+	for_each_set_bit(cnt, &info->active_channels_mask, info->phys_channels) {
+		info->chip_reg_data.vsense_avg[cnt] = get_unaligned_be16(offset_reg_data_p);
+
+		if (info->chip_reg_data.vsense_mode[cnt] != PAC1944_UNIPOLAR_FSR_CFG)
+			info->chip_reg_data.vsense_avg[cnt] =
+			sign_extend32(info->chip_reg_data.vsense_avg[cnt], 15);
+
+		offset_reg_data_p += PAC1944_VBUS_SENSE_REG_LEN;
+	}
+
+	for_each_set_bit(cnt, &info->active_channels_mask, info->phys_channels) {
+		info->chip_reg_data.vpower[cnt] = get_unaligned_be32(offset_reg_data_p) >> 2;
+
+		if (info->chip_reg_data.vbus_mode[cnt] != PAC1944_UNIPOLAR_FSR_CFG ||
+		    info->chip_reg_data.vsense_mode[cnt] != PAC1944_UNIPOLAR_FSR_CFG)
+			info->chip_reg_data.vpower[cnt] =
+			sign_extend32(info->chip_reg_data.vpower[cnt], 29);
+
+		offset_reg_data_p += PAC1944_VPOWER_REG_LEN;
+	}
+
+	return 0;
+}
 
+static ssize_t pac1944_in_power_acc_scale_show(struct device *dev,
+					       struct device_attribute *attr,
+					       char *buf)
+{

drivers/iio/adc/pac1944.c new file +9 -0

+
+static ssize_t pac1944_in_enable_acc_store(struct device *dev,
+					   struct device_attribute *attr,
+					   const char *buf, size_t count)
+{
+	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+	struct pac1944_chip_info *info = iio_priv(indio_dev);
+	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
+	int val;

drivers/iio/adc/pac1944.c new file +24 -0

+			info->chip_reg_data.total_samples_nr[this_attr->address] = 0;
+		}
+	}
+
+	return count;
+}
 
+
+static ssize_t pac1944_in_current_acc_scale_show(struct device *dev,
+						 struct device_attribute *attr,
+						 char *buf)
+{
+	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+	struct pac1944_chip_info *info = iio_priv(indio_dev);
+	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
+	int shunt, rem;
+	u64 tmp_u64, ref;
+
+	/*
+	 * Currents - scale for mA - depends on the channel's shunt value
+	 * (100mV * 1000000) / (2^16 * shunt(uOhm))
+	 */
+	ref = (u64)PAC1944_MAX_VSENSE_NANO;
+
+	switch (info->chip_reg_data.vsense_mode[this_attr->address]) {

drivers/iio/adc/pac1944.c new file +37 -0

+	}
+
+	/*
+	 * Increasing precision
+	 * (100mV * 1000000 * 1000000000) / 2^16 )
+	 */
+	tmp_u64 = div_u64(ref, shunt);
+	rem = do_div(tmp_u64, 1000000000LL);
+
+	return sysfs_emit(buf, "%lld.%09u\n", tmp_u64, rem);
+}
 
 
+
+static int pac1944_frequency_set(struct iio_dev *indio_dev,
+				 const struct iio_chan_spec *chan,
+				 unsigned int mode)
+{
+	struct pac1944_chip_info *info = iio_priv(indio_dev);
+	struct i2c_client *client = info->client;
+	int ret;
+	u16 tmp_u16;
+	__be16 tmp_be16;
+
+	ret = i2c_smbus_read_i2c_block_data(client, PAC1944_CTRL_ACT_REG_ADDR,
+					    sizeof(tmp_u16), (u8 *)&tmp_be16);
+	if (ret < 0) {
+		dev_err(&indio_dev->dev, "%s - cannot read PAC1944 regs from 0x%02X\n",
+			__func__, PAC1944_CTRL_ACT_REG_ADDR);
+		return ret;
+	}
+
+	tmp_u16 = be16_to_cpu(tmp_be16);
+	tmp_u16 &= ~PAC1944_CTRL_SAMPLE_MASK;
+	tmp_u16 |= FIELD_PREP(PAC1944_CTRL_SAMPLE_MASK, mode);
+	tmp_be16 = cpu_to_be16(tmp_u16);
+
+	scoped_guard(mutex, &info->lock) {
+		ret = i2c_smbus_write_word_data(client, PAC1944_CTRL_REG_ADDR, tmp_be16);

drivers/iio/adc/pac1944.c new file +3 -0

+
+	return info->sampling_mode;
+}

drivers/iio/adc/pac1944.c new file +4 -0

+};
+
 
 
+static int pac1944_read_thresh(struct iio_dev *indio_dev,
+			       const struct iio_chan_spec *chan, enum iio_event_type type,

drivers/iio/adc/pac1944.c new file +27 -0

+		switch (chan->type) {
+		case IIO_VOLTAGE:
+			switch (dir) {
+			case IIO_EV_DIR_RISING:
+				*val = chip_info->overvoltage[idx];
+				return IIO_VAL_INT;
+			case IIO_EV_DIR_FALLING:
+				*val = chip_info->undervoltage[idx];
+				return IIO_VAL_INT;
+			default:
+				return -EINVAL;
+			}
+		case IIO_CURRENT:
+			switch (dir) {
+			case IIO_EV_DIR_RISING:
+				*val = chip_info->overcurrent[idx];
+				return IIO_VAL_INT;
+			case IIO_EV_DIR_FALLING:
+				*val = chip_info->undercurrent[idx];
+				return IIO_VAL_INT;
+			default:
+				return -EINVAL;
+			}
+		case IIO_POWER:
+			switch (dir) {
+			case IIO_EV_DIR_RISING:
+				*val = chip_info->overpower[idx];

drivers/iio/adc/pac1944.c new file +4 -0

+}
+
+static int pac1944_write_thresh(struct iio_dev *indio_dev,
+				const struct iio_chan_spec *chan, enum iio_event_type type,

drivers/iio/adc/pac1944.c new file +69 -0

+			case IIO_EV_DIR_FALLING:
+				ret = pac1944_update_alert_16b(&indio_dev->dev,
+							       PAC1944_UV_LIMIT_REG_ADDR + idx,
+							       pac1944_undervoltage_mask_tbl[idx],
+							       val);
+				if (!ret)
+					chip_info->undervoltage[idx] = val;
+				return ret;
+			default:
+				return -EINVAL;
+			}
+		case IIO_CURRENT:
+			switch (dir) {
+			case IIO_EV_DIR_RISING:
+				ret = pac1944_update_alert_16b(&indio_dev->dev,
+							       PAC1944_OC_LIMIT_REG_ADDR + idx,
+							       pac1944_overcurrent_mask_tbl[idx],
+							       val);
+				if (!ret)
+					chip_info->overcurrent[idx] = val;
+				return ret;
+			case IIO_EV_DIR_FALLING:
+				ret = pac1944_update_alert_16b(&indio_dev->dev,
+							       PAC1944_UC_LIMIT_REG_ADDR + idx,
+							       pac1944_undercurrent_mask_tbl[idx],
+							       val);
+				if (!ret)
+					chip_info->undercurrent[idx] = val;
+				return ret;
+			default:
+				return -EINVAL;
+			}
+		case IIO_POWER:
+			switch (dir) {
+			case IIO_EV_DIR_RISING:
+				ret = pac1944_update_alert_24b(&indio_dev->dev,
+							       PAC1944_OP_LIMIT_REG_ADDR + idx,
+							       pac1944_overpower_mask_tbl[idx],
+							       val);
+				if (!ret)
+					chip_info->overpower[idx] = val;
+				return ret;
+			default:
+				return -EINVAL;
+			}
+		default:
+			return -EINVAL;
+		}
+	}
+	unreachable();
+}
 
+static int pac1944_write_event_config(struct iio_dev *indio_dev,
+				      const struct iio_chan_spec *chan,
+				      enum iio_event_type type,
+				      enum iio_event_direction dir,
+				      bool state)
+{
+	struct pac1944_chip_info *info = iio_priv(indio_dev);
+	struct i2c_client *client = info->client;
+	int idx, val, mask, ret;
+	bool update = false;
+	u8 tmp[PAC1944_ALERT_ENABLE_REG_LEN];
+
+	/* into the datasheet channels are noted from 1 to 4 */
+	idx = chan->channel - 1;
+
+	switch (chan->type) {
+	case IIO_VOLTAGE:
+		switch (dir) {

drivers/iio/adc/pac1944.c new file +7 -0

+	case IIO_CURRENT:
+		switch (dir) {
+		case IIO_EV_DIR_RISING:
+			mask = pac1944_overcurrent_mask_tbl[idx];
+			break;
+		case IIO_EV_DIR_FALLING:
+			mask = pac1944_undercurrent_mask_tbl[idx];

drivers/iio/adc/pac1944.c new file +2 -0

+		break;
+	default:

drivers/iio/adc/pac1944.c new file +45 -0

+	struct i2c_client *client = info->client;
+
+	dev_dbg(&client->dev, "%s - Periodic refresh\n", __func__);
+
+	pac1944_reg_snapshot(info, true, PAC1944_REFRESH_REG_ADDR,
+			     PAC1944_MIN_UPDATE_WAIT_TIME_US);
+
+	schedule_delayed_work(&info->work_chip_rfsh,
+			      msecs_to_jiffies(PAC1944_MAX_RFSH_LIMIT_MS));
+}
+
+/*
+ * documentation related to the ACPI device definition
+ * https://ww1.microchip.com/downloads/aemDocuments/documents/MSLD/ProductDocuments/UserGuides/PAC194X_5X-UEFI-BIOS-Integration-and-Microsoft-Windows-10-and-Windows-11-Energy-Meter-Interface-Device-Driver-Users-Guide-DS50003155.pdf
+ */
+static int pac1944_acpi_parse_channel_config(struct i2c_client *client,
+					     struct pac1944_chip_info *info)
+{
+	acpi_handle handle;
+	union acpi_object *rez;
+	struct device *dev = &client->dev;
+	unsigned short bi_dir_mask;
+	int i;
+	guid_t guid;
+	const struct acpi_device_id *id;
+
+	handle = ACPI_HANDLE(dev);
+
+	id = acpi_match_device(dev->driver->acpi_match_table, dev);
+	if (!id)
+		return -ENODEV;
+
+	guid_parse(PAC1944_DSM_UUID, &guid);
+
+	rez = acpi_evaluate_dsm(handle, &guid, 0, PAC1944_ACPI_GET_NAMES, NULL);
+	if (!rez)
+		return -EINVAL;
+
+	for (i = 0; i < rez->package.count; i++) {
+		info->labels[i] = devm_kmemdup(dev, rez->package.elements[i].string.pointer,
+					       (size_t)rez->package.elements[i].string.length + 1,
+					       GFP_KERNEL);
+		info->labels[i][rez->package.elements[i].string.length] = '\0';
+	}
+

drivers/iio/adc/pac1944.c new file +12 -0

+
+static int pac1944_of_parse_channel_config(struct i2c_client *client,
+					   struct pac1944_chip_info *info)
+{
+	unsigned int current_channel;
+	struct device *dev = &client->dev;
+	int idx, ret, temp;
+
+	current_channel = 1;
+
+	device_for_each_child_node_scoped(dev, child) {
+		ret = fwnode_property_read_u32(child, "reg", &idx);

drivers/iio/adc/pac1944.c new file +2 -0

+
+		/* enable channel */

drivers/iio/adc/pac1944.c new file +16 -0

+
+static int pac1944_prep_iio_channels(struct pac1944_chip_info *info,
+				     struct iio_dev *indio_dev)
+{
+	struct device *dev = &info->client->dev;
+	struct iio_chan_spec *ch_sp;
+	int channel_size, attribute_count, cnt;
+	void *dyn_ch_struct;
+
+	/* Finding out dynamically how many IIO channels we need */
+	attribute_count = 0;
+	channel_size = 0;
+
+	for_each_set_bit(cnt, &info->active_channels_mask, info->phys_channels) {
+		/* add the size of the properties of one chip physical channel */
+		channel_size += sizeof(pac1944_single_channel);

drivers/iio/adc/pac1944.c new file +16 -0

+	/* Populate the dynamic channels and make all the adjustments */
+	for_each_set_bit(cnt, &info->active_channels_mask, info->phys_channels) {
+		memcpy(ch_sp, pac1944_single_channel, sizeof(pac1944_single_channel));
+		/*
+		 * Into the datasheet channels are noted from 1 to 4 so we will adjust
+		 * the channel to match channel index (1 to 4) from the datasheet
+		 */
+		ch_sp[PAC1944_CH_POWER].channel = cnt + 1;
+		ch_sp[PAC1944_CH_POWER].address = cnt + PAC1944_VPOWER_1_ADDR;
+		ch_sp[PAC1944_CH_VOLTAGE].channel = cnt + 1;
+		ch_sp[PAC1944_CH_VOLTAGE].address = cnt + PAC1944_VBUS_1_ADDR;
+		ch_sp[PAC1944_CH_CURRENT].channel = cnt + 1;
+		ch_sp[PAC1944_CH_CURRENT].address = cnt + PAC1944_VSENSE_1_ADDR;
+		/*
+		 * In order to be able to use labels for PAC1944_CH_VOLTAGE and
+		 * PAC1944_CH_VOLTAGE_AVERAGE, respectively PAC1944_CH_CURRENT

drivers/iio/adc/pac1944.c new file +23 -0

+
+	return 0;
+}
 
 
+static int pac1944_probe(struct i2c_client *client)
+{
+	struct pac1944_chip_info *info;
+	struct iio_dev *indio_dev;
+	const struct pac1944_features *chip;
+	int cnt, ret;
+	struct device *dev = &client->dev;
+
+	indio_dev = devm_iio_device_alloc(dev, sizeof(*info));
+	if (!indio_dev)
+		return -ENOMEM;
+
+	info = iio_priv(indio_dev);
+	info->client = client;
+
+	ret = pac1944_chip_identify(info);
+	if (ret < 0) {
+		/*
+		 * If failed to identify the hardware based on internal
+		 * registers, try using fallback compatible in device

drivers/iio/adc/pac1944.c new file +3 -0

+		info->phys_channels = pac1944_chip_config[ret].phys_channels;
+		indio_dev->name = pac1944_chip_config[ret].name;
+	}

drivers/iio/adc/pac1944.c new file +6 -0

+}
+
+static const struct i2c_device_id pac1944_id[] = {
+	{ .name = "pac1941", .driver_data = (kernel_ulong_t)&pac1944_chip_config[PAC1941] },
+	{ .name = "pac19412", .driver_data = (kernel_ulong_t)&pac1944_chip_config[PAC1941_2] },
+	{ .name = "pac1942", .driver_data = (kernel_ulong_t)&pac1944_chip_config[PAC1942] },

drivers/iio/adc/pac1944.c new file +8 -0

+};
+MODULE_DEVICE_TABLE(i2c, pac1944_id);
+
+static const struct of_device_id pac1944_of_match[] = {
+	{
+		.compatible = "microchip,pac1941",
+		.data = (void *)&pac1944_chip_config[PAC1941]
+	},

+module_i2c_driver(pac1944_driver);