[PATCH v7 0/3] Add Richtek RTQ6056 support

[PATCH v7 0/3] Add Richtek RTQ6056 support

[cy_huang]

From: ChiYuan Huang <cy_huang@richtek.com>

This patch series is to enable Richtek RTQ6056 support.

The RTQ6056 is a high accuracy current-sense monitor with I2C interface, and
the device provides full information for system by reading out the load current
and power.

Since v7
- Use 'DEFINE_RUNTIME_DEV_PM_OPS' to replace the explicit declaration of pm_ops.

Since v6
- Remove specific rtq6056 ABI document.
- Update integration time description in general ABI document.
- Remove the redundant blank line.
- To prevent the race condition for attribute wrtie and shunt resistor write,
  use 'iio_device_claim_direct_mode' API.
- Refine the order for 'action_reset' and 'pm_runtime'.
- Fix text typo in comment like as ohm to Ohm and timea to time.

Since v5
- Fix kernel version text for ABI.

Since v4
- Add '__aligned(8)' for timestamp member.
- Declare timestamp from 'int64_t' to more unified 's64'.

Since v3
- change the node name to be generic 'adc' in binding example.
- Refine pm_runtime API calling order in 'read_channel' API.
- Fix vshunt wrong scale for divider.
- Refine the comment text.
- Use 'devm_add_action_or_reset' to decrease the code usage in probe
  function.
- Use RUNTIME_PM_OPS to replace SET_RUNTIME_PM_OPS.
- minor fix for the comma.
- Use pm_ptr to replace the direct assigned pm_ops.

Since v2
- Change the resistor property name to be generic 'shunt-resistor-micro-ohms'.
- Rename file from 'rtq6056-adc' to 'rtq6056'.
- Refine the ABI, if generic already defined it, remove it and check the channel
  report unit.
- Add copyright text.
- include the correct header.
- change the property parsing name.
- To use iio_chan_spec address field.
- Refine each channel separate and shared_by_all.
- Use pm_runtime and pm_runtime_autosuspend.
- Remove the shutdown callback. From the HW suggestion, it's not recommended to
  use battery as the power supply.
- Check all scale unit (voltage->mV, current->mA, power->milliWatt).
- Use the read_avail to provide the interface for attribute value list.
- Add comma for the last element in the const integer array.
- Refine each ADC label text.
- In read_label callback, replace snprintf to sysfs_emit.

ChiYuan Huang (3):
  dt-bindings: iio: adc: Add rtq6056 adc support
  iio: adc: Add rtq6056 support
  Documentation: ABI: testing: rtq6056: Update ABI docs

 Documentation/ABI/testing/sysfs-bus-iio            |  10 +
 .../bindings/iio/adc/richtek,rtq6056.yaml          |  56 ++
 drivers/iio/adc/Kconfig                            |  15 +
 drivers/iio/adc/Makefile                           |   1 +
 drivers/iio/adc/rtq6056.c                          | 663 +++++++++++++++++++++
 5 files changed, 745 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/iio/adc/richtek,rtq6056.yaml
 create mode 100644 drivers/iio/adc/rtq6056.c

-- 
2.7.4

[PATCH v7 1/3] dt-bindings: iio: adc: Add rtq6056 adc support

[cy_huang]

From: ChiYuan Huang <cy_huang@richtek.com>

Add the documentation for Richtek rtq6056.

Signed-off-by: ChiYuan Huang <cy_huang@richtek.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
---
Since v3
- change the node name to be generic 'adc' in binding example.

Since v2
- Change the resistor property name to be generic 'shunt-resistor-micro-ohms'.

---
 .../bindings/iio/adc/richtek,rtq6056.yaml          | 56 ++++++++++++++++++++++
 1 file changed, 56 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/iio/adc/richtek,rtq6056.yaml

diff --git a/Documentation/devicetree/bindings/iio/adc/richtek,rtq6056.yaml b/Documentation/devicetree/bindings/iio/adc/richtek,rtq6056.yaml
new file mode 100644
index 00000000..88e0086
--- /dev/null
+++ b/Documentation/devicetree/bindings/iio/adc/richtek,rtq6056.yaml
@@ -0,0 +1,56 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/iio/adc/richtek,rtq6056.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: RTQ6056 Bi-Directional Current and Power Monitor with 16-bit ADC
+
+maintainers:
+  - ChiYuan Huang <cy_huang@richtek.com>
+
+description: |
+  The RTQ6056 is a high accuracy current-sense monitor with I2C and SMBus
+  interface, and the device provides full information for system by reading
+  out the loading current and power.
+
+  The device monitors both of the drops across sense resistor and the BUS
+  voltage, converts into the current in amperes, and power in watts through
+  internal analog-to-digital converter ADC. The programmable calibration,
+  adjustable conversion time, and averaging function are also built in for
+  more design flexibility.
+
+  Datasheet is available at
+  https://www.richtek.com/assets/product_file/RTQ6056/DSQ6056-00.pdf
+
+properties:
+  compatible:
+    const: richtek,rtq6056
+
+  reg:
+    maxItems: 1
+
+  "#io-channel-cells":
+    const: 1
+
+  shunt-resistor-micro-ohms:
+    description: Shunt IN+/IN- sensing node resistor
+
+required:
+  - compatible
+  - reg
+  - "#io-channel-cells"
+
+additionalProperties: false
+
+examples:
+  - |
+    i2c {
+      #address-cells = <1>;
+      #size-cells = <0>;
+      adc@40 {
+        compatible = "richtek,rtq6056";
+        reg = <0x40>;
+        #io-channel-cells = <1>;
+      };
+    };
-- 
2.7.4

[PATCH v7 2/3] iio: adc: Add rtq6056 support

[cy_huang]

From: ChiYuan Huang <cy_huang@richtek.com>

Add Richtek rtq6056 supporting.

It can be used for the system to monitor load current and power with 16-bit
resolution.

Signed-off-by: ChiYuan Huang <cy_huang@richtek.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
---
Since v7
- Use 'DEFINE_RUNTIME_DEV_PM_OPS' to replace the explicit declaration of pm_ops.

Since v6
- Remove specific rtq6056 ABI document.
- Remove the redundant blank line.
- To prevent the race condition for attribute wrtie and shunt resistor write,
  use 'iio_device_claim_direct_mode' API.
- Refine the order for 'action_reset' and 'pm_runtime'.
- Fix text typo in comment like as ohm to Ohm and timea to time.

Since v5
- Fix kernel version text for ABI.

Since v4
- Add '__aligned(8)' for timestamp member in buffer_trigger_handler function.
- Declare timestamp from 'int64_t' to more unified 's64'.

Since v3
- Refine pm_runtime API calling order in 'read_channel' API.
- Fix vshunt wrong scale for divider.
- Refine the comment text.
- Use 'devm_add_action_or_reset' to decrease the code usage in probe
  function.
- Use RUNTIME_PM_OPS to replace SET_RUNTIME_PM_OPS.
- minor fix for the comma.
- Use pm_ptr to replace the direct assigned pm_ops.

Since v2
- Rename file from 'rtq6056-adc' to 'rtq6056'.
- Refine the ABI, if generic already defined it, remove it and check the channel
  report unit.
- Add copyright text.
- include the correct header.
- change the property parsing name.
- To use iio_chan_spec address field.
- Refine each channel separate and shared_by_all.
- Use pm_runtime and pm_runtime_autosuspend.
- Remove the shutdown callback. From the HW suggestion, it's not recommended to
  use battery as the power supply.
- Check all scale unit (voltage->mV, current->mA, power->milliWatt).
- Use the read_avail to provide the interface for attribute value list.
- Add comma for the last element in the const integer array.
- Refine each ADC label text.
- In read_label callback, replace snprintf to sysfs_emit.

---
 drivers/iio/adc/Kconfig   |  15 ++
 drivers/iio/adc/Makefile  |   1 +
 drivers/iio/adc/rtq6056.c | 663 ++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 679 insertions(+)
 create mode 100644 drivers/iio/adc/rtq6056.c

diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index 48ace74..caebd1a 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -908,6 +908,21 @@ config ROCKCHIP_SARADC
 	  To compile this driver as a module, choose M here: the
 	  module will be called rockchip_saradc.
 
+config RICHTEK_RTQ6056
+	tristate "Richtek RTQ6056 Current and Power Monitor ADC"
+	depends on I2C
+	select REGMAP_I2C
+	select IIO_BUFFER
+	select IIO_TRIGGERED_BUFFER
+	help
+	  Say yes here to enable RQT6056 ADC support.
+	  RTQ6056 is a high accuracy current-sense monitor with I2C and SMBus
+	  compatible interface, and the device provides full information for
+	  system by reading out the load current and power.
+
+	  This driver can also be built as a module. If so, the module will be
+	  called rtq6056.
+
 config RZG2L_ADC
 	tristate "Renesas RZ/G2L ADC driver"
 	depends on ARCH_RZG2L || COMPILE_TEST
diff --git a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile
index 39d806f..cda7580 100644
--- a/drivers/iio/adc/Makefile
+++ b/drivers/iio/adc/Makefile
@@ -84,6 +84,7 @@ obj-$(CONFIG_QCOM_PM8XXX_XOADC) += qcom-pm8xxx-xoadc.o
 obj-$(CONFIG_RCAR_GYRO_ADC) += rcar-gyroadc.o
 obj-$(CONFIG_RN5T618_ADC) += rn5t618-adc.o
 obj-$(CONFIG_ROCKCHIP_SARADC) += rockchip_saradc.o
+obj-$(CONFIG_RICHTEK_RTQ6056) += rtq6056.o
 obj-$(CONFIG_RZG2L_ADC) += rzg2l_adc.o
 obj-$(CONFIG_SC27XX_ADC) += sc27xx_adc.o
 obj-$(CONFIG_SPEAR_ADC) += spear_adc.o
diff --git a/drivers/iio/adc/rtq6056.c b/drivers/iio/adc/rtq6056.c
new file mode 100644
index 00000000..7c843cf
--- /dev/null
+++ b/drivers/iio/adc/rtq6056.c
@@ -0,0 +1,663 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2022 Richtek Technology Corp.
+ *
+ * ChiYuan Huang <cy_huang@richtek.com>
+ */
+
+#include <linux/bitops.h>
+#include <linux/delay.h>
+#include <linux/i2c.h>
+#include <linux/kernel.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/pm_runtime.h>
+#include <linux/property.h>
+#include <linux/regmap.h>
+#include <linux/sysfs.h>
+#include <linux/types.h>
+#include <linux/util_macros.h>
+
+#include <linux/iio/buffer.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+#include <linux/iio/trigger_consumer.h>
+#include <linux/iio/triggered_buffer.h>
+
+#define RTQ6056_REG_CONFIG	0x00
+#define RTQ6056_REG_SHUNTVOLT	0x01
+#define RTQ6056_REG_BUSVOLT	0x02
+#define RTQ6056_REG_POWER	0x03
+#define RTQ6056_REG_CURRENT	0x04
+#define RTQ6056_REG_CALIBRATION	0x05
+#define RTQ6056_REG_MASKENABLE	0x06
+#define RTQ6056_REG_ALERTLIMIT	0x07
+#define RTQ6056_REG_MANUFACTID	0xFE
+#define RTQ6056_REG_DIEID	0xFF
+
+#define RTQ6056_VENDOR_ID	0x1214
+#define RTQ6056_DEFAULT_CONFIG	0x4127
+#define RTQ6056_CONT_ALLON	7
+
+enum {
+	RTQ6056_CH_VSHUNT = 0,
+	RTQ6056_CH_VBUS,
+	RTQ6056_CH_POWER,
+	RTQ6056_CH_CURRENT,
+	RTQ6056_MAX_CHANNEL
+};
+
+enum {
+	F_OPMODE = 0,
+	F_VSHUNTCT,
+	F_VBUSCT,
+	F_AVG,
+	F_RESET,
+	F_MAX_FIELDS
+};
+
+struct rtq6056_priv {
+	struct device *dev;
+	struct regmap *regmap;
+	struct regmap_field *rm_fields[F_MAX_FIELDS];
+	u32 shunt_resistor_uohm;
+	int vshuntct_us;
+	int vbusct_us;
+	int avg_sample;
+};
+
+static const struct reg_field rtq6056_reg_fields[F_MAX_FIELDS] = {
+	[F_OPMODE] = REG_FIELD(RTQ6056_REG_CONFIG, 0, 2),
+	[F_VSHUNTCT] = REG_FIELD(RTQ6056_REG_CONFIG, 3, 5),
+	[F_VBUSCT] = REG_FIELD(RTQ6056_REG_CONFIG, 6, 8),
+	[F_AVG]	= REG_FIELD(RTQ6056_REG_CONFIG, 9, 11),
+	[F_RESET] = REG_FIELD(RTQ6056_REG_CONFIG, 15, 15),
+};
+
+static const struct iio_chan_spec rtq6056_channels[RTQ6056_MAX_CHANNEL + 1] = {
+	{
+		.type = IIO_VOLTAGE,
+		.indexed = 1,
+		.channel = 0,
+		.address = RTQ6056_REG_SHUNTVOLT,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+				      BIT(IIO_CHAN_INFO_SCALE) |
+				      BIT(IIO_CHAN_INFO_INT_TIME),
+		.info_mask_separate_available = BIT(IIO_CHAN_INFO_INT_TIME),
+		.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ) |
+					   BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO),
+		.info_mask_shared_by_all_available = BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO),
+		.scan_index = 0,
+		.scan_type = {
+			.sign = 's',
+			.realbits = 16,
+			.storagebits = 16,
+			.endianness = IIO_CPU,
+		},
+	},
+	{
+		.type = IIO_VOLTAGE,
+		.indexed = 1,
+		.channel = 1,
+		.address = RTQ6056_REG_BUSVOLT,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+				      BIT(IIO_CHAN_INFO_SCALE) |
+				      BIT(IIO_CHAN_INFO_INT_TIME),
+		.info_mask_separate_available = BIT(IIO_CHAN_INFO_INT_TIME),
+		.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ) |
+					   BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO),
+		.info_mask_shared_by_all_available = BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO),
+		.scan_index = 1,
+		.scan_type = {
+			.sign = 'u',
+			.realbits = 16,
+			.storagebits = 16,
+			.endianness = IIO_CPU,
+		},
+	},
+	{
+		.type = IIO_POWER,
+		.indexed = 1,
+		.channel = 2,
+		.address = RTQ6056_REG_POWER,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
+				      BIT(IIO_CHAN_INFO_SCALE),
+		.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ) |
+					   BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO),
+		.info_mask_shared_by_all_available = BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO),
+		.scan_index = 2,
+		.scan_type = {
+			.sign = 'u',
+			.realbits = 16,
+			.storagebits = 16,
+			.endianness = IIO_CPU,
+		},
+	},
+	{
+		.type = IIO_CURRENT,
+		.indexed = 1,
+		.channel = 3,
+		.address = RTQ6056_REG_CURRENT,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
+		.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ) |
+					   BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO),
+		.info_mask_shared_by_all_available = BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO),
+		.scan_index = 3,
+		.scan_type = {
+			.sign = 's',
+			.realbits = 16,
+			.storagebits = 16,
+			.endianness = IIO_CPU,
+		},
+	},
+	IIO_CHAN_SOFT_TIMESTAMP(RTQ6056_MAX_CHANNEL),
+};
+
+static int rtq6056_adc_read_channel(struct rtq6056_priv *priv,
+				    struct iio_chan_spec const *ch,
+				    int *val)
+{
+	struct device *dev = priv->dev;
+	unsigned int addr = ch->address;
+	unsigned int regval;
+	int ret;
+
+	pm_runtime_get_sync(dev);
+	ret = regmap_read(priv->regmap, addr, &regval);
+	pm_runtime_mark_last_busy(dev);
+	pm_runtime_put(dev);
+	if (ret)
+		return ret;
+
+	/* Power and VBUS is unsigned 16-bit, others are signed 16-bit */
+	if (addr == RTQ6056_REG_BUSVOLT || addr == RTQ6056_REG_POWER)
+		*val = regval;
+	else
+		*val = sign_extend32(regval, 16);
+
+	return IIO_VAL_INT;
+}
+
+static int rtq6056_adc_read_scale(struct iio_chan_spec const *ch, int *val,
+				  int *val2)
+{
+	switch (ch->address) {
+	case RTQ6056_REG_SHUNTVOLT:
+		/* VSHUNT lsb  2.5uV */
+		*val = 2500;
+		*val2 = 1000000;
+		return IIO_VAL_FRACTIONAL;
+	case RTQ6056_REG_BUSVOLT:
+		/* VBUS lsb 1.25mV */
+		*val = 1250;
+		*val2 = 1000;
+		return IIO_VAL_FRACTIONAL;
+	case RTQ6056_REG_POWER:
+		/* Power lsb 25mW */
+		*val = 25;
+		return IIO_VAL_INT;
+	default:
+		return -EINVAL;
+	}
+}
+
+/*
+ * Conversion time in uS for channel VSHUNT and VBUS. The indices correspond
+ * with the bit value expected by the chip. And it can be found at
+ * https://www.richtek.com/assets/product_file/RTQ6056/DSQ6056-00.pdf
+ */
+static const int rtq6056_conv_time_list[] = {
+	139, 203, 269, 525, 1037, 2061, 4109, 8205,
+};
+
+static int rtq6056_adc_set_conv_time(struct rtq6056_priv *priv,
+				     struct iio_chan_spec const *ch,
+				     int val)
+{
+	struct regmap_field *rm_field;
+	unsigned int selector;
+	int *ct, ret;
+
+	if (val > 8205 || val < 139)
+		return -EINVAL;
+
+	if (ch->address == RTQ6056_REG_SHUNTVOLT) {
+		rm_field = priv->rm_fields[F_VSHUNTCT];
+		ct = &priv->vshuntct_us;
+	} else {
+		rm_field = priv->rm_fields[F_VBUSCT];
+		ct = &priv->vbusct_us;
+	}
+
+	selector = find_closest(val, rtq6056_conv_time_list,
+				ARRAY_SIZE(rtq6056_conv_time_list));
+
+	ret = regmap_field_write(rm_field, selector);
+	if (ret)
+		return ret;
+
+	*ct = rtq6056_conv_time_list[selector];
+
+	return 0;
+}
+
+/*
+ * Available averaging rate for rtq6056. The indices correspond with the bit
+ * value expected by the chip. And it can be found at
+ * https://www.richtek.com/assets/product_file/RTQ6056/DSQ6056-00.pdf
+ */
+static const int rtq6056_avg_sample_list[] = {
+	1, 4, 16, 64, 128, 256, 512, 1024,
+};
+
+static int rtq6056_adc_set_average(struct rtq6056_priv *priv, int val)
+{
+	unsigned int selector;
+	int ret;
+
+	if (val > 1024 || val < 1)
+		return -EINVAL;
+
+	selector = find_closest(val, rtq6056_avg_sample_list,
+				ARRAY_SIZE(rtq6056_avg_sample_list));
+
+	ret = regmap_field_write(priv->rm_fields[F_AVG], selector);
+	if (ret)
+		return ret;
+
+	priv->avg_sample = rtq6056_avg_sample_list[selector];
+
+	return 0;
+}
+
+static int rtq6056_adc_get_sample_freq(struct rtq6056_priv *priv, int *val)
+{
+	int sample_time;
+
+	sample_time = priv->vshuntct_us + priv->vbusct_us;
+	sample_time *= priv->avg_sample;
+
+	*val = DIV_ROUND_UP(1000000, sample_time);
+
+	return IIO_VAL_INT;
+}
+
+static int rtq6056_adc_read_raw(struct iio_dev *indio_dev,
+				struct iio_chan_spec const *chan, int *val,
+				int *val2, long mask)
+{
+	struct rtq6056_priv *priv = iio_priv(indio_dev);
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		return rtq6056_adc_read_channel(priv, chan, val);
+	case IIO_CHAN_INFO_SCALE:
+		return rtq6056_adc_read_scale(chan, val, val2);
+	case IIO_CHAN_INFO_INT_TIME:
+		if (chan->address == RTQ6056_REG_SHUNTVOLT)
+			*val = priv->vshuntct_us;
+		else
+			*val = priv->vbusct_us;
+
+		return IIO_VAL_INT;
+	case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
+		*val = priv->avg_sample;
+		return IIO_VAL_INT;
+	case IIO_CHAN_INFO_SAMP_FREQ:
+		return rtq6056_adc_get_sample_freq(priv, val);
+	default:
+		return -EINVAL;
+	}
+}
+
+static int rtq6056_adc_read_avail(struct iio_dev *indio_dev,
+				  struct iio_chan_spec const *chan,
+				  const int **vals, int *type, int *length,
+				  long mask)
+{
+	switch (mask) {
+	case IIO_CHAN_INFO_INT_TIME:
+		*vals = rtq6056_conv_time_list;
+		*type = IIO_VAL_INT;
+		*length = ARRAY_SIZE(rtq6056_conv_time_list);
+		return IIO_AVAIL_LIST;
+	case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
+		*vals = rtq6056_avg_sample_list;
+		*type = IIO_VAL_INT;
+		*length = ARRAY_SIZE(rtq6056_avg_sample_list);
+		return IIO_AVAIL_LIST;
+	default:
+		return -EINVAL;
+	}
+}
+
+static int rtq6056_adc_write_raw(struct iio_dev *indio_dev,
+				 struct iio_chan_spec const *chan, int val,
+				 int val2, long mask)
+{
+	struct rtq6056_priv *priv = iio_priv(indio_dev);
+	int ret;
+
+	ret = iio_device_claim_direct_mode(indio_dev);
+	if (ret)
+		return ret;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_INT_TIME:
+		ret = rtq6056_adc_set_conv_time(priv, chan, val);
+		break;
+	case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
+		ret = rtq6056_adc_set_average(priv, val);
+		break;
+	default:
+		ret = -EINVAL;
+		break;
+	}
+
+	iio_device_release_direct_mode(indio_dev);
+
+	return ret;
+}
+
+static const char *rtq6056_channel_labels[RTQ6056_MAX_CHANNEL] = {
+	[RTQ6056_CH_VSHUNT] = "Vshunt",
+	[RTQ6056_CH_VBUS] = "Vbus",
+	[RTQ6056_CH_POWER] = "Power",
+	[RTQ6056_CH_CURRENT] = "Current",
+};
+
+static int rtq6056_adc_read_label(struct iio_dev *indio_dev,
+				  struct iio_chan_spec const *chan,
+				  char *label)
+{
+	return sysfs_emit(label, "%s\n", rtq6056_channel_labels[chan->channel]);
+}
+
+static int rtq6056_set_shunt_resistor(struct rtq6056_priv *priv,
+				      int resistor_uohm)
+{
+	unsigned int calib_val;
+	int ret;
+
+	if (resistor_uohm <= 0) {
+		dev_err(priv->dev, "Invalid resistor [%d]\n", resistor_uohm);
+		return -EINVAL;
+	}
+
+	/* calibration = 5120000 / (Rshunt (uOhm) * current lsb (1mA)) */
+	calib_val = 5120000 / resistor_uohm;
+	ret = regmap_write(priv->regmap, RTQ6056_REG_CALIBRATION, calib_val);
+	if (ret)
+		return ret;
+
+	priv->shunt_resistor_uohm = resistor_uohm;
+
+	return 0;
+}
+
+static ssize_t shunt_resistor_show(struct device *dev,
+				   struct device_attribute *attr, char *buf)
+{
+	struct rtq6056_priv *priv = iio_priv(dev_to_iio_dev(dev));
+	int vals[2] = { priv->shunt_resistor_uohm, 1000000 };
+
+	return iio_format_value(buf, IIO_VAL_FRACTIONAL, 1, vals);
+}
+
+static ssize_t shunt_resistor_store(struct device *dev,
+				    struct device_attribute *attr,
+				    const char *buf, size_t len)
+{
+	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+	struct rtq6056_priv *priv = iio_priv(indio_dev);
+	int val, val_fract, ret;
+
+	ret = iio_device_claim_direct_mode(indio_dev);
+	if (ret)
+		return ret;
+
+	ret = iio_str_to_fixpoint(buf, 100000, &val, &val_fract);
+	if (ret)
+		goto out_store;
+
+	ret = rtq6056_set_shunt_resistor(priv, val * 1000000 + val_fract);
+
+out_store:
+	iio_device_release_direct_mode(indio_dev);
+
+	return ret ?: len;
+}
+
+static IIO_DEVICE_ATTR_RW(shunt_resistor, 0);
+
+static struct attribute *rtq6056_attributes[] = {
+	&iio_dev_attr_shunt_resistor.dev_attr.attr,
+	NULL
+};
+
+static const struct attribute_group rtq6056_attribute_group = {
+	.attrs = rtq6056_attributes,
+};
+
+static const struct iio_info rtq6056_info = {
+	.attrs = &rtq6056_attribute_group,
+	.read_raw = rtq6056_adc_read_raw,
+	.read_avail = rtq6056_adc_read_avail,
+	.write_raw = rtq6056_adc_write_raw,
+	.read_label = rtq6056_adc_read_label,
+};
+
+static irqreturn_t rtq6056_buffer_trigger_handler(int irq, void *p)
+{
+	struct iio_poll_func *pf = p;
+	struct iio_dev *indio_dev = pf->indio_dev;
+	struct rtq6056_priv *priv = iio_priv(indio_dev);
+	struct device *dev = priv->dev;
+	struct {
+		u16 vals[RTQ6056_MAX_CHANNEL];
+		s64 timestamp __aligned(8);
+	} data;
+	unsigned int raw;
+	int i = 0, bit, ret;
+
+	memset(&data, 0, sizeof(data));
+
+	pm_runtime_get_sync(dev);
+
+	for_each_set_bit(bit, indio_dev->active_scan_mask, indio_dev->masklength) {
+		unsigned int addr = rtq6056_channels[bit].address;
+
+		ret = regmap_read(priv->regmap, addr, &raw);
+		if (ret)
+			goto out;
+
+		data.vals[i++] = raw;
+	}
+
+	iio_push_to_buffers_with_timestamp(indio_dev, &data, iio_get_time_ns(indio_dev));
+
+out:
+	pm_runtime_mark_last_busy(dev);
+	pm_runtime_put(dev);
+
+	iio_trigger_notify_done(indio_dev->trig);
+
+	return IRQ_HANDLED;
+}
+
+static void rtq6056_enter_shutdown_state(void *dev)
+{
+	struct rtq6056_priv *priv = dev_get_drvdata(dev);
+
+	/* Enter shutdown state */
+	regmap_field_write(priv->rm_fields[F_OPMODE], 0);
+}
+
+static bool rtq6056_is_readable_reg(struct device *dev, unsigned int reg)
+{
+	switch (reg) {
+	case RTQ6056_REG_CONFIG ... RTQ6056_REG_ALERTLIMIT:
+	case RTQ6056_REG_MANUFACTID ... RTQ6056_REG_DIEID:
+		return true;
+	default:
+		return false;
+	}
+}
+
+static bool rtq6056_is_writeable_reg(struct device *dev, unsigned int reg)
+{
+	switch (reg) {
+	case RTQ6056_REG_CONFIG:
+	case RTQ6056_REG_CALIBRATION ... RTQ6056_REG_ALERTLIMIT:
+		return true;
+	default:
+		return false;
+	}
+}
+
+static const struct regmap_config rtq6056_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 16,
+	.val_format_endian = REGMAP_ENDIAN_BIG,
+	.max_register = RTQ6056_REG_DIEID,
+	.readable_reg = rtq6056_is_readable_reg,
+	.writeable_reg = rtq6056_is_writeable_reg,
+};
+
+static int rtq6056_probe(struct i2c_client *i2c)
+{
+	struct iio_dev *indio_dev;
+	struct rtq6056_priv *priv;
+	struct device *dev = &i2c->dev;
+	struct regmap *regmap;
+	unsigned int vendor_id, shunt_resistor_uohm;
+	int ret;
+
+	if (!i2c_check_functionality(i2c->adapter, I2C_FUNC_SMBUS_WORD_DATA))
+		return -EOPNOTSUPP;
+
+	indio_dev = devm_iio_device_alloc(dev, sizeof(*priv));
+	if (!indio_dev)
+		return -ENOMEM;
+
+	priv = iio_priv(indio_dev);
+	priv->dev = dev;
+	priv->vshuntct_us = priv->vbusct_us = 1037;
+	priv->avg_sample = 1;
+	i2c_set_clientdata(i2c, priv);
+
+	regmap = devm_regmap_init_i2c(i2c, &rtq6056_regmap_config);
+	if (IS_ERR(regmap))
+		return dev_err_probe(dev, PTR_ERR(regmap),
+				     "Failed to init regmap\n");
+
+	priv->regmap = regmap;
+
+	ret = regmap_read(regmap, RTQ6056_REG_MANUFACTID, &vendor_id);
+	if (ret)
+		return dev_err_probe(dev, ret,
+				     "Failed to get manufacturer info\n");
+
+	if (vendor_id != RTQ6056_VENDOR_ID)
+		return dev_err_probe(dev, -ENODEV,
+				     "Invalid vendor id 0x%04x\n", vendor_id);
+
+	ret = devm_regmap_field_bulk_alloc(dev, regmap, priv->rm_fields,
+					   rtq6056_reg_fields, F_MAX_FIELDS);
+	if (ret)
+		return dev_err_probe(dev, ret, "Failed to init regmap field\n");
+
+	/*
+	 * By default, configure average sample as 1, bus and shunt conversion
+	 * time as 1037 microsecond, and operating mode to all on.
+	 */
+	ret = regmap_write(regmap, RTQ6056_REG_CONFIG, RTQ6056_DEFAULT_CONFIG);
+	if (ret)
+		return dev_err_probe(dev, ret,
+				     "Failed to enable continuous sensing\n");
+
+	ret = devm_add_action_or_reset(dev, rtq6056_enter_shutdown_state, dev);
+	if (ret)
+		return ret;
+
+	pm_runtime_set_autosuspend_delay(dev, MSEC_PER_SEC);
+	pm_runtime_use_autosuspend(dev);
+	pm_runtime_set_active(dev);
+	pm_runtime_mark_last_busy(dev);
+	ret = devm_pm_runtime_enable(dev);
+	if (ret)
+		return dev_err_probe(dev, ret, "Failed to enable pm_runtime\n");
+
+	/* By default, use 2000 micro-Ohm resistor */
+	shunt_resistor_uohm = 2000;
+	device_property_read_u32(dev, "shunt-resistor-micro-ohms",
+				 &shunt_resistor_uohm);
+
+	ret = rtq6056_set_shunt_resistor(priv, shunt_resistor_uohm);
+	if (ret)
+		return dev_err_probe(dev, ret,
+				     "Failed to init shunt resistor\n");
+
+	indio_dev->name = "rtq6056";
+	indio_dev->modes = INDIO_DIRECT_MODE;
+	indio_dev->channels = rtq6056_channels;
+	indio_dev->num_channels = ARRAY_SIZE(rtq6056_channels);
+	indio_dev->info = &rtq6056_info;
+
+	ret = devm_iio_triggered_buffer_setup(dev, indio_dev, NULL,
+					      rtq6056_buffer_trigger_handler,
+					      NULL);
+	if (ret)
+		return dev_err_probe(dev, ret,
+				     "Failed to allocate iio trigger buffer\n");
+
+	return devm_iio_device_register(dev, indio_dev);
+}
+
+static int rtq6056_runtime_suspend(struct device *dev)
+{
+	struct rtq6056_priv *priv = dev_get_drvdata(dev);
+
+	/* Configure to shutdown mode */
+	return regmap_field_write(priv->rm_fields[F_OPMODE], 0);
+}
+
+static int rtq6056_runtime_resume(struct device *dev)
+{
+	struct rtq6056_priv *priv = dev_get_drvdata(dev);
+	int sample_rdy_time_us, ret;
+
+	ret = regmap_field_write(priv->rm_fields[F_OPMODE], RTQ6056_CONT_ALLON);
+	if (ret)
+		return ret;
+
+	sample_rdy_time_us = priv->vbusct_us + priv->vshuntct_us;
+	sample_rdy_time_us *= priv->avg_sample;
+
+	usleep_range(sample_rdy_time_us, sample_rdy_time_us + 100);
+
+	return 0;
+}
+
+static DEFINE_RUNTIME_DEV_PM_OPS(rtq6056_pm_ops, rtq6056_runtime_suspend,
+				 rtq6056_runtime_resume, NULL);
+
+static const struct of_device_id rtq6056_device_match[] = {
+	{ .compatible = "richtek,rtq6056" },
+	{}
+};
+MODULE_DEVICE_TABLE(of, rtq6056_device_match);
+
+static struct i2c_driver rtq6056_driver = {
+	.driver = {
+		.name = "rtq6056",
+		.of_match_table = rtq6056_device_match,
+		.pm = pm_ptr(&rtq6056_pm_ops),
+	},
+	.probe_new = rtq6056_probe,
+};
+module_i2c_driver(rtq6056_driver);
+
+MODULE_AUTHOR("ChiYuan Huang <cy_huang@richtek.com>");
+MODULE_DESCRIPTION("Richtek RTQ6056 Driver");
+MODULE_LICENSE("GPL v2");
-- 
2.7.4

[PATCH v7 3/3] Documentation: ABI: testing: rtq6056: Update ABI docs

[cy_huang]

From: ChiYuan Huang <cy_huang@richtek.com>

Add documentation for the usage of voltage channel integration time.

Signed-off-by: ChiYuan Huang <cy_huang@richtek.com>
---
 Documentation/ABI/testing/sysfs-bus-iio | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/Documentation/ABI/testing/sysfs-bus-iio b/Documentation/ABI/testing/sysfs-bus-iio
index d4ccc68..1f7d327 100644
--- a/Documentation/ABI/testing/sysfs-bus-iio
+++ b/Documentation/ABI/testing/sysfs-bus-iio
@@ -2030,3 +2030,13 @@ Description:
 		Available range for the forced calibration value, expressed as:
 
 		- a range specified as "[min step max]"
+
+What:		/sys/bus/iio/devices/iio:deviceX/in_voltageY_integration_time
+KernelVersion:	5.20
+Contact:	linux-iio@vger.kernel.org
+Description:
+		For voltage sensing hardware, there may be different time between
+		channel conversion and sample update. 'Integration time' is used to
+		specify the channel internal conversion time. And sample update
+		interval is equal to average sample count multiple integration time.
+		Unit as microsecond.
-- 
2.7.4

Re: [PATCH v7 0/3] Add Richtek RTQ6056 support

[Jonathan Cameron]

On Mon, 18 Jul 2022 13:46:00 +0800
cy_huang <u0084500@gmail.com> wrote:

> From: ChiYuan Huang <cy_huang@richtek.com>
> 
> This patch series is to enable Richtek RTQ6056 support.
> 
> The RTQ6056 is a high accuracy current-sense monitor with I2C interface, and
> the device provides full information for system by reading out the load current
> and power.

If sending a new version without there being any public replies to the previous version
please reply to that thread yourself to say you are resending and why.
Greatly reduces the chances of me picking up the wrong version!
> 
> Since v7
> - Use 'DEFINE_RUNTIME_DEV_PM_OPS' to replace the explicit declaration of pm_ops.
> 
> Since v6
> - Remove specific rtq6056 ABI document.
> - Update integration time description in general ABI document.
> - Remove the redundant blank line.
> - To prevent the race condition for attribute wrtie and shunt resistor write,
>   use 'iio_device_claim_direct_mode' API.
> - Refine the order for 'action_reset' and 'pm_runtime'.
> - Fix text typo in comment like as ohm to Ohm and timea to time.
> 
> Since v5
> - Fix kernel version text for ABI.
> 
> Since v4
> - Add '__aligned(8)' for timestamp member.
> - Declare timestamp from 'int64_t' to more unified 's64'.
> 
> Since v3
> - change the node name to be generic 'adc' in binding example.
> - Refine pm_runtime API calling order in 'read_channel' API.
> - Fix vshunt wrong scale for divider.
> - Refine the comment text.
> - Use 'devm_add_action_or_reset' to decrease the code usage in probe
>   function.
> - Use RUNTIME_PM_OPS to replace SET_RUNTIME_PM_OPS.
> - minor fix for the comma.
> - Use pm_ptr to replace the direct assigned pm_ops.
> 
> Since v2
> - Change the resistor property name to be generic 'shunt-resistor-micro-ohms'.
> - Rename file from 'rtq6056-adc' to 'rtq6056'.
> - Refine the ABI, if generic already defined it, remove it and check the channel
>   report unit.
> - Add copyright text.
> - include the correct header.
> - change the property parsing name.
> - To use iio_chan_spec address field.
> - Refine each channel separate and shared_by_all.
> - Use pm_runtime and pm_runtime_autosuspend.
> - Remove the shutdown callback. From the HW suggestion, it's not recommended to
>   use battery as the power supply.
> - Check all scale unit (voltage->mV, current->mA, power->milliWatt).
> - Use the read_avail to provide the interface for attribute value list.
> - Add comma for the last element in the const integer array.
> - Refine each ADC label text.
> - In read_label callback, replace snprintf to sysfs_emit.
> 
> ChiYuan Huang (3):
>   dt-bindings: iio: adc: Add rtq6056 adc support
>   iio: adc: Add rtq6056 support
>   Documentation: ABI: testing: rtq6056: Update ABI docs
> 
>  Documentation/ABI/testing/sysfs-bus-iio            |  10 +
>  .../bindings/iio/adc/richtek,rtq6056.yaml          |  56 ++
>  drivers/iio/adc/Kconfig                            |  15 +
>  drivers/iio/adc/Makefile                           |   1 +
>  drivers/iio/adc/rtq6056.c                          | 663 +++++++++++++++++++++
>  5 files changed, 745 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/iio/adc/richtek,rtq6056.yaml
>  create mode 100644 drivers/iio/adc/rtq6056.c
> 

Re: [PATCH v7 3/3] Documentation: ABI: testing: rtq6056: Update ABI docs

[Jonathan Cameron]

On Mon, 18 Jul 2022 13:46:03 +0800
cy_huang <u0084500@gmail.com> wrote:

> From: ChiYuan Huang <cy_huang@richtek.com>
> 
> Add documentation for the usage of voltage channel integration time.
> 
> Signed-off-by: ChiYuan Huang <cy_huang@richtek.com>
> ---
>  Documentation/ABI/testing/sysfs-bus-iio | 10 ++++++++++
>  1 file changed, 10 insertions(+)
> 
> diff --git a/Documentation/ABI/testing/sysfs-bus-iio b/Documentation/ABI/testing/sysfs-bus-iio
> index d4ccc68..1f7d327 100644
> --- a/Documentation/ABI/testing/sysfs-bus-iio
> +++ b/Documentation/ABI/testing/sysfs-bus-iio
> @@ -2030,3 +2030,13 @@ Description:
>  		Available range for the forced calibration value, expressed as:
>  
>  		- a range specified as "[min step max]"
> +
> +What:		/sys/bus/iio/devices/iio:deviceX/in_voltageY_integration_time
> +KernelVersion:	5.20
> +Contact:	linux-iio@vger.kernel.org
> +Description:
> +		For voltage sensing hardware, there may be different time between
> +		channel conversion and sample update. 'Integration time' is used to
> +		specify the channel internal conversion time. And sample update
> +		interval is equal to average sample count multiple integration time.
> +		Unit as microsecond.

Whilst I did suggest moving this to this file, I also suggested that it was the
wrong interface to use.  For similar cases we've used in_voltageY_sampling_frequency
in the past because this isn't really an integration time, but rather a reflection of
a bunch of other stuff that makes up the conversion time.  In IIO we chose a long
time ago to use 1/conversion_time as the exposed interface == sampling_frequency

So, unless there is a strong reason to do otherwise, drop the overall sampling_frequency
attribute and use per channel ones instead.  Then update the main documentation
to make this usecase clear. Something in the block
https://elixir.bootlin.com/linux/latest/source/Documentation/ABI/testing/sysfs-bus-iio#L89
like adding the in_voltageY_sampling_frequency entry to the What: list and a
sentence at the end that says something like:

"Some devices have separate controls of sampling frequency for individual channels.
If multiple channels are enabled in a scan, then the sampling_frequency of the the
scan may be computed from the per channel sampling_frequencies."

Not something to put in the documentation, but for devices which do simultaneous sampling
it is very unlikely we'll have per channel sampling frequencies so there isn't an
ambiguity. The alternative we 'could' consider is to allow both overall sampling_frequency
and per channel in_voltageY_sampling_frequency but that is a bad idea because the
ABI (and most userspace software) assumes that more specific attributes override the
values of more generic ones (rather than them having different meanings as would be
the case here).

Jonathan

Re: [PATCH v7 2/3] iio: adc: Add rtq6056 support

[Jonathan Cameron]

On Mon, 18 Jul 2022 13:46:02 +0800
cy_huang <u0084500@gmail.com> wrote:

> From: ChiYuan Huang <cy_huang@richtek.com>
> 
> Add Richtek rtq6056 supporting.
> 
> It can be used for the system to monitor load current and power with 16-bit
> resolution.
> 
> Signed-off-by: ChiYuan Huang <cy_huang@richtek.com>
> Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
> ---

other than the ABI question around integration_time vs sampling_frequency
in review of patch 3, this looks good to me.

Thanks,

Jonathan

Re: [PATCH v7 3/3] Documentation: ABI: testing: rtq6056: Update ABI docs

[ChiYuan Huang]

Jonathan Cameron <jic23@kernel.org> 於 2022年7月19日 週二 凌晨12:54寫道：
>
> On Mon, 18 Jul 2022 13:46:03 +0800
> cy_huang <u0084500@gmail.com> wrote:
>
> > From: ChiYuan Huang <cy_huang@richtek.com>
> >
> > Add documentation for the usage of voltage channel integration time.
> >
> > Signed-off-by: ChiYuan Huang <cy_huang@richtek.com>
> > ---
> >  Documentation/ABI/testing/sysfs-bus-iio | 10 ++++++++++
> >  1 file changed, 10 insertions(+)
> >
> > diff --git a/Documentation/ABI/testing/sysfs-bus-iio b/Documentation/ABI/testing/sysfs-bus-iio
> > index d4ccc68..1f7d327 100644
> > --- a/Documentation/ABI/testing/sysfs-bus-iio
> > +++ b/Documentation/ABI/testing/sysfs-bus-iio
> > @@ -2030,3 +2030,13 @@ Description:
> >               Available range for the forced calibration value, expressed as:
> >
> >               - a range specified as "[min step max]"
> > +
> > +What:                /sys/bus/iio/devices/iio:deviceX/in_voltageY_integration_time
> > +KernelVersion:       5.20
> > +Contact:     linux-iio@vger.kernel.org
> > +Description:
> > +             For voltage sensing hardware, there may be different time between
> > +             channel conversion and sample update. 'Integration time' is used to
> > +             specify the channel internal conversion time. And sample update
> > +             interval is equal to average sample count multiple integration time.
> > +             Unit as microsecond.
>
> Whilst I did suggest moving this to this file, I also suggested that it was the
> wrong interface to use.  For similar cases we've used in_voltageY_sampling_frequency
> in the past because this isn't really an integration time, but rather a reflection of
> a bunch of other stuff that makes up the conversion time.  In IIO we chose a long
> time ago to use 1/conversion_time as the exposed interface == sampling_frequency
>
> So, unless there is a strong reason to do otherwise, drop the overall sampling_frequency
> attribute and use per channel ones instead.  Then update the main documentation
> to make this usecase clear. Something in the block
> https://elixir.bootlin.com/linux/latest/source/Documentation/ABI/testing/sysfs-bus-iio#L89
> like adding the in_voltageY_sampling_frequency entry to the What: list and a
> sentence at the end that says something like:
>
> "Some devices have separate controls of sampling frequency for individual channels.
> If multiple channels are enabled in a scan, then the sampling_frequency of the the
> scan may be computed from the per channel sampling_frequencies."
>
From my case, I need to specify
in_voltageX_sampling_frequency/in_powerY_sampling_frequency/
in_currentZ_sampling_frequency.

And describe all in the same sentence.
Can I directly copy the sentence that you described above?
I read the comment. The sentence that you wrote seems more generic.

If any misunderstanding, please correct me.
> Not something to put in the documentation, but for devices which do simultaneous sampling
> it is very unlikely we'll have per channel sampling frequencies so there isn't an
> ambiguity. The alternative we 'could' consider is to allow both overall sampling_frequency
> and per channel in_voltageY_sampling_frequency but that is a bad idea because the
> ABI (and most userspace software) assumes that more specific attributes override the
> values of more generic ones (rather than them having different meanings as would be
> the case here).
>
> Jonathan