[U-Boot] [PATCH V3 07/14] dm: adc: add simple ADC uclass implementation

Przemyslaw Marczak
2015-10-27T12:08:00Z

This commit adds:
- new uclass id: UCLASS_ADC
- new uclass driver: drivers/adc/adc-uclass.c

The new uclass's API allows for ADC operation on:
* single-channel with channel selection by a number
* multti-channel with channel selection by bit mask

ADC uclass's functions:
* single-channel:
- adc_start_channel() - start channel conversion
- adc_channel_data() - get conversion data
- adc_channel_single_shot() - start/get conversion data
* multi-channel:
- adc_start_channels() - start selected channels conversion
- adc_channels_data() - get conversion data
- adc_channels_single_shot() - start/get conversion data for channels
selected by bit mask
* general:
- adc_stop() - stop the conversion
- adc_vdd_value() - positive reference Voltage value with polarity [uV]
- adc_vss_value() - negative reference Voltage value with polarity [uV]
- adc_data_mask() - conversion data bit mask

The device tree can provide below constraints/properties:
- vdd-polarity-negative: if true: Vdd = vdd-microvolts * (-1)
- vss-polarity-negative: if true: Vss = vss-microvolts * (-1)
- vdd-supply: phandle to Vdd regulator's node
- vss-supply: phandle to Vss regulator's node
And optional, checked only if the above corresponding, doesn't exist:
- vdd-microvolts: positive reference Voltage [uV]
- vss-microvolts: negative reference Voltage [uV]

Signed-off-by: Przemyslaw Marczak <p.marczak@samsung.com>
Cc: Simon Glass <sjg@chromium.org>
---
Changes V2:
- new commit - introduce ADC uclass driver
Changes V3:
- Add binding info
- ADC uclass's code rework, add single/multi-channel API
- Select single channel by a number and multi, by a bit mask
- Wait for conversion end in uclass's internal function
- Add ADC supply polarity constraint
- Add function for getting supply Voltage with polarity
---
doc/device-tree-bindings/adc/adc.txt | 62 ++++++
drivers/Kconfig | 2 +
drivers/Makefile | 1 +
drivers/adc/Kconfig | 12 +
drivers/adc/Makefile | 8 +
drivers/adc/adc-uclass.c | 409 +++++++++++++++++++++++++++++++++++
include/adc.h | 288 ++++++++++++++++++++++++
include/dm/uclass-id.h | 1 +
8 files changed, 783 insertions(+)
create mode 100644 doc/device-tree-bindings/adc/adc.txt
create mode 100644 drivers/adc/Kconfig
create mode 100644 drivers/adc/Makefile
create mode 100644 drivers/adc/adc-uclass.c
create mode 100644 include/adc.h

diff --git a/doc/device-tree-bindings/adc/adc.txt b/doc/device-tree-bindings/adc/adc.txt
new file mode 100644
index 0000000..463de3c
--- /dev/null
+++ b/doc/device-tree-bindings/adc/adc.txt
@@ -0,0 +1,62 @@
+ADC device binding
+
+There are no mandatory properties for ADC. However, if Voltage info is required,
+then there are two options:
+- use microvolts constraint or
+- use regulator phandle to enable/read supply's Voltage
+
+Properties and constraints:
+*optional and always checked, Voltage polarity info:
+- vdd-polarity-negative: positive reference Voltage has a negative polarity
+- vss-polarity-negative: negative reference Voltage has a negative polarity
+
+Chose one option, for each supply (Vdd/Vss):
+
+*optional and always checked, supply Voltage constants:
+- vdd-supply: phandle to Vdd regulator's node
+- vss-supply: phandle to Vss regulator's node
+
+*optional and checked only if the above corresponding, doesn't exist:
+- vdd-microvolts: positive reference Voltage value [uV]
+- vss-microvolts: negative reference Voltage value [uV]
+
+Example with constant 'Vdd' value:
+adc at 1000000 {
+ compatible = "some-adc";
+ reg = <0xaabb000 0x100>;
+ status = "enabled";
+ vdd-microvolts = <1800000>;
+};
+
+Example of supply phandle usage, for the ADC's VDD/VSS references as below:
+ _______ _______
+ |Sandbox| |Sandbox|
+ : PMIC : : ADC :
+ . . . .
+ | | (Vdd) | AIN0|-->
+ | BUCK2|-------|VDDref |
+ | (3.3V)| _|VSSref |
+ |_______| | |_______|
+ _|_
+
+For the above PMIC, the node can be defined as follows:
+sandbox_pmic {
+ compatible = "sandbox,pmic";
+ ...
+ buck2: buck2 {
+ regulator-name = "SUPPLY_3.3V";
+ regulator-min-microvolt = <3300000>;
+ regulator-max-microvolt = <3300000>;
+ };
+ ...
+};
+
+For the above ADC, the node can be defined as follows:
+adc at 0 {
+ compatible = "sandbox,adc";
+ vdd-supply = <&buck2>;
+ vss-microvolts = <0>;
+};
+
+The ADC uclass code, will enable the supply before start of the conversion,
+but it will not configure the regulator settings.
diff --git a/drivers/Kconfig b/drivers/Kconfig
index ba88b5e..c481e93 100644
--- a/drivers/Kconfig
+++ b/drivers/Kconfig
@@ -4,6 +4,8 @@ source "drivers/core/Kconfig"

# types of drivers sorted in alphabetical order

+source "drivers/adc/Kconfig"
+
source "drivers/block/Kconfig"

source "drivers/clk/Kconfig"
diff --git a/drivers/Makefile b/drivers/Makefile
index 4f49bfd..ad29a4f 100644
--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -35,6 +35,7 @@ obj-$(CONFIG_SPL_SATA_SUPPORT) += block/

else

+obj-y += adc/
obj-$(CONFIG_DM_DEMO) += demo/
obj-$(CONFIG_BIOSEMU) += bios_emulator/
obj-y += block/
diff --git a/drivers/adc/Kconfig b/drivers/adc/Kconfig
new file mode 100644
index 0000000..b6e226a
--- /dev/null
+++ b/drivers/adc/Kconfig
@@ -0,0 +1,12 @@
+config ADC
+ bool "Enable ADC drivers using Driver Model"
+ help
+ This enables ADC API for drivers, which allows driving ADC features
+ by single and multi-channel methods for:
+ - start/stop/get data for conversion of a single-channel selected by
+ a number or multi-channels selected by a bitmask
+ - get data mask (ADC resolution)
+ ADC reference Voltage supply options:
+ - methods for get Vdd/Vss reference Voltage values with polarity
+ - support supply's phandle with auto-enable
+ - supply polarity setting in fdt
diff --git a/drivers/adc/Makefile b/drivers/adc/Makefile
new file mode 100644
index 0000000..c4d9618
--- /dev/null
+++ b/drivers/adc/Makefile
@@ -0,0 +1,8 @@
+#
+# Copyright (C) 2015 Samsung Electronics
+# Przemyslaw Marczak <p.marczak@samsung.com>
+#
+# SPDX-License-Identifier: GPL-2.0+
+#
+
+obj-$(CONFIG_ADC) += adc-uclass.o
diff --git a/drivers/adc/adc-uclass.c b/drivers/adc/adc-uclass.c
new file mode 100644
index 0000000..9233fcd
--- /dev/null
+++ b/drivers/adc/adc-uclass.c
@@ -0,0 +1,409 @@
+/*
+ * Copyright (C) 2015 Samsung Electronics
+ * Przemyslaw Marczak <p.marczak@samsung.com>
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ */
+
+#include <common.h>
+#include <errno.h>
+#include <dm.h>
+#include <dm/lists.h>
+#include <dm/device-internal.h>
+#include <dm/uclass-internal.h>
+#include <adc.h>
+#include <power/regulator.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+#define ADC_UCLASS_PLATDATA_SIZE sizeof(struct adc_uclass_platdata)
+#define CHECK_NUMBER true
+#define CHECK_MASK (!CHECK_NUMBER)
+
+/* TODO: add support for timer uclass (for early calls) */
+#ifdef CONFIG_SANDBOX_ARCH
+#define sdelay(x) udelay(x)
+#else
+extern void sdelay(unsigned long loops);
+#endif
+
+static int check_channel(struct udevice *dev, int value, bool number_or_mask,
+ const char *caller_function)
+{
+ struct adc_uclass_platdata *uc_pdata = dev_get_uclass_platdata(dev);
+ unsigned mask = number_or_mask ? (1 << value) : value;
+
+ /* For the real ADC hardware, some ADC channels can be inactive.
+ * For example if device has 4 analog channels, and only channels
+ * 1-st and 3-rd are valid, then channel mask is: 0b1010, so request
+ * with mask 0b1110 should return an error.
+ */
+ if ((uc_pdata->channel_mask >= mask) && (uc_pdata->channel_mask & mask))
+ return 0;
+
+ printf("Error in %s/%s().\nWrong channel selection for device: %s\n",
+ __FILE__, caller_function, dev->name);
+
+ return -EINVAL;
+}
+
+static int adc_supply_enable(struct udevice *dev)
+{
+ struct adc_uclass_platdata *uc_pdata = dev_get_uclass_platdata(dev);
+ const char *supply_type;
+ int ret = 0;
+
+ if (uc_pdata->vdd_supply) {
+ supply_type = "vdd";
+ ret = regulator_set_enable(uc_pdata->vdd_supply, true);
+ }
+
+ if (!ret && uc_pdata->vss_supply) {
+ supply_type = "vss";
+ ret = regulator_set_enable(uc_pdata->vss_supply, true);
+ }
+
+ if (ret)
+ error("%s: can't enable %s-supply!", dev->name, supply_type);
+
+ return ret;
+}
+
+int adc_data_mask(struct udevice *dev, unsigned int *data_mask)
+{
+ struct adc_uclass_platdata *uc_pdata = dev_get_uclass_platdata(dev);
+
+ if (!uc_pdata)
+ return -ENOSYS;
+
+ *data_mask = uc_pdata->data_mask;
+ return 0;
+}
+
+int adc_stop(struct udevice *dev)
+{
+ const struct adc_ops *ops = dev_get_driver_ops(dev);
+
+ if (!ops->stop)
+ return -ENOSYS;
+
+ return ops->stop(dev);
+}
+
+int adc_start_channel(struct udevice *dev, int channel)
+{
+ const struct adc_ops *ops = dev_get_driver_ops(dev);
+ int ret;
+
+ if (!ops->start_channel)
+ return -ENOSYS;
+
+ ret = check_channel(dev, channel, CHECK_NUMBER, __func__);
+ if (ret)
+ return ret;
+
+ ret = adc_supply_enable(dev);
+ if (ret)
+ return ret;
+
+ return ops->start_channel(dev, channel);
+}
+
+int adc_start_channels(struct udevice *dev, unsigned int channel_mask)
+{
+ const struct adc_ops *ops = dev_get_driver_ops(dev);
+ int ret;
+
+ if (!ops->start_channels)
+ return -ENOSYS;
+
+ ret = check_channel(dev, channel_mask, CHECK_MASK, __func__);
+ if (ret)
+ return ret;
+
+ ret = adc_supply_enable(dev);
+ if (ret)
+ return ret;
+
+ return ops->start_channels(dev, channel_mask);
+}
+
+int adc_channel_data(struct udevice *dev, int channel, unsigned int *data)
+{
+ struct adc_uclass_platdata *uc_pdata = dev_get_uclass_platdata(dev);
+ const struct adc_ops *ops = dev_get_driver_ops(dev);
+ unsigned int timeout_us = uc_pdata->data_timeout_us;
+ int ret;
+
+ if (!ops->channel_data)
+ return -ENOSYS;
+
+ ret = check_channel(dev, channel, CHECK_NUMBER, __func__);
+ if (ret)
+ return ret;
+
+ do {
+ ret = ops->channel_data(dev, channel, data);
+ if (!ret || ret != -EBUSY)
+ break;
+
+ /* TODO: use timer uclass (for early calls). */
+ sdelay(5);
+ } while (timeout_us--);
+
+ return ret;
+}
+
+int adc_channels_data(struct udevice *dev, unsigned int channel_mask,
+ struct adc_channel *channels)
+{
+ struct adc_uclass_platdata *uc_pdata = dev_get_uclass_platdata(dev);
+ unsigned int timeout_us = uc_pdata->multidata_timeout_us;
+ const struct adc_ops *ops = dev_get_driver_ops(dev);
+ int ret;
+
+ if (!ops->channels_data)
+ return -ENOSYS;
+
+ ret = check_channel(dev, channel_mask, CHECK_MASK, __func__);
+ if (ret)
+ return ret;
+
+ do {
+ ret = ops->channels_data(dev, channel_mask, channels);
+ if (!ret || ret != -EBUSY)
+ break;
+
+ /* TODO: use timer uclass (for early calls). */
+ sdelay(5);
+ } while (timeout_us--);
+
+ return ret;
+}
+
+int adc_channel_single_shot(const char *name, int channel, unsigned int *data)
+{
+ struct udevice *dev;
+ int ret;
+
+ ret = uclass_get_device_by_name(UCLASS_ADC, name, &dev);
+ if (ret)
+ return ret;
+
+ ret = adc_start_channel(dev, channel);
+ if (ret)
+ return ret;
+
+ ret = adc_channel_data(dev, channel, data);
+ if (ret)
+ return ret;
+
+ return 0;
+}
+
+static int _adc_channels_single_shot(struct udevice *dev,
+ unsigned int channel_mask,
+ struct adc_channel *channels)
+{
+ unsigned int data;
+ int channel, ret;
+
+ for (channel = 0; channel <= ADC_MAX_CHANNEL; channel++) {
+ /* Check channel bit. */
+ if (!((channel_mask >> channel) & 0x1))
+ continue;
+
+ ret = adc_start_channel(dev, channel);
+ if (ret)
+ return ret;
+
+ ret = adc_channel_data(dev, channel, &data);
+ if (ret)
+ return ret;
+
+ channels->id = channel;
+ channels->data = data;
+ channels++;
+ }
+
+ return 0;
+}
+
+int adc_channels_single_shot(const char *name, unsigned int channel_mask,
+ struct adc_channel *channels)
+{
+ struct udevice *dev;
+ int ret;
+
+ ret = uclass_get_device_by_name(UCLASS_ADC, name, &dev);
+ if (ret)
+ return ret;
+
+ ret = adc_start_channels(dev, channel_mask);
+ if (ret)
+ goto try_manual;
+
+ ret = adc_channels_data(dev, channel_mask, channels);
+ if (ret)
+ return ret;
+
+ return 0;
+
+try_manual:
+ if (ret != -ENOSYS)
+ return ret;
+
+ return _adc_channels_single_shot(dev, channel_mask, channels);
+}
+
+static int adc_vdd_platdata_update(struct udevice *dev)
+{
+ struct adc_uclass_platdata *uc_pdata = dev_get_uclass_platdata(dev);
+ int ret;
+
+ /* Warning!
+ * This function can't return supply device before its bind.
+ * Please pay attention to proper fdt scan sequence. If ADC device
+ * will bind before its supply regulator device, then the below 'get'
+ * will return an error.
+ */
+ ret = device_get_supply_regulator(dev, "vdd-supply",
+ &uc_pdata->vdd_supply);
+ if (ret)
+ return ret;
+
+ ret = regulator_get_value(uc_pdata->vdd_supply);
+ if (ret < 0)
+ return ret;
+
+ uc_pdata->vdd_microvolts = ret;
+
+ return 0;
+}
+
+static int adc_vss_platdata_update(struct udevice *dev)
+{
+ struct adc_uclass_platdata *uc_pdata = dev_get_uclass_platdata(dev);
+ int ret;
+
+ ret = device_get_supply_regulator(dev, "vss-supply",
+ &uc_pdata->vss_supply);
+ if (ret)
+ return ret;
+
+ ret = regulator_get_value(uc_pdata->vss_supply);
+ if (ret < 0)
+ return ret;
+
+ uc_pdata->vss_microvolts = ret;
+
+ return 0;
+}
+
+int adc_vdd_value(struct udevice *dev, int *uV)
+{
+ struct adc_uclass_platdata *uc_pdata = dev_get_uclass_platdata(dev);
+ int ret, value_sign = uc_pdata->vdd_polarity_negative ? -1 : 1;
+
+ if (!uc_pdata->vdd_supply)
+ goto nodev;
+
+ /* Update the regulator Value. */
+ ret = adc_vdd_platdata_update(dev);
+ if (ret)
+ return ret;
+nodev:
+ if (uc_pdata->vdd_microvolts == -ENODATA)
+ return -ENODATA;
+
+ *uV = uc_pdata->vdd_microvolts * value_sign;
+
+ return 0;
+}
+
+int adc_vss_value(struct udevice *dev, int *uV)
+{
+ struct adc_uclass_platdata *uc_pdata = dev_get_uclass_platdata(dev);
+ int ret, value_sign = uc_pdata->vss_polarity_negative ? -1 : 1;
+
+ if (!uc_pdata->vss_supply)
+ goto nodev;
+
+ /* Update the regulator Value. */
+ ret = adc_vss_platdata_update(dev);
+ if (ret)
+ return ret;
+nodev:
+ if (uc_pdata->vss_microvolts == -ENODATA)
+ return -ENODATA;
+
+ *uV = uc_pdata->vss_microvolts * value_sign;
+
+ return 0;
+}
+
+static int adc_vdd_platdata_set(struct udevice *dev)
+{
+ struct adc_uclass_platdata *uc_pdata = dev_get_uclass_platdata(dev);
+ int ret, offset = dev->of_offset;
+ const void *fdt = gd->fdt_blob;
+ char *prop;
+
+ prop = "vdd-polarity-negative";
+ uc_pdata->vdd_polarity_negative = fdtdec_get_bool(fdt, offset, prop);
+
+ ret = adc_vdd_platdata_update(dev);
+ if (ret != -ENOENT)
+ return ret;
+
+ /* No vdd-supply phandle. */
+ prop = "vdd-microvolts";
+ uc_pdata->vdd_microvolts = fdtdec_get_int(fdt, offset, prop, -ENODATA);
+
+ return 0;
+}
+
+static int adc_vss_platdata_set(struct udevice *dev)
+{
+ struct adc_uclass_platdata *uc_pdata = dev_get_uclass_platdata(dev);
+ int ret, offset = dev->of_offset;
+ const void *fdt = gd->fdt_blob;
+ char *prop;
+
+ prop = "vss-polarity-negative";
+ uc_pdata->vss_polarity_negative = fdtdec_get_bool(fdt, offset, prop);
+
+ ret = adc_vss_platdata_update(dev);
+ if (ret != -ENOENT)
+ return ret;
+
+ /* No vss-supply phandle. */
+ prop = "vss-microvolts";
+ uc_pdata->vss_microvolts = fdtdec_get_int(fdt, offset, prop, -ENODATA);
+
+ return 0;
+}
+
+static int adc_pre_probe(struct udevice *dev)
+{
+ int ret;
+
+ /* Set ADC VDD platdata: polarity, uV, regulator (phandle). */
+ ret = adc_vdd_platdata_set(dev);
+ if (ret)
+ error("%s: Can't update Vdd. Error: %d", dev->name, ret);
+
+ /* Set ADC VSS platdata: polarity, uV, regulator (phandle). */
+ ret = adc_vss_platdata_set(dev);
+ if (ret)
+ error("%s: Can't update Vss. Error: %d", dev->name, ret);
+
+ return 0;
+}
+
+UCLASS_DRIVER(adc) = {
+ .id = UCLASS_ADC,
+ .name = "adc",
+ .pre_probe = adc_pre_probe,
+ .per_device_platdata_auto_alloc_size = ADC_UCLASS_PLATDATA_SIZE,
+};
diff --git a/include/adc.h b/include/adc.h
new file mode 100644
index 0000000..4b14017
--- /dev/null
+++ b/include/adc.h
@@ -0,0 +1,288 @@
+/*
+ * Copyright (C) 2015 Samsung Electronics
+ * Przemyslaw Marczak <p.marczak@samsung.com>
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ */
+
+#ifndef _ADC_H_
+#define _ADC_H_
+
+/* ADC_CHANNEL() - ADC channel bit mask, to select only required channels */
+#define ADC_CHANNEL(x) (1 << x)
+
+/* The last possible selected channel with 32-bit mask */
+#define ADC_MAX_CHANNEL 31
+
+/**
+ * adc_data_format: define the ADC output data format, can be useful when
+ * the device's input Voltage range is bipolar.
+ * - ADC_DATA_FORMAT_BIN - binary offset
+ * - ADC_DATA_FORMAT_2S - two's complement
+ *
+ * Note: Device's driver should fill the 'data_format' field of its uclass's
+ * platform data using one of the above data format types.
+ */
+enum adc_data_format {
+ ADC_DATA_FORMAT_BIN,
+ ADC_DATA_FORMAT_2S,
+};
+
+/**
+ * struct adc_channel - structure to hold channel conversion data.
+ * Useful to keep the result of a multi-channel conversion output.
+ *
+ * @id - channel id
+ * @data - channel conversion data
+ */
+struct adc_channel {
+ int id;
+ unsigned int data;
+};
+
+/**
+ * struct adc_uclass_platdata - basic ADC info
+ *
+ * Note: The positive/negative reference Voltage is only a name and it doesn't
+ * provide an information about the value polarity. It is possible, for both
+ * values to be a negative or positive. For this purpose the uclass's platform
+ * data provides a bool fields: 'vdd/vss_supply_is_negative'. This is useful,
+ * since the regulator API returns only a positive Voltage values.
+ *
+ * To get the reference Voltage values with polarity, use functions:
+ * - adc_vdd_value()
+ * - adc_vss_value()
+ * Those are useful for some cases of ADC's references, e.g.:
+ * * Vdd: +3.3V; Vss: -3.3V -> 6.6 Vdiff
+ * * Vdd: +3.3V; Vss: +0.3V -> 3.0 Vdiff
+ * * Vdd: +3.3V; Vss: 0.0V -> 3.3 Vdiff
+ * The last one is usually standard and doesn't require the fdt polarity info.
+ *
+ * For more informations read binding info:
+ * - doc/device-tree-bindings/adc/adc.txt
+ *
+ * @data_mask - conversion output data mask
+ * @data_timeout_us - single channel conversion timeout
+ * @multidata_timeout_us - multi channel conversion timeout
+ * @channel_mask - bit mask of available channels [0:31]
+ * @vdd_supply - positive reference Voltage supply (regulator)
+ * @vss_supply - negative reference Voltage supply (regulator)
+ * @vdd_polarity_negative - positive reference Voltage has negative polarity
+ * @vss_polarity_negative - negative reference Voltage has negative polarity
+ * @vdd_microvolts - positive reference Voltage value
+ * @vss_microvolts - negative reference Voltage value
+ */
+struct adc_uclass_platdata {
+ int data_format;
+ unsigned int data_mask;
+ unsigned int data_timeout_us;
+ unsigned int multidata_timeout_us;
+ unsigned int channel_mask;
+ struct udevice *vdd_supply;
+ struct udevice *vss_supply;
+ bool vdd_polarity_negative;
+ bool vss_polarity_negative;
+ int vdd_microvolts;
+ int vss_microvolts;
+};
+
+/**
+ * struct adc_ops - ADC device operations for single/multi-channel operation.
+ */
+struct adc_ops {
+ /**
+ * start_channel() - start conversion with its default parameters
+ * for the given channel number.
+ *
+ * @dev: ADC device to init
+ * @channel: analog channel number
+ * @return: 0 if OK, -ve on error
+ */
+ int (*start_channel)(struct udevice *dev, int channel);
+
+ /**
+ * start_channels() - start conversion with its default parameters
+ * for the channel numbers selected by the bit mask.
+ *
+ * This is optional, useful when the hardware supports multichannel
+ * conversion by the single software trigger.
+ *
+ * @dev: ADC device to init
+ * @channel_mask: bit mask of selected analog channels
+ * @return: 0 if OK, -ve on error
+ */
+ int (*start_channels)(struct udevice *dev, unsigned int channel_mask);
+
+ /**
+ * channel_data() - get conversion output data for the given channel.
+ *
+ * Note: The implementation of this function should only check, that
+ * the conversion data is available at the call time. If the hardware
+ * requires some delay to get the data, then this function should
+ * return with -EBUSY value. The ADC API will call it in a loop,
+ * until the data is available or the timeout expires. The maximum
+ * timeout for this operation is defined by the field 'data_timeout_us'
+ * in ADC uclasses platform data structure.
+ *
+ * @dev: ADC device to trigger
+ * @channel: selected analog channel number
+ * @data: returned pointer to selected channel's output data
+ * @return: 0 if OK, -EBUSY if busy, and other negative on error
+ */
+ int (*channel_data)(struct udevice *dev, int channel,
+ unsigned int *data);
+
+ /**
+ * channels_data() - get conversion data for the selected channels.
+ *
+ * This is optional, useful when multichannel conversion is supported
+ * by the hardware, by the single software trigger.
+ *
+ * For the proper implementation, please look at the 'Note' for the
+ * above method. The only difference is in used timeout value, which
+ * is defined by field 'multidata_timeout_us'.
+ *
+ * @dev: ADC device to trigger
+ * @channel_mask: bit mask of selected analog channels
+ * @channels: returned pointer to array of output data for channels
+ * selected by the given mask
+ * @return: 0 if OK, -ve on error
+ */
+ int (*channels_data)(struct udevice *dev, unsigned int channel_mask,
+ struct adc_channel *channels);
+
+ /**
+ * stop() - stop conversion of the given ADC device
+ *
+ * @dev: ADC device to stop
+ * @return: 0 if OK, -ve on error
+ */
+ int (*stop)(struct udevice *dev);
+};
+
+/**
+ * adc_start_channel() - start conversion for given device/channel and exit.
+ *
+ * @dev: ADC device
+ * @channel: analog channel number
+ * @return: 0 if OK, -ve on error
+ */
+int adc_start_channel(struct udevice *dev, int channel);
+
+/**
+ * adc_start_channels() - start conversion for given device/channels and exit.
+ *
+ * Note:
+ * To use this function, device must implement method: start_channels().
+ *
+ * @dev: ADC device to start
+ * @channel_mask: channel selection - a bit mask
+ * @channel_mask: bit mask of analog channels
+ * @return: 0 if OK, -ve on error
+ */
+int adc_start_channels(struct udevice *dev, unsigned int channel_mask);
+
+/**
+ * adc_channel_data() - get conversion data for the given device channel number.
+ *
+ * @dev: ADC device to read
+ * @channel: analog channel number
+ * @data: pointer to returned channel's data
+ * @return: 0 if OK, -ve on error
+ */
+int adc_channel_data(struct udevice *dev, int channel, unsigned int *data);
+
+/**
+ * adc_channels_data() - get conversion data for the channels selected by mask
+ *
+ * Note:
+ * To use this function, device must implement methods:
+ * - start_channels()
+ * - channels_data()
+ *
+ * @dev: ADC device to read
+ * @channel_mask: channel selection - a bit mask
+ * @channels: pointer to structure array of returned data for each channel
+ * @return: 0 if OK, -ve on error
+ */
+int adc_channels_data(struct udevice *dev, unsigned int channel_mask,
+ struct adc_channel *channels);
+
+/**
+ * adc_data_mask() - get data mask (ADC resolution bitmask) for given ADC device
+ *
+ * This can be used if adc uclass platform data is filled.
+ *
+ * @dev: ADC device to check
+ * @data_mask: pointer to the returned data bitmask
+ * @return: 0 if OK, -ve on error
+ */
+int adc_data_mask(struct udevice *dev, unsigned int *data_mask);
+
+/**
+ * adc_channel_single_shot() - get output data of conversion for the ADC
+ * device's channel. This function searches for the device with the given name,
+ * starts the given channel conversion and returns the output data.
+ *
+ * Note: To use this function, device must implement metods:
+ * - start_channel()
+ * - channel_data()
+ *
+ * @name: device's name to search
+ * @channel: device's input channel to init
+ * @data: pointer to conversion output data
+ * @return: 0 if OK, -ve on error
+ */
+int adc_channel_single_shot(const char *name, int channel, unsigned int *data);
+
+/**
+ * adc_channels_single_shot() - get ADC conversion output data for the selected
+ * device's channels. This function searches for the device by the given name,
+ * starts the selected channels conversion and returns the output data as array
+ * of type 'struct adc_channel'.
+ *
+ * Note: This function can be used if device implements one of ADC's single
+ * or multi-channel operation API. If multi-channel operation is not supported,
+ * then each selected channel is triggered by the sequence start/data in a loop.
+ *
+ * @name: device's name to search
+ * @channel_mask: channel selection - a bit mask
+ * @channels: pointer to conversion output data for the selected channels
+ * @return: 0 if OK, -ve on error
+ */
+int adc_channels_single_shot(const char *name, unsigned int channel_mask,
+ struct adc_channel *channels);
+
+/**
+ * adc_vdd_value() - get the ADC device's positive reference Voltage value
+ *
+ * Note: Depending on bool value 'vdd_supply_is_negative' of platform data,
+ * the returned uV value can be negative, and it's not an error.
+ *
+ * @dev: ADC device to check
+ * @uV: Voltage value with polarization sign (uV)
+ * @return: 0 on success or -ve on error
+*/
+int adc_vdd_value(struct udevice *dev, int *uV);
+
+/**
+ * adc_vss_value() - get the ADC device's negative reference Voltage value
+ *
+ * Note: Depending on bool value 'vdd_supply_is_negative' of platform data,
+ * the returned uV value can be negative, and it's not an error.
+ *
+ * @dev: ADC device to check
+ * @uV: Voltage value with polarization sign (uV)
+ * @return: 0 on success or -ve on error
+*/
+int adc_vss_value(struct udevice *dev, int *uV);
+
+/**
+ * adc_stop() - stop operation for given ADC device.
+ *
+ * @dev: ADC device to stop
+ * @return: 0 if OK, -ve on error
+ */
+int adc_stop(struct udevice *dev);
+
+#endif
diff --git a/include/dm/uclass-id.h b/include/dm/uclass-id.h
index 886a44c..d0cf4ce 100644
--- a/include/dm/uclass-id.h
+++ b/include/dm/uclass-id.h
@@ -25,6 +25,7 @@ enum uclass_id {
UCLASS_SIMPLE_BUS, /* bus with child devices */

/* U-Boot uclasses start here - in alphabetical order */
+ UCLASS_ADC, /* Analog-to-digital converter */
UCLASS_CLK, /* Clock source, e.g. used by peripherals */
UCLASS_CPU, /* CPU, typically part of an SoC */
UCLASS_CROS_EC, /* Chrome OS EC */
--
1.9.1