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Diffstat (limited to 'include/adc.h')
| -rw-r--r-- | include/adc.h | 288 |
1 files changed, 288 insertions, 0 deletions
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 |