1 /* SPDX-License-Identifier: GPL-2.0-only */
2 /*
3  * Support code for Analog Devices Sigma-Delta ADCs
4  *
5  * Copyright 2012 Analog Devices Inc.
6  *  Author: Lars-Peter Clausen <lars@metafoo.de>
7  */
8 #ifndef __AD_SIGMA_DELTA_H__
9 #define __AD_SIGMA_DELTA_H__
10 
11 enum ad_sigma_delta_mode {
12 	AD_SD_MODE_CONTINUOUS = 0,
13 	AD_SD_MODE_SINGLE = 1,
14 	AD_SD_MODE_IDLE = 2,
15 	AD_SD_MODE_POWERDOWN = 3,
16 };
17 
18 /**
19  * struct ad_sigma_delta_calib_data - Calibration data for Sigma Delta devices
20  * @mode: Calibration mode.
21  * @channel: Calibration channel.
22  */
23 struct ad_sd_calib_data {
24 	unsigned int mode;
25 	unsigned int channel;
26 };
27 
28 struct ad_sigma_delta;
29 struct device;
30 struct iio_dev;
31 
32 /**
33  * struct ad_sigma_delta_info - Sigma Delta driver specific callbacks and options
34  * @set_channel: Will be called to select the current channel, may be NULL.
35  * @append_status: Will be called to enable status append at the end of the sample, may be NULL.
36  * @set_mode: Will be called to select the current mode, may be NULL.
37  * @disable_all: Will be called to disable all channels, may be NULL.
38  * @postprocess_sample: Is called for each sampled data word, can be used to
39  *		modify or drop the sample data, it, may be NULL.
40  * @has_registers: true if the device has writable and readable registers, false
41  *		if there is just one read-only sample data shift register.
42  * @addr_shift: Shift of the register address in the communications register.
43  * @read_mask: Mask for the communications register having the read bit set.
44  * @status_ch_mask: Mask for the channel number stored in status register.
45  * @data_reg: Address of the data register, if 0 the default address of 0x3 will
46  *   be used.
47  * @irq_flags: flags for the interrupt used by the triggered buffer
48  * @num_slots: Number of sequencer slots
49  */
50 struct ad_sigma_delta_info {
51 	int (*set_channel)(struct ad_sigma_delta *, unsigned int channel);
52 	int (*append_status)(struct ad_sigma_delta *, bool append);
53 	int (*set_mode)(struct ad_sigma_delta *, enum ad_sigma_delta_mode mode);
54 	int (*disable_all)(struct ad_sigma_delta *);
55 	int (*postprocess_sample)(struct ad_sigma_delta *, unsigned int raw_sample);
56 	bool has_registers;
57 	unsigned int addr_shift;
58 	unsigned int read_mask;
59 	unsigned int status_ch_mask;
60 	unsigned int data_reg;
61 	unsigned long irq_flags;
62 	unsigned int num_slots;
63 };
64 
65 /**
66  * struct ad_sigma_delta - Sigma Delta device struct
67  * @spi: The spi device associated with the Sigma Delta device.
68  * @trig: The IIO trigger associated with the Sigma Delta device.
69  *
70  * Most of the fields are private to the sigma delta library code and should not
71  * be accessed by individual drivers.
72  */
73 struct ad_sigma_delta {
74 	struct spi_device	*spi;
75 	struct iio_trigger	*trig;
76 
77 /* private: */
78 	struct completion	completion;
79 	bool			irq_dis;
80 
81 	bool			bus_locked;
82 	bool			keep_cs_asserted;
83 
84 	uint8_t			comm;
85 
86 	const struct ad_sigma_delta_info *info;
87 	unsigned int		active_slots;
88 	unsigned int		current_slot;
89 	unsigned int		num_slots;
90 	bool			status_appended;
91 	/* map slots to channels in order to know what to expect from devices */
92 	unsigned int		*slots;
93 	uint8_t			*samples_buf;
94 
95 	/*
96 	 * DMA (thus cache coherency maintenance) requires the
97 	 * transfer buffers to live in their own cache lines.
98 	 * 'tx_buf' is up to 32 bits.
99 	 * 'rx_buf' is up to 32 bits per sample + 64 bit timestamp,
100 	 * rounded to 16 bytes to take into account padding.
101 	 */
102 	uint8_t				tx_buf[4] ____cacheline_aligned;
103 	uint8_t				rx_buf[16] __aligned(8);
104 };
105 
ad_sigma_delta_set_channel(struct ad_sigma_delta * sd,unsigned int channel)106 static inline int ad_sigma_delta_set_channel(struct ad_sigma_delta *sd,
107 	unsigned int channel)
108 {
109 	if (sd->info->set_channel)
110 		return sd->info->set_channel(sd, channel);
111 
112 	return 0;
113 }
114 
ad_sigma_delta_append_status(struct ad_sigma_delta * sd,bool append)115 static inline int ad_sigma_delta_append_status(struct ad_sigma_delta *sd, bool append)
116 {
117 	int ret;
118 
119 	if (sd->info->append_status) {
120 		ret = sd->info->append_status(sd, append);
121 		if (ret < 0)
122 			return ret;
123 
124 		sd->status_appended = append;
125 	}
126 
127 	return 0;
128 }
129 
ad_sigma_delta_disable_all(struct ad_sigma_delta * sd)130 static inline int ad_sigma_delta_disable_all(struct ad_sigma_delta *sd)
131 {
132 	if (sd->info->disable_all)
133 		return sd->info->disable_all(sd);
134 
135 	return 0;
136 }
137 
ad_sigma_delta_set_mode(struct ad_sigma_delta * sd,unsigned int mode)138 static inline int ad_sigma_delta_set_mode(struct ad_sigma_delta *sd,
139 	unsigned int mode)
140 {
141 	if (sd->info->set_mode)
142 		return sd->info->set_mode(sd, mode);
143 
144 	return 0;
145 }
146 
ad_sigma_delta_postprocess_sample(struct ad_sigma_delta * sd,unsigned int raw_sample)147 static inline int ad_sigma_delta_postprocess_sample(struct ad_sigma_delta *sd,
148 	unsigned int raw_sample)
149 {
150 	if (sd->info->postprocess_sample)
151 		return sd->info->postprocess_sample(sd, raw_sample);
152 
153 	return 0;
154 }
155 
156 void ad_sd_set_comm(struct ad_sigma_delta *sigma_delta, uint8_t comm);
157 int ad_sd_write_reg(struct ad_sigma_delta *sigma_delta, unsigned int reg,
158 	unsigned int size, unsigned int val);
159 int ad_sd_read_reg(struct ad_sigma_delta *sigma_delta, unsigned int reg,
160 	unsigned int size, unsigned int *val);
161 
162 int ad_sd_reset(struct ad_sigma_delta *sigma_delta,
163 	unsigned int reset_length);
164 
165 int ad_sigma_delta_single_conversion(struct iio_dev *indio_dev,
166 	const struct iio_chan_spec *chan, int *val);
167 int ad_sd_calibrate(struct ad_sigma_delta *sigma_delta,
168 	unsigned int mode, unsigned int channel);
169 int ad_sd_calibrate_all(struct ad_sigma_delta *sigma_delta,
170 	const struct ad_sd_calib_data *cd, unsigned int n);
171 int ad_sd_init(struct ad_sigma_delta *sigma_delta, struct iio_dev *indio_dev,
172 	struct spi_device *spi, const struct ad_sigma_delta_info *info);
173 
174 int devm_ad_sd_setup_buffer_and_trigger(struct device *dev, struct iio_dev *indio_dev);
175 
176 int ad_sd_validate_trigger(struct iio_dev *indio_dev, struct iio_trigger *trig);
177 
178 #endif
179