1 /*
2 * Copyright 2021 Google LLC
3 * Copyright 2022 TOKITA Hiroshi <tokita.hiroshi@fujitsu.com>
4 *
5 * SPDX-License-Identifier: Apache-2.0
6 */
7
8 #define DT_DRV_COMPAT raspberrypi_pico_adc
9
10 #include <zephyr/drivers/adc.h>
11 #include <zephyr/drivers/clock_control.h>
12 #include <zephyr/drivers/pinctrl.h>
13 #include <zephyr/drivers/reset.h>
14 #include <zephyr/logging/log.h>
15
16 #include <hardware/adc.h>
17 #include <zephyr/irq.h>
18
19 LOG_MODULE_REGISTER(adc_rpi, CONFIG_ADC_LOG_LEVEL);
20
21 #define ADC_CONTEXT_USES_KERNEL_TIMER
22 #include "adc_context.h"
23
24 #define ADC_RPI_MAX_RESOLUTION 12
25
26 /** Bits numbers of rrobin register mean an available number of channels. */
27 #define ADC_RPI_CHANNEL_NUM (ADC_CS_RROBIN_MSB - ADC_CS_RROBIN_LSB + 1)
28
29 /**
30 * @brief RaspberryPi Pico ADC config
31 *
32 * This structure contains constant data for given instance of RaspberryPi Pico ADC.
33 */
34 struct adc_rpi_config {
35 /** Number of supported channels */
36 uint8_t num_channels;
37 /** pinctrl configs */
38 const struct pinctrl_dev_config *pcfg;
39 /** function pointer to irq setup */
40 void (*irq_configure)(void);
41 /** Pointer to clock controller device */
42 const struct device *clk_dev;
43 /** Clock id of ADC clock */
44 clock_control_subsys_t clk_id;
45 /** Reset controller config */
46 const struct reset_dt_spec reset;
47 };
48
49 /**
50 * @brief RaspberryPi Pico ADC data
51 *
52 * This structure contains data structures used by a RaspberryPi Pico ADC.
53 */
54 struct adc_rpi_data {
55 /** Structure that handle state of ongoing read operation */
56 struct adc_context ctx;
57 /** Pointer to RaspberryPi Pico ADC own device structure */
58 const struct device *dev;
59 /** Pointer to memory where next sample will be written */
60 uint16_t *buf;
61 /** Pointer to where will be data stored in case of repeated sampling */
62 uint16_t *repeat_buf;
63 /** Mask with channels that will be sampled */
64 uint32_t channels;
65 };
66
adc_start_once(void)67 static inline void adc_start_once(void)
68 {
69 hw_set_bits(&adc_hw->cs, ADC_CS_START_ONCE_BITS);
70 }
71
adc_get_result(void)72 static inline uint16_t adc_get_result(void)
73 {
74 return (uint16_t)adc_hw->result;
75 }
76
adc_get_err(void)77 static inline bool adc_get_err(void)
78 {
79 return (adc_hw->cs & ADC_CS_ERR_BITS) ? true : false;
80 }
81
adc_clear_errors(void)82 static inline void adc_clear_errors(void)
83 {
84 /* write 1 to clear */
85 hw_set_bits(&adc_hw->fcs, ADC_FCS_OVER_BITS);
86 hw_set_bits(&adc_hw->fcs, ADC_FCS_UNDER_BITS);
87 hw_set_bits(&adc_hw->fcs, ADC_FCS_ERR_BITS);
88 hw_set_bits(&adc_hw->cs, ADC_CS_ERR_STICKY_BITS);
89 }
90
adc_enable(void)91 static inline void adc_enable(void)
92 {
93 adc_hw->cs = ADC_CS_EN_BITS;
94 while (!(adc_hw->cs & ADC_CS_READY_BITS))
95 ;
96 }
97
adc_rpi_channel_setup(const struct device * dev,const struct adc_channel_cfg * channel_cfg)98 static int adc_rpi_channel_setup(const struct device *dev,
99 const struct adc_channel_cfg *channel_cfg)
100 {
101 const struct adc_rpi_config *config = dev->config;
102
103 if (channel_cfg->channel_id >= config->num_channels) {
104 LOG_ERR("unsupported channel id '%d'", channel_cfg->channel_id);
105 return -ENOTSUP;
106 }
107
108 if (channel_cfg->acquisition_time != ADC_ACQ_TIME_DEFAULT) {
109 LOG_ERR("Acquisition time is not valid");
110 return -EINVAL;
111 }
112
113 if (channel_cfg->differential) {
114 LOG_ERR("unsupported differential mode");
115 return -ENOTSUP;
116 }
117
118 if (channel_cfg->gain != ADC_GAIN_1) {
119 LOG_ERR("Gain is not valid");
120 return -EINVAL;
121 }
122
123 return 0;
124 }
125
126 /**
127 * @brief Check if buffer in @p sequence is big enough to hold all ADC samples
128 *
129 * @param dev RaspberryPi Pico ADC device
130 * @param sequence ADC sequence description
131 *
132 * @return 0 on success
133 * @return -ENOMEM if buffer is not big enough
134 */
adc_rpi_check_buffer_size(const struct device * dev,const struct adc_sequence * sequence)135 static int adc_rpi_check_buffer_size(const struct device *dev,
136 const struct adc_sequence *sequence)
137 {
138 const struct adc_rpi_config *config = dev->config;
139 uint8_t channels = 0;
140 size_t needed;
141 uint32_t mask;
142
143 for (mask = BIT(config->num_channels - 1); mask != 0; mask >>= 1) {
144 if (mask & sequence->channels) {
145 channels++;
146 }
147 }
148
149 needed = channels * sizeof(uint16_t);
150 if (sequence->options) {
151 needed *= (1 + sequence->options->extra_samplings);
152 }
153
154 if (sequence->buffer_size < needed) {
155 return -ENOMEM;
156 }
157
158 return 0;
159 }
160
161 /**
162 * @brief Start processing read request
163 *
164 * @param dev RaspberryPi Pico ADC device
165 * @param sequence ADC sequence description
166 *
167 * @return 0 on success
168 * @return -ENOTSUP if requested resolution or channel is out side of supported
169 * range
170 * @return -ENOMEM if buffer is not big enough
171 * (see @ref adc_rpi_check_buffer_size)
172 * @return other error code returned by adc_context_wait_for_completion
173 */
adc_rpi_start_read(const struct device * dev,const struct adc_sequence * sequence)174 static int adc_rpi_start_read(const struct device *dev,
175 const struct adc_sequence *sequence)
176 {
177 const struct adc_rpi_config *config = dev->config;
178 struct adc_rpi_data *data = dev->data;
179 int err;
180
181 if (sequence->resolution > ADC_RPI_MAX_RESOLUTION ||
182 sequence->resolution == 0) {
183 LOG_ERR("unsupported resolution %d", sequence->resolution);
184 return -ENOTSUP;
185 }
186
187 if (find_msb_set(sequence->channels) > config->num_channels) {
188 LOG_ERR("unsupported channels in mask: 0x%08x",
189 sequence->channels);
190 return -ENOTSUP;
191 }
192
193 err = adc_rpi_check_buffer_size(dev, sequence);
194 if (err) {
195 LOG_ERR("buffer size too small");
196 return err;
197 }
198
199 data->buf = sequence->buffer;
200 adc_context_start_read(&data->ctx, sequence);
201
202 return adc_context_wait_for_completion(&data->ctx);
203 }
204
205 /**
206 * Interrupt handler
207 */
adc_rpi_isr(const struct device * dev)208 static void adc_rpi_isr(const struct device *dev)
209 {
210 struct adc_rpi_data *data = dev->data;
211 uint16_t result;
212 uint8_t ainsel;
213
214 /* Fetch result */
215 result = adc_get_result();
216 ainsel = adc_get_selected_input();
217
218 /* Drain FIFO */
219 while (!adc_fifo_is_empty()) {
220 (void)adc_fifo_get();
221 }
222
223 /* Abort converting if error detected. */
224 if (adc_get_err()) {
225 adc_context_complete(&data->ctx, -EIO);
226 return;
227 }
228
229 /* Copy to buffer and mark this channel as completed to channels bitmap. */
230 *data->buf++ = result;
231 data->channels &= ~(BIT(ainsel));
232
233 /* Notify result if all data gathered. */
234 if (data->channels == 0) {
235 adc_context_on_sampling_done(&data->ctx, dev);
236 return;
237 }
238
239 /* Kick next channel conversion */
240 ainsel = (uint8_t)(find_lsb_set(data->channels) - 1);
241 adc_select_input(ainsel);
242 adc_start_once();
243 }
244
adc_rpi_read_async(const struct device * dev,const struct adc_sequence * sequence,struct k_poll_signal * async)245 static int adc_rpi_read_async(const struct device *dev,
246 const struct adc_sequence *sequence,
247 struct k_poll_signal *async)
248 {
249 struct adc_rpi_data *data = dev->data;
250 int err;
251
252 adc_context_lock(&data->ctx, async ? true : false, async);
253 err = adc_rpi_start_read(dev, sequence);
254 adc_context_release(&data->ctx, err);
255
256 return err;
257 }
258
adc_rpi_read(const struct device * dev,const struct adc_sequence * sequence)259 static int adc_rpi_read(const struct device *dev,
260 const struct adc_sequence *sequence)
261 {
262 return adc_rpi_read_async(dev, sequence, NULL);
263 }
264
adc_context_start_sampling(struct adc_context * ctx)265 static void adc_context_start_sampling(struct adc_context *ctx)
266 {
267 struct adc_rpi_data *data = CONTAINER_OF(ctx, struct adc_rpi_data,
268 ctx);
269
270 data->channels = ctx->sequence.channels;
271 data->repeat_buf = data->buf;
272
273 adc_clear_errors();
274
275 /* Find next channel and start conversion */
276 adc_select_input(find_lsb_set(data->channels) - 1);
277 adc_start_once();
278 }
279
adc_context_update_buffer_pointer(struct adc_context * ctx,bool repeat_sampling)280 static void adc_context_update_buffer_pointer(struct adc_context *ctx,
281 bool repeat_sampling)
282 {
283 struct adc_rpi_data *data = CONTAINER_OF(ctx, struct adc_rpi_data,
284 ctx);
285
286 if (repeat_sampling) {
287 data->buf = data->repeat_buf;
288 }
289 }
290
291 /**
292 * @brief Function called on init for each RaspberryPi Pico ADC device. It setups all
293 * channels to return constant 0 mV and create acquisition thread.
294 *
295 * @param dev RaspberryPi Pico ADC device
296 *
297 * @return 0 on success
298 */
adc_rpi_init(const struct device * dev)299 static int adc_rpi_init(const struct device *dev)
300 {
301 const struct adc_rpi_config *config = dev->config;
302 struct adc_rpi_data *data = dev->data;
303 int ret;
304
305 ret = pinctrl_apply_state(config->pcfg, PINCTRL_STATE_DEFAULT);
306 if (ret < 0) {
307 return ret;
308 }
309
310 ret = clock_control_on(config->clk_dev, config->clk_id);
311 if (ret < 0) {
312 return ret;
313 }
314
315 ret = reset_line_toggle_dt(&config->reset);
316 if (ret < 0) {
317 return ret;
318 }
319
320 config->irq_configure();
321
322 /*
323 * Configure the FIFO control register.
324 * Set the threshold as 1 for getting notification immediately
325 * on converting completed.
326 */
327 adc_fifo_setup(true, false, 1, true, true);
328
329 /* Set max speed to conversion */
330 adc_set_clkdiv(0.f);
331
332 /* Enable ADC and wait becoming READY */
333 adc_enable();
334
335 /* Enable FIFO interrupt */
336 adc_irq_set_enabled(true);
337
338 adc_context_unlock_unconditionally(&data->ctx);
339
340 return 0;
341 }
342
343 #define IRQ_CONFIGURE_FUNC(idx) \
344 static void adc_rpi_configure_func_##idx(void) \
345 { \
346 IRQ_CONNECT(DT_INST_IRQN(idx), DT_INST_IRQ(idx, priority), \
347 adc_rpi_isr, DEVICE_DT_INST_GET(idx), 0); \
348 irq_enable(DT_INST_IRQN(idx)); \
349 }
350
351 #define IRQ_CONFIGURE_DEFINE(idx) .irq_configure = adc_rpi_configure_func_##idx
352
353 #define ADC_RPI_INIT(idx) \
354 IRQ_CONFIGURE_FUNC(idx) \
355 PINCTRL_DT_INST_DEFINE(idx); \
356 static struct adc_driver_api adc_rpi_api_##idx = { \
357 .channel_setup = adc_rpi_channel_setup, \
358 .read = adc_rpi_read, \
359 .ref_internal = DT_INST_PROP(idx, vref_mv), \
360 IF_ENABLED(CONFIG_ADC_ASYNC, (.read_async = adc_rpi_read_async,)) \
361 }; \
362 static const struct adc_rpi_config adc_rpi_config_##idx = { \
363 .num_channels = ADC_RPI_CHANNEL_NUM, \
364 .pcfg = PINCTRL_DT_INST_DEV_CONFIG_GET(idx), \
365 .clk_dev = DEVICE_DT_GET(DT_INST_CLOCKS_CTLR(idx)), \
366 .clk_id = (clock_control_subsys_t)DT_INST_PHA_BY_IDX(idx, clocks, 0, clk_id), \
367 .reset = RESET_DT_SPEC_INST_GET(idx), \
368 IRQ_CONFIGURE_DEFINE(idx), \
369 }; \
370 static struct adc_rpi_data adc_rpi_data_##idx = { \
371 ADC_CONTEXT_INIT_TIMER(adc_rpi_data_##idx, ctx), \
372 ADC_CONTEXT_INIT_LOCK(adc_rpi_data_##idx, ctx), \
373 ADC_CONTEXT_INIT_SYNC(adc_rpi_data_##idx, ctx), \
374 .dev = DEVICE_DT_INST_GET(idx), \
375 }; \
376 \
377 DEVICE_DT_INST_DEFINE(idx, adc_rpi_init, NULL, \
378 &adc_rpi_data_##idx, \
379 &adc_rpi_config_##idx, POST_KERNEL, \
380 CONFIG_ADC_INIT_PRIORITY, \
381 &adc_rpi_api_##idx)
382
383 DT_INST_FOREACH_STATUS_OKAY(ADC_RPI_INIT);
384
