1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (C) 2020 Microchip
4  *
5  * Author: Kamel Bouhara <kamel.bouhara@bootlin.com>
6  */
7 #include <linux/clk.h>
8 #include <linux/counter.h>
9 #include <linux/mfd/syscon.h>
10 #include <linux/module.h>
11 #include <linux/mutex.h>
12 #include <linux/of.h>
13 #include <linux/platform_device.h>
14 #include <linux/regmap.h>
15 #include <soc/at91/atmel_tcb.h>
16 
17 #define ATMEL_TC_CMR_MASK	(ATMEL_TC_LDRA_RISING | ATMEL_TC_LDRB_FALLING | \
18 				 ATMEL_TC_ETRGEDG_RISING | ATMEL_TC_LDBDIS | \
19 				 ATMEL_TC_LDBSTOP)
20 
21 #define ATMEL_TC_QDEN			BIT(8)
22 #define ATMEL_TC_POSEN			BIT(9)
23 
24 struct mchp_tc_data {
25 	const struct atmel_tcb_config *tc_cfg;
26 	struct regmap *regmap;
27 	int qdec_mode;
28 	int num_channels;
29 	int channel[2];
30 };
31 
32 static const enum counter_function mchp_tc_count_functions[] = {
33 	COUNTER_FUNCTION_INCREASE,
34 	COUNTER_FUNCTION_QUADRATURE_X4,
35 };
36 
37 static const enum counter_synapse_action mchp_tc_synapse_actions[] = {
38 	COUNTER_SYNAPSE_ACTION_NONE,
39 	COUNTER_SYNAPSE_ACTION_RISING_EDGE,
40 	COUNTER_SYNAPSE_ACTION_FALLING_EDGE,
41 	COUNTER_SYNAPSE_ACTION_BOTH_EDGES,
42 };
43 
44 static struct counter_signal mchp_tc_count_signals[] = {
45 	{
46 		.id = 0,
47 		.name = "Channel A",
48 	},
49 	{
50 		.id = 1,
51 		.name = "Channel B",
52 	}
53 };
54 
55 static struct counter_synapse mchp_tc_count_synapses[] = {
56 	{
57 		.actions_list = mchp_tc_synapse_actions,
58 		.num_actions = ARRAY_SIZE(mchp_tc_synapse_actions),
59 		.signal = &mchp_tc_count_signals[0]
60 	},
61 	{
62 		.actions_list = mchp_tc_synapse_actions,
63 		.num_actions = ARRAY_SIZE(mchp_tc_synapse_actions),
64 		.signal = &mchp_tc_count_signals[1]
65 	}
66 };
67 
mchp_tc_count_function_read(struct counter_device * counter,struct counter_count * count,enum counter_function * function)68 static int mchp_tc_count_function_read(struct counter_device *counter,
69 				       struct counter_count *count,
70 				       enum counter_function *function)
71 {
72 	struct mchp_tc_data *const priv = counter_priv(counter);
73 
74 	if (priv->qdec_mode)
75 		*function = COUNTER_FUNCTION_QUADRATURE_X4;
76 	else
77 		*function = COUNTER_FUNCTION_INCREASE;
78 
79 	return 0;
80 }
81 
mchp_tc_count_function_write(struct counter_device * counter,struct counter_count * count,enum counter_function function)82 static int mchp_tc_count_function_write(struct counter_device *counter,
83 					struct counter_count *count,
84 					enum counter_function function)
85 {
86 	struct mchp_tc_data *const priv = counter_priv(counter);
87 	u32 bmr, cmr;
88 
89 	regmap_read(priv->regmap, ATMEL_TC_BMR, &bmr);
90 	regmap_read(priv->regmap, ATMEL_TC_REG(priv->channel[0], CMR), &cmr);
91 
92 	/* Set capture mode */
93 	cmr &= ~ATMEL_TC_WAVE;
94 
95 	switch (function) {
96 	case COUNTER_FUNCTION_INCREASE:
97 		priv->qdec_mode = 0;
98 		/* Set highest rate based on whether soc has gclk or not */
99 		bmr &= ~(ATMEL_TC_QDEN | ATMEL_TC_POSEN);
100 		if (!priv->tc_cfg->has_gclk)
101 			cmr |= ATMEL_TC_TIMER_CLOCK2;
102 		else
103 			cmr |= ATMEL_TC_TIMER_CLOCK1;
104 		/* Setup the period capture mode */
105 		cmr |=  ATMEL_TC_CMR_MASK;
106 		cmr &= ~(ATMEL_TC_ABETRG | ATMEL_TC_XC0);
107 		break;
108 	case COUNTER_FUNCTION_QUADRATURE_X4:
109 		if (!priv->tc_cfg->has_qdec)
110 			return -EINVAL;
111 		/* In QDEC mode settings both channels 0 and 1 are required */
112 		if (priv->num_channels < 2 || priv->channel[0] != 0 ||
113 		    priv->channel[1] != 1) {
114 			pr_err("Invalid channels number or id for quadrature mode\n");
115 			return -EINVAL;
116 		}
117 		priv->qdec_mode = 1;
118 		bmr |= ATMEL_TC_QDEN | ATMEL_TC_POSEN;
119 		cmr |= ATMEL_TC_ETRGEDG_RISING | ATMEL_TC_ABETRG | ATMEL_TC_XC0;
120 		break;
121 	default:
122 		/* should never reach this path */
123 		return -EINVAL;
124 	}
125 
126 	regmap_write(priv->regmap, ATMEL_TC_BMR, bmr);
127 	regmap_write(priv->regmap, ATMEL_TC_REG(priv->channel[0], CMR), cmr);
128 
129 	/* Enable clock and trigger counter */
130 	regmap_write(priv->regmap, ATMEL_TC_REG(priv->channel[0], CCR),
131 		     ATMEL_TC_CLKEN | ATMEL_TC_SWTRG);
132 
133 	if (priv->qdec_mode) {
134 		regmap_write(priv->regmap,
135 			     ATMEL_TC_REG(priv->channel[1], CMR), cmr);
136 		regmap_write(priv->regmap,
137 			     ATMEL_TC_REG(priv->channel[1], CCR),
138 			     ATMEL_TC_CLKEN | ATMEL_TC_SWTRG);
139 	}
140 
141 	return 0;
142 }
143 
mchp_tc_count_signal_read(struct counter_device * counter,struct counter_signal * signal,enum counter_signal_level * lvl)144 static int mchp_tc_count_signal_read(struct counter_device *counter,
145 				     struct counter_signal *signal,
146 				     enum counter_signal_level *lvl)
147 {
148 	struct mchp_tc_data *const priv = counter_priv(counter);
149 	bool sigstatus;
150 	u32 sr;
151 
152 	regmap_read(priv->regmap, ATMEL_TC_REG(priv->channel[0], SR), &sr);
153 
154 	if (signal->id == 1)
155 		sigstatus = (sr & ATMEL_TC_MTIOB);
156 	else
157 		sigstatus = (sr & ATMEL_TC_MTIOA);
158 
159 	*lvl = sigstatus ? COUNTER_SIGNAL_LEVEL_HIGH : COUNTER_SIGNAL_LEVEL_LOW;
160 
161 	return 0;
162 }
163 
mchp_tc_count_action_read(struct counter_device * counter,struct counter_count * count,struct counter_synapse * synapse,enum counter_synapse_action * action)164 static int mchp_tc_count_action_read(struct counter_device *counter,
165 				     struct counter_count *count,
166 				     struct counter_synapse *synapse,
167 				     enum counter_synapse_action *action)
168 {
169 	struct mchp_tc_data *const priv = counter_priv(counter);
170 	u32 cmr;
171 
172 	if (priv->qdec_mode) {
173 		*action = COUNTER_SYNAPSE_ACTION_BOTH_EDGES;
174 		return 0;
175 	}
176 
177 	/* Only TIOA signal is evaluated in non-QDEC mode */
178 	if (synapse->signal->id != 0) {
179 		*action = COUNTER_SYNAPSE_ACTION_NONE;
180 		return 0;
181 	}
182 
183 	regmap_read(priv->regmap, ATMEL_TC_REG(priv->channel[0], CMR), &cmr);
184 
185 	switch (cmr & ATMEL_TC_ETRGEDG) {
186 	default:
187 		*action = COUNTER_SYNAPSE_ACTION_NONE;
188 		break;
189 	case ATMEL_TC_ETRGEDG_RISING:
190 		*action = COUNTER_SYNAPSE_ACTION_RISING_EDGE;
191 		break;
192 	case ATMEL_TC_ETRGEDG_FALLING:
193 		*action = COUNTER_SYNAPSE_ACTION_FALLING_EDGE;
194 		break;
195 	case ATMEL_TC_ETRGEDG_BOTH:
196 		*action = COUNTER_SYNAPSE_ACTION_BOTH_EDGES;
197 		break;
198 	}
199 
200 	return 0;
201 }
202 
mchp_tc_count_action_write(struct counter_device * counter,struct counter_count * count,struct counter_synapse * synapse,enum counter_synapse_action action)203 static int mchp_tc_count_action_write(struct counter_device *counter,
204 				      struct counter_count *count,
205 				      struct counter_synapse *synapse,
206 				      enum counter_synapse_action action)
207 {
208 	struct mchp_tc_data *const priv = counter_priv(counter);
209 	u32 edge = ATMEL_TC_ETRGEDG_NONE;
210 
211 	/* QDEC mode is rising edge only; only TIOA handled in non-QDEC mode */
212 	if (priv->qdec_mode || synapse->signal->id != 0)
213 		return -EINVAL;
214 
215 	switch (action) {
216 	case COUNTER_SYNAPSE_ACTION_NONE:
217 		edge = ATMEL_TC_ETRGEDG_NONE;
218 		break;
219 	case COUNTER_SYNAPSE_ACTION_RISING_EDGE:
220 		edge = ATMEL_TC_ETRGEDG_RISING;
221 		break;
222 	case COUNTER_SYNAPSE_ACTION_FALLING_EDGE:
223 		edge = ATMEL_TC_ETRGEDG_FALLING;
224 		break;
225 	case COUNTER_SYNAPSE_ACTION_BOTH_EDGES:
226 		edge = ATMEL_TC_ETRGEDG_BOTH;
227 		break;
228 	default:
229 		/* should never reach this path */
230 		return -EINVAL;
231 	}
232 
233 	return regmap_write_bits(priv->regmap,
234 				ATMEL_TC_REG(priv->channel[0], CMR),
235 				ATMEL_TC_ETRGEDG, edge);
236 }
237 
mchp_tc_count_read(struct counter_device * counter,struct counter_count * count,u64 * val)238 static int mchp_tc_count_read(struct counter_device *counter,
239 			      struct counter_count *count, u64 *val)
240 {
241 	struct mchp_tc_data *const priv = counter_priv(counter);
242 	u32 cnt;
243 
244 	regmap_read(priv->regmap, ATMEL_TC_REG(priv->channel[0], CV), &cnt);
245 	*val = cnt;
246 
247 	return 0;
248 }
249 
250 static struct counter_count mchp_tc_counts[] = {
251 	{
252 		.id = 0,
253 		.name = "Timer Counter",
254 		.functions_list = mchp_tc_count_functions,
255 		.num_functions = ARRAY_SIZE(mchp_tc_count_functions),
256 		.synapses = mchp_tc_count_synapses,
257 		.num_synapses = ARRAY_SIZE(mchp_tc_count_synapses),
258 	},
259 };
260 
261 static const struct counter_ops mchp_tc_ops = {
262 	.signal_read    = mchp_tc_count_signal_read,
263 	.count_read     = mchp_tc_count_read,
264 	.function_read  = mchp_tc_count_function_read,
265 	.function_write = mchp_tc_count_function_write,
266 	.action_read    = mchp_tc_count_action_read,
267 	.action_write   = mchp_tc_count_action_write
268 };
269 
270 static const struct atmel_tcb_config tcb_rm9200_config = {
271 		.counter_width = 16,
272 };
273 
274 static const struct atmel_tcb_config tcb_sam9x5_config = {
275 		.counter_width = 32,
276 };
277 
278 static const struct atmel_tcb_config tcb_sama5d2_config = {
279 		.counter_width = 32,
280 		.has_gclk = true,
281 		.has_qdec = true,
282 };
283 
284 static const struct atmel_tcb_config tcb_sama5d3_config = {
285 		.counter_width = 32,
286 		.has_qdec = true,
287 };
288 
289 static const struct of_device_id atmel_tc_of_match[] = {
290 	{ .compatible = "atmel,at91rm9200-tcb", .data = &tcb_rm9200_config, },
291 	{ .compatible = "atmel,at91sam9x5-tcb", .data = &tcb_sam9x5_config, },
292 	{ .compatible = "atmel,sama5d2-tcb", .data = &tcb_sama5d2_config, },
293 	{ .compatible = "atmel,sama5d3-tcb", .data = &tcb_sama5d3_config, },
294 	{ /* sentinel */ }
295 };
296 
mchp_tc_clk_remove(void * ptr)297 static void mchp_tc_clk_remove(void *ptr)
298 {
299 	clk_disable_unprepare((struct clk *)ptr);
300 }
301 
mchp_tc_probe(struct platform_device * pdev)302 static int mchp_tc_probe(struct platform_device *pdev)
303 {
304 	struct device_node *np = pdev->dev.of_node;
305 	const struct atmel_tcb_config *tcb_config;
306 	const struct of_device_id *match;
307 	struct counter_device *counter;
308 	struct mchp_tc_data *priv;
309 	char clk_name[7];
310 	struct regmap *regmap;
311 	struct clk *clk[3];
312 	int channel;
313 	int ret, i;
314 
315 	counter = devm_counter_alloc(&pdev->dev, sizeof(*priv));
316 	if (!counter)
317 		return -ENOMEM;
318 	priv = counter_priv(counter);
319 
320 	match = of_match_node(atmel_tc_of_match, np->parent);
321 	tcb_config = match->data;
322 	if (!tcb_config) {
323 		dev_err(&pdev->dev, "No matching parent node found\n");
324 		return -ENODEV;
325 	}
326 
327 	regmap = syscon_node_to_regmap(np->parent);
328 	if (IS_ERR(regmap))
329 		return PTR_ERR(regmap);
330 
331 	/* max. channels number is 2 when in QDEC mode */
332 	priv->num_channels = of_property_count_u32_elems(np, "reg");
333 	if (priv->num_channels < 0) {
334 		dev_err(&pdev->dev, "Invalid or missing channel\n");
335 		return -EINVAL;
336 	}
337 
338 	/* Register channels and initialize clocks */
339 	for (i = 0; i < priv->num_channels; i++) {
340 		ret = of_property_read_u32_index(np, "reg", i, &channel);
341 		if (ret < 0 || channel > 2)
342 			return -ENODEV;
343 
344 		priv->channel[i] = channel;
345 
346 		snprintf(clk_name, sizeof(clk_name), "t%d_clk", channel);
347 
348 		clk[i] = of_clk_get_by_name(np->parent, clk_name);
349 		if (IS_ERR(clk[i])) {
350 			/* Fallback to t0_clk */
351 			clk[i] = of_clk_get_by_name(np->parent, "t0_clk");
352 			if (IS_ERR(clk[i]))
353 				return PTR_ERR(clk[i]);
354 		}
355 
356 		ret = clk_prepare_enable(clk[i]);
357 		if (ret)
358 			return ret;
359 
360 		ret = devm_add_action_or_reset(&pdev->dev,
361 					       mchp_tc_clk_remove,
362 					       clk[i]);
363 		if (ret)
364 			return ret;
365 
366 		dev_dbg(&pdev->dev,
367 			"Initialized capture mode on channel %d\n",
368 			channel);
369 	}
370 
371 	priv->tc_cfg = tcb_config;
372 	priv->regmap = regmap;
373 	counter->name = dev_name(&pdev->dev);
374 	counter->parent = &pdev->dev;
375 	counter->ops = &mchp_tc_ops;
376 	counter->num_counts = ARRAY_SIZE(mchp_tc_counts);
377 	counter->counts = mchp_tc_counts;
378 	counter->num_signals = ARRAY_SIZE(mchp_tc_count_signals);
379 	counter->signals = mchp_tc_count_signals;
380 
381 	ret = devm_counter_add(&pdev->dev, counter);
382 	if (ret < 0)
383 		return dev_err_probe(&pdev->dev, ret, "Failed to add counter\n");
384 
385 	return 0;
386 }
387 
388 static const struct of_device_id mchp_tc_dt_ids[] = {
389 	{ .compatible = "microchip,tcb-capture", },
390 	{ /* sentinel */ },
391 };
392 MODULE_DEVICE_TABLE(of, mchp_tc_dt_ids);
393 
394 static struct platform_driver mchp_tc_driver = {
395 	.probe = mchp_tc_probe,
396 	.driver = {
397 		.name = "microchip-tcb-capture",
398 		.of_match_table = mchp_tc_dt_ids,
399 	},
400 };
401 module_platform_driver(mchp_tc_driver);
402 
403 MODULE_AUTHOR("Kamel Bouhara <kamel.bouhara@bootlin.com>");
404 MODULE_DESCRIPTION("Microchip TCB Capture driver");
405 MODULE_LICENSE("GPL v2");
406 MODULE_IMPORT_NS(COUNTER);
407