1 // SPDX-License-Identifier: GPL-2.0
3  * STM32 Low-Power Timer Encoder and Counter driver
9  * Inspired by 104-quad-8 and stm32-timer-trigger drivers.
14 #include <linux/counter.h>
15 #include <linux/mfd/stm32-lptimer.h>
22 	struct counter_device counter;  member
37 	ret = regmap_read(priv->regmap, STM32_LPTIM_CR, &val);  in stm32_lptim_is_enabled()
51 	ret = regmap_write(priv->regmap, STM32_LPTIM_CR, val);  in stm32_lptim_set_enable_state()
56 		clk_disable(priv->clk);  in stm32_lptim_set_enable_state()
57 		priv->enabled = false;  in stm32_lptim_set_enable_state()
61 	/* LP timer must be enabled before writing CMP & ARR */  in stm32_lptim_set_enable_state()
62 	ret = regmap_write(priv->regmap, STM32_LPTIM_ARR, priv->ceiling);  in stm32_lptim_set_enable_state()
66 	ret = regmap_write(priv->regmap, STM32_LPTIM_CMP, 0);  in stm32_lptim_set_enable_state()
71 	ret = regmap_read_poll_timeout(priv->regmap, STM32_LPTIM_ISR, val,  in stm32_lptim_set_enable_state()
77 	ret = regmap_write(priv->regmap, STM32_LPTIM_ICR,  in stm32_lptim_set_enable_state()
82 	ret = clk_enable(priv->clk);  in stm32_lptim_set_enable_state()
84 		regmap_write(priv->regmap, STM32_LPTIM_CR, 0);  in stm32_lptim_set_enable_state()
87 	priv->enabled = true;  in stm32_lptim_set_enable_state()
89 	/* Start LP timer in continuous mode */  in stm32_lptim_set_enable_state()
90 	return regmap_update_bits(priv->regmap, STM32_LPTIM_CR,  in stm32_lptim_set_enable_state()
100 	/* Setup LP timer encoder/counter and polarity, without prescaler */  in stm32_lptim_setup()
101 	if (priv->quadrature_mode)  in stm32_lptim_setup()
105 	val |= FIELD_PREP(STM32_LPTIM_CKPOL, enable ? priv->polarity : 0);  in stm32_lptim_setup()
107 	return regmap_update_bits(priv->regmap, STM32_LPTIM_CFGR, mask, val);  in stm32_lptim_setup()
111  * enum stm32_lptim_cnt_function - enumerates LPTimer counter & encoder modes
115  * In non-quadrature mode, device counts up on active edge.
117  * +---------+----------+--------------------+--------------------+
119  * | edge    | opposite +----------+---------+----------+---------+
121  * +---------+----------+----------+---------+----------+---------+
122  * | Rising  | High ->  |   Down   |    -    |   Up     |    -    |
123  * | edge    | Low  ->  |   Up     |    -    |   Down   |    -    |
124  * +---------+----------+----------+---------+----------+---------+
125  * | Falling | High ->  |    -     |   Up    |    -     |   Down  |
126  * | edge    | Low  ->  |    -     |   Down  |    -     |   Up    |
127  * +---------+----------+----------+---------+----------+---------+
128  * | Both    | High ->  |   Down   |   Up    |   Up     |   Down  |
129  * | edges   | Low  ->  |   Up     |   Down  |   Down   |   Up    |
130  * +---------+----------+----------+---------+----------+---------+
150 	/* Index must match with stm32_lptim_cnt_polarity[] (priv->polarity) */
157 static int stm32_lptim_cnt_read(struct counter_device *counter,  in stm32_lptim_cnt_read()  argument
160 	struct stm32_lptim_cnt *const priv = counter->priv;  in stm32_lptim_cnt_read()
164 	ret = regmap_read(priv->regmap, STM32_LPTIM_CNT, &cnt);  in stm32_lptim_cnt_read()
173 static int stm32_lptim_cnt_function_get(struct counter_device *counter,  in stm32_lptim_cnt_function_get()  argument
177 	struct stm32_lptim_cnt *const priv = counter->priv;  in stm32_lptim_cnt_function_get()
179 	if (!priv->quadrature_mode) {  in stm32_lptim_cnt_function_get()
184 	if (priv->polarity == STM32_LPTIM_SYNAPSE_ACTION_BOTH_EDGES) {  in stm32_lptim_cnt_function_get()
189 	return -EINVAL;  in stm32_lptim_cnt_function_get()
192 static int stm32_lptim_cnt_function_set(struct counter_device *counter,  in stm32_lptim_cnt_function_set()  argument
196 	struct stm32_lptim_cnt *const priv = counter->priv;  in stm32_lptim_cnt_function_set()
199 		return -EBUSY;  in stm32_lptim_cnt_function_set()
203 		priv->quadrature_mode = 0;  in stm32_lptim_cnt_function_set()
206 		priv->quadrature_mode = 1;  in stm32_lptim_cnt_function_set()
207 		priv->polarity = STM32_LPTIM_SYNAPSE_ACTION_BOTH_EDGES;  in stm32_lptim_cnt_function_set()
211 		return -EINVAL;  in stm32_lptim_cnt_function_set()
215 static ssize_t stm32_lptim_cnt_enable_read(struct counter_device *counter,  in stm32_lptim_cnt_enable_read()  argument
219 	struct stm32_lptim_cnt *const priv = counter->priv;  in stm32_lptim_cnt_enable_read()
229 static ssize_t stm32_lptim_cnt_enable_write(struct counter_device *counter,  in stm32_lptim_cnt_enable_write()  argument
234 	struct stm32_lptim_cnt *const priv = counter->priv;  in stm32_lptim_cnt_enable_write()
242 	/* Check nobody uses the timer, or already disabled/enabled */  in stm32_lptim_cnt_enable_write()
247 		return -EBUSY;  in stm32_lptim_cnt_enable_write()
260 static ssize_t stm32_lptim_cnt_ceiling_read(struct counter_device *counter,  in stm32_lptim_cnt_ceiling_read()  argument
264 	struct stm32_lptim_cnt *const priv = counter->priv;  in stm32_lptim_cnt_ceiling_read()
266 	return snprintf(buf, PAGE_SIZE, "%u\n", priv->ceiling);  in stm32_lptim_cnt_ceiling_read()
269 static ssize_t stm32_lptim_cnt_ceiling_write(struct counter_device *counter,  in stm32_lptim_cnt_ceiling_write()  argument
274 	struct stm32_lptim_cnt *const priv = counter->priv;  in stm32_lptim_cnt_ceiling_write()
279 		return -EBUSY;  in stm32_lptim_cnt_ceiling_write()
286 		return -ERANGE;  in stm32_lptim_cnt_ceiling_write()
288 	priv->ceiling = ceiling;  in stm32_lptim_cnt_ceiling_write()
306 static int stm32_lptim_cnt_action_get(struct counter_device *counter,  in stm32_lptim_cnt_action_get()  argument
311 	struct stm32_lptim_cnt *const priv = counter->priv;  in stm32_lptim_cnt_action_get()
315 	err = stm32_lptim_cnt_function_get(counter, count, &function);  in stm32_lptim_cnt_action_get()
321 		/* LP Timer acts as up-counter on input 1 */  in stm32_lptim_cnt_action_get()
322 		if (synapse->signal->id == count->synapses[0].signal->id)  in stm32_lptim_cnt_action_get()
323 			*action = priv->polarity;  in stm32_lptim_cnt_action_get()
328 		*action = priv->polarity;  in stm32_lptim_cnt_action_get()
332 		return -EINVAL;  in stm32_lptim_cnt_action_get()
336 static int stm32_lptim_cnt_action_set(struct counter_device *counter,  in stm32_lptim_cnt_action_set()  argument
341 	struct stm32_lptim_cnt *const priv = counter->priv;  in stm32_lptim_cnt_action_set()
346 		return -EBUSY;  in stm32_lptim_cnt_action_set()
348 	err = stm32_lptim_cnt_function_get(counter, count, &function);  in stm32_lptim_cnt_action_set()
352 	/* only set polarity when in counter mode (on input 1) */  in stm32_lptim_cnt_action_set()
354 	    && synapse->signal->id == count->synapses[0].signal->id) {  in stm32_lptim_cnt_action_set()
359 			priv->polarity = action;  in stm32_lptim_cnt_action_set()
364 	return -EINVAL;  in stm32_lptim_cnt_action_set()
399 /* LP timer with encoder */
411 /* LP timer without encoder (counter only) */
425 	struct stm32_lptimer *ddata = dev_get_drvdata(pdev->dev.parent);  in stm32_lptim_cnt_probe()
429 		return -EINVAL;  in stm32_lptim_cnt_probe()
431 	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);  in stm32_lptim_cnt_probe()
433 		return -ENOMEM;  in stm32_lptim_cnt_probe()
435 	priv->dev = &pdev->dev;  in stm32_lptim_cnt_probe()
436 	priv->regmap = ddata->regmap;  in stm32_lptim_cnt_probe()
437 	priv->clk = ddata->clk;  in stm32_lptim_cnt_probe()
438 	priv->ceiling = STM32_LPTIM_MAX_ARR;  in stm32_lptim_cnt_probe()
440 	/* Initialize Counter device */  in stm32_lptim_cnt_probe()
441 	priv->counter.name = dev_name(&pdev->dev);  in stm32_lptim_cnt_probe()
442 	priv->counter.parent = &pdev->dev;  in stm32_lptim_cnt_probe()
443 	priv->counter.ops = &stm32_lptim_cnt_ops;  in stm32_lptim_cnt_probe()
444 	if (ddata->has_encoder) {  in stm32_lptim_cnt_probe()
445 		priv->counter.counts = &stm32_lptim_enc_counts;  in stm32_lptim_cnt_probe()
446 		priv->counter.num_signals = ARRAY_SIZE(stm32_lptim_cnt_signals);  in stm32_lptim_cnt_probe()
448 		priv->counter.counts = &stm32_lptim_in1_counts;  in stm32_lptim_cnt_probe()
449 		priv->counter.num_signals = 1;  in stm32_lptim_cnt_probe()
451 	priv->counter.num_counts = 1;  in stm32_lptim_cnt_probe()
452 	priv->counter.signals = stm32_lptim_cnt_signals;  in stm32_lptim_cnt_probe()
453 	priv->counter.priv = priv;  in stm32_lptim_cnt_probe()
457 	return devm_counter_register(&pdev->dev, &priv->counter);  in stm32_lptim_cnt_probe()
466 	/* Only take care of enabled counter: don't disturb other MFD child */  in stm32_lptim_cnt_suspend()
467 	if (priv->enabled) {  in stm32_lptim_cnt_suspend()
477 		priv->enabled = true;  in stm32_lptim_cnt_suspend()
492 	if (priv->enabled) {  in stm32_lptim_cnt_resume()
493 		priv->enabled = false;  in stm32_lptim_cnt_resume()
511 	{ .compatible = "st,stm32-lptimer-counter", },
519 		.name = "stm32-lptimer-counter",
527 MODULE_ALIAS("platform:stm32-lptimer-counter");
528 MODULE_DESCRIPTION("STMicroelectronics STM32 LPTIM counter driver");