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>
16 #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()
120 			return -EINVAL;  in stm32_lptim_write_raw()
122 		/* Check nobody uses the timer, or already disabled/enabled */  in stm32_lptim_write_raw()
127 			return -EBUSY;  in stm32_lptim_write_raw()
135 		return -EINVAL;  in stm32_lptim_write_raw()
149 		ret = regmap_read(priv->regmap, STM32_LPTIM_CNT, &dat);  in stm32_lptim_read_raw()
163 		/* Non-quadrature mode: scale = 1 */  in stm32_lptim_read_raw()
166 		if (priv->quadrature_mode) {  in stm32_lptim_read_raw()
169 			 * - both edges, quarter cycle, scale is 0.25  in stm32_lptim_read_raw()
170 			 * - either rising/falling edge scale is 0.5  in stm32_lptim_read_raw()
172 			if (priv->polarity > 1)  in stm32_lptim_read_raw()
180 		return -EINVAL;  in stm32_lptim_read_raw()
190 	"non-quadrature",
199 	return priv->quadrature_mode;  in stm32_lptim_get_quadrature_mode()
209 		return -EBUSY;  in stm32_lptim_set_quadrature_mode()
211 	priv->quadrature_mode = type;  in stm32_lptim_set_quadrature_mode()
224 	"rising-edge", "falling-edge", "both-edges",
232 	return priv->polarity;  in stm32_lptim_cnt_get_polarity()
242 		return -EBUSY;  in stm32_lptim_cnt_set_polarity()
244 	priv->polarity = type;  in stm32_lptim_cnt_set_polarity()
259 	return snprintf(buf, PAGE_SIZE, "%u\n", priv->ceiling);  in stm32_lptim_cnt_get_ceiling()
268 		return -EBUSY;  in stm32_lptim_cnt_set_ceiling()
270 	ret = kstrtouint(buf, 0, &priv->ceiling);  in stm32_lptim_cnt_set_ceiling()
274 	if (priv->ceiling > STM32_LPTIM_MAX_ARR)  in stm32_lptim_cnt_set_ceiling()
275 		return -EINVAL;  in stm32_lptim_cnt_set_ceiling()
300 /* LP timer with encoder */
326 /* LP timer without encoder (counter only) */
350  * enum stm32_lptim_cnt_function - enumerates LPTimer counter & encoder modes
372 	/* Index must match with stm32_lptim_cnt_polarity[] (priv->polarity) */
379 static int stm32_lptim_cnt_read(struct counter_device *counter,  in stm32_lptim_cnt_read()  argument
382 	struct stm32_lptim_cnt *const priv = counter->priv;  in stm32_lptim_cnt_read()
386 	ret = regmap_read(priv->regmap, STM32_LPTIM_CNT, &cnt);  in stm32_lptim_cnt_read()
395 static int stm32_lptim_cnt_function_get(struct counter_device *counter,  in stm32_lptim_cnt_function_get()  argument
399 	struct stm32_lptim_cnt *const priv = counter->priv;  in stm32_lptim_cnt_function_get()
401 	if (!priv->quadrature_mode) {  in stm32_lptim_cnt_function_get()
406 	if (priv->polarity == STM32_LPTIM_SYNAPSE_ACTION_BOTH_EDGES) {  in stm32_lptim_cnt_function_get()
411 	return -EINVAL;  in stm32_lptim_cnt_function_get()
414 static int stm32_lptim_cnt_function_set(struct counter_device *counter,  in stm32_lptim_cnt_function_set()  argument
418 	struct stm32_lptim_cnt *const priv = counter->priv;  in stm32_lptim_cnt_function_set()
421 		return -EBUSY;  in stm32_lptim_cnt_function_set()
425 		priv->quadrature_mode = 0;  in stm32_lptim_cnt_function_set()
428 		priv->quadrature_mode = 1;  in stm32_lptim_cnt_function_set()
429 		priv->polarity = STM32_LPTIM_SYNAPSE_ACTION_BOTH_EDGES;  in stm32_lptim_cnt_function_set()
433 	return -EINVAL;  in stm32_lptim_cnt_function_set()
436 static ssize_t stm32_lptim_cnt_enable_read(struct counter_device *counter,  in stm32_lptim_cnt_enable_read()  argument
440 	struct stm32_lptim_cnt *const priv = counter->priv;  in stm32_lptim_cnt_enable_read()
450 static ssize_t stm32_lptim_cnt_enable_write(struct counter_device *counter,  in stm32_lptim_cnt_enable_write()  argument
455 	struct stm32_lptim_cnt *const priv = counter->priv;  in stm32_lptim_cnt_enable_write()
463 	/* Check nobody uses the timer, or already disabled/enabled */  in stm32_lptim_cnt_enable_write()
468 		return -EBUSY;  in stm32_lptim_cnt_enable_write()
481 static ssize_t stm32_lptim_cnt_ceiling_read(struct counter_device *counter,  in stm32_lptim_cnt_ceiling_read()  argument
485 	struct stm32_lptim_cnt *const priv = counter->priv;  in stm32_lptim_cnt_ceiling_read()
490 static ssize_t stm32_lptim_cnt_ceiling_write(struct counter_device *counter,  in stm32_lptim_cnt_ceiling_write()  argument
495 	struct stm32_lptim_cnt *const priv = counter->priv;  in stm32_lptim_cnt_ceiling_write()
513 static int stm32_lptim_cnt_action_get(struct counter_device *counter,  in stm32_lptim_cnt_action_get()  argument
518 	struct stm32_lptim_cnt *const priv = counter->priv;  in stm32_lptim_cnt_action_get()
522 	err = stm32_lptim_cnt_function_get(counter, count, &function);  in stm32_lptim_cnt_action_get()
528 		/* LP Timer acts as up-counter on input 1 */  in stm32_lptim_cnt_action_get()
529 		if (synapse->signal->id == count->synapses[0].signal->id)  in stm32_lptim_cnt_action_get()
530 			*action = priv->polarity;  in stm32_lptim_cnt_action_get()
535 		*action = priv->polarity;  in stm32_lptim_cnt_action_get()
539 	return -EINVAL;  in stm32_lptim_cnt_action_get()
542 static int stm32_lptim_cnt_action_set(struct counter_device *counter,  in stm32_lptim_cnt_action_set()  argument
547 	struct stm32_lptim_cnt *const priv = counter->priv;  in stm32_lptim_cnt_action_set()
552 		return -EBUSY;  in stm32_lptim_cnt_action_set()
554 	err = stm32_lptim_cnt_function_get(counter, count, &function);  in stm32_lptim_cnt_action_set()
558 	/* only set polarity when in counter mode (on input 1) */  in stm32_lptim_cnt_action_set()
560 	    && synapse->signal->id == count->synapses[0].signal->id) {  in stm32_lptim_cnt_action_set()
565 			priv->polarity = action;  in stm32_lptim_cnt_action_set()
570 	return -EINVAL;  in stm32_lptim_cnt_action_set()
605 /* LP timer with encoder */
617 /* LP timer without encoder (counter only) */
631 	struct stm32_lptimer *ddata = dev_get_drvdata(pdev->dev.parent);  in stm32_lptim_cnt_probe()
637 		return -EINVAL;  in stm32_lptim_cnt_probe()
639 	indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*priv));  in stm32_lptim_cnt_probe()
641 		return -ENOMEM;  in stm32_lptim_cnt_probe()
644 	priv->dev = &pdev->dev;  in stm32_lptim_cnt_probe()
645 	priv->regmap = ddata->regmap;  in stm32_lptim_cnt_probe()
646 	priv->clk = ddata->clk;  in stm32_lptim_cnt_probe()
647 	priv->ceiling = STM32_LPTIM_MAX_ARR;  in stm32_lptim_cnt_probe()
650 	indio_dev->name = dev_name(&pdev->dev);  in stm32_lptim_cnt_probe()
651 	indio_dev->dev.of_node = pdev->dev.of_node;  in stm32_lptim_cnt_probe()
652 	indio_dev->info = &stm32_lptim_cnt_iio_info;  in stm32_lptim_cnt_probe()
653 	if (ddata->has_encoder)  in stm32_lptim_cnt_probe()
654 		indio_dev->channels = &stm32_lptim_enc_channels;  in stm32_lptim_cnt_probe()
656 		indio_dev->channels = &stm32_lptim_cnt_channels;  in stm32_lptim_cnt_probe()
657 	indio_dev->num_channels = 1;  in stm32_lptim_cnt_probe()
659 	/* Initialize Counter device */  in stm32_lptim_cnt_probe()
660 	priv->counter.name = dev_name(&pdev->dev);  in stm32_lptim_cnt_probe()
661 	priv->counter.parent = &pdev->dev;  in stm32_lptim_cnt_probe()
662 	priv->counter.ops = &stm32_lptim_cnt_ops;  in stm32_lptim_cnt_probe()
663 	if (ddata->has_encoder) {  in stm32_lptim_cnt_probe()
664 		priv->counter.counts = &stm32_lptim_enc_counts;  in stm32_lptim_cnt_probe()
665 		priv->counter.num_signals = ARRAY_SIZE(stm32_lptim_cnt_signals);  in stm32_lptim_cnt_probe()
667 		priv->counter.counts = &stm32_lptim_in1_counts;  in stm32_lptim_cnt_probe()
668 		priv->counter.num_signals = 1;  in stm32_lptim_cnt_probe()
670 	priv->counter.num_counts = 1;  in stm32_lptim_cnt_probe()
671 	priv->counter.signals = stm32_lptim_cnt_signals;  in stm32_lptim_cnt_probe()
672 	priv->counter.priv = priv;  in stm32_lptim_cnt_probe()
676 	ret = devm_iio_device_register(&pdev->dev, indio_dev);  in stm32_lptim_cnt_probe()
680 	return devm_counter_register(&pdev->dev, &priv->counter);  in stm32_lptim_cnt_probe()
689 	/* Only take care of enabled counter: don't disturb other MFD child */  in stm32_lptim_cnt_suspend()
690 	if (priv->enabled) {  in stm32_lptim_cnt_suspend()
700 		priv->enabled = true;  in stm32_lptim_cnt_suspend()
715 	if (priv->enabled) {  in stm32_lptim_cnt_resume()
716 		priv->enabled = false;  in stm32_lptim_cnt_resume()
734 	{ .compatible = "st,stm32-lptimer-counter", },
742 		.name = "stm32-lptimer-counter",
750 MODULE_ALIAS("platform:stm32-lptimer-counter");
751 MODULE_DESCRIPTION("STMicroelectronics STM32 LPTIM counter driver");