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>
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 	ret = clk_enable(priv->clk);  in stm32_lptim_set_enable_state()
65 	/* LP timer must be enabled before writing CMP & ARR */  in stm32_lptim_set_enable_state()
66 	ret = regmap_write(priv->regmap, STM32_LPTIM_ARR, priv->ceiling);  in stm32_lptim_set_enable_state()
70 	ret = regmap_write(priv->regmap, STM32_LPTIM_CMP, 0);  in stm32_lptim_set_enable_state()
75 	ret = regmap_read_poll_timeout(priv->regmap, STM32_LPTIM_ISR, val,  in stm32_lptim_set_enable_state()
81 	ret = regmap_write(priv->regmap, STM32_LPTIM_ICR,  in stm32_lptim_set_enable_state()
86 	priv->enabled = true;  in stm32_lptim_set_enable_state()
88 	/* Start LP timer in continuous mode */  in stm32_lptim_set_enable_state()
89 	return regmap_update_bits(priv->regmap, STM32_LPTIM_CR,  in stm32_lptim_set_enable_state()
93 	clk_disable(priv->clk);  in stm32_lptim_set_enable_state()
95 	regmap_write(priv->regmap, STM32_LPTIM_CR, 0);  in stm32_lptim_set_enable_state()
106 	/* Setup LP timer encoder/counter and polarity, without prescaler */  in stm32_lptim_setup()
107 	if (priv->quadrature_mode)  in stm32_lptim_setup()
111 	val |= FIELD_PREP(STM32_LPTIM_CKPOL, enable ? priv->polarity : 0);  in stm32_lptim_setup()
113 	return regmap_update_bits(priv->regmap, STM32_LPTIM_CFGR, mask, val);  in stm32_lptim_setup()
117  * In non-quadrature mode, device counts up on active edge.
119  * +---------+----------+--------------------+--------------------+
121  * | edge    | opposite +----------+---------+----------+---------+
123  * +---------+----------+----------+---------+----------+---------+
124  * | Rising  | High ->  |   Down   |    -    |   Up     |    -    |
125  * | edge    | Low  ->  |   Up     |    -    |   Down   |    -    |
126  * +---------+----------+----------+---------+----------+---------+
127  * | Falling | High ->  |    -     |   Up    |    -     |   Down  |
128  * | edge    | Low  ->  |    -     |   Down  |    -     |   Up    |
129  * +---------+----------+----------+---------+----------+---------+
130  * | Both    | High ->  |   Down   |   Up    |   Up     |   Down  |
131  * | edges   | Low  ->  |   Up     |   Down  |   Down   |   Up    |
132  * +---------+----------+----------+---------+----------+---------+
146 static int stm32_lptim_cnt_read(struct counter_device *counter,  in stm32_lptim_cnt_read()  argument
149 	struct stm32_lptim_cnt *const priv = counter_priv(counter);  in stm32_lptim_cnt_read()
153 	ret = regmap_read(priv->regmap, STM32_LPTIM_CNT, &cnt);  in stm32_lptim_cnt_read()
162 static int stm32_lptim_cnt_function_read(struct counter_device *counter,  in stm32_lptim_cnt_function_read()  argument
166 	struct stm32_lptim_cnt *const priv = counter_priv(counter);  in stm32_lptim_cnt_function_read()
168 	if (!priv->quadrature_mode) {  in stm32_lptim_cnt_function_read()
173 	if (priv->polarity == STM32_LPTIM_CKPOL_BOTH_EDGES) {  in stm32_lptim_cnt_function_read()
178 	return -EINVAL;  in stm32_lptim_cnt_function_read()
181 static int stm32_lptim_cnt_function_write(struct counter_device *counter,  in stm32_lptim_cnt_function_write()  argument
185 	struct stm32_lptim_cnt *const priv = counter_priv(counter);  in stm32_lptim_cnt_function_write()
188 		return -EBUSY;  in stm32_lptim_cnt_function_write()
192 		priv->quadrature_mode = 0;  in stm32_lptim_cnt_function_write()
195 		priv->quadrature_mode = 1;  in stm32_lptim_cnt_function_write()
196 		priv->polarity = STM32_LPTIM_CKPOL_BOTH_EDGES;  in stm32_lptim_cnt_function_write()
200 		return -EINVAL;  in stm32_lptim_cnt_function_write()
204 static int stm32_lptim_cnt_enable_read(struct counter_device *counter,  in stm32_lptim_cnt_enable_read()  argument
208 	struct stm32_lptim_cnt *const priv = counter_priv(counter);  in stm32_lptim_cnt_enable_read()
220 static int stm32_lptim_cnt_enable_write(struct counter_device *counter,  in stm32_lptim_cnt_enable_write()  argument
224 	struct stm32_lptim_cnt *const priv = counter_priv(counter);  in stm32_lptim_cnt_enable_write()
227 	/* Check nobody uses the timer, or already disabled/enabled */  in stm32_lptim_cnt_enable_write()
232 		return -EBUSY;  in stm32_lptim_cnt_enable_write()
245 static int stm32_lptim_cnt_ceiling_read(struct counter_device *counter,  in stm32_lptim_cnt_ceiling_read()  argument
249 	struct stm32_lptim_cnt *const priv = counter_priv(counter);  in stm32_lptim_cnt_ceiling_read()
251 	*ceiling = priv->ceiling;  in stm32_lptim_cnt_ceiling_read()
256 static int stm32_lptim_cnt_ceiling_write(struct counter_device *counter,  in stm32_lptim_cnt_ceiling_write()  argument
260 	struct stm32_lptim_cnt *const priv = counter_priv(counter);  in stm32_lptim_cnt_ceiling_write()
263 		return -EBUSY;  in stm32_lptim_cnt_ceiling_write()
266 		return -ERANGE;  in stm32_lptim_cnt_ceiling_write()
268 	priv->ceiling = ceiling;  in stm32_lptim_cnt_ceiling_write()
280 static int stm32_lptim_cnt_action_read(struct counter_device *counter,  in stm32_lptim_cnt_action_read()  argument
285 	struct stm32_lptim_cnt *const priv = counter_priv(counter);  in stm32_lptim_cnt_action_read()
289 	err = stm32_lptim_cnt_function_read(counter, count, &function);  in stm32_lptim_cnt_action_read()
295 		/* LP Timer acts as up-counter on input 1 */  in stm32_lptim_cnt_action_read()
296 		if (synapse->signal->id != count->synapses[0].signal->id) {  in stm32_lptim_cnt_action_read()
301 		switch (priv->polarity) {  in stm32_lptim_cnt_action_read()
313 			return -EINVAL;  in stm32_lptim_cnt_action_read()
320 		return -EINVAL;  in stm32_lptim_cnt_action_read()
324 static int stm32_lptim_cnt_action_write(struct counter_device *counter,  in stm32_lptim_cnt_action_write()  argument
329 	struct stm32_lptim_cnt *const priv = counter_priv(counter);  in stm32_lptim_cnt_action_write()
334 		return -EBUSY;  in stm32_lptim_cnt_action_write()
336 	err = stm32_lptim_cnt_function_read(counter, count, &function);  in stm32_lptim_cnt_action_write()
340 	/* only set polarity when in counter mode (on input 1) */  in stm32_lptim_cnt_action_write()
342 	    || synapse->signal->id != count->synapses[0].signal->id)  in stm32_lptim_cnt_action_write()
343 		return -EINVAL;  in stm32_lptim_cnt_action_write()
347 		priv->polarity = STM32_LPTIM_CKPOL_RISING_EDGE;  in stm32_lptim_cnt_action_write()
350 		priv->polarity = STM32_LPTIM_CKPOL_FALLING_EDGE;  in stm32_lptim_cnt_action_write()
353 		priv->polarity = STM32_LPTIM_CKPOL_BOTH_EDGES;  in stm32_lptim_cnt_action_write()
356 		return -EINVAL;  in stm32_lptim_cnt_action_write()
392 /* LP timer with encoder */
404 /* LP timer without encoder (counter only) */
418 	struct stm32_lptimer *ddata = dev_get_drvdata(pdev->dev.parent);  in stm32_lptim_cnt_probe()
419 	struct counter_device *counter;  in stm32_lptim_cnt_probe()  local
424 		return -EINVAL;  in stm32_lptim_cnt_probe()
426 	counter = devm_counter_alloc(&pdev->dev, sizeof(*priv));  in stm32_lptim_cnt_probe()
427 	if (!counter)  in stm32_lptim_cnt_probe()
428 		return -ENOMEM;  in stm32_lptim_cnt_probe()
429 	priv = counter_priv(counter);  in stm32_lptim_cnt_probe()
431 	priv->dev = &pdev->dev;  in stm32_lptim_cnt_probe()
432 	priv->regmap = ddata->regmap;  in stm32_lptim_cnt_probe()
433 	priv->clk = ddata->clk;  in stm32_lptim_cnt_probe()
434 	priv->ceiling = STM32_LPTIM_MAX_ARR;  in stm32_lptim_cnt_probe()
436 	/* Initialize Counter device */  in stm32_lptim_cnt_probe()
437 	counter->name = dev_name(&pdev->dev);  in stm32_lptim_cnt_probe()
438 	counter->parent = &pdev->dev;  in stm32_lptim_cnt_probe()
439 	counter->ops = &stm32_lptim_cnt_ops;  in stm32_lptim_cnt_probe()
440 	if (ddata->has_encoder) {  in stm32_lptim_cnt_probe()
441 		counter->counts = &stm32_lptim_enc_counts;  in stm32_lptim_cnt_probe()
442 		counter->num_signals = ARRAY_SIZE(stm32_lptim_cnt_signals);  in stm32_lptim_cnt_probe()
444 		counter->counts = &stm32_lptim_in1_counts;  in stm32_lptim_cnt_probe()
445 		counter->num_signals = 1;  in stm32_lptim_cnt_probe()
447 	counter->num_counts = 1;  in stm32_lptim_cnt_probe()
448 	counter->signals = stm32_lptim_cnt_signals;  in stm32_lptim_cnt_probe()
452 	ret = devm_counter_add(&pdev->dev, counter);  in stm32_lptim_cnt_probe()
454 		return dev_err_probe(&pdev->dev, ret, "Failed to add counter\n");  in stm32_lptim_cnt_probe()
465 	/* Only take care of enabled counter: don't disturb other MFD child */  in stm32_lptim_cnt_suspend()
466 	if (priv->enabled) {  in stm32_lptim_cnt_suspend()
476 		priv->enabled = true;  in stm32_lptim_cnt_suspend()
491 	if (priv->enabled) {  in stm32_lptim_cnt_resume()
492 		priv->enabled = false;  in stm32_lptim_cnt_resume()
510 	{ .compatible = "st,stm32-lptimer-counter", },
518 		.name = "stm32-lptimer-counter",
526 MODULE_ALIAS("platform:stm32-lptimer-counter");
527 MODULE_DESCRIPTION("STMicroelectronics STM32 LPTIM counter driver");
529 MODULE_IMPORT_NS(COUNTER);