1 // SPDX-License-Identifier: GPL-2.0-only
9  * Also based on pwm-samsung.c
13  *   PWM driver / controller, using the OMAP's dual-mode timers
15  *   reloaded with the load value and the pwm output goes up.
20  * - When PWM is stopped, timer counter gets stopped immediately. This
21  *   doesn't allow the current PWM period to complete and stops abruptly.
22  * - When PWM is running and changing both duty cycle and period,
25  *   is updated while the pwm pin is high, current pwm period/duty_cycle
27  *   	- period for current cycle =  current_period + new period
28  *   	- duty_cycle for current period = current period + new duty_cycle.
29  * - PWM OMAP DM timer cannot change the polarity when pwm is active. When
30  *   user requests a change in polarity when in active state:
31  *	- PWM is stopped abruptly(without completing the current cycle)
32  *	- Polarity is changed
33  *	- A fresh cycle is started.
43 #include <clocksource/timer-ti-dm.h>
44 #include <linux/platform_data/dmtimer-omap.h>
47 #include <linux/pwm.h>
55  * struct pwm_omap_dmtimer_chip - Structure representing a pwm chip
57  * @chip:		PWM chip structure representing PWM controller
58  * @mutex:		Mutex to protect pwm apply state
65 	/* Mutex to protect pwm apply state */
79  * pwm_omap_dmtimer_get_clock_cycles() - Get clock cycles in a time frame
80  * @clk_rate:	pwm timer clock rate
91  * pwm_omap_dmtimer_start() - Start the pwm omap dm timer in pwm mode
92  * @omap:	Pointer to pwm omap dm timer chip
99 	 * that the PWM line is toggled on the first event.  in pwm_omap_dmtimer_start()
104 	omap->pdata->enable(omap->dm_timer);  in pwm_omap_dmtimer_start()
105 	omap->pdata->write_counter(omap->dm_timer, DM_TIMER_LOAD_MIN);  in pwm_omap_dmtimer_start()
106 	omap->pdata->disable(omap->dm_timer);  in pwm_omap_dmtimer_start()
108 	omap->pdata->start(omap->dm_timer);  in pwm_omap_dmtimer_start()
112  * pwm_omap_dmtimer_is_enabled() -  Detect if the pwm is enabled.
113  * @omap:	Pointer to pwm omap dm timer chip
115  * Return true if pwm is enabled else false.
121 	status = omap->pdata->get_pwm_status(omap->dm_timer);  in pwm_omap_dmtimer_is_enabled()
127  * pwm_omap_dmtimer_polarity() -  Detect the polarity of pwm.
128  * @omap:	Pointer to pwm omap dm timer chip
130  * Return the polarity of pwm.
136 	status = omap->pdata->get_pwm_status(omap->dm_timer);  in pwm_omap_dmtimer_polarity()
142  * pwm_omap_dmtimer_config() - Update the configuration of pwm omap dm timer
143  * @chip:	Pointer to PWM controller
144  * @pwm:	Pointer to PWM channel
152 				   struct pwm_device *pwm,  in pwm_omap_dmtimer_config()  argument
161 	dev_dbg(chip->dev, "requested duty cycle: %d ns, period: %d ns\n",  in pwm_omap_dmtimer_config()
164 	if (duty_ns == pwm_get_duty_cycle(pwm) &&  in pwm_omap_dmtimer_config()
165 	    period_ns == pwm_get_period(pwm))  in pwm_omap_dmtimer_config()
168 	fclk = omap->pdata->get_fclk(omap->dm_timer);  in pwm_omap_dmtimer_config()
170 		dev_err(chip->dev, "invalid pmtimer fclk\n");  in pwm_omap_dmtimer_config()
171 		return -EINVAL;  in pwm_omap_dmtimer_config()
176 		dev_err(chip->dev, "invalid pmtimer fclk rate\n");  in pwm_omap_dmtimer_config()
177 		return -EINVAL;  in pwm_omap_dmtimer_config()
180 	dev_dbg(chip->dev, "clk rate: %luHz\n", clk_rate);  in pwm_omap_dmtimer_config()
187 	 * The period lasts for (DM_TIMER_MAX-load_value+1) clock cycles.  in pwm_omap_dmtimer_config()
188 	 * Similarly, the active time lasts (match_value-load_value+1) cycles.  in pwm_omap_dmtimer_config()
189 	 * The non-active time is the remainder: (DM_TIMER_MAX-match_value)  in pwm_omap_dmtimer_config()
202 		dev_info(chip->dev,  in pwm_omap_dmtimer_config()
205 		return -EINVAL;  in pwm_omap_dmtimer_config()
209 		dev_dbg(chip->dev,  in pwm_omap_dmtimer_config()
212 		dev_dbg(chip->dev, "using minimum of 1 clock cycle\n");  in pwm_omap_dmtimer_config()
215 		dev_dbg(chip->dev,  in pwm_omap_dmtimer_config()
218 		dev_dbg(chip->dev, "using maximum of 1 clock cycle less than period\n");  in pwm_omap_dmtimer_config()
219 		duty_cycles = period_cycles - 1;  in pwm_omap_dmtimer_config()
222 	dev_dbg(chip->dev, "effective duty cycle: %lld ns, period: %lld ns\n",  in pwm_omap_dmtimer_config()
228 	load_value = (DM_TIMER_MAX - period_cycles) + 1;  in pwm_omap_dmtimer_config()
229 	match_value = load_value + duty_cycles - 1;  in pwm_omap_dmtimer_config()
231 	omap->pdata->set_load(omap->dm_timer, load_value);  in pwm_omap_dmtimer_config()
232 	omap->pdata->set_match(omap->dm_timer, true, match_value);  in pwm_omap_dmtimer_config()
234 	dev_dbg(chip->dev, "load value: %#08x (%d), match value: %#08x (%d)\n",  in pwm_omap_dmtimer_config()
241  * pwm_omap_dmtimer_set_polarity() - Changes the polarity of the pwm dm timer.
242  * @chip:	Pointer to PWM controller
243  * @pwm:	Pointer to PWM channel
244  * @polarity:	New pwm polarity to be set
247 					  struct pwm_device *pwm,  in pwm_omap_dmtimer_set_polarity()  argument
253 	/* Disable the PWM before changing the polarity. */  in pwm_omap_dmtimer_set_polarity()
256 		omap->pdata->stop(omap->dm_timer);  in pwm_omap_dmtimer_set_polarity()
258 	omap->pdata->set_pwm(omap->dm_timer,  in pwm_omap_dmtimer_set_polarity()
268  * pwm_omap_dmtimer_apply() - Changes the state of the pwm omap dm timer.
269  * @chip:	Pointer to PWM controller
270  * @pwm:	Pointer to PWM channel
271  * @state:	New state to apply
273  * Return 0 if successfully changed the state else appropriate error.
276 				  struct pwm_device *pwm,  in pwm_omap_dmtimer_apply()  argument
277 				  const struct pwm_state *state)  in pwm_omap_dmtimer_apply()  argument
282 	mutex_lock(&omap->mutex);  in pwm_omap_dmtimer_apply()
284 	if (pwm_omap_dmtimer_is_enabled(omap) && !state->enabled) {  in pwm_omap_dmtimer_apply()
285 		omap->pdata->stop(omap->dm_timer);  in pwm_omap_dmtimer_apply()
289 	if (pwm_omap_dmtimer_polarity(omap) != state->polarity)  in pwm_omap_dmtimer_apply()
290 		pwm_omap_dmtimer_set_polarity(chip, pwm, state->polarity);  in pwm_omap_dmtimer_apply()
292 	ret = pwm_omap_dmtimer_config(chip, pwm, state->duty_cycle,  in pwm_omap_dmtimer_apply()
293 				      state->period);  in pwm_omap_dmtimer_apply()
297 	if (!pwm_omap_dmtimer_is_enabled(omap) && state->enabled) {  in pwm_omap_dmtimer_apply()
298 		omap->pdata->set_pwm(omap->dm_timer,  in pwm_omap_dmtimer_apply()
299 				     state->polarity == PWM_POLARITY_INVERSED,  in pwm_omap_dmtimer_apply()
307 	mutex_unlock(&omap->mutex);  in pwm_omap_dmtimer_apply()
319 	struct device_node *np = pdev->dev.of_node;  in pwm_omap_dmtimer_probe()
331 		return -ENODEV;  in pwm_omap_dmtimer_probe()
335 		dev_err(&pdev->dev, "Unable to find Timer pdev\n");  in pwm_omap_dmtimer_probe()
336 		ret = -ENODEV;  in pwm_omap_dmtimer_probe()
340 	timer_pdata = dev_get_platdata(&timer_pdev->dev);  in pwm_omap_dmtimer_probe()
342 		dev_dbg(&pdev->dev,  in pwm_omap_dmtimer_probe()
344 		ret = -EPROBE_DEFER;  in pwm_omap_dmtimer_probe()
348 	pdata = timer_pdata->timer_ops;  in pwm_omap_dmtimer_probe()
350 	if (!pdata || !pdata->request_by_node ||  in pwm_omap_dmtimer_probe()
351 	    !pdata->free ||  in pwm_omap_dmtimer_probe()
352 	    !pdata->enable ||  in pwm_omap_dmtimer_probe()
353 	    !pdata->disable ||  in pwm_omap_dmtimer_probe()
354 	    !pdata->get_fclk ||  in pwm_omap_dmtimer_probe()
355 	    !pdata->start ||  in pwm_omap_dmtimer_probe()
356 	    !pdata->stop ||  in pwm_omap_dmtimer_probe()
357 	    !pdata->set_load ||  in pwm_omap_dmtimer_probe()
358 	    !pdata->set_match ||  in pwm_omap_dmtimer_probe()
359 	    !pdata->set_pwm ||  in pwm_omap_dmtimer_probe()
360 	    !pdata->get_pwm_status ||  in pwm_omap_dmtimer_probe()
361 	    !pdata->set_prescaler ||  in pwm_omap_dmtimer_probe()
362 	    !pdata->write_counter) {  in pwm_omap_dmtimer_probe()
363 		dev_err(&pdev->dev, "Incomplete dmtimer pdata structure\n");  in pwm_omap_dmtimer_probe()
364 		ret = -EINVAL;  in pwm_omap_dmtimer_probe()
368 	if (!of_get_property(timer, "ti,timer-pwm", NULL)) {  in pwm_omap_dmtimer_probe()
369 		dev_err(&pdev->dev, "Missing ti,timer-pwm capability\n");  in pwm_omap_dmtimer_probe()
370 		ret = -ENODEV;  in pwm_omap_dmtimer_probe()
374 	dm_timer = pdata->request_by_node(timer);  in pwm_omap_dmtimer_probe()
376 		ret = -EPROBE_DEFER;  in pwm_omap_dmtimer_probe()
380 	omap = devm_kzalloc(&pdev->dev, sizeof(*omap), GFP_KERNEL);  in pwm_omap_dmtimer_probe()
382 		ret = -ENOMEM;  in pwm_omap_dmtimer_probe()
386 	omap->pdata = pdata;  in pwm_omap_dmtimer_probe()
387 	omap->dm_timer = dm_timer;  in pwm_omap_dmtimer_probe()
388 	omap->dm_timer_pdev = timer_pdev;  in pwm_omap_dmtimer_probe()
391 	 * Ensure that the timer is stopped before we allow PWM core to call  in pwm_omap_dmtimer_probe()
394 	if (pm_runtime_active(&omap->dm_timer_pdev->dev))  in pwm_omap_dmtimer_probe()
395 		omap->pdata->stop(omap->dm_timer);  in pwm_omap_dmtimer_probe()
397 	if (!of_property_read_u32(pdev->dev.of_node, "ti,prescaler", &v))  in pwm_omap_dmtimer_probe()
398 		omap->pdata->set_prescaler(omap->dm_timer, v);  in pwm_omap_dmtimer_probe()
401 	if (!of_property_read_u32(pdev->dev.of_node, "ti,clock-source", &v))  in pwm_omap_dmtimer_probe()
402 		omap->pdata->set_source(omap->dm_timer, v);  in pwm_omap_dmtimer_probe()
404 	omap->chip.dev = &pdev->dev;  in pwm_omap_dmtimer_probe()
405 	omap->chip.ops = &pwm_omap_dmtimer_ops;  in pwm_omap_dmtimer_probe()
406 	omap->chip.npwm = 1;  in pwm_omap_dmtimer_probe()
408 	mutex_init(&omap->mutex);  in pwm_omap_dmtimer_probe()
410 	ret = pwmchip_add(&omap->chip);  in pwm_omap_dmtimer_probe()
412 		dev_err(&pdev->dev, "failed to register PWM\n");  in pwm_omap_dmtimer_probe()
430 	pdata->free(dm_timer);  in pwm_omap_dmtimer_probe()
436 	put_device(&timer_pdev->dev);  in pwm_omap_dmtimer_probe()
448 	pwmchip_remove(&omap->chip);  in pwm_omap_dmtimer_remove()
450 	if (pm_runtime_active(&omap->dm_timer_pdev->dev))  in pwm_omap_dmtimer_remove()
451 		omap->pdata->stop(omap->dm_timer);  in pwm_omap_dmtimer_remove()
453 	omap->pdata->free(omap->dm_timer);  in pwm_omap_dmtimer_remove()
455 	put_device(&omap->dm_timer_pdev->dev);  in pwm_omap_dmtimer_remove()
457 	mutex_destroy(&omap->mutex);  in pwm_omap_dmtimer_remove()
463 	{.compatible = "ti,omap-dmtimer-pwm"},
470 		.name = "omap-dmtimer-pwm",
482 MODULE_DESCRIPTION("OMAP PWM Driver using Dual-mode Timers");