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.
42 #include <clocksource/timer-ti-dm.h>
43 #include <linux/platform_data/dmtimer-omap.h>
46 #include <linux/pwm.h>
54  * struct pwm_omap_dmtimer_chip - Structure representing a pwm chip
61 	/* Mutex to protect pwm apply state */
74  * pwm_omap_dmtimer_get_clock_cycles() - Get clock cycles in a time frame
75  * @clk_rate:	pwm timer clock rate
86  * pwm_omap_dmtimer_start() - Start the pwm omap dm timer in pwm mode
87  * @omap:	Pointer to pwm omap dm timer chip
94 	 * that the PWM line is toggled on the first event.  in pwm_omap_dmtimer_start()
99 	omap->pdata->enable(omap->dm_timer);  in pwm_omap_dmtimer_start()
100 	omap->pdata->write_counter(omap->dm_timer, DM_TIMER_LOAD_MIN);  in pwm_omap_dmtimer_start()
101 	omap->pdata->disable(omap->dm_timer);  in pwm_omap_dmtimer_start()
103 	omap->pdata->start(omap->dm_timer);  in pwm_omap_dmtimer_start()
107  * pwm_omap_dmtimer_is_enabled() -  Detect if the pwm is enabled.
108  * @omap:	Pointer to pwm omap dm timer chip
110  * Return true if pwm is enabled else false.
116 	status = omap->pdata->get_pwm_status(omap->dm_timer);  in pwm_omap_dmtimer_is_enabled()
122  * pwm_omap_dmtimer_polarity() -  Detect the polarity of pwm.
123  * @omap:	Pointer to pwm omap dm timer chip
125  * Return the polarity of pwm.
131 	status = omap->pdata->get_pwm_status(omap->dm_timer);  in pwm_omap_dmtimer_polarity()
137  * pwm_omap_dmtimer_config() - Update the configuration of pwm omap dm timer
138  * @chip:	Pointer to PWM controller
139  * @pwm:	Pointer to PWM channel
147 				   struct pwm_device *pwm,  in pwm_omap_dmtimer_config()  argument
159 	if (duty_ns == pwm_get_duty_cycle(pwm) &&  in pwm_omap_dmtimer_config()
160 	    period_ns == pwm_get_period(pwm))  in pwm_omap_dmtimer_config()
163 	fclk = omap->pdata->get_fclk(omap->dm_timer);  in pwm_omap_dmtimer_config()
166 		return -EINVAL;  in pwm_omap_dmtimer_config()
172 		return -EINVAL;  in pwm_omap_dmtimer_config()
182 	 * The period lasts for (DM_TIMER_MAX-load_value+1) clock cycles.  in pwm_omap_dmtimer_config()
183 	 * Similarly, the active time lasts (match_value-load_value+1) cycles.  in pwm_omap_dmtimer_config()
184 	 * The non-active time is the remainder: (DM_TIMER_MAX-match_value)  in pwm_omap_dmtimer_config()
200 		return -EINVAL;  in pwm_omap_dmtimer_config()
214 		duty_cycles = period_cycles - 1;  in pwm_omap_dmtimer_config()
223 	load_value = (DM_TIMER_MAX - period_cycles) + 1;  in pwm_omap_dmtimer_config()
224 	match_value = load_value + duty_cycles - 1;  in pwm_omap_dmtimer_config()
226 	omap->pdata->set_load(omap->dm_timer, load_value);  in pwm_omap_dmtimer_config()
227 	omap->pdata->set_match(omap->dm_timer, true, match_value);  in pwm_omap_dmtimer_config()
236  * pwm_omap_dmtimer_set_polarity() - Changes the polarity of the pwm dm timer.
237  * @chip:	Pointer to PWM controller
238  * @pwm:	Pointer to PWM channel
239  * @polarity:	New pwm polarity to be set
242 					  struct pwm_device *pwm,  in pwm_omap_dmtimer_set_polarity()  argument
248 	/* Disable the PWM before changing the polarity. */  in pwm_omap_dmtimer_set_polarity()
251 		omap->pdata->stop(omap->dm_timer);  in pwm_omap_dmtimer_set_polarity()
253 	omap->pdata->set_pwm(omap->dm_timer,  in pwm_omap_dmtimer_set_polarity()
263  * pwm_omap_dmtimer_apply() - Changes the state of the pwm omap dm timer.
264  * @chip:	Pointer to PWM controller
265  * @pwm:	Pointer to PWM channel
266  * @state:	New state to apply
268  * Return 0 if successfully changed the state else appropriate error.
271 				  struct pwm_device *pwm,  in pwm_omap_dmtimer_apply()  argument
272 				  const struct pwm_state *state)  in pwm_omap_dmtimer_apply()  argument
277 	if (pwm_omap_dmtimer_is_enabled(omap) && !state->enabled) {  in pwm_omap_dmtimer_apply()
278 		omap->pdata->stop(omap->dm_timer);  in pwm_omap_dmtimer_apply()
282 	if (pwm_omap_dmtimer_polarity(omap) != state->polarity)  in pwm_omap_dmtimer_apply()
283 		pwm_omap_dmtimer_set_polarity(chip, pwm, state->polarity);  in pwm_omap_dmtimer_apply()
285 	ret = pwm_omap_dmtimer_config(chip, pwm, state->duty_cycle,  in pwm_omap_dmtimer_apply()
286 				      state->period);  in pwm_omap_dmtimer_apply()
290 	if (!pwm_omap_dmtimer_is_enabled(omap) && state->enabled) {  in pwm_omap_dmtimer_apply()
291 		omap->pdata->set_pwm(omap->dm_timer,  in pwm_omap_dmtimer_apply()
292 				     state->polarity == PWM_POLARITY_INVERSED,  in pwm_omap_dmtimer_apply()
308 	struct device_node *np = pdev->dev.of_node;  in pwm_omap_dmtimer_probe()
321 		return -ENODEV;  in pwm_omap_dmtimer_probe()
325 		dev_err(&pdev->dev, "Unable to find Timer pdev\n");  in pwm_omap_dmtimer_probe()
326 		ret = -ENODEV;  in pwm_omap_dmtimer_probe()
330 	timer_pdata = dev_get_platdata(&timer_pdev->dev);  in pwm_omap_dmtimer_probe()
332 		dev_dbg(&pdev->dev,  in pwm_omap_dmtimer_probe()
334 		ret = -EPROBE_DEFER;  in pwm_omap_dmtimer_probe()
338 	pdata = timer_pdata->timer_ops;  in pwm_omap_dmtimer_probe()
340 	if (!pdata || !pdata->request_by_node ||  in pwm_omap_dmtimer_probe()
341 	    !pdata->free ||  in pwm_omap_dmtimer_probe()
342 	    !pdata->enable ||  in pwm_omap_dmtimer_probe()
343 	    !pdata->disable ||  in pwm_omap_dmtimer_probe()
344 	    !pdata->get_fclk ||  in pwm_omap_dmtimer_probe()
345 	    !pdata->start ||  in pwm_omap_dmtimer_probe()
346 	    !pdata->stop ||  in pwm_omap_dmtimer_probe()
347 	    !pdata->set_load ||  in pwm_omap_dmtimer_probe()
348 	    !pdata->set_match ||  in pwm_omap_dmtimer_probe()
349 	    !pdata->set_pwm ||  in pwm_omap_dmtimer_probe()
350 	    !pdata->get_pwm_status ||  in pwm_omap_dmtimer_probe()
351 	    !pdata->set_prescaler ||  in pwm_omap_dmtimer_probe()
352 	    !pdata->write_counter) {  in pwm_omap_dmtimer_probe()
353 		dev_err(&pdev->dev, "Incomplete dmtimer pdata structure\n");  in pwm_omap_dmtimer_probe()
354 		ret = -EINVAL;  in pwm_omap_dmtimer_probe()
358 	if (!of_property_read_bool(timer, "ti,timer-pwm")) {  in pwm_omap_dmtimer_probe()
359 		dev_err(&pdev->dev, "Missing ti,timer-pwm capability\n");  in pwm_omap_dmtimer_probe()
360 		ret = -ENODEV;  in pwm_omap_dmtimer_probe()
364 	dm_timer = pdata->request_by_node(timer);  in pwm_omap_dmtimer_probe()
366 		ret = -EPROBE_DEFER;  in pwm_omap_dmtimer_probe()
370 	chip = devm_pwmchip_alloc(&pdev->dev, 1, sizeof(*omap));  in pwm_omap_dmtimer_probe()
377 	omap->pdata = pdata;  in pwm_omap_dmtimer_probe()
378 	omap->dm_timer = dm_timer;  in pwm_omap_dmtimer_probe()
379 	omap->dm_timer_pdev = timer_pdev;  in pwm_omap_dmtimer_probe()
382 	 * Ensure that the timer is stopped before we allow PWM core to call  in pwm_omap_dmtimer_probe()
385 	if (pm_runtime_active(&omap->dm_timer_pdev->dev))  in pwm_omap_dmtimer_probe()
386 		omap->pdata->stop(omap->dm_timer);  in pwm_omap_dmtimer_probe()
388 	if (!of_property_read_u32(pdev->dev.of_node, "ti,prescaler", &v))  in pwm_omap_dmtimer_probe()
389 		omap->pdata->set_prescaler(omap->dm_timer, v);  in pwm_omap_dmtimer_probe()
392 	if (!of_property_read_u32(pdev->dev.of_node, "ti,clock-source", &v))  in pwm_omap_dmtimer_probe()
393 		omap->pdata->set_source(omap->dm_timer, v);  in pwm_omap_dmtimer_probe()
395 	chip->ops = &pwm_omap_dmtimer_ops;  in pwm_omap_dmtimer_probe()
399 		dev_err(&pdev->dev, "failed to register PWM\n");  in pwm_omap_dmtimer_probe()
417 	pdata->free(dm_timer);  in pwm_omap_dmtimer_probe()
423 	put_device(&timer_pdev->dev);  in pwm_omap_dmtimer_probe()
438 	if (pm_runtime_active(&omap->dm_timer_pdev->dev))  in pwm_omap_dmtimer_remove()
439 		omap->pdata->stop(omap->dm_timer);  in pwm_omap_dmtimer_remove()
441 	omap->pdata->free(omap->dm_timer);  in pwm_omap_dmtimer_remove()
443 	put_device(&omap->dm_timer_pdev->dev);  in pwm_omap_dmtimer_remove()
447 	{.compatible = "ti,omap-dmtimer-pwm"},
454 		.name = "omap-dmtimer-pwm",
466 MODULE_DESCRIPTION("OMAP PWM Driver using Dual-mode Timers");