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
20  * - When PWM is stopped, timer counter gets stopped immediately. This
22  * - When PWM is running and changing both duty cycle and period,
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
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>
54  * struct pwm_omap_dmtimer_chip - Structure representing a pwm chip
74  * pwm_omap_dmtimer_get_clock_cycles() - Get clock cycles in a time frame
86  * pwm_omap_dmtimer_start() - Start the pwm omap dm timer in pwm mode
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.
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.
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
140  * @duty_ns:	New duty cycle in nano seconds
156 	dev_dbg(pwmchip_parent(chip), "requested duty cycle: %d ns, period: %d ns\n",  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()
179 	 * specified period and duty cycle. The load value determines the  in pwm_omap_dmtimer_config()
180 	 * period time and the match value determines the duty time.  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()
205 			"duty cycle %d ns is too short for clock rate %lu Hz\n",  in pwm_omap_dmtimer_config()
207 		dev_dbg(pwmchip_parent(chip), "using minimum of 1 clock cycle\n");  in pwm_omap_dmtimer_config()
211 			"duty cycle %d ns is too long for period %d ns at clock rate %lu Hz\n",  in pwm_omap_dmtimer_config()
213 		dev_dbg(pwmchip_parent(chip), "using maximum of 1 clock cycle less than period\n");  in pwm_omap_dmtimer_config()
214 		duty_cycles = period_cycles - 1;  in pwm_omap_dmtimer_config()
217 	dev_dbg(pwmchip_parent(chip), "effective duty cycle: %lld ns, period: %lld ns\n",  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.
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.
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()
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");