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6604c655 NA |
1 | /* |
2 | * Copyright (c) 2015 Neil Armstrong <narmstrong@baylibre.com> | |
3 | * Copyright (c) 2014 Joachim Eastwood <manabian@gmail.com> | |
4 | * Copyright (c) 2012 NeilBrown <neilb@suse.de> | |
5 | * Heavily based on earlier code which is: | |
6 | * Copyright (c) 2010 Grant Erickson <marathon96@gmail.com> | |
7 | * | |
8 | * Also based on pwm-samsung.c | |
9 | * | |
10 | * This program is free software; you can redistribute it and/or | |
11 | * modify it under the terms of the GNU General Public License | |
12 | * version 2 as published by the Free Software Foundation. | |
13 | * | |
14 | * Description: | |
15 | * This file is the core OMAP support for the generic, Linux | |
16 | * PWM driver / controller, using the OMAP's dual-mode timers. | |
17 | */ | |
18 | ||
19 | #include <linux/clk.h> | |
20 | #include <linux/err.h> | |
21 | #include <linux/kernel.h> | |
22 | #include <linux/module.h> | |
23 | #include <linux/mutex.h> | |
24 | #include <linux/of.h> | |
25 | #include <linux/of_platform.h> | |
26 | #include <linux/platform_data/pwm_omap_dmtimer.h> | |
27 | #include <linux/platform_device.h> | |
28 | #include <linux/pm_runtime.h> | |
29 | #include <linux/pwm.h> | |
30 | #include <linux/slab.h> | |
31 | #include <linux/time.h> | |
32 | ||
33 | #define DM_TIMER_LOAD_MIN 0xfffffffe | |
f8caa792 | 34 | #define DM_TIMER_MAX 0xffffffff |
6604c655 NA |
35 | |
36 | struct pwm_omap_dmtimer_chip { | |
37 | struct pwm_chip chip; | |
38 | struct mutex mutex; | |
39 | pwm_omap_dmtimer *dm_timer; | |
40 | struct pwm_omap_dmtimer_pdata *pdata; | |
41 | struct platform_device *dm_timer_pdev; | |
42 | }; | |
43 | ||
44 | static inline struct pwm_omap_dmtimer_chip * | |
45 | to_pwm_omap_dmtimer_chip(struct pwm_chip *chip) | |
46 | { | |
47 | return container_of(chip, struct pwm_omap_dmtimer_chip, chip); | |
48 | } | |
49 | ||
f8caa792 | 50 | static u32 pwm_omap_dmtimer_get_clock_cycles(unsigned long clk_rate, int ns) |
6604c655 NA |
51 | { |
52 | u64 c = (u64)clk_rate * ns; | |
53 | ||
54 | do_div(c, NSEC_PER_SEC); | |
55 | ||
f8caa792 | 56 | return c; |
6604c655 NA |
57 | } |
58 | ||
59 | static void pwm_omap_dmtimer_start(struct pwm_omap_dmtimer_chip *omap) | |
60 | { | |
61 | /* | |
62 | * According to OMAP 4 TRM section 22.2.4.10 the counter should be | |
63 | * started at 0xFFFFFFFE when overflow and match is used to ensure | |
64 | * that the PWM line is toggled on the first event. | |
65 | * | |
66 | * Note that omap_dm_timer_enable/disable is for register access and | |
67 | * not the timer counter itself. | |
68 | */ | |
69 | omap->pdata->enable(omap->dm_timer); | |
70 | omap->pdata->write_counter(omap->dm_timer, DM_TIMER_LOAD_MIN); | |
71 | omap->pdata->disable(omap->dm_timer); | |
72 | ||
73 | omap->pdata->start(omap->dm_timer); | |
74 | } | |
75 | ||
76 | static int pwm_omap_dmtimer_enable(struct pwm_chip *chip, | |
77 | struct pwm_device *pwm) | |
78 | { | |
79 | struct pwm_omap_dmtimer_chip *omap = to_pwm_omap_dmtimer_chip(chip); | |
80 | ||
81 | mutex_lock(&omap->mutex); | |
82 | pwm_omap_dmtimer_start(omap); | |
83 | mutex_unlock(&omap->mutex); | |
84 | ||
85 | return 0; | |
86 | } | |
87 | ||
88 | static void pwm_omap_dmtimer_disable(struct pwm_chip *chip, | |
89 | struct pwm_device *pwm) | |
90 | { | |
91 | struct pwm_omap_dmtimer_chip *omap = to_pwm_omap_dmtimer_chip(chip); | |
92 | ||
93 | mutex_lock(&omap->mutex); | |
94 | omap->pdata->stop(omap->dm_timer); | |
95 | mutex_unlock(&omap->mutex); | |
96 | } | |
97 | ||
98 | static int pwm_omap_dmtimer_config(struct pwm_chip *chip, | |
99 | struct pwm_device *pwm, | |
100 | int duty_ns, int period_ns) | |
101 | { | |
102 | struct pwm_omap_dmtimer_chip *omap = to_pwm_omap_dmtimer_chip(chip); | |
f8caa792 DR |
103 | u32 period_cycles, duty_cycles; |
104 | u32 load_value, match_value; | |
6604c655 NA |
105 | struct clk *fclk; |
106 | unsigned long clk_rate; | |
107 | bool timer_active; | |
108 | ||
109 | dev_dbg(chip->dev, "duty cycle: %d, period %d\n", duty_ns, period_ns); | |
110 | ||
111 | mutex_lock(&omap->mutex); | |
112 | if (duty_ns == pwm_get_duty_cycle(pwm) && | |
113 | period_ns == pwm_get_period(pwm)) { | |
114 | /* No change - don't cause any transients. */ | |
115 | mutex_unlock(&omap->mutex); | |
116 | return 0; | |
117 | } | |
118 | ||
119 | fclk = omap->pdata->get_fclk(omap->dm_timer); | |
120 | if (!fclk) { | |
121 | dev_err(chip->dev, "invalid pmtimer fclk\n"); | |
cd378881 | 122 | goto err_einval; |
6604c655 NA |
123 | } |
124 | ||
125 | clk_rate = clk_get_rate(fclk); | |
126 | if (!clk_rate) { | |
127 | dev_err(chip->dev, "invalid pmtimer fclk rate\n"); | |
cd378881 | 128 | goto err_einval; |
6604c655 NA |
129 | } |
130 | ||
131 | dev_dbg(chip->dev, "clk rate: %luHz\n", clk_rate); | |
132 | ||
133 | /* | |
134 | * Calculate the appropriate load and match values based on the | |
135 | * specified period and duty cycle. The load value determines the | |
f8caa792 DR |
136 | * period time and the match value determines the duty time. |
137 | * | |
138 | * The period lasts for (DM_TIMER_MAX-load_value+1) clock cycles. | |
139 | * Similarly, the active time lasts (match_value-load_value+1) cycles. | |
140 | * The non-active time is the remainder: (DM_TIMER_MAX-match_value) | |
141 | * clock cycles. | |
142 | * | |
cd378881 DR |
143 | * NOTE: It is required that: load_value <= match_value < DM_TIMER_MAX |
144 | * | |
f8caa792 DR |
145 | * References: |
146 | * OMAP4430/60/70 TRM sections 22.2.4.10 and 22.2.4.11 | |
147 | * AM335x Sitara TRM sections 20.1.3.5 and 20.1.3.6 | |
6604c655 | 148 | */ |
f8caa792 DR |
149 | period_cycles = pwm_omap_dmtimer_get_clock_cycles(clk_rate, period_ns); |
150 | duty_cycles = pwm_omap_dmtimer_get_clock_cycles(clk_rate, duty_ns); | |
151 | ||
cd378881 DR |
152 | if (period_cycles < 2) { |
153 | dev_info(chip->dev, | |
154 | "period %d ns too short for clock rate %lu Hz\n", | |
155 | period_ns, clk_rate); | |
156 | goto err_einval; | |
157 | } | |
158 | ||
159 | if (duty_cycles < 1) { | |
160 | dev_dbg(chip->dev, | |
161 | "duty cycle %d ns is too short for clock rate %lu Hz\n", | |
162 | duty_ns, clk_rate); | |
163 | dev_dbg(chip->dev, "using minimum of 1 clock cycle\n"); | |
164 | duty_cycles = 1; | |
165 | } else if (duty_cycles >= period_cycles) { | |
166 | dev_dbg(chip->dev, | |
167 | "duty cycle %d ns is too long for period %d ns at clock rate %lu Hz\n", | |
168 | duty_ns, period_ns, clk_rate); | |
169 | dev_dbg(chip->dev, "using maximum of 1 clock cycle less than period\n"); | |
170 | duty_cycles = period_cycles - 1; | |
171 | } | |
172 | ||
f8caa792 DR |
173 | load_value = (DM_TIMER_MAX - period_cycles) + 1; |
174 | match_value = load_value + duty_cycles - 1; | |
6604c655 NA |
175 | |
176 | /* | |
177 | * We MUST stop the associated dual-mode timer before attempting to | |
178 | * write its registers, but calls to omap_dm_timer_start/stop must | |
179 | * be balanced so check if timer is active before calling timer_stop. | |
180 | */ | |
181 | timer_active = pm_runtime_active(&omap->dm_timer_pdev->dev); | |
182 | if (timer_active) | |
183 | omap->pdata->stop(omap->dm_timer); | |
184 | ||
185 | omap->pdata->set_load(omap->dm_timer, true, load_value); | |
186 | omap->pdata->set_match(omap->dm_timer, true, match_value); | |
187 | ||
188 | dev_dbg(chip->dev, "load value: %#08x (%d), match value: %#08x (%d)\n", | |
189 | load_value, load_value, match_value, match_value); | |
190 | ||
191 | omap->pdata->set_pwm(omap->dm_timer, | |
192 | pwm->polarity == PWM_POLARITY_INVERSED, | |
193 | true, | |
194 | PWM_OMAP_DMTIMER_TRIGGER_OVERFLOW_AND_COMPARE); | |
195 | ||
196 | /* If config was called while timer was running it must be reenabled. */ | |
197 | if (timer_active) | |
198 | pwm_omap_dmtimer_start(omap); | |
199 | ||
200 | mutex_unlock(&omap->mutex); | |
201 | ||
202 | return 0; | |
cd378881 DR |
203 | |
204 | err_einval: | |
205 | mutex_unlock(&omap->mutex); | |
206 | ||
207 | return -EINVAL; | |
6604c655 NA |
208 | } |
209 | ||
210 | static int pwm_omap_dmtimer_set_polarity(struct pwm_chip *chip, | |
211 | struct pwm_device *pwm, | |
212 | enum pwm_polarity polarity) | |
213 | { | |
214 | struct pwm_omap_dmtimer_chip *omap = to_pwm_omap_dmtimer_chip(chip); | |
215 | ||
216 | /* | |
217 | * PWM core will not call set_polarity while PWM is enabled so it's | |
218 | * safe to reconfigure the timer here without stopping it first. | |
219 | */ | |
220 | mutex_lock(&omap->mutex); | |
221 | omap->pdata->set_pwm(omap->dm_timer, | |
222 | polarity == PWM_POLARITY_INVERSED, | |
223 | true, | |
224 | PWM_OMAP_DMTIMER_TRIGGER_OVERFLOW_AND_COMPARE); | |
225 | mutex_unlock(&omap->mutex); | |
226 | ||
227 | return 0; | |
228 | } | |
229 | ||
230 | static const struct pwm_ops pwm_omap_dmtimer_ops = { | |
231 | .enable = pwm_omap_dmtimer_enable, | |
232 | .disable = pwm_omap_dmtimer_disable, | |
233 | .config = pwm_omap_dmtimer_config, | |
234 | .set_polarity = pwm_omap_dmtimer_set_polarity, | |
235 | .owner = THIS_MODULE, | |
236 | }; | |
237 | ||
238 | static int pwm_omap_dmtimer_probe(struct platform_device *pdev) | |
239 | { | |
240 | struct device_node *np = pdev->dev.of_node; | |
241 | struct device_node *timer; | |
242 | struct pwm_omap_dmtimer_chip *omap; | |
243 | struct pwm_omap_dmtimer_pdata *pdata; | |
244 | pwm_omap_dmtimer *dm_timer; | |
245 | u32 prescaler; | |
246 | int status; | |
247 | ||
248 | pdata = dev_get_platdata(&pdev->dev); | |
249 | if (!pdata) { | |
250 | dev_err(&pdev->dev, "Missing dmtimer platform data\n"); | |
251 | return -EINVAL; | |
252 | } | |
253 | ||
254 | if (!pdata->request_by_node || | |
255 | !pdata->free || | |
256 | !pdata->enable || | |
257 | !pdata->disable || | |
258 | !pdata->get_fclk || | |
259 | !pdata->start || | |
260 | !pdata->stop || | |
261 | !pdata->set_load || | |
262 | !pdata->set_match || | |
263 | !pdata->set_pwm || | |
264 | !pdata->set_prescaler || | |
265 | !pdata->write_counter) { | |
266 | dev_err(&pdev->dev, "Incomplete dmtimer pdata structure\n"); | |
267 | return -EINVAL; | |
268 | } | |
269 | ||
270 | timer = of_parse_phandle(np, "ti,timers", 0); | |
271 | if (!timer) | |
272 | return -ENODEV; | |
273 | ||
274 | if (!of_get_property(timer, "ti,timer-pwm", NULL)) { | |
275 | dev_err(&pdev->dev, "Missing ti,timer-pwm capability\n"); | |
276 | return -ENODEV; | |
277 | } | |
278 | ||
279 | dm_timer = pdata->request_by_node(timer); | |
280 | if (!dm_timer) | |
281 | return -EPROBE_DEFER; | |
282 | ||
283 | omap = devm_kzalloc(&pdev->dev, sizeof(*omap), GFP_KERNEL); | |
284 | if (!omap) { | |
07472640 | 285 | pdata->free(dm_timer); |
6604c655 NA |
286 | return -ENOMEM; |
287 | } | |
288 | ||
289 | omap->pdata = pdata; | |
290 | omap->dm_timer = dm_timer; | |
291 | ||
292 | omap->dm_timer_pdev = of_find_device_by_node(timer); | |
293 | if (!omap->dm_timer_pdev) { | |
294 | dev_err(&pdev->dev, "Unable to find timer pdev\n"); | |
295 | omap->pdata->free(dm_timer); | |
296 | return -EINVAL; | |
297 | } | |
298 | ||
299 | /* | |
300 | * Ensure that the timer is stopped before we allow PWM core to call | |
301 | * pwm_enable. | |
302 | */ | |
303 | if (pm_runtime_active(&omap->dm_timer_pdev->dev)) | |
304 | omap->pdata->stop(omap->dm_timer); | |
305 | ||
306 | /* setup dmtimer prescaler */ | |
307 | if (!of_property_read_u32(pdev->dev.of_node, "ti,prescaler", | |
308 | &prescaler)) | |
309 | omap->pdata->set_prescaler(omap->dm_timer, prescaler); | |
310 | ||
311 | omap->chip.dev = &pdev->dev; | |
312 | omap->chip.ops = &pwm_omap_dmtimer_ops; | |
313 | omap->chip.base = -1; | |
314 | omap->chip.npwm = 1; | |
315 | omap->chip.of_xlate = of_pwm_xlate_with_flags; | |
316 | omap->chip.of_pwm_n_cells = 3; | |
317 | ||
318 | mutex_init(&omap->mutex); | |
319 | ||
320 | status = pwmchip_add(&omap->chip); | |
321 | if (status < 0) { | |
322 | dev_err(&pdev->dev, "failed to register PWM\n"); | |
323 | omap->pdata->free(omap->dm_timer); | |
324 | return status; | |
325 | } | |
326 | ||
327 | platform_set_drvdata(pdev, omap); | |
328 | ||
329 | return 0; | |
330 | } | |
331 | ||
332 | static int pwm_omap_dmtimer_remove(struct platform_device *pdev) | |
333 | { | |
334 | struct pwm_omap_dmtimer_chip *omap = platform_get_drvdata(pdev); | |
335 | ||
336 | if (pm_runtime_active(&omap->dm_timer_pdev->dev)) | |
337 | omap->pdata->stop(omap->dm_timer); | |
338 | ||
339 | omap->pdata->free(omap->dm_timer); | |
340 | ||
341 | mutex_destroy(&omap->mutex); | |
342 | ||
343 | return pwmchip_remove(&omap->chip); | |
344 | } | |
345 | ||
346 | static const struct of_device_id pwm_omap_dmtimer_of_match[] = { | |
347 | {.compatible = "ti,omap-dmtimer-pwm"}, | |
348 | {} | |
349 | }; | |
350 | MODULE_DEVICE_TABLE(of, pwm_omap_dmtimer_of_match); | |
351 | ||
352 | static struct platform_driver pwm_omap_dmtimer_driver = { | |
353 | .driver = { | |
354 | .name = "omap-dmtimer-pwm", | |
355 | .of_match_table = of_match_ptr(pwm_omap_dmtimer_of_match), | |
356 | }, | |
357 | .probe = pwm_omap_dmtimer_probe, | |
358 | .remove = pwm_omap_dmtimer_remove, | |
359 | }; | |
360 | module_platform_driver(pwm_omap_dmtimer_driver); | |
361 | ||
362 | MODULE_AUTHOR("Grant Erickson <marathon96@gmail.com>"); | |
363 | MODULE_AUTHOR("NeilBrown <neilb@suse.de>"); | |
364 | MODULE_AUTHOR("Neil Armstrong <narmstrong@baylibre.com>"); | |
365 | MODULE_LICENSE("GPL v2"); | |
366 | MODULE_DESCRIPTION("OMAP PWM Driver using Dual-mode Timers"); |