1 /*
2 * Copyright (C) 2014 Free Electrons
3 * Copyright (C) 2014 Atmel
4 *
5 * Author: Boris BREZILLON <boris.brezillon@free-electrons.com>
6 *
7 * This program is free software; you can redistribute it and/or modify it
8 * under the terms of the GNU General Public License version 2 as published by
9 * the Free Software Foundation.
10 *
11 * This program is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
14 * more details.
15 *
16 * You should have received a copy of the GNU General Public License along with
17 * this program. If not, see <http://www.gnu.org/licenses/>.
18 */
19
20 #include <linux/clk.h>
21 #include <linux/delay.h>
22 #include <linux/mfd/atmel-hlcdc.h>
23 #include <linux/module.h>
24 #include <linux/platform_device.h>
25 #include <linux/pwm.h>
26 #include <linux/regmap.h>
27
28 #define ATMEL_HLCDC_PWMCVAL_MASK GENMASK(15, 8)
29 #define ATMEL_HLCDC_PWMCVAL(x) (((x) << 8) & ATMEL_HLCDC_PWMCVAL_MASK)
30 #define ATMEL_HLCDC_PWMPOL BIT(4)
31 #define ATMEL_HLCDC_PWMPS_MASK GENMASK(2, 0)
32 #define ATMEL_HLCDC_PWMPS_MAX 0x6
33 #define ATMEL_HLCDC_PWMPS(x) ((x) & ATMEL_HLCDC_PWMPS_MASK)
34
35 struct atmel_hlcdc_pwm_errata {
36 bool slow_clk_erratum;
37 bool div1_clk_erratum;
38 };
39
40 struct atmel_hlcdc_pwm {
41 struct pwm_chip chip;
42 struct atmel_hlcdc *hlcdc;
43 struct clk *cur_clk;
44 const struct atmel_hlcdc_pwm_errata *errata;
45 };
46
to_atmel_hlcdc_pwm(struct pwm_chip * chip)47 static inline struct atmel_hlcdc_pwm *to_atmel_hlcdc_pwm(struct pwm_chip *chip)
48 {
49 return container_of(chip, struct atmel_hlcdc_pwm, chip);
50 }
51
atmel_hlcdc_pwm_config(struct pwm_chip * c,struct pwm_device * pwm,int duty_ns,int period_ns)52 static int atmel_hlcdc_pwm_config(struct pwm_chip *c,
53 struct pwm_device *pwm,
54 int duty_ns, int period_ns)
55 {
56 struct atmel_hlcdc_pwm *chip = to_atmel_hlcdc_pwm(c);
57 struct atmel_hlcdc *hlcdc = chip->hlcdc;
58 struct clk *new_clk = hlcdc->slow_clk;
59 u64 pwmcval = duty_ns * 256;
60 unsigned long clk_freq;
61 u64 clk_period_ns;
62 u32 pwmcfg;
63 int pres;
64
65 if (!chip->errata || !chip->errata->slow_clk_erratum) {
66 clk_freq = clk_get_rate(new_clk);
67 if (!clk_freq)
68 return -EINVAL;
69
70 clk_period_ns = (u64)NSEC_PER_SEC * 256;
71 do_div(clk_period_ns, clk_freq);
72 }
73
74 /* Errata: cannot use slow clk on some IP revisions */
75 if ((chip->errata && chip->errata->slow_clk_erratum) ||
76 clk_period_ns > period_ns) {
77 new_clk = hlcdc->sys_clk;
78 clk_freq = clk_get_rate(new_clk);
79 if (!clk_freq)
80 return -EINVAL;
81
82 clk_period_ns = (u64)NSEC_PER_SEC * 256;
83 do_div(clk_period_ns, clk_freq);
84 }
85
86 for (pres = 0; pres <= ATMEL_HLCDC_PWMPS_MAX; pres++) {
87 /* Errata: cannot divide by 1 on some IP revisions */
88 if (!pres && chip->errata && chip->errata->div1_clk_erratum)
89 continue;
90
91 if ((clk_period_ns << pres) >= period_ns)
92 break;
93 }
94
95 if (pres > ATMEL_HLCDC_PWMPS_MAX)
96 return -EINVAL;
97
98 pwmcfg = ATMEL_HLCDC_PWMPS(pres);
99
100 if (new_clk != chip->cur_clk) {
101 u32 gencfg = 0;
102 int ret;
103
104 ret = clk_prepare_enable(new_clk);
105 if (ret)
106 return ret;
107
108 clk_disable_unprepare(chip->cur_clk);
109 chip->cur_clk = new_clk;
110
111 if (new_clk == hlcdc->sys_clk)
112 gencfg = ATMEL_HLCDC_CLKPWMSEL;
113
114 ret = regmap_update_bits(hlcdc->regmap, ATMEL_HLCDC_CFG(0),
115 ATMEL_HLCDC_CLKPWMSEL, gencfg);
116 if (ret)
117 return ret;
118 }
119
120 do_div(pwmcval, period_ns);
121
122 /*
123 * The PWM duty cycle is configurable from 0/256 to 255/256 of the
124 * period cycle. Hence we can't set a duty cycle occupying the
125 * whole period cycle if we're asked to.
126 * Set it to 255 if pwmcval is greater than 256.
127 */
128 if (pwmcval > 255)
129 pwmcval = 255;
130
131 pwmcfg |= ATMEL_HLCDC_PWMCVAL(pwmcval);
132
133 return regmap_update_bits(hlcdc->regmap, ATMEL_HLCDC_CFG(6),
134 ATMEL_HLCDC_PWMCVAL_MASK |
135 ATMEL_HLCDC_PWMPS_MASK,
136 pwmcfg);
137 }
138
atmel_hlcdc_pwm_set_polarity(struct pwm_chip * c,struct pwm_device * pwm,enum pwm_polarity polarity)139 static int atmel_hlcdc_pwm_set_polarity(struct pwm_chip *c,
140 struct pwm_device *pwm,
141 enum pwm_polarity polarity)
142 {
143 struct atmel_hlcdc_pwm *chip = to_atmel_hlcdc_pwm(c);
144 struct atmel_hlcdc *hlcdc = chip->hlcdc;
145 u32 cfg = 0;
146
147 if (polarity == PWM_POLARITY_NORMAL)
148 cfg = ATMEL_HLCDC_PWMPOL;
149
150 return regmap_update_bits(hlcdc->regmap, ATMEL_HLCDC_CFG(6),
151 ATMEL_HLCDC_PWMPOL, cfg);
152 }
153
atmel_hlcdc_pwm_enable(struct pwm_chip * c,struct pwm_device * pwm)154 static int atmel_hlcdc_pwm_enable(struct pwm_chip *c, struct pwm_device *pwm)
155 {
156 struct atmel_hlcdc_pwm *chip = to_atmel_hlcdc_pwm(c);
157 struct atmel_hlcdc *hlcdc = chip->hlcdc;
158 u32 status;
159 int ret;
160
161 ret = regmap_write(hlcdc->regmap, ATMEL_HLCDC_EN, ATMEL_HLCDC_PWM);
162 if (ret)
163 return ret;
164
165 while (true) {
166 ret = regmap_read(hlcdc->regmap, ATMEL_HLCDC_SR, &status);
167 if (ret)
168 return ret;
169
170 if ((status & ATMEL_HLCDC_PWM) != 0)
171 break;
172
173 usleep_range(1, 10);
174 }
175
176 return 0;
177 }
178
atmel_hlcdc_pwm_disable(struct pwm_chip * c,struct pwm_device * pwm)179 static void atmel_hlcdc_pwm_disable(struct pwm_chip *c,
180 struct pwm_device *pwm)
181 {
182 struct atmel_hlcdc_pwm *chip = to_atmel_hlcdc_pwm(c);
183 struct atmel_hlcdc *hlcdc = chip->hlcdc;
184 u32 status;
185 int ret;
186
187 ret = regmap_write(hlcdc->regmap, ATMEL_HLCDC_DIS, ATMEL_HLCDC_PWM);
188 if (ret)
189 return;
190
191 while (true) {
192 ret = regmap_read(hlcdc->regmap, ATMEL_HLCDC_SR, &status);
193 if (ret)
194 return;
195
196 if ((status & ATMEL_HLCDC_PWM) == 0)
197 break;
198
199 usleep_range(1, 10);
200 }
201 }
202
203 static const struct pwm_ops atmel_hlcdc_pwm_ops = {
204 .config = atmel_hlcdc_pwm_config,
205 .set_polarity = atmel_hlcdc_pwm_set_polarity,
206 .enable = atmel_hlcdc_pwm_enable,
207 .disable = atmel_hlcdc_pwm_disable,
208 .owner = THIS_MODULE,
209 };
210
211 static const struct atmel_hlcdc_pwm_errata atmel_hlcdc_pwm_at91sam9x5_errata = {
212 .slow_clk_erratum = true,
213 };
214
215 static const struct atmel_hlcdc_pwm_errata atmel_hlcdc_pwm_sama5d3_errata = {
216 .div1_clk_erratum = true,
217 };
218
219 static const struct of_device_id atmel_hlcdc_dt_ids[] = {
220 {
221 .compatible = "atmel,at91sam9n12-hlcdc",
222 /* 9n12 has same errata as 9x5 HLCDC PWM */
223 .data = &atmel_hlcdc_pwm_at91sam9x5_errata,
224 },
225 {
226 .compatible = "atmel,at91sam9x5-hlcdc",
227 .data = &atmel_hlcdc_pwm_at91sam9x5_errata,
228 },
229 {
230 .compatible = "atmel,sama5d2-hlcdc",
231 },
232 {
233 .compatible = "atmel,sama5d3-hlcdc",
234 .data = &atmel_hlcdc_pwm_sama5d3_errata,
235 },
236 {
237 .compatible = "atmel,sama5d4-hlcdc",
238 .data = &atmel_hlcdc_pwm_sama5d3_errata,
239 },
240 { /* sentinel */ },
241 };
242 MODULE_DEVICE_TABLE(of, atmel_hlcdc_dt_ids);
243
atmel_hlcdc_pwm_probe(struct platform_device * pdev)244 static int atmel_hlcdc_pwm_probe(struct platform_device *pdev)
245 {
246 const struct of_device_id *match;
247 struct device *dev = &pdev->dev;
248 struct atmel_hlcdc_pwm *chip;
249 struct atmel_hlcdc *hlcdc;
250 int ret;
251
252 hlcdc = dev_get_drvdata(dev->parent);
253
254 chip = devm_kzalloc(dev, sizeof(*chip), GFP_KERNEL);
255 if (!chip)
256 return -ENOMEM;
257
258 ret = clk_prepare_enable(hlcdc->periph_clk);
259 if (ret)
260 return ret;
261
262 match = of_match_node(atmel_hlcdc_dt_ids, dev->parent->of_node);
263 if (match)
264 chip->errata = match->data;
265
266 chip->hlcdc = hlcdc;
267 chip->chip.ops = &atmel_hlcdc_pwm_ops;
268 chip->chip.dev = dev;
269 chip->chip.base = -1;
270 chip->chip.npwm = 1;
271 chip->chip.of_xlate = of_pwm_xlate_with_flags;
272 chip->chip.of_pwm_n_cells = 3;
273 chip->chip.can_sleep = 1;
274
275 ret = pwmchip_add(&chip->chip);
276 if (ret) {
277 clk_disable_unprepare(hlcdc->periph_clk);
278 return ret;
279 }
280
281 platform_set_drvdata(pdev, chip);
282
283 return 0;
284 }
285
atmel_hlcdc_pwm_remove(struct platform_device * pdev)286 static int atmel_hlcdc_pwm_remove(struct platform_device *pdev)
287 {
288 struct atmel_hlcdc_pwm *chip = platform_get_drvdata(pdev);
289 int ret;
290
291 ret = pwmchip_remove(&chip->chip);
292 if (ret)
293 return ret;
294
295 clk_disable_unprepare(chip->hlcdc->periph_clk);
296
297 return 0;
298 }
299
300 static const struct of_device_id atmel_hlcdc_pwm_dt_ids[] = {
301 { .compatible = "atmel,hlcdc-pwm" },
302 { /* sentinel */ },
303 };
304
305 static struct platform_driver atmel_hlcdc_pwm_driver = {
306 .driver = {
307 .name = "atmel-hlcdc-pwm",
308 .of_match_table = atmel_hlcdc_pwm_dt_ids,
309 },
310 .probe = atmel_hlcdc_pwm_probe,
311 .remove = atmel_hlcdc_pwm_remove,
312 };
313 module_platform_driver(atmel_hlcdc_pwm_driver);
314
315 MODULE_ALIAS("platform:atmel-hlcdc-pwm");
316 MODULE_AUTHOR("Boris Brezillon <boris.brezillon@free-electrons.com>");
317 MODULE_DESCRIPTION("Atmel HLCDC PWM driver");
318 MODULE_LICENSE("GPL v2");
319