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2b4984be BB |
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 | ||
39e046f2 BB |
35 | struct atmel_hlcdc_pwm_errata { |
36 | bool slow_clk_erratum; | |
37 | bool div1_clk_erratum; | |
38 | }; | |
39 | ||
2b4984be BB |
40 | struct atmel_hlcdc_pwm { |
41 | struct pwm_chip chip; | |
42 | struct atmel_hlcdc *hlcdc; | |
43 | struct clk *cur_clk; | |
39e046f2 | 44 | const struct atmel_hlcdc_pwm_errata *errata; |
2b4984be BB |
45 | }; |
46 | ||
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 | ||
2267517c BB |
52 | static int atmel_hlcdc_pwm_apply(struct pwm_chip *c, struct pwm_device *pwm, |
53 | struct pwm_state *state) | |
2b4984be BB |
54 | { |
55 | struct atmel_hlcdc_pwm *chip = to_atmel_hlcdc_pwm(c); | |
56 | struct atmel_hlcdc *hlcdc = chip->hlcdc; | |
2267517c BB |
57 | unsigned int status; |
58 | int ret; | |
2b4984be | 59 | |
2267517c BB |
60 | if (state->enabled) { |
61 | struct clk *new_clk = hlcdc->slow_clk; | |
62 | u64 pwmcval = state->duty_cycle * 256; | |
63 | unsigned long clk_freq; | |
64 | u64 clk_period_ns; | |
65 | u32 pwmcfg; | |
66 | int pres; | |
67 | ||
68 | if (!chip->errata || !chip->errata->slow_clk_erratum) { | |
69 | clk_freq = clk_get_rate(new_clk); | |
70 | if (!clk_freq) | |
71 | return -EINVAL; | |
72 | ||
73 | clk_period_ns = (u64)NSEC_PER_SEC * 256; | |
74 | do_div(clk_period_ns, clk_freq); | |
75 | } | |
76 | ||
77 | /* Errata: cannot use slow clk on some IP revisions */ | |
78 | if ((chip->errata && chip->errata->slow_clk_erratum) || | |
79 | clk_period_ns > state->period) { | |
80 | new_clk = hlcdc->sys_clk; | |
81 | clk_freq = clk_get_rate(new_clk); | |
82 | if (!clk_freq) | |
83 | return -EINVAL; | |
84 | ||
85 | clk_period_ns = (u64)NSEC_PER_SEC * 256; | |
86 | do_div(clk_period_ns, clk_freq); | |
87 | } | |
88 | ||
89 | for (pres = 0; pres <= ATMEL_HLCDC_PWMPS_MAX; pres++) { | |
39e046f2 | 90 | /* Errata: cannot divide by 1 on some IP revisions */ |
2267517c BB |
91 | if (!pres && chip->errata && |
92 | chip->errata->div1_clk_erratum) | |
93 | continue; | |
2b4984be | 94 | |
2267517c BB |
95 | if ((clk_period_ns << pres) >= state->period) |
96 | break; | |
97 | } | |
2b4984be | 98 | |
2267517c BB |
99 | if (pres > ATMEL_HLCDC_PWMPS_MAX) |
100 | return -EINVAL; | |
2b4984be | 101 | |
2267517c | 102 | pwmcfg = ATMEL_HLCDC_PWMPS(pres); |
2b4984be | 103 | |
2267517c BB |
104 | if (new_clk != chip->cur_clk) { |
105 | u32 gencfg = 0; | |
106 | int ret; | |
2b4984be | 107 | |
2267517c BB |
108 | ret = clk_prepare_enable(new_clk); |
109 | if (ret) | |
110 | return ret; | |
2b4984be | 111 | |
2267517c BB |
112 | clk_disable_unprepare(chip->cur_clk); |
113 | chip->cur_clk = new_clk; | |
2b4984be | 114 | |
2267517c BB |
115 | if (new_clk == hlcdc->sys_clk) |
116 | gencfg = ATMEL_HLCDC_CLKPWMSEL; | |
2b4984be | 117 | |
2267517c BB |
118 | ret = regmap_update_bits(hlcdc->regmap, |
119 | ATMEL_HLCDC_CFG(0), | |
120 | ATMEL_HLCDC_CLKPWMSEL, | |
121 | gencfg); | |
122 | if (ret) | |
123 | return ret; | |
124 | } | |
2b4984be | 125 | |
2267517c | 126 | do_div(pwmcval, state->period); |
2b4984be | 127 | |
2267517c BB |
128 | /* |
129 | * The PWM duty cycle is configurable from 0/256 to 255/256 of | |
130 | * the period cycle. Hence we can't set a duty cycle occupying | |
131 | * the whole period cycle if we're asked to. | |
132 | * Set it to 255 if pwmcval is greater than 256. | |
133 | */ | |
134 | if (pwmcval > 255) | |
135 | pwmcval = 255; | |
2b4984be | 136 | |
2267517c | 137 | pwmcfg |= ATMEL_HLCDC_PWMCVAL(pwmcval); |
2b4984be | 138 | |
2267517c BB |
139 | if (state->polarity == PWM_POLARITY_NORMAL) |
140 | pwmcfg |= ATMEL_HLCDC_PWMPOL; | |
2b4984be | 141 | |
2267517c BB |
142 | ret = regmap_update_bits(hlcdc->regmap, ATMEL_HLCDC_CFG(6), |
143 | ATMEL_HLCDC_PWMCVAL_MASK | | |
144 | ATMEL_HLCDC_PWMPS_MASK | | |
145 | ATMEL_HLCDC_PWMPOL, | |
146 | pwmcfg); | |
147 | if (ret) | |
148 | return ret; | |
2b4984be | 149 | |
2267517c BB |
150 | ret = regmap_write(hlcdc->regmap, ATMEL_HLCDC_EN, |
151 | ATMEL_HLCDC_PWM); | |
152 | if (ret) | |
153 | return ret; | |
2b4984be | 154 | |
2267517c BB |
155 | ret = regmap_read_poll_timeout(hlcdc->regmap, ATMEL_HLCDC_SR, |
156 | status, | |
157 | status & ATMEL_HLCDC_PWM, | |
158 | 10, 0); | |
159 | if (ret) | |
160 | return ret; | |
161 | } else { | |
162 | ret = regmap_write(hlcdc->regmap, ATMEL_HLCDC_DIS, | |
163 | ATMEL_HLCDC_PWM); | |
2b4984be BB |
164 | if (ret) |
165 | return ret; | |
166 | ||
2267517c BB |
167 | ret = regmap_read_poll_timeout(hlcdc->regmap, ATMEL_HLCDC_SR, |
168 | status, | |
169 | !(status & ATMEL_HLCDC_PWM), | |
170 | 10, 0); | |
171 | if (ret) | |
172 | return ret; | |
2b4984be | 173 | |
2267517c BB |
174 | clk_disable_unprepare(chip->cur_clk); |
175 | chip->cur_clk = NULL; | |
2b4984be BB |
176 | } |
177 | ||
178 | return 0; | |
179 | } | |
180 | ||
2b4984be | 181 | static const struct pwm_ops atmel_hlcdc_pwm_ops = { |
2267517c | 182 | .apply = atmel_hlcdc_pwm_apply, |
2b4984be BB |
183 | .owner = THIS_MODULE, |
184 | }; | |
185 | ||
39e046f2 BB |
186 | static const struct atmel_hlcdc_pwm_errata atmel_hlcdc_pwm_at91sam9x5_errata = { |
187 | .slow_clk_erratum = true, | |
188 | }; | |
189 | ||
190 | static const struct atmel_hlcdc_pwm_errata atmel_hlcdc_pwm_sama5d3_errata = { | |
191 | .div1_clk_erratum = true, | |
192 | }; | |
193 | ||
194 | static const struct of_device_id atmel_hlcdc_dt_ids[] = { | |
7a593820 JW |
195 | { |
196 | .compatible = "atmel,at91sam9n12-hlcdc", | |
197 | /* 9n12 has same errata as 9x5 HLCDC PWM */ | |
198 | .data = &atmel_hlcdc_pwm_at91sam9x5_errata, | |
199 | }, | |
39e046f2 BB |
200 | { |
201 | .compatible = "atmel,at91sam9x5-hlcdc", | |
202 | .data = &atmel_hlcdc_pwm_at91sam9x5_errata, | |
203 | }, | |
2b8b0ef3 NF |
204 | { |
205 | .compatible = "atmel,sama5d2-hlcdc", | |
206 | }, | |
39e046f2 BB |
207 | { |
208 | .compatible = "atmel,sama5d3-hlcdc", | |
209 | .data = &atmel_hlcdc_pwm_sama5d3_errata, | |
210 | }, | |
054d3e1f NF |
211 | { |
212 | .compatible = "atmel,sama5d4-hlcdc", | |
213 | .data = &atmel_hlcdc_pwm_sama5d3_errata, | |
214 | }, | |
39e046f2 BB |
215 | { /* sentinel */ }, |
216 | }; | |
a83a6a82 | 217 | MODULE_DEVICE_TABLE(of, atmel_hlcdc_dt_ids); |
39e046f2 | 218 | |
2b4984be BB |
219 | static int atmel_hlcdc_pwm_probe(struct platform_device *pdev) |
220 | { | |
39e046f2 | 221 | const struct of_device_id *match; |
2b4984be BB |
222 | struct device *dev = &pdev->dev; |
223 | struct atmel_hlcdc_pwm *chip; | |
224 | struct atmel_hlcdc *hlcdc; | |
225 | int ret; | |
226 | ||
227 | hlcdc = dev_get_drvdata(dev->parent); | |
228 | ||
229 | chip = devm_kzalloc(dev, sizeof(*chip), GFP_KERNEL); | |
230 | if (!chip) | |
231 | return -ENOMEM; | |
232 | ||
233 | ret = clk_prepare_enable(hlcdc->periph_clk); | |
234 | if (ret) | |
235 | return ret; | |
236 | ||
39e046f2 BB |
237 | match = of_match_node(atmel_hlcdc_dt_ids, dev->parent->of_node); |
238 | if (match) | |
239 | chip->errata = match->data; | |
240 | ||
2b4984be BB |
241 | chip->hlcdc = hlcdc; |
242 | chip->chip.ops = &atmel_hlcdc_pwm_ops; | |
243 | chip->chip.dev = dev; | |
244 | chip->chip.base = -1; | |
245 | chip->chip.npwm = 1; | |
246 | chip->chip.of_xlate = of_pwm_xlate_with_flags; | |
247 | chip->chip.of_pwm_n_cells = 3; | |
2b4984be | 248 | |
cc51846b | 249 | ret = pwmchip_add_with_polarity(&chip->chip, PWM_POLARITY_INVERSED); |
2b4984be BB |
250 | if (ret) { |
251 | clk_disable_unprepare(hlcdc->periph_clk); | |
252 | return ret; | |
253 | } | |
254 | ||
255 | platform_set_drvdata(pdev, chip); | |
256 | ||
257 | return 0; | |
258 | } | |
259 | ||
260 | static int atmel_hlcdc_pwm_remove(struct platform_device *pdev) | |
261 | { | |
262 | struct atmel_hlcdc_pwm *chip = platform_get_drvdata(pdev); | |
263 | int ret; | |
264 | ||
265 | ret = pwmchip_remove(&chip->chip); | |
266 | if (ret) | |
267 | return ret; | |
268 | ||
269 | clk_disable_unprepare(chip->hlcdc->periph_clk); | |
270 | ||
271 | return 0; | |
272 | } | |
273 | ||
274 | static const struct of_device_id atmel_hlcdc_pwm_dt_ids[] = { | |
275 | { .compatible = "atmel,hlcdc-pwm" }, | |
276 | { /* sentinel */ }, | |
277 | }; | |
278 | ||
279 | static struct platform_driver atmel_hlcdc_pwm_driver = { | |
280 | .driver = { | |
281 | .name = "atmel-hlcdc-pwm", | |
282 | .of_match_table = atmel_hlcdc_pwm_dt_ids, | |
283 | }, | |
284 | .probe = atmel_hlcdc_pwm_probe, | |
285 | .remove = atmel_hlcdc_pwm_remove, | |
286 | }; | |
287 | module_platform_driver(atmel_hlcdc_pwm_driver); | |
288 | ||
289 | MODULE_ALIAS("platform:atmel-hlcdc-pwm"); | |
290 | MODULE_AUTHOR("Boris Brezillon <boris.brezillon@free-electrons.com>"); | |
291 | MODULE_DESCRIPTION("Atmel HLCDC PWM driver"); | |
292 | MODULE_LICENSE("GPL v2"); |