1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * MediaTek Pulse Width Modulator driver
4 *
5 * Copyright (C) 2015 John Crispin <blogic@openwrt.org>
6 * Copyright (C) 2017 Zhi Mao <zhi.mao@mediatek.com>
7 *
8 */
9
10 #include <linux/err.h>
11 #include <linux/io.h>
12 #include <linux/ioport.h>
13 #include <linux/kernel.h>
14 #include <linux/module.h>
15 #include <linux/clk.h>
16 #include <linux/of.h>
17 #include <linux/of_device.h>
18 #include <linux/platform_device.h>
19 #include <linux/pwm.h>
20 #include <linux/slab.h>
21 #include <linux/types.h>
22
23 /* PWM registers and bits definitions */
24 #define PWMCON 0x00
25 #define PWMHDUR 0x04
26 #define PWMLDUR 0x08
27 #define PWMGDUR 0x0c
28 #define PWMWAVENUM 0x28
29 #define PWMDWIDTH 0x2c
30 #define PWM45DWIDTH_FIXUP 0x30
31 #define PWMTHRES 0x30
32 #define PWM45THRES_FIXUP 0x34
33 #define PWM_CK_26M_SEL 0x210
34
35 #define PWM_CLK_DIV_MAX 7
36
37 struct pwm_mediatek_of_data {
38 unsigned int num_pwms;
39 bool pwm45_fixup;
40 bool has_ck_26m_sel;
41 };
42
43 /**
44 * struct pwm_mediatek_chip - struct representing PWM chip
45 * @chip: linux PWM chip representation
46 * @regs: base address of PWM chip
47 * @clk_top: the top clock generator
48 * @clk_main: the clock used by PWM core
49 * @clk_pwms: the clock used by each PWM channel
50 * @clk_freq: the fix clock frequency of legacy MIPS SoC
51 * @soc: pointer to chip's platform data
52 */
53 struct pwm_mediatek_chip {
54 struct pwm_chip chip;
55 void __iomem *regs;
56 struct clk *clk_top;
57 struct clk *clk_main;
58 struct clk **clk_pwms;
59 const struct pwm_mediatek_of_data *soc;
60 };
61
62 static const unsigned int pwm_mediatek_reg_offset[] = {
63 0x0010, 0x0050, 0x0090, 0x00d0, 0x0110, 0x0150, 0x0190, 0x0220
64 };
65
66 static inline struct pwm_mediatek_chip *
to_pwm_mediatek_chip(struct pwm_chip * chip)67 to_pwm_mediatek_chip(struct pwm_chip *chip)
68 {
69 return container_of(chip, struct pwm_mediatek_chip, chip);
70 }
71
pwm_mediatek_clk_enable(struct pwm_chip * chip,struct pwm_device * pwm)72 static int pwm_mediatek_clk_enable(struct pwm_chip *chip,
73 struct pwm_device *pwm)
74 {
75 struct pwm_mediatek_chip *pc = to_pwm_mediatek_chip(chip);
76 int ret;
77
78 ret = clk_prepare_enable(pc->clk_top);
79 if (ret < 0)
80 return ret;
81
82 ret = clk_prepare_enable(pc->clk_main);
83 if (ret < 0)
84 goto disable_clk_top;
85
86 ret = clk_prepare_enable(pc->clk_pwms[pwm->hwpwm]);
87 if (ret < 0)
88 goto disable_clk_main;
89
90 return 0;
91
92 disable_clk_main:
93 clk_disable_unprepare(pc->clk_main);
94 disable_clk_top:
95 clk_disable_unprepare(pc->clk_top);
96
97 return ret;
98 }
99
pwm_mediatek_clk_disable(struct pwm_chip * chip,struct pwm_device * pwm)100 static void pwm_mediatek_clk_disable(struct pwm_chip *chip,
101 struct pwm_device *pwm)
102 {
103 struct pwm_mediatek_chip *pc = to_pwm_mediatek_chip(chip);
104
105 clk_disable_unprepare(pc->clk_pwms[pwm->hwpwm]);
106 clk_disable_unprepare(pc->clk_main);
107 clk_disable_unprepare(pc->clk_top);
108 }
109
pwm_mediatek_writel(struct pwm_mediatek_chip * chip,unsigned int num,unsigned int offset,u32 value)110 static inline void pwm_mediatek_writel(struct pwm_mediatek_chip *chip,
111 unsigned int num, unsigned int offset,
112 u32 value)
113 {
114 writel(value, chip->regs + pwm_mediatek_reg_offset[num] + offset);
115 }
116
pwm_mediatek_config(struct pwm_chip * chip,struct pwm_device * pwm,int duty_ns,int period_ns)117 static int pwm_mediatek_config(struct pwm_chip *chip, struct pwm_device *pwm,
118 int duty_ns, int period_ns)
119 {
120 struct pwm_mediatek_chip *pc = to_pwm_mediatek_chip(chip);
121 u32 clkdiv = 0, cnt_period, cnt_duty, reg_width = PWMDWIDTH,
122 reg_thres = PWMTHRES;
123 u64 resolution;
124 int ret;
125
126 ret = pwm_mediatek_clk_enable(chip, pwm);
127
128 if (ret < 0)
129 return ret;
130
131 /* Make sure we use the bus clock and not the 26MHz clock */
132 if (pc->soc->has_ck_26m_sel)
133 writel(0, pc->regs + PWM_CK_26M_SEL);
134
135 /* Using resolution in picosecond gets accuracy higher */
136 resolution = (u64)NSEC_PER_SEC * 1000;
137 do_div(resolution, clk_get_rate(pc->clk_pwms[pwm->hwpwm]));
138
139 cnt_period = DIV_ROUND_CLOSEST_ULL((u64)period_ns * 1000, resolution);
140 while (cnt_period > 8191) {
141 resolution *= 2;
142 clkdiv++;
143 cnt_period = DIV_ROUND_CLOSEST_ULL((u64)period_ns * 1000,
144 resolution);
145 }
146
147 if (clkdiv > PWM_CLK_DIV_MAX) {
148 pwm_mediatek_clk_disable(chip, pwm);
149 dev_err(chip->dev, "period %d not supported\n", period_ns);
150 return -EINVAL;
151 }
152
153 if (pc->soc->pwm45_fixup && pwm->hwpwm > 2) {
154 /*
155 * PWM[4,5] has distinct offset for PWMDWIDTH and PWMTHRES
156 * from the other PWMs on MT7623.
157 */
158 reg_width = PWM45DWIDTH_FIXUP;
159 reg_thres = PWM45THRES_FIXUP;
160 }
161
162 cnt_duty = DIV_ROUND_CLOSEST_ULL((u64)duty_ns * 1000, resolution);
163 pwm_mediatek_writel(pc, pwm->hwpwm, PWMCON, BIT(15) | clkdiv);
164 pwm_mediatek_writel(pc, pwm->hwpwm, reg_width, cnt_period);
165 pwm_mediatek_writel(pc, pwm->hwpwm, reg_thres, cnt_duty);
166
167 pwm_mediatek_clk_disable(chip, pwm);
168
169 return 0;
170 }
171
pwm_mediatek_enable(struct pwm_chip * chip,struct pwm_device * pwm)172 static int pwm_mediatek_enable(struct pwm_chip *chip, struct pwm_device *pwm)
173 {
174 struct pwm_mediatek_chip *pc = to_pwm_mediatek_chip(chip);
175 u32 value;
176 int ret;
177
178 ret = pwm_mediatek_clk_enable(chip, pwm);
179 if (ret < 0)
180 return ret;
181
182 value = readl(pc->regs);
183 value |= BIT(pwm->hwpwm);
184 writel(value, pc->regs);
185
186 return 0;
187 }
188
pwm_mediatek_disable(struct pwm_chip * chip,struct pwm_device * pwm)189 static void pwm_mediatek_disable(struct pwm_chip *chip, struct pwm_device *pwm)
190 {
191 struct pwm_mediatek_chip *pc = to_pwm_mediatek_chip(chip);
192 u32 value;
193
194 value = readl(pc->regs);
195 value &= ~BIT(pwm->hwpwm);
196 writel(value, pc->regs);
197
198 pwm_mediatek_clk_disable(chip, pwm);
199 }
200
201 static const struct pwm_ops pwm_mediatek_ops = {
202 .config = pwm_mediatek_config,
203 .enable = pwm_mediatek_enable,
204 .disable = pwm_mediatek_disable,
205 .owner = THIS_MODULE,
206 };
207
pwm_mediatek_probe(struct platform_device * pdev)208 static int pwm_mediatek_probe(struct platform_device *pdev)
209 {
210 struct pwm_mediatek_chip *pc;
211 unsigned int i;
212 int ret;
213
214 pc = devm_kzalloc(&pdev->dev, sizeof(*pc), GFP_KERNEL);
215 if (!pc)
216 return -ENOMEM;
217
218 pc->soc = of_device_get_match_data(&pdev->dev);
219
220 pc->regs = devm_platform_ioremap_resource(pdev, 0);
221 if (IS_ERR(pc->regs))
222 return PTR_ERR(pc->regs);
223
224 pc->clk_pwms = devm_kcalloc(&pdev->dev, pc->soc->num_pwms,
225 sizeof(*pc->clk_pwms), GFP_KERNEL);
226 if (!pc->clk_pwms)
227 return -ENOMEM;
228
229 pc->clk_top = devm_clk_get(&pdev->dev, "top");
230 if (IS_ERR(pc->clk_top)) {
231 dev_err(&pdev->dev, "clock: top fail: %ld\n",
232 PTR_ERR(pc->clk_top));
233 return PTR_ERR(pc->clk_top);
234 }
235
236 pc->clk_main = devm_clk_get(&pdev->dev, "main");
237 if (IS_ERR(pc->clk_main)) {
238 dev_err(&pdev->dev, "clock: main fail: %ld\n",
239 PTR_ERR(pc->clk_main));
240 return PTR_ERR(pc->clk_main);
241 }
242
243 for (i = 0; i < pc->soc->num_pwms; i++) {
244 char name[8];
245
246 snprintf(name, sizeof(name), "pwm%d", i + 1);
247
248 pc->clk_pwms[i] = devm_clk_get(&pdev->dev, name);
249 if (IS_ERR(pc->clk_pwms[i])) {
250 dev_err(&pdev->dev, "clock: %s fail: %ld\n",
251 name, PTR_ERR(pc->clk_pwms[i]));
252 return PTR_ERR(pc->clk_pwms[i]);
253 }
254 }
255
256 pc->chip.dev = &pdev->dev;
257 pc->chip.ops = &pwm_mediatek_ops;
258 pc->chip.npwm = pc->soc->num_pwms;
259
260 ret = devm_pwmchip_add(&pdev->dev, &pc->chip);
261 if (ret < 0) {
262 dev_err(&pdev->dev, "pwmchip_add() failed: %d\n", ret);
263 return ret;
264 }
265
266 return 0;
267 }
268
269 static const struct pwm_mediatek_of_data mt2712_pwm_data = {
270 .num_pwms = 8,
271 .pwm45_fixup = false,
272 .has_ck_26m_sel = false,
273 };
274
275 static const struct pwm_mediatek_of_data mt7622_pwm_data = {
276 .num_pwms = 6,
277 .pwm45_fixup = false,
278 .has_ck_26m_sel = false,
279 };
280
281 static const struct pwm_mediatek_of_data mt7623_pwm_data = {
282 .num_pwms = 5,
283 .pwm45_fixup = true,
284 .has_ck_26m_sel = false,
285 };
286
287 static const struct pwm_mediatek_of_data mt7628_pwm_data = {
288 .num_pwms = 4,
289 .pwm45_fixup = true,
290 .has_ck_26m_sel = false,
291 };
292
293 static const struct pwm_mediatek_of_data mt7629_pwm_data = {
294 .num_pwms = 1,
295 .pwm45_fixup = false,
296 .has_ck_26m_sel = false,
297 };
298
299 static const struct pwm_mediatek_of_data mt8183_pwm_data = {
300 .num_pwms = 4,
301 .pwm45_fixup = false,
302 .has_ck_26m_sel = true,
303 };
304
305 static const struct pwm_mediatek_of_data mt8516_pwm_data = {
306 .num_pwms = 5,
307 .pwm45_fixup = false,
308 .has_ck_26m_sel = true,
309 };
310
311 static const struct of_device_id pwm_mediatek_of_match[] = {
312 { .compatible = "mediatek,mt2712-pwm", .data = &mt2712_pwm_data },
313 { .compatible = "mediatek,mt7622-pwm", .data = &mt7622_pwm_data },
314 { .compatible = "mediatek,mt7623-pwm", .data = &mt7623_pwm_data },
315 { .compatible = "mediatek,mt7628-pwm", .data = &mt7628_pwm_data },
316 { .compatible = "mediatek,mt7629-pwm", .data = &mt7629_pwm_data },
317 { .compatible = "mediatek,mt8183-pwm", .data = &mt8183_pwm_data },
318 { .compatible = "mediatek,mt8516-pwm", .data = &mt8516_pwm_data },
319 { },
320 };
321 MODULE_DEVICE_TABLE(of, pwm_mediatek_of_match);
322
323 static struct platform_driver pwm_mediatek_driver = {
324 .driver = {
325 .name = "pwm-mediatek",
326 .of_match_table = pwm_mediatek_of_match,
327 },
328 .probe = pwm_mediatek_probe,
329 };
330 module_platform_driver(pwm_mediatek_driver);
331
332 MODULE_AUTHOR("John Crispin <blogic@openwrt.org>");
333 MODULE_LICENSE("GPL v2");
334