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59d5c8b1 AT |
1 | /* |
2 | * Marvell Berlin PWM driver | |
3 | * | |
4 | * Copyright (C) 2015 Marvell Technology Group Ltd. | |
5 | * | |
6 | * Author: Antoine Tenart <antoine.tenart@free-electrons.com> | |
7 | * | |
8 | * This file is licensed under the terms of the GNU General Public | |
9 | * License version 2. This program is licensed "as is" without any | |
10 | * warranty of any kind, whether express or implied. | |
11 | */ | |
12 | ||
13 | #include <linux/clk.h> | |
14 | #include <linux/io.h> | |
15 | #include <linux/kernel.h> | |
16 | #include <linux/module.h> | |
17 | #include <linux/platform_device.h> | |
18 | #include <linux/pwm.h> | |
bbf0722c | 19 | #include <linux/slab.h> |
59d5c8b1 AT |
20 | |
21 | #define BERLIN_PWM_EN 0x0 | |
22 | #define BERLIN_PWM_ENABLE BIT(0) | |
23 | #define BERLIN_PWM_CONTROL 0x4 | |
4de445cb TH |
24 | /* |
25 | * The prescaler claims to support 8 different moduli, configured using the | |
26 | * low three bits of PWM_CONTROL. (Sequentially, they are 1, 4, 8, 16, 64, | |
27 | * 256, 1024, and 4096.) However, the moduli from 4 to 1024 appear to be | |
28 | * implemented by internally shifting TCNT left without adding additional | |
29 | * bits. So, the max TCNT that actually works for a modulus of 4 is 0x3fff; | |
30 | * for 8, 0x1fff; and so on. This means that those moduli are entirely | |
31 | * useless, as we could just do the shift ourselves. The 4096 modulus is | |
32 | * implemented with a real prescaler, so we do use that, but we treat it | |
33 | * as a flag instead of pretending the modulus is actually configurable. | |
34 | */ | |
35 | #define BERLIN_PWM_PRESCALE_4096 0x7 | |
59d5c8b1 AT |
36 | #define BERLIN_PWM_INVERT_POLARITY BIT(3) |
37 | #define BERLIN_PWM_DUTY 0x8 | |
38 | #define BERLIN_PWM_TCNT 0xc | |
39 | #define BERLIN_PWM_MAX_TCNT 65535 | |
40 | ||
bbf0722c JZ |
41 | struct berlin_pwm_channel { |
42 | u32 enable; | |
43 | u32 ctrl; | |
44 | u32 duty; | |
45 | u32 tcnt; | |
46 | }; | |
47 | ||
59d5c8b1 AT |
48 | struct berlin_pwm_chip { |
49 | struct pwm_chip chip; | |
50 | struct clk *clk; | |
51 | void __iomem *base; | |
52 | }; | |
53 | ||
54 | static inline struct berlin_pwm_chip *to_berlin_pwm_chip(struct pwm_chip *chip) | |
55 | { | |
56 | return container_of(chip, struct berlin_pwm_chip, chip); | |
57 | } | |
58 | ||
59d5c8b1 AT |
59 | static inline u32 berlin_pwm_readl(struct berlin_pwm_chip *chip, |
60 | unsigned int channel, unsigned long offset) | |
61 | { | |
62 | return readl_relaxed(chip->base + channel * 0x10 + offset); | |
63 | } | |
64 | ||
65 | static inline void berlin_pwm_writel(struct berlin_pwm_chip *chip, | |
66 | unsigned int channel, u32 value, | |
67 | unsigned long offset) | |
68 | { | |
69 | writel_relaxed(value, chip->base + channel * 0x10 + offset); | |
70 | } | |
71 | ||
bbf0722c JZ |
72 | static int berlin_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm) |
73 | { | |
74 | struct berlin_pwm_channel *channel; | |
75 | ||
76 | channel = kzalloc(sizeof(*channel), GFP_KERNEL); | |
77 | if (!channel) | |
78 | return -ENOMEM; | |
79 | ||
80 | return pwm_set_chip_data(pwm, channel); | |
81 | } | |
82 | ||
83 | static void berlin_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm) | |
84 | { | |
85 | struct berlin_pwm_channel *channel = pwm_get_chip_data(pwm); | |
86 | ||
bbf0722c JZ |
87 | kfree(channel); |
88 | } | |
89 | ||
59d5c8b1 AT |
90 | static int berlin_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm_dev, |
91 | int duty_ns, int period_ns) | |
92 | { | |
93 | struct berlin_pwm_chip *pwm = to_berlin_pwm_chip(chip); | |
4de445cb | 94 | bool prescale_4096 = false; |
59d5c8b1 | 95 | u32 value, duty, period; |
4de445cb | 96 | u64 cycles; |
59d5c8b1 AT |
97 | |
98 | cycles = clk_get_rate(pwm->clk); | |
99 | cycles *= period_ns; | |
100 | do_div(cycles, NSEC_PER_SEC); | |
101 | ||
4de445cb TH |
102 | if (cycles > BERLIN_PWM_MAX_TCNT) { |
103 | prescale_4096 = true; | |
104 | cycles >>= 12; // Prescaled by 4096 | |
59d5c8b1 | 105 | |
4de445cb TH |
106 | if (cycles > BERLIN_PWM_MAX_TCNT) |
107 | return -ERANGE; | |
59d5c8b1 AT |
108 | } |
109 | ||
4de445cb TH |
110 | period = cycles; |
111 | cycles *= duty_ns; | |
59d5c8b1 AT |
112 | do_div(cycles, period_ns); |
113 | duty = cycles; | |
114 | ||
115 | value = berlin_pwm_readl(pwm, pwm_dev->hwpwm, BERLIN_PWM_CONTROL); | |
4de445cb TH |
116 | if (prescale_4096) |
117 | value |= BERLIN_PWM_PRESCALE_4096; | |
118 | else | |
119 | value &= ~BERLIN_PWM_PRESCALE_4096; | |
59d5c8b1 AT |
120 | berlin_pwm_writel(pwm, pwm_dev->hwpwm, value, BERLIN_PWM_CONTROL); |
121 | ||
122 | berlin_pwm_writel(pwm, pwm_dev->hwpwm, duty, BERLIN_PWM_DUTY); | |
123 | berlin_pwm_writel(pwm, pwm_dev->hwpwm, period, BERLIN_PWM_TCNT); | |
124 | ||
125 | return 0; | |
126 | } | |
127 | ||
128 | static int berlin_pwm_set_polarity(struct pwm_chip *chip, | |
129 | struct pwm_device *pwm_dev, | |
130 | enum pwm_polarity polarity) | |
131 | { | |
132 | struct berlin_pwm_chip *pwm = to_berlin_pwm_chip(chip); | |
133 | u32 value; | |
134 | ||
135 | value = berlin_pwm_readl(pwm, pwm_dev->hwpwm, BERLIN_PWM_CONTROL); | |
136 | ||
137 | if (polarity == PWM_POLARITY_NORMAL) | |
138 | value &= ~BERLIN_PWM_INVERT_POLARITY; | |
139 | else | |
140 | value |= BERLIN_PWM_INVERT_POLARITY; | |
141 | ||
142 | berlin_pwm_writel(pwm, pwm_dev->hwpwm, value, BERLIN_PWM_CONTROL); | |
143 | ||
144 | return 0; | |
145 | } | |
146 | ||
147 | static int berlin_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm_dev) | |
148 | { | |
149 | struct berlin_pwm_chip *pwm = to_berlin_pwm_chip(chip); | |
150 | u32 value; | |
151 | ||
152 | value = berlin_pwm_readl(pwm, pwm_dev->hwpwm, BERLIN_PWM_EN); | |
153 | value |= BERLIN_PWM_ENABLE; | |
154 | berlin_pwm_writel(pwm, pwm_dev->hwpwm, value, BERLIN_PWM_EN); | |
155 | ||
156 | return 0; | |
157 | } | |
158 | ||
159 | static void berlin_pwm_disable(struct pwm_chip *chip, | |
160 | struct pwm_device *pwm_dev) | |
161 | { | |
162 | struct berlin_pwm_chip *pwm = to_berlin_pwm_chip(chip); | |
163 | u32 value; | |
164 | ||
165 | value = berlin_pwm_readl(pwm, pwm_dev->hwpwm, BERLIN_PWM_EN); | |
166 | value &= ~BERLIN_PWM_ENABLE; | |
167 | berlin_pwm_writel(pwm, pwm_dev->hwpwm, value, BERLIN_PWM_EN); | |
168 | } | |
169 | ||
170 | static const struct pwm_ops berlin_pwm_ops = { | |
bbf0722c JZ |
171 | .request = berlin_pwm_request, |
172 | .free = berlin_pwm_free, | |
59d5c8b1 AT |
173 | .config = berlin_pwm_config, |
174 | .set_polarity = berlin_pwm_set_polarity, | |
175 | .enable = berlin_pwm_enable, | |
176 | .disable = berlin_pwm_disable, | |
177 | .owner = THIS_MODULE, | |
178 | }; | |
179 | ||
180 | static const struct of_device_id berlin_pwm_match[] = { | |
181 | { .compatible = "marvell,berlin-pwm" }, | |
182 | { }, | |
183 | }; | |
184 | MODULE_DEVICE_TABLE(of, berlin_pwm_match); | |
185 | ||
186 | static int berlin_pwm_probe(struct platform_device *pdev) | |
187 | { | |
188 | struct berlin_pwm_chip *pwm; | |
189 | struct resource *res; | |
190 | int ret; | |
191 | ||
192 | pwm = devm_kzalloc(&pdev->dev, sizeof(*pwm), GFP_KERNEL); | |
193 | if (!pwm) | |
194 | return -ENOMEM; | |
195 | ||
196 | res = platform_get_resource(pdev, IORESOURCE_MEM, 0); | |
197 | pwm->base = devm_ioremap_resource(&pdev->dev, res); | |
198 | if (IS_ERR(pwm->base)) | |
199 | return PTR_ERR(pwm->base); | |
200 | ||
201 | pwm->clk = devm_clk_get(&pdev->dev, NULL); | |
202 | if (IS_ERR(pwm->clk)) | |
203 | return PTR_ERR(pwm->clk); | |
204 | ||
205 | ret = clk_prepare_enable(pwm->clk); | |
206 | if (ret) | |
207 | return ret; | |
208 | ||
209 | pwm->chip.dev = &pdev->dev; | |
210 | pwm->chip.ops = &berlin_pwm_ops; | |
211 | pwm->chip.base = -1; | |
212 | pwm->chip.npwm = 4; | |
59d5c8b1 AT |
213 | pwm->chip.of_xlate = of_pwm_xlate_with_flags; |
214 | pwm->chip.of_pwm_n_cells = 3; | |
215 | ||
216 | ret = pwmchip_add(&pwm->chip); | |
217 | if (ret < 0) { | |
218 | dev_err(&pdev->dev, "failed to add PWM chip: %d\n", ret); | |
219 | clk_disable_unprepare(pwm->clk); | |
220 | return ret; | |
221 | } | |
222 | ||
223 | platform_set_drvdata(pdev, pwm); | |
224 | ||
225 | return 0; | |
226 | } | |
227 | ||
228 | static int berlin_pwm_remove(struct platform_device *pdev) | |
229 | { | |
230 | struct berlin_pwm_chip *pwm = platform_get_drvdata(pdev); | |
231 | int ret; | |
232 | ||
233 | ret = pwmchip_remove(&pwm->chip); | |
234 | clk_disable_unprepare(pwm->clk); | |
235 | ||
236 | return ret; | |
237 | } | |
238 | ||
bbf0722c JZ |
239 | #ifdef CONFIG_PM_SLEEP |
240 | static int berlin_pwm_suspend(struct device *dev) | |
241 | { | |
242 | struct berlin_pwm_chip *pwm = dev_get_drvdata(dev); | |
243 | unsigned int i; | |
244 | ||
245 | for (i = 0; i < pwm->chip.npwm; i++) { | |
246 | struct berlin_pwm_channel *channel; | |
247 | ||
248 | channel = pwm_get_chip_data(&pwm->chip.pwms[i]); | |
249 | if (!channel) | |
250 | continue; | |
251 | ||
252 | channel->enable = berlin_pwm_readl(pwm, i, BERLIN_PWM_ENABLE); | |
253 | channel->ctrl = berlin_pwm_readl(pwm, i, BERLIN_PWM_CONTROL); | |
254 | channel->duty = berlin_pwm_readl(pwm, i, BERLIN_PWM_DUTY); | |
255 | channel->tcnt = berlin_pwm_readl(pwm, i, BERLIN_PWM_TCNT); | |
256 | } | |
257 | ||
258 | clk_disable_unprepare(pwm->clk); | |
259 | ||
260 | return 0; | |
261 | } | |
262 | ||
263 | static int berlin_pwm_resume(struct device *dev) | |
264 | { | |
265 | struct berlin_pwm_chip *pwm = dev_get_drvdata(dev); | |
266 | unsigned int i; | |
267 | int ret; | |
268 | ||
269 | ret = clk_prepare_enable(pwm->clk); | |
270 | if (ret) | |
271 | return ret; | |
272 | ||
273 | for (i = 0; i < pwm->chip.npwm; i++) { | |
274 | struct berlin_pwm_channel *channel; | |
275 | ||
276 | channel = pwm_get_chip_data(&pwm->chip.pwms[i]); | |
277 | if (!channel) | |
278 | continue; | |
279 | ||
280 | berlin_pwm_writel(pwm, i, channel->ctrl, BERLIN_PWM_CONTROL); | |
281 | berlin_pwm_writel(pwm, i, channel->duty, BERLIN_PWM_DUTY); | |
282 | berlin_pwm_writel(pwm, i, channel->tcnt, BERLIN_PWM_TCNT); | |
283 | berlin_pwm_writel(pwm, i, channel->enable, BERLIN_PWM_ENABLE); | |
284 | } | |
285 | ||
286 | return 0; | |
287 | } | |
288 | #endif | |
289 | ||
290 | static SIMPLE_DEV_PM_OPS(berlin_pwm_pm_ops, berlin_pwm_suspend, | |
291 | berlin_pwm_resume); | |
292 | ||
59d5c8b1 AT |
293 | static struct platform_driver berlin_pwm_driver = { |
294 | .probe = berlin_pwm_probe, | |
295 | .remove = berlin_pwm_remove, | |
296 | .driver = { | |
297 | .name = "berlin-pwm", | |
298 | .of_match_table = berlin_pwm_match, | |
bbf0722c | 299 | .pm = &berlin_pwm_pm_ops, |
59d5c8b1 AT |
300 | }, |
301 | }; | |
302 | module_platform_driver(berlin_pwm_driver); | |
303 | ||
304 | MODULE_AUTHOR("Antoine Tenart <antoine.tenart@free-electrons.com>"); | |
305 | MODULE_DESCRIPTION("Marvell Berlin PWM driver"); | |
306 | MODULE_LICENSE("GPL v2"); |