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