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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> | |
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 | ||
30 | struct berlin_pwm_chip { | |
31 | struct pwm_chip chip; | |
32 | struct clk *clk; | |
33 | void __iomem *base; | |
34 | }; | |
35 | ||
36 | static 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 | ||
41 | static const u32 prescaler_table[] = { | |
42 | 1, 4, 8, 16, 64, 256, 1024, 4096 | |
43 | }; | |
44 | ||
45 | static 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 | ||
51 | static 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 | ||
58 | static 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 | ||
97 | static 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 | ||
116 | static 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 | ||
128 | static 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 | ||
139 | static 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 | ||
147 | static const struct of_device_id berlin_pwm_match[] = { | |
148 | { .compatible = "marvell,berlin-pwm" }, | |
149 | { }, | |
150 | }; | |
151 | MODULE_DEVICE_TABLE(of, berlin_pwm_match); | |
152 | ||
153 | static 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 | ||
196 | static 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 | ||
207 | static 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 | }; | |
215 | module_platform_driver(berlin_pwm_driver); | |
216 | ||
217 | MODULE_AUTHOR("Antoine Tenart <antoine.tenart@free-electrons.com>"); | |
218 | MODULE_DESCRIPTION("Marvell Berlin PWM driver"); | |
219 | MODULE_LICENSE("GPL v2"); |