1
2
3
4
5
6
7
8
9
10
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");
220
