1 /*
2 * Blackfin Pulse Width Modulation (PWM) core
3 *
4 * Copyright (c) 2011 Analog Devices Inc.
5 *
6 * Licensed under the GPL-2 or later.
7 */
8
9 #include <linux/module.h>
10 #include <linux/platform_device.h>
11 #include <linux/pwm.h>
12 #include <linux/slab.h>
13
14 #include <asm/gptimers.h>
15 #include <asm/portmux.h>
16
17 struct bfin_pwm_chip {
18 struct pwm_chip chip;
19 };
20
21 struct bfin_pwm {
22 unsigned short pin;
23 };
24
25 static const unsigned short pwm_to_gptimer_per[] = {
26 P_TMR0, P_TMR1, P_TMR2, P_TMR3, P_TMR4, P_TMR5,
27 P_TMR6, P_TMR7, P_TMR8, P_TMR9, P_TMR10, P_TMR11,
28 };
29
bfin_pwm_request(struct pwm_chip * chip,struct pwm_device * pwm)30 static int bfin_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
31 {
32 struct bfin_pwm *priv;
33 int ret;
34
35 if (pwm->hwpwm >= ARRAY_SIZE(pwm_to_gptimer_per))
36 return -EINVAL;
37
38 priv = kzalloc(sizeof(*priv), GFP_KERNEL);
39 if (!priv)
40 return -ENOMEM;
41
42 priv->pin = pwm_to_gptimer_per[pwm->hwpwm];
43
44 ret = peripheral_request(priv->pin, NULL);
45 if (ret) {
46 kfree(priv);
47 return ret;
48 }
49
50 pwm_set_chip_data(pwm, priv);
51
52 return 0;
53 }
54
bfin_pwm_free(struct pwm_chip * chip,struct pwm_device * pwm)55 static void bfin_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
56 {
57 struct bfin_pwm *priv = pwm_get_chip_data(pwm);
58
59 if (priv) {
60 peripheral_free(priv->pin);
61 kfree(priv);
62 }
63 }
64
bfin_pwm_config(struct pwm_chip * chip,struct pwm_device * pwm,int duty_ns,int period_ns)65 static int bfin_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
66 int duty_ns, int period_ns)
67 {
68 struct bfin_pwm *priv = pwm_get_chip_data(pwm);
69 unsigned long period, duty;
70 unsigned long long val;
71
72 val = (unsigned long long)get_sclk() * period_ns;
73 do_div(val, NSEC_PER_SEC);
74 period = val;
75
76 val = (unsigned long long)period * duty_ns;
77 do_div(val, period_ns);
78 duty = period - val;
79
80 if (duty >= period)
81 duty = period - 1;
82
83 set_gptimer_config(priv->pin, TIMER_MODE_PWM | TIMER_PERIOD_CNT);
84 set_gptimer_pwidth(priv->pin, duty);
85 set_gptimer_period(priv->pin, period);
86
87 return 0;
88 }
89
bfin_pwm_enable(struct pwm_chip * chip,struct pwm_device * pwm)90 static int bfin_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
91 {
92 struct bfin_pwm *priv = pwm_get_chip_data(pwm);
93
94 enable_gptimer(priv->pin);
95
96 return 0;
97 }
98
bfin_pwm_disable(struct pwm_chip * chip,struct pwm_device * pwm)99 static void bfin_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
100 {
101 struct bfin_pwm *priv = pwm_get_chip_data(pwm);
102
103 disable_gptimer(priv->pin);
104 }
105
106 static struct pwm_ops bfin_pwm_ops = {
107 .request = bfin_pwm_request,
108 .free = bfin_pwm_free,
109 .config = bfin_pwm_config,
110 .enable = bfin_pwm_enable,
111 .disable = bfin_pwm_disable,
112 .owner = THIS_MODULE,
113 };
114
bfin_pwm_probe(struct platform_device * pdev)115 static int bfin_pwm_probe(struct platform_device *pdev)
116 {
117 struct bfin_pwm_chip *pwm;
118 int ret;
119
120 pwm = devm_kzalloc(&pdev->dev, sizeof(*pwm), GFP_KERNEL);
121 if (!pwm) {
122 dev_err(&pdev->dev, "failed to allocate memory\n");
123 return -ENOMEM;
124 }
125
126 platform_set_drvdata(pdev, pwm);
127
128 pwm->chip.dev = &pdev->dev;
129 pwm->chip.ops = &bfin_pwm_ops;
130 pwm->chip.base = -1;
131 pwm->chip.npwm = 12;
132
133 ret = pwmchip_add(&pwm->chip);
134 if (ret < 0) {
135 dev_err(&pdev->dev, "pwmchip_add() failed: %d\n", ret);
136 return ret;
137 }
138
139 return 0;
140 }
141
bfin_pwm_remove(struct platform_device * pdev)142 static int bfin_pwm_remove(struct platform_device *pdev)
143 {
144 struct bfin_pwm_chip *pwm = platform_get_drvdata(pdev);
145
146 return pwmchip_remove(&pwm->chip);
147 }
148
149 static struct platform_driver bfin_pwm_driver = {
150 .driver = {
151 .name = "bfin-pwm",
152 },
153 .probe = bfin_pwm_probe,
154 .remove = bfin_pwm_remove,
155 };
156
157 module_platform_driver(bfin_pwm_driver);
158
159 MODULE_LICENSE("GPL");
160