This source file includes following definitions.
- mxs_pwm_config
- mxs_pwm_enable
- mxs_pwm_disable
- mxs_pwm_probe
- mxs_pwm_remove
1
2
3
4
5
6 #include <linux/clk.h>
7 #include <linux/err.h>
8 #include <linux/io.h>
9 #include <linux/kernel.h>
10 #include <linux/module.h>
11 #include <linux/of.h>
12 #include <linux/of_address.h>
13 #include <linux/platform_device.h>
14 #include <linux/pwm.h>
15 #include <linux/slab.h>
16 #include <linux/stmp_device.h>
17
18 #define SET 0x4
19 #define CLR 0x8
20 #define TOG 0xc
21
22 #define PWM_CTRL 0x0
23 #define PWM_ACTIVE0 0x10
24 #define PWM_PERIOD0 0x20
25 #define PERIOD_PERIOD(p) ((p) & 0xffff)
26 #define PERIOD_PERIOD_MAX 0x10000
27 #define PERIOD_ACTIVE_HIGH (3 << 16)
28 #define PERIOD_INACTIVE_LOW (2 << 18)
29 #define PERIOD_CDIV(div) (((div) & 0x7) << 20)
30 #define PERIOD_CDIV_MAX 8
31
32 static const unsigned int cdiv[PERIOD_CDIV_MAX] = {
33 1, 2, 4, 8, 16, 64, 256, 1024
34 };
35
36 struct mxs_pwm_chip {
37 struct pwm_chip chip;
38 struct clk *clk;
39 void __iomem *base;
40 };
41
42 #define to_mxs_pwm_chip(_chip) container_of(_chip, struct mxs_pwm_chip, chip)
43
44 static int mxs_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
45 int duty_ns, int period_ns)
46 {
47 struct mxs_pwm_chip *mxs = to_mxs_pwm_chip(chip);
48 int ret, div = 0;
49 unsigned int period_cycles, duty_cycles;
50 unsigned long rate;
51 unsigned long long c;
52
53 rate = clk_get_rate(mxs->clk);
54 while (1) {
55 c = rate / cdiv[div];
56 c = c * period_ns;
57 do_div(c, 1000000000);
58 if (c < PERIOD_PERIOD_MAX)
59 break;
60 div++;
61 if (div >= PERIOD_CDIV_MAX)
62 return -EINVAL;
63 }
64
65 period_cycles = c;
66 c *= duty_ns;
67 do_div(c, period_ns);
68 duty_cycles = c;
69
70
71
72
73
74 if (!pwm_is_enabled(pwm)) {
75 ret = clk_prepare_enable(mxs->clk);
76 if (ret)
77 return ret;
78 }
79
80 writel(duty_cycles << 16,
81 mxs->base + PWM_ACTIVE0 + pwm->hwpwm * 0x20);
82 writel(PERIOD_PERIOD(period_cycles) | PERIOD_ACTIVE_HIGH |
83 PERIOD_INACTIVE_LOW | PERIOD_CDIV(div),
84 mxs->base + PWM_PERIOD0 + pwm->hwpwm * 0x20);
85
86
87
88
89 if (!pwm_is_enabled(pwm))
90 clk_disable_unprepare(mxs->clk);
91
92 return 0;
93 }
94
95 static int mxs_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
96 {
97 struct mxs_pwm_chip *mxs = to_mxs_pwm_chip(chip);
98 int ret;
99
100 ret = clk_prepare_enable(mxs->clk);
101 if (ret)
102 return ret;
103
104 writel(1 << pwm->hwpwm, mxs->base + PWM_CTRL + SET);
105
106 return 0;
107 }
108
109 static void mxs_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
110 {
111 struct mxs_pwm_chip *mxs = to_mxs_pwm_chip(chip);
112
113 writel(1 << pwm->hwpwm, mxs->base + PWM_CTRL + CLR);
114
115 clk_disable_unprepare(mxs->clk);
116 }
117
118 static const struct pwm_ops mxs_pwm_ops = {
119 .config = mxs_pwm_config,
120 .enable = mxs_pwm_enable,
121 .disable = mxs_pwm_disable,
122 .owner = THIS_MODULE,
123 };
124
125 static int mxs_pwm_probe(struct platform_device *pdev)
126 {
127 struct device_node *np = pdev->dev.of_node;
128 struct mxs_pwm_chip *mxs;
129 int ret;
130
131 mxs = devm_kzalloc(&pdev->dev, sizeof(*mxs), GFP_KERNEL);
132 if (!mxs)
133 return -ENOMEM;
134
135 mxs->base = devm_platform_ioremap_resource(pdev, 0);
136 if (IS_ERR(mxs->base))
137 return PTR_ERR(mxs->base);
138
139 mxs->clk = devm_clk_get(&pdev->dev, NULL);
140 if (IS_ERR(mxs->clk))
141 return PTR_ERR(mxs->clk);
142
143 mxs->chip.dev = &pdev->dev;
144 mxs->chip.ops = &mxs_pwm_ops;
145 mxs->chip.base = -1;
146
147 ret = of_property_read_u32(np, "fsl,pwm-number", &mxs->chip.npwm);
148 if (ret < 0) {
149 dev_err(&pdev->dev, "failed to get pwm number: %d\n", ret);
150 return ret;
151 }
152
153 ret = pwmchip_add(&mxs->chip);
154 if (ret < 0) {
155 dev_err(&pdev->dev, "failed to add pwm chip %d\n", ret);
156 return ret;
157 }
158
159 platform_set_drvdata(pdev, mxs);
160
161 ret = stmp_reset_block(mxs->base);
162 if (ret)
163 goto pwm_remove;
164
165 return 0;
166
167 pwm_remove:
168 pwmchip_remove(&mxs->chip);
169 return ret;
170 }
171
172 static int mxs_pwm_remove(struct platform_device *pdev)
173 {
174 struct mxs_pwm_chip *mxs = platform_get_drvdata(pdev);
175
176 return pwmchip_remove(&mxs->chip);
177 }
178
179 static const struct of_device_id mxs_pwm_dt_ids[] = {
180 { .compatible = "fsl,imx23-pwm", },
181 { }
182 };
183 MODULE_DEVICE_TABLE(of, mxs_pwm_dt_ids);
184
185 static struct platform_driver mxs_pwm_driver = {
186 .driver = {
187 .name = "mxs-pwm",
188 .of_match_table = mxs_pwm_dt_ids,
189 },
190 .probe = mxs_pwm_probe,
191 .remove = mxs_pwm_remove,
192 };
193 module_platform_driver(mxs_pwm_driver);
194
195 MODULE_ALIAS("platform:mxs-pwm");
196 MODULE_AUTHOR("Shawn Guo <shawn.guo@linaro.org>");
197 MODULE_DESCRIPTION("Freescale MXS PWM Driver");
198 MODULE_LICENSE("GPL v2");