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1 | /* |
2 | * Copyright 2012 Freescale Semiconductor, Inc. | |
3 | * | |
4 | * The code contained herein is licensed under the GNU General Public | |
5 | * License. You may obtain a copy of the GNU General Public License | |
6 | * Version 2 or later at the following locations: | |
7 | * | |
8 | * http://www.opensource.org/licenses/gpl-license.html | |
9 | * http://www.gnu.org/copyleft/gpl.html | |
10 | */ | |
11 | ||
12 | #include <linux/clk.h> | |
13 | #include <linux/err.h> | |
14 | #include <linux/io.h> | |
15 | #include <linux/kernel.h> | |
16 | #include <linux/module.h> | |
17 | #include <linux/of.h> | |
18 | #include <linux/of_address.h> | |
19 | #include <linux/platform_device.h> | |
20 | #include <linux/pwm.h> | |
21 | #include <linux/slab.h> | |
22 | #include <mach/common.h> | |
23 | ||
24 | #define SET 0x4 | |
25 | #define CLR 0x8 | |
26 | #define TOG 0xc | |
27 | ||
28 | #define PWM_CTRL 0x0 | |
29 | #define PWM_ACTIVE0 0x10 | |
30 | #define PWM_PERIOD0 0x20 | |
31 | #define PERIOD_PERIOD(p) ((p) & 0xffff) | |
32 | #define PERIOD_PERIOD_MAX 0x10000 | |
33 | #define PERIOD_ACTIVE_HIGH (3 << 16) | |
34 | #define PERIOD_INACTIVE_LOW (2 << 18) | |
35 | #define PERIOD_CDIV(div) (((div) & 0x7) << 20) | |
36 | #define PERIOD_CDIV_MAX 8 | |
37 | ||
38 | struct mxs_pwm_chip { | |
39 | struct pwm_chip chip; | |
40 | struct device *dev; | |
41 | struct clk *clk; | |
42 | void __iomem *base; | |
43 | }; | |
44 | ||
45 | #define to_mxs_pwm_chip(_chip) container_of(_chip, struct mxs_pwm_chip, chip) | |
46 | ||
47 | static int mxs_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, | |
48 | int duty_ns, int period_ns) | |
49 | { | |
50 | struct mxs_pwm_chip *mxs = to_mxs_pwm_chip(chip); | |
51 | int ret, div = 0; | |
52 | unsigned int period_cycles, duty_cycles; | |
53 | unsigned long rate; | |
54 | unsigned long long c; | |
55 | ||
56 | rate = clk_get_rate(mxs->clk); | |
57 | while (1) { | |
58 | c = rate / (1 << div); | |
59 | c = c * period_ns; | |
60 | do_div(c, 1000000000); | |
61 | if (c < PERIOD_PERIOD_MAX) | |
62 | break; | |
63 | div++; | |
64 | if (div > PERIOD_CDIV_MAX) | |
65 | return -EINVAL; | |
66 | } | |
67 | ||
68 | period_cycles = c; | |
69 | c *= duty_ns; | |
70 | do_div(c, period_ns); | |
71 | duty_cycles = c; | |
72 | ||
73 | /* | |
74 | * If the PWM channel is disabled, make sure to turn on the clock | |
75 | * before writing the register. Otherwise, keep it enabled. | |
76 | */ | |
77 | if (!test_bit(PWMF_ENABLED, &pwm->flags)) { | |
78 | ret = clk_prepare_enable(mxs->clk); | |
79 | if (ret) | |
80 | return ret; | |
81 | } | |
82 | ||
83 | writel(duty_cycles << 16, | |
84 | mxs->base + PWM_ACTIVE0 + pwm->hwpwm * 0x20); | |
85 | writel(PERIOD_PERIOD(period_cycles) | PERIOD_ACTIVE_HIGH | | |
86 | PERIOD_INACTIVE_LOW | PERIOD_CDIV(div), | |
87 | mxs->base + PWM_PERIOD0 + pwm->hwpwm * 0x20); | |
88 | ||
89 | /* | |
90 | * If the PWM is not enabled, turn the clock off again to save power. | |
91 | */ | |
92 | if (!test_bit(PWMF_ENABLED, &pwm->flags)) | |
93 | clk_disable_unprepare(mxs->clk); | |
94 | ||
95 | return 0; | |
96 | } | |
97 | ||
98 | static int mxs_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm) | |
99 | { | |
100 | struct mxs_pwm_chip *mxs = to_mxs_pwm_chip(chip); | |
101 | int ret; | |
102 | ||
103 | ret = clk_prepare_enable(mxs->clk); | |
104 | if (ret) | |
105 | return ret; | |
106 | ||
107 | writel(1 << pwm->hwpwm, mxs->base + PWM_CTRL + SET); | |
108 | ||
109 | return 0; | |
110 | } | |
111 | ||
112 | static void mxs_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm) | |
113 | { | |
114 | struct mxs_pwm_chip *mxs = to_mxs_pwm_chip(chip); | |
115 | ||
116 | writel(1 << pwm->hwpwm, mxs->base + PWM_CTRL + CLR); | |
117 | ||
118 | clk_disable_unprepare(mxs->clk); | |
119 | } | |
120 | ||
121 | static const struct pwm_ops mxs_pwm_ops = { | |
122 | .config = mxs_pwm_config, | |
123 | .enable = mxs_pwm_enable, | |
124 | .disable = mxs_pwm_disable, | |
125 | .owner = THIS_MODULE, | |
126 | }; | |
127 | ||
128 | static int mxs_pwm_probe(struct platform_device *pdev) | |
129 | { | |
130 | struct device_node *np = pdev->dev.of_node; | |
131 | struct mxs_pwm_chip *mxs; | |
132 | int ret; | |
133 | ||
134 | mxs = devm_kzalloc(&pdev->dev, sizeof(*mxs), GFP_KERNEL); | |
135 | if (!mxs) | |
136 | return -ENOMEM; | |
137 | ||
138 | mxs->base = of_iomap(np, 0); | |
139 | if (!mxs->base) | |
140 | return -EADDRNOTAVAIL; | |
141 | ||
142 | mxs->clk = clk_get(&pdev->dev, NULL); | |
143 | if (IS_ERR(mxs->clk)) { | |
144 | ret = PTR_ERR(mxs->clk); | |
145 | goto iounmap; | |
146 | } | |
147 | ||
148 | mxs->chip.dev = &pdev->dev; | |
149 | mxs->chip.ops = &mxs_pwm_ops; | |
150 | mxs->chip.base = -1; | |
151 | ret = of_property_read_u32(np, "fsl,pwm-number", &mxs->chip.npwm); | |
152 | if (ret < 0) { | |
153 | dev_err(&pdev->dev, "failed to get pwm number: %d\n", ret); | |
154 | goto clk_put; | |
155 | } | |
156 | ||
157 | ret = pwmchip_add(&mxs->chip); | |
158 | if (ret < 0) { | |
159 | dev_err(&pdev->dev, "failed to add pwm chip %d\n", ret); | |
160 | goto clk_put; | |
161 | } | |
162 | ||
163 | mxs->dev = &pdev->dev; | |
164 | platform_set_drvdata(pdev, mxs); | |
165 | ||
166 | mxs_reset_block(mxs->base); | |
167 | ||
168 | return 0; | |
169 | ||
170 | clk_put: | |
171 | clk_put(mxs->clk); | |
172 | iounmap: | |
173 | iounmap(mxs->base); | |
174 | return ret; | |
175 | } | |
176 | ||
177 | static int __devexit mxs_pwm_remove(struct platform_device *pdev) | |
178 | { | |
179 | struct mxs_pwm_chip *mxs = platform_get_drvdata(pdev); | |
180 | ||
181 | pwmchip_remove(&mxs->chip); | |
182 | clk_put(mxs->clk); | |
183 | iounmap(mxs->base); | |
184 | ||
185 | return 0; | |
186 | } | |
187 | ||
188 | static struct of_device_id mxs_pwm_dt_ids[] = { | |
189 | { .compatible = "fsl,mxs-pwm", }, | |
190 | { /* sentinel */ } | |
191 | }; | |
192 | MODULE_DEVICE_TABLE(of, mxs_pwm_dt_ids); | |
193 | ||
194 | static struct platform_driver mxs_pwm_driver = { | |
195 | .driver = { | |
196 | .name = "mxs-pwm", | |
197 | .of_match_table = of_match_ptr(mxs_pwm_dt_ids), | |
198 | }, | |
199 | .probe = mxs_pwm_probe, | |
200 | .remove = __devexit_p(mxs_pwm_remove), | |
201 | }; | |
202 | module_platform_driver(mxs_pwm_driver); | |
203 | ||
204 | MODULE_ALIAS("platform:mxs-pwm"); | |
205 | MODULE_AUTHOR("Shawn Guo <shawn.guo@linaro.org>"); | |
206 | MODULE_DESCRIPTION("Freescale MXS PWM Driver"); | |
207 | MODULE_LICENSE("GPL v2"); |