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4dce82c1 SG |
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> | |
1112fe88 | 19 | #include <linux/pinctrl/consumer.h> |
4dce82c1 SG |
20 | #include <linux/platform_device.h> |
21 | #include <linux/pwm.h> | |
22 | #include <linux/slab.h> | |
01bf32e9 | 23 | #include <linux/stmp_device.h> |
4dce82c1 SG |
24 | |
25 | #define SET 0x4 | |
26 | #define CLR 0x8 | |
27 | #define TOG 0xc | |
28 | ||
29 | #define PWM_CTRL 0x0 | |
30 | #define PWM_ACTIVE0 0x10 | |
31 | #define PWM_PERIOD0 0x20 | |
32 | #define PERIOD_PERIOD(p) ((p) & 0xffff) | |
33 | #define PERIOD_PERIOD_MAX 0x10000 | |
34 | #define PERIOD_ACTIVE_HIGH (3 << 16) | |
35 | #define PERIOD_INACTIVE_LOW (2 << 18) | |
36 | #define PERIOD_CDIV(div) (((div) & 0x7) << 20) | |
37 | #define PERIOD_CDIV_MAX 8 | |
38 | ||
39 | struct mxs_pwm_chip { | |
40 | struct pwm_chip chip; | |
41 | struct device *dev; | |
42 | struct clk *clk; | |
43 | void __iomem *base; | |
44 | }; | |
45 | ||
46 | #define to_mxs_pwm_chip(_chip) container_of(_chip, struct mxs_pwm_chip, chip) | |
47 | ||
48 | static int mxs_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, | |
49 | int duty_ns, int period_ns) | |
50 | { | |
51 | struct mxs_pwm_chip *mxs = to_mxs_pwm_chip(chip); | |
52 | int ret, div = 0; | |
53 | unsigned int period_cycles, duty_cycles; | |
54 | unsigned long rate; | |
55 | unsigned long long c; | |
56 | ||
57 | rate = clk_get_rate(mxs->clk); | |
58 | while (1) { | |
59 | c = rate / (1 << div); | |
60 | c = c * period_ns; | |
61 | do_div(c, 1000000000); | |
62 | if (c < PERIOD_PERIOD_MAX) | |
63 | break; | |
64 | div++; | |
65 | if (div > PERIOD_CDIV_MAX) | |
66 | return -EINVAL; | |
67 | } | |
68 | ||
69 | period_cycles = c; | |
70 | c *= duty_ns; | |
71 | do_div(c, period_ns); | |
72 | duty_cycles = c; | |
73 | ||
74 | /* | |
75 | * If the PWM channel is disabled, make sure to turn on the clock | |
76 | * before writing the register. Otherwise, keep it enabled. | |
77 | */ | |
78 | if (!test_bit(PWMF_ENABLED, &pwm->flags)) { | |
79 | ret = clk_prepare_enable(mxs->clk); | |
80 | if (ret) | |
81 | return ret; | |
82 | } | |
83 | ||
84 | writel(duty_cycles << 16, | |
85 | mxs->base + PWM_ACTIVE0 + pwm->hwpwm * 0x20); | |
86 | writel(PERIOD_PERIOD(period_cycles) | PERIOD_ACTIVE_HIGH | | |
87 | PERIOD_INACTIVE_LOW | PERIOD_CDIV(div), | |
88 | mxs->base + PWM_PERIOD0 + pwm->hwpwm * 0x20); | |
89 | ||
90 | /* | |
91 | * If the PWM is not enabled, turn the clock off again to save power. | |
92 | */ | |
93 | if (!test_bit(PWMF_ENABLED, &pwm->flags)) | |
94 | clk_disable_unprepare(mxs->clk); | |
95 | ||
96 | return 0; | |
97 | } | |
98 | ||
99 | static int mxs_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm) | |
100 | { | |
101 | struct mxs_pwm_chip *mxs = to_mxs_pwm_chip(chip); | |
102 | int ret; | |
103 | ||
104 | ret = clk_prepare_enable(mxs->clk); | |
105 | if (ret) | |
106 | return ret; | |
107 | ||
108 | writel(1 << pwm->hwpwm, mxs->base + PWM_CTRL + SET); | |
109 | ||
110 | return 0; | |
111 | } | |
112 | ||
113 | static void mxs_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm) | |
114 | { | |
115 | struct mxs_pwm_chip *mxs = to_mxs_pwm_chip(chip); | |
116 | ||
117 | writel(1 << pwm->hwpwm, mxs->base + PWM_CTRL + CLR); | |
118 | ||
119 | clk_disable_unprepare(mxs->clk); | |
120 | } | |
121 | ||
122 | static const struct pwm_ops mxs_pwm_ops = { | |
123 | .config = mxs_pwm_config, | |
124 | .enable = mxs_pwm_enable, | |
125 | .disable = mxs_pwm_disable, | |
126 | .owner = THIS_MODULE, | |
127 | }; | |
128 | ||
129 | static int mxs_pwm_probe(struct platform_device *pdev) | |
130 | { | |
131 | struct device_node *np = pdev->dev.of_node; | |
132 | struct mxs_pwm_chip *mxs; | |
22d260bd | 133 | struct resource *res; |
1112fe88 | 134 | struct pinctrl *pinctrl; |
4dce82c1 SG |
135 | int ret; |
136 | ||
137 | mxs = devm_kzalloc(&pdev->dev, sizeof(*mxs), GFP_KERNEL); | |
138 | if (!mxs) | |
139 | return -ENOMEM; | |
140 | ||
22d260bd SG |
141 | res = platform_get_resource(pdev, IORESOURCE_MEM, 0); |
142 | mxs->base = devm_request_and_ioremap(&pdev->dev, res); | |
4dce82c1 SG |
143 | if (!mxs->base) |
144 | return -EADDRNOTAVAIL; | |
145 | ||
1112fe88 SG |
146 | pinctrl = devm_pinctrl_get_select_default(&pdev->dev); |
147 | if (IS_ERR(pinctrl)) | |
148 | return PTR_ERR(pinctrl); | |
149 | ||
22d260bd SG |
150 | mxs->clk = devm_clk_get(&pdev->dev, NULL); |
151 | if (IS_ERR(mxs->clk)) | |
152 | return PTR_ERR(mxs->clk); | |
4dce82c1 SG |
153 | |
154 | mxs->chip.dev = &pdev->dev; | |
155 | mxs->chip.ops = &mxs_pwm_ops; | |
156 | mxs->chip.base = -1; | |
157 | ret = of_property_read_u32(np, "fsl,pwm-number", &mxs->chip.npwm); | |
158 | if (ret < 0) { | |
159 | dev_err(&pdev->dev, "failed to get pwm number: %d\n", ret); | |
22d260bd | 160 | return ret; |
4dce82c1 SG |
161 | } |
162 | ||
163 | ret = pwmchip_add(&mxs->chip); | |
164 | if (ret < 0) { | |
165 | dev_err(&pdev->dev, "failed to add pwm chip %d\n", ret); | |
22d260bd | 166 | return ret; |
4dce82c1 SG |
167 | } |
168 | ||
169 | mxs->dev = &pdev->dev; | |
170 | platform_set_drvdata(pdev, mxs); | |
171 | ||
01bf32e9 | 172 | stmp_reset_block(mxs->base); |
4dce82c1 SG |
173 | |
174 | return 0; | |
4dce82c1 SG |
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 | ||
457fd768 | 181 | return pwmchip_remove(&mxs->chip); |
4dce82c1 SG |
182 | } |
183 | ||
184 | static struct of_device_id mxs_pwm_dt_ids[] = { | |
071407ee | 185 | { .compatible = "fsl,imx23-pwm", }, |
4dce82c1 SG |
186 | { /* sentinel */ } |
187 | }; | |
188 | MODULE_DEVICE_TABLE(of, mxs_pwm_dt_ids); | |
189 | ||
190 | static struct platform_driver mxs_pwm_driver = { | |
191 | .driver = { | |
192 | .name = "mxs-pwm", | |
193 | .of_match_table = of_match_ptr(mxs_pwm_dt_ids), | |
194 | }, | |
195 | .probe = mxs_pwm_probe, | |
fd109112 | 196 | .remove = mxs_pwm_remove, |
4dce82c1 SG |
197 | }; |
198 | module_platform_driver(mxs_pwm_driver); | |
199 | ||
200 | MODULE_ALIAS("platform:mxs-pwm"); | |
201 | MODULE_AUTHOR("Shawn Guo <shawn.guo@linaro.org>"); | |
202 | MODULE_DESCRIPTION("Freescale MXS PWM Driver"); | |
203 | MODULE_LICENSE("GPL v2"); |