diff options
author | Tomi Valkeinen <tomi.valkeinen@ti.com> | 2012-09-03 02:26:33 -0400 |
---|---|---|
committer | Tomi Valkeinen <tomi.valkeinen@ti.com> | 2012-09-03 02:26:33 -0400 |
commit | c50e86ce7c2961a41f2f7aa6e4fd6c99229ba205 (patch) | |
tree | 4ea36009719bd8fc523239fe1bdccb90f0dce3ae /drivers/pwm/pwm-vt8500.c | |
parent | 14d33d384693eb6083396199de516fdef320f7af (diff) | |
parent | 4cbe5a555fa58a79b6ecbb6c531b8bab0650778d (diff) |
Merge tag 'v3.6-rc4'
Merge 3.6-rc4 to get latest OMAP and device tree fixes.
Diffstat (limited to 'drivers/pwm/pwm-vt8500.c')
-rw-r--r-- | drivers/pwm/pwm-vt8500.c | 177 |
1 files changed, 177 insertions, 0 deletions
diff --git a/drivers/pwm/pwm-vt8500.c b/drivers/pwm/pwm-vt8500.c new file mode 100644 index 000000000000..ad14389b7144 --- /dev/null +++ b/drivers/pwm/pwm-vt8500.c | |||
@@ -0,0 +1,177 @@ | |||
1 | /* | ||
2 | * drivers/pwm/pwm-vt8500.c | ||
3 | * | ||
4 | * Copyright (C) 2010 Alexey Charkov <alchark@gmail.com> | ||
5 | * | ||
6 | * This software is licensed under the terms of the GNU General Public | ||
7 | * License version 2, as published by the Free Software Foundation, and | ||
8 | * may be copied, distributed, and modified under those terms. | ||
9 | * | ||
10 | * This program is distributed in the hope that it will be useful, | ||
11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | ||
12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | ||
13 | * GNU General Public License for more details. | ||
14 | */ | ||
15 | |||
16 | #include <linux/module.h> | ||
17 | #include <linux/kernel.h> | ||
18 | #include <linux/platform_device.h> | ||
19 | #include <linux/slab.h> | ||
20 | #include <linux/err.h> | ||
21 | #include <linux/io.h> | ||
22 | #include <linux/pwm.h> | ||
23 | #include <linux/delay.h> | ||
24 | |||
25 | #include <asm/div64.h> | ||
26 | |||
27 | #define VT8500_NR_PWMS 4 | ||
28 | |||
29 | struct vt8500_chip { | ||
30 | struct pwm_chip chip; | ||
31 | void __iomem *base; | ||
32 | }; | ||
33 | |||
34 | #define to_vt8500_chip(chip) container_of(chip, struct vt8500_chip, chip) | ||
35 | |||
36 | #define msecs_to_loops(t) (loops_per_jiffy / 1000 * HZ * t) | ||
37 | static inline void pwm_busy_wait(void __iomem *reg, u8 bitmask) | ||
38 | { | ||
39 | int loops = msecs_to_loops(10); | ||
40 | while ((readb(reg) & bitmask) && --loops) | ||
41 | cpu_relax(); | ||
42 | |||
43 | if (unlikely(!loops)) | ||
44 | pr_warn("Waiting for status bits 0x%x to clear timed out\n", | ||
45 | bitmask); | ||
46 | } | ||
47 | |||
48 | static int vt8500_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, | ||
49 | int duty_ns, int period_ns) | ||
50 | { | ||
51 | struct vt8500_chip *vt8500 = to_vt8500_chip(chip); | ||
52 | unsigned long long c; | ||
53 | unsigned long period_cycles, prescale, pv, dc; | ||
54 | |||
55 | c = 25000000/2; /* wild guess --- need to implement clocks */ | ||
56 | c = c * period_ns; | ||
57 | do_div(c, 1000000000); | ||
58 | period_cycles = c; | ||
59 | |||
60 | if (period_cycles < 1) | ||
61 | period_cycles = 1; | ||
62 | prescale = (period_cycles - 1) / 4096; | ||
63 | pv = period_cycles / (prescale + 1) - 1; | ||
64 | if (pv > 4095) | ||
65 | pv = 4095; | ||
66 | |||
67 | if (prescale > 1023) | ||
68 | return -EINVAL; | ||
69 | |||
70 | c = (unsigned long long)pv * duty_ns; | ||
71 | do_div(c, period_ns); | ||
72 | dc = c; | ||
73 | |||
74 | pwm_busy_wait(vt8500->base + 0x40 + pwm->hwpwm, (1 << 1)); | ||
75 | writel(prescale, vt8500->base + 0x4 + (pwm->hwpwm << 4)); | ||
76 | |||
77 | pwm_busy_wait(vt8500->base + 0x40 + pwm->hwpwm, (1 << 2)); | ||
78 | writel(pv, vt8500->base + 0x8 + (pwm->hwpwm << 4)); | ||
79 | |||
80 | pwm_busy_wait(vt8500->base + 0x40 + pwm->hwpwm, (1 << 3)); | ||
81 | writel(dc, vt8500->base + 0xc + (pwm->hwpwm << 4)); | ||
82 | |||
83 | return 0; | ||
84 | } | ||
85 | |||
86 | static int vt8500_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm) | ||
87 | { | ||
88 | struct vt8500_chip *vt8500 = to_vt8500_chip(chip); | ||
89 | |||
90 | pwm_busy_wait(vt8500->base + 0x40 + pwm->hwpwm, (1 << 0)); | ||
91 | writel(5, vt8500->base + (pwm->hwpwm << 4)); | ||
92 | return 0; | ||
93 | } | ||
94 | |||
95 | static void vt8500_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm) | ||
96 | { | ||
97 | struct vt8500_chip *vt8500 = to_vt8500_chip(chip); | ||
98 | |||
99 | pwm_busy_wait(vt8500->base + 0x40 + pwm->hwpwm, (1 << 0)); | ||
100 | writel(0, vt8500->base + (pwm->hwpwm << 4)); | ||
101 | } | ||
102 | |||
103 | static struct pwm_ops vt8500_pwm_ops = { | ||
104 | .enable = vt8500_pwm_enable, | ||
105 | .disable = vt8500_pwm_disable, | ||
106 | .config = vt8500_pwm_config, | ||
107 | .owner = THIS_MODULE, | ||
108 | }; | ||
109 | |||
110 | static int __devinit pwm_probe(struct platform_device *pdev) | ||
111 | { | ||
112 | struct vt8500_chip *chip; | ||
113 | struct resource *r; | ||
114 | int ret; | ||
115 | |||
116 | chip = devm_kzalloc(&pdev->dev, sizeof(*chip), GFP_KERNEL); | ||
117 | if (chip == NULL) { | ||
118 | dev_err(&pdev->dev, "failed to allocate memory\n"); | ||
119 | return -ENOMEM; | ||
120 | } | ||
121 | |||
122 | chip->chip.dev = &pdev->dev; | ||
123 | chip->chip.ops = &vt8500_pwm_ops; | ||
124 | chip->chip.base = -1; | ||
125 | chip->chip.npwm = VT8500_NR_PWMS; | ||
126 | |||
127 | r = platform_get_resource(pdev, IORESOURCE_MEM, 0); | ||
128 | if (r == NULL) { | ||
129 | dev_err(&pdev->dev, "no memory resource defined\n"); | ||
130 | return -ENODEV; | ||
131 | } | ||
132 | |||
133 | chip->base = devm_request_and_ioremap(&pdev->dev, r); | ||
134 | if (chip->base == NULL) | ||
135 | return -EADDRNOTAVAIL; | ||
136 | |||
137 | ret = pwmchip_add(&chip->chip); | ||
138 | if (ret < 0) | ||
139 | return ret; | ||
140 | |||
141 | platform_set_drvdata(pdev, chip); | ||
142 | return ret; | ||
143 | } | ||
144 | |||
145 | static int __devexit pwm_remove(struct platform_device *pdev) | ||
146 | { | ||
147 | struct vt8500_chip *chip; | ||
148 | |||
149 | chip = platform_get_drvdata(pdev); | ||
150 | if (chip == NULL) | ||
151 | return -ENODEV; | ||
152 | |||
153 | return pwmchip_remove(&chip->chip); | ||
154 | } | ||
155 | |||
156 | static struct platform_driver pwm_driver = { | ||
157 | .driver = { | ||
158 | .name = "vt8500-pwm", | ||
159 | .owner = THIS_MODULE, | ||
160 | }, | ||
161 | .probe = pwm_probe, | ||
162 | .remove = __devexit_p(pwm_remove), | ||
163 | }; | ||
164 | |||
165 | static int __init pwm_init(void) | ||
166 | { | ||
167 | return platform_driver_register(&pwm_driver); | ||
168 | } | ||
169 | arch_initcall(pwm_init); | ||
170 | |||
171 | static void __exit pwm_exit(void) | ||
172 | { | ||
173 | platform_driver_unregister(&pwm_driver); | ||
174 | } | ||
175 | module_exit(pwm_exit); | ||
176 | |||
177 | MODULE_LICENSE("GPL"); | ||