diff options
author | Tomi Valkeinen <tomi.valkeinen@ti.com> | 2012-09-03 02:26:33 -0400 |
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committer | Tomi Valkeinen <tomi.valkeinen@ti.com> | 2012-09-03 02:26:33 -0400 |
commit | c50e86ce7c2961a41f2f7aa6e4fd6c99229ba205 (patch) | |
tree | 4ea36009719bd8fc523239fe1bdccb90f0dce3ae /drivers/pwm/pwm-pxa.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-pxa.c')
-rw-r--r-- | drivers/pwm/pwm-pxa.c | 218 |
1 files changed, 218 insertions, 0 deletions
diff --git a/drivers/pwm/pwm-pxa.c b/drivers/pwm/pwm-pxa.c new file mode 100644 index 000000000000..bd5867a1c700 --- /dev/null +++ b/drivers/pwm/pwm-pxa.c | |||
@@ -0,0 +1,218 @@ | |||
1 | /* | ||
2 | * drivers/pwm/pwm-pxa.c | ||
3 | * | ||
4 | * simple driver for PWM (Pulse Width Modulator) controller | ||
5 | * | ||
6 | * This program is free software; you can redistribute it and/or modify | ||
7 | * it under the terms of the GNU General Public License version 2 as | ||
8 | * published by the Free Software Foundation. | ||
9 | * | ||
10 | * 2008-02-13 initial version | ||
11 | * eric miao <eric.miao@marvell.com> | ||
12 | */ | ||
13 | |||
14 | #include <linux/module.h> | ||
15 | #include <linux/kernel.h> | ||
16 | #include <linux/platform_device.h> | ||
17 | #include <linux/slab.h> | ||
18 | #include <linux/err.h> | ||
19 | #include <linux/clk.h> | ||
20 | #include <linux/io.h> | ||
21 | #include <linux/pwm.h> | ||
22 | |||
23 | #include <asm/div64.h> | ||
24 | |||
25 | #define HAS_SECONDARY_PWM 0x10 | ||
26 | #define PWM_ID_BASE(d) ((d) & 0xf) | ||
27 | |||
28 | static const struct platform_device_id pwm_id_table[] = { | ||
29 | /* PWM has_secondary_pwm? */ | ||
30 | { "pxa25x-pwm", 0 }, | ||
31 | { "pxa27x-pwm", 0 | HAS_SECONDARY_PWM }, | ||
32 | { "pxa168-pwm", 1 }, | ||
33 | { "pxa910-pwm", 1 }, | ||
34 | { }, | ||
35 | }; | ||
36 | MODULE_DEVICE_TABLE(platform, pwm_id_table); | ||
37 | |||
38 | /* PWM registers and bits definitions */ | ||
39 | #define PWMCR (0x00) | ||
40 | #define PWMDCR (0x04) | ||
41 | #define PWMPCR (0x08) | ||
42 | |||
43 | #define PWMCR_SD (1 << 6) | ||
44 | #define PWMDCR_FD (1 << 10) | ||
45 | |||
46 | struct pxa_pwm_chip { | ||
47 | struct pwm_chip chip; | ||
48 | struct device *dev; | ||
49 | |||
50 | struct clk *clk; | ||
51 | int clk_enabled; | ||
52 | void __iomem *mmio_base; | ||
53 | }; | ||
54 | |||
55 | static inline struct pxa_pwm_chip *to_pxa_pwm_chip(struct pwm_chip *chip) | ||
56 | { | ||
57 | return container_of(chip, struct pxa_pwm_chip, chip); | ||
58 | } | ||
59 | |||
60 | /* | ||
61 | * period_ns = 10^9 * (PRESCALE + 1) * (PV + 1) / PWM_CLK_RATE | ||
62 | * duty_ns = 10^9 * (PRESCALE + 1) * DC / PWM_CLK_RATE | ||
63 | */ | ||
64 | static int pxa_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm, | ||
65 | int duty_ns, int period_ns) | ||
66 | { | ||
67 | struct pxa_pwm_chip *pc = to_pxa_pwm_chip(chip); | ||
68 | unsigned long long c; | ||
69 | unsigned long period_cycles, prescale, pv, dc; | ||
70 | unsigned long offset; | ||
71 | int rc; | ||
72 | |||
73 | if (period_ns == 0 || duty_ns > period_ns) | ||
74 | return -EINVAL; | ||
75 | |||
76 | offset = pwm->hwpwm ? 0x10 : 0; | ||
77 | |||
78 | c = clk_get_rate(pc->clk); | ||
79 | c = c * period_ns; | ||
80 | do_div(c, 1000000000); | ||
81 | period_cycles = c; | ||
82 | |||
83 | if (period_cycles < 1) | ||
84 | period_cycles = 1; | ||
85 | prescale = (period_cycles - 1) / 1024; | ||
86 | pv = period_cycles / (prescale + 1) - 1; | ||
87 | |||
88 | if (prescale > 63) | ||
89 | return -EINVAL; | ||
90 | |||
91 | if (duty_ns == period_ns) | ||
92 | dc = PWMDCR_FD; | ||
93 | else | ||
94 | dc = (pv + 1) * duty_ns / period_ns; | ||
95 | |||
96 | /* NOTE: the clock to PWM has to be enabled first | ||
97 | * before writing to the registers | ||
98 | */ | ||
99 | rc = clk_prepare_enable(pc->clk); | ||
100 | if (rc < 0) | ||
101 | return rc; | ||
102 | |||
103 | writel(prescale, pc->mmio_base + offset + PWMCR); | ||
104 | writel(dc, pc->mmio_base + offset + PWMDCR); | ||
105 | writel(pv, pc->mmio_base + offset + PWMPCR); | ||
106 | |||
107 | clk_disable_unprepare(pc->clk); | ||
108 | return 0; | ||
109 | } | ||
110 | |||
111 | static int pxa_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm) | ||
112 | { | ||
113 | struct pxa_pwm_chip *pc = to_pxa_pwm_chip(chip); | ||
114 | int rc = 0; | ||
115 | |||
116 | if (!pc->clk_enabled) { | ||
117 | rc = clk_prepare_enable(pc->clk); | ||
118 | if (!rc) | ||
119 | pc->clk_enabled++; | ||
120 | } | ||
121 | return rc; | ||
122 | } | ||
123 | |||
124 | static void pxa_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm) | ||
125 | { | ||
126 | struct pxa_pwm_chip *pc = to_pxa_pwm_chip(chip); | ||
127 | |||
128 | if (pc->clk_enabled) { | ||
129 | clk_disable_unprepare(pc->clk); | ||
130 | pc->clk_enabled--; | ||
131 | } | ||
132 | } | ||
133 | |||
134 | static struct pwm_ops pxa_pwm_ops = { | ||
135 | .config = pxa_pwm_config, | ||
136 | .enable = pxa_pwm_enable, | ||
137 | .disable = pxa_pwm_disable, | ||
138 | .owner = THIS_MODULE, | ||
139 | }; | ||
140 | |||
141 | static int __devinit pwm_probe(struct platform_device *pdev) | ||
142 | { | ||
143 | const struct platform_device_id *id = platform_get_device_id(pdev); | ||
144 | struct pxa_pwm_chip *pwm; | ||
145 | struct resource *r; | ||
146 | int ret = 0; | ||
147 | |||
148 | pwm = devm_kzalloc(&pdev->dev, sizeof(*pwm), GFP_KERNEL); | ||
149 | if (pwm == NULL) { | ||
150 | dev_err(&pdev->dev, "failed to allocate memory\n"); | ||
151 | return -ENOMEM; | ||
152 | } | ||
153 | |||
154 | pwm->clk = devm_clk_get(&pdev->dev, NULL); | ||
155 | if (IS_ERR(pwm->clk)) | ||
156 | return PTR_ERR(pwm->clk); | ||
157 | |||
158 | pwm->clk_enabled = 0; | ||
159 | |||
160 | pwm->chip.dev = &pdev->dev; | ||
161 | pwm->chip.ops = &pxa_pwm_ops; | ||
162 | pwm->chip.base = -1; | ||
163 | pwm->chip.npwm = (id->driver_data & HAS_SECONDARY_PWM) ? 2 : 1; | ||
164 | |||
165 | r = platform_get_resource(pdev, IORESOURCE_MEM, 0); | ||
166 | if (r == NULL) { | ||
167 | dev_err(&pdev->dev, "no memory resource defined\n"); | ||
168 | return -ENODEV; | ||
169 | } | ||
170 | |||
171 | pwm->mmio_base = devm_request_and_ioremap(&pdev->dev, r); | ||
172 | if (pwm->mmio_base == NULL) | ||
173 | return -EADDRNOTAVAIL; | ||
174 | |||
175 | ret = pwmchip_add(&pwm->chip); | ||
176 | if (ret < 0) { | ||
177 | dev_err(&pdev->dev, "pwmchip_add() failed: %d\n", ret); | ||
178 | return ret; | ||
179 | } | ||
180 | |||
181 | platform_set_drvdata(pdev, pwm); | ||
182 | return 0; | ||
183 | } | ||
184 | |||
185 | static int __devexit pwm_remove(struct platform_device *pdev) | ||
186 | { | ||
187 | struct pxa_pwm_chip *chip; | ||
188 | |||
189 | chip = platform_get_drvdata(pdev); | ||
190 | if (chip == NULL) | ||
191 | return -ENODEV; | ||
192 | |||
193 | return pwmchip_remove(&chip->chip); | ||
194 | } | ||
195 | |||
196 | static struct platform_driver pwm_driver = { | ||
197 | .driver = { | ||
198 | .name = "pxa25x-pwm", | ||
199 | .owner = THIS_MODULE, | ||
200 | }, | ||
201 | .probe = pwm_probe, | ||
202 | .remove = __devexit_p(pwm_remove), | ||
203 | .id_table = pwm_id_table, | ||
204 | }; | ||
205 | |||
206 | static int __init pwm_init(void) | ||
207 | { | ||
208 | return platform_driver_register(&pwm_driver); | ||
209 | } | ||
210 | arch_initcall(pwm_init); | ||
211 | |||
212 | static void __exit pwm_exit(void) | ||
213 | { | ||
214 | platform_driver_unregister(&pwm_driver); | ||
215 | } | ||
216 | module_exit(pwm_exit); | ||
217 | |||
218 | MODULE_LICENSE("GPL v2"); | ||