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31fc03df H |
1 | /* |
2 | * twl6030_pwm.c | |
3 | * Driver for PHOENIX (TWL6030) Pulse Width Modulator | |
4 | * | |
5 | * Copyright (C) 2010 Texas Instruments | |
6 | * Author: Hemanth V <hemanthv@ti.com> | |
7 | * | |
8 | * This program is free software; you can redistribute it and/or modify it | |
9 | * under the terms of the GNU General Public License version 2 as published by | |
10 | * the Free Software Foundation. | |
11 | * | |
12 | * This program is distributed in the hope that it will be useful, but WITHOUT | |
13 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
14 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for | |
15 | * more details. | |
16 | * | |
17 | * You should have received a copy of the GNU General Public License along with | |
18 | * this program. If not, see <http://www.gnu.org/licenses/>. | |
19 | */ | |
20 | ||
21 | #include <linux/module.h> | |
22 | #include <linux/platform_device.h> | |
23 | #include <linux/i2c/twl.h> | |
24 | #include <linux/slab.h> | |
25 | ||
26 | #define LED_PWM_CTRL1 0xF4 | |
27 | #define LED_PWM_CTRL2 0xF5 | |
28 | ||
29 | /* Max value for CTRL1 register */ | |
30 | #define PWM_CTRL1_MAX 255 | |
31 | ||
32 | /* Pull down disable */ | |
33 | #define PWM_CTRL2_DIS_PD (1 << 6) | |
34 | ||
35 | /* Current control 2.5 milli Amps */ | |
36 | #define PWM_CTRL2_CURR_02 (2 << 4) | |
37 | ||
38 | /* LED supply source */ | |
39 | #define PWM_CTRL2_SRC_VAC (1 << 2) | |
40 | ||
41 | /* LED modes */ | |
42 | #define PWM_CTRL2_MODE_HW (0 << 0) | |
43 | #define PWM_CTRL2_MODE_SW (1 << 0) | |
44 | #define PWM_CTRL2_MODE_DIS (2 << 0) | |
45 | ||
46 | #define PWM_CTRL2_MODE_MASK 0x3 | |
47 | ||
48 | struct pwm_device { | |
49 | const char *label; | |
50 | unsigned int pwm_id; | |
51 | }; | |
52 | ||
53 | int pwm_config(struct pwm_device *pwm, int duty_ns, int period_ns) | |
54 | { | |
55 | u8 duty_cycle; | |
56 | int ret; | |
57 | ||
58 | if (pwm == NULL || period_ns == 0 || duty_ns > period_ns) | |
59 | return -EINVAL; | |
60 | ||
61 | duty_cycle = (duty_ns * PWM_CTRL1_MAX) / period_ns; | |
62 | ||
63 | ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, duty_cycle, LED_PWM_CTRL1); | |
64 | ||
65 | if (ret < 0) { | |
66 | pr_err("%s: Failed to configure PWM, Error %d\n", | |
67 | pwm->label, ret); | |
68 | return ret; | |
69 | } | |
70 | return 0; | |
71 | } | |
72 | EXPORT_SYMBOL(pwm_config); | |
73 | ||
74 | int pwm_enable(struct pwm_device *pwm) | |
75 | { | |
76 | u8 val; | |
77 | int ret; | |
78 | ||
79 | ret = twl_i2c_read_u8(TWL6030_MODULE_ID1, &val, LED_PWM_CTRL2); | |
80 | if (ret < 0) { | |
81 | pr_err("%s: Failed to enable PWM, Error %d\n", pwm->label, ret); | |
82 | return ret; | |
83 | } | |
84 | ||
85 | /* Change mode to software control */ | |
86 | val &= ~PWM_CTRL2_MODE_MASK; | |
87 | val |= PWM_CTRL2_MODE_SW; | |
88 | ||
89 | ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, val, LED_PWM_CTRL2); | |
90 | if (ret < 0) { | |
91 | pr_err("%s: Failed to enable PWM, Error %d\n", pwm->label, ret); | |
92 | return ret; | |
93 | } | |
94 | ||
95 | twl_i2c_read_u8(TWL6030_MODULE_ID1, &val, LED_PWM_CTRL2); | |
96 | return 0; | |
97 | } | |
98 | EXPORT_SYMBOL(pwm_enable); | |
99 | ||
100 | void pwm_disable(struct pwm_device *pwm) | |
101 | { | |
102 | u8 val; | |
103 | int ret; | |
104 | ||
105 | ret = twl_i2c_read_u8(TWL6030_MODULE_ID1, &val, LED_PWM_CTRL2); | |
106 | if (ret < 0) { | |
107 | pr_err("%s: Failed to disable PWM, Error %d\n", | |
108 | pwm->label, ret); | |
109 | return; | |
110 | } | |
111 | ||
112 | val &= ~PWM_CTRL2_MODE_MASK; | |
113 | val |= PWM_CTRL2_MODE_HW; | |
114 | ||
115 | ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, val, LED_PWM_CTRL2); | |
116 | if (ret < 0) { | |
117 | pr_err("%s: Failed to disable PWM, Error %d\n", | |
118 | pwm->label, ret); | |
119 | return; | |
120 | } | |
121 | return; | |
122 | } | |
123 | EXPORT_SYMBOL(pwm_disable); | |
124 | ||
125 | struct pwm_device *pwm_request(int pwm_id, const char *label) | |
126 | { | |
127 | u8 val; | |
128 | int ret; | |
129 | struct pwm_device *pwm; | |
130 | ||
131 | pwm = kzalloc(sizeof(struct pwm_device), GFP_KERNEL); | |
132 | if (pwm == NULL) { | |
133 | pr_err("%s: failed to allocate memory\n", label); | |
134 | return NULL; | |
135 | } | |
136 | ||
137 | pwm->label = label; | |
138 | pwm->pwm_id = pwm_id; | |
139 | ||
140 | /* Configure PWM */ | |
141 | val = PWM_CTRL2_DIS_PD | PWM_CTRL2_CURR_02 | PWM_CTRL2_SRC_VAC | | |
142 | PWM_CTRL2_MODE_HW; | |
143 | ||
144 | ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, val, LED_PWM_CTRL2); | |
145 | ||
146 | if (ret < 0) { | |
147 | pr_err("%s: Failed to configure PWM, Error %d\n", | |
148 | pwm->label, ret); | |
149 | ||
150 | kfree(pwm); | |
151 | return NULL; | |
152 | } | |
153 | ||
154 | return pwm; | |
155 | } | |
156 | EXPORT_SYMBOL(pwm_request); | |
157 | ||
158 | void pwm_free(struct pwm_device *pwm) | |
159 | { | |
160 | pwm_disable(pwm); | |
161 | kfree(pwm); | |
162 | } | |
163 | EXPORT_SYMBOL(pwm_free); |