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pwm-twl6030.c
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1 /*
2  * twl6030_pwm.c
3  * Driver for PHOENIX (TWL6030) Pulse Width Modulator
4  *
5  * Copyright (C) 2010 Texas Instruments
6  * Author: Hemanth V <[email protected]>
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/pwm.h>
24 #include <linux/i2c/twl.h>
25 #include <linux/slab.h>
26 
27 #define LED_PWM_CTRL1 0xF4
28 #define LED_PWM_CTRL2 0xF5
29 
30 /* Max value for CTRL1 register */
31 #define PWM_CTRL1_MAX 255
32 
33 /* Pull down disable */
34 #define PWM_CTRL2_DIS_PD (1 << 6)
35 
36 /* Current control 2.5 milli Amps */
37 #define PWM_CTRL2_CURR_02 (2 << 4)
38 
39 /* LED supply source */
40 #define PWM_CTRL2_SRC_VAC (1 << 2)
41 
42 /* LED modes */
43 #define PWM_CTRL2_MODE_HW (0 << 0)
44 #define PWM_CTRL2_MODE_SW (1 << 0)
45 #define PWM_CTRL2_MODE_DIS (2 << 0)
46 
47 #define PWM_CTRL2_MODE_MASK 0x3
48 
50  struct pwm_chip chip;
51 };
52 
53 static int twl6030_pwm_request(struct pwm_chip *chip, struct pwm_device *pwm)
54 {
55  int ret;
56  u8 val;
57 
58  /* Configure PWM */
61 
63  if (ret < 0) {
64  dev_err(chip->dev, "%s: Failed to configure PWM, Error %d\n",
65  pwm->label, ret);
66  return ret;
67  }
68 
69  return 0;
70 }
71 
72 static int twl6030_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
73  int duty_ns, int period_ns)
74 {
75  u8 duty_cycle = (duty_ns * PWM_CTRL1_MAX) / period_ns;
76  int ret;
77 
79  if (ret < 0) {
80  pr_err("%s: Failed to configure PWM, Error %d\n",
81  pwm->label, ret);
82  return ret;
83  }
84 
85  return 0;
86 }
87 
88 static int twl6030_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
89 {
90  int ret;
91  u8 val;
92 
94  if (ret < 0) {
95  dev_err(chip->dev, "%s: Failed to enable PWM, Error %d\n",
96  pwm->label, ret);
97  return ret;
98  }
99 
100  /* Change mode to software control */
101  val &= ~PWM_CTRL2_MODE_MASK;
102  val |= PWM_CTRL2_MODE_SW;
103 
105  if (ret < 0) {
106  dev_err(chip->dev, "%s: Failed to enable PWM, Error %d\n",
107  pwm->label, ret);
108  return ret;
109  }
110 
112  return 0;
113 }
114 
115 static void twl6030_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
116 {
117  int ret;
118  u8 val;
119 
121  if (ret < 0) {
122  dev_err(chip->dev, "%s: Failed to disable PWM, Error %d\n",
123  pwm->label, ret);
124  return;
125  }
126 
127  val &= ~PWM_CTRL2_MODE_MASK;
128  val |= PWM_CTRL2_MODE_HW;
129 
131  if (ret < 0) {
132  dev_err(chip->dev, "%s: Failed to disable PWM, Error %d\n",
133  pwm->label, ret);
134  }
135 }
136 
137 static const struct pwm_ops twl6030_pwm_ops = {
138  .request = twl6030_pwm_request,
139  .config = twl6030_pwm_config,
140  .enable = twl6030_pwm_enable,
141  .disable = twl6030_pwm_disable,
142 };
143 
144 static int twl6030_pwm_probe(struct platform_device *pdev)
145 {
146  struct twl6030_pwm_chip *twl6030;
147  int ret;
148 
149  twl6030 = devm_kzalloc(&pdev->dev, sizeof(*twl6030), GFP_KERNEL);
150  if (!twl6030)
151  return -ENOMEM;
152 
153  twl6030->chip.dev = &pdev->dev;
154  twl6030->chip.ops = &twl6030_pwm_ops;
155  twl6030->chip.base = -1;
156  twl6030->chip.npwm = 1;
157 
158  ret = pwmchip_add(&twl6030->chip);
159  if (ret < 0)
160  return ret;
161 
162  platform_set_drvdata(pdev, twl6030);
163 
164  return 0;
165 }
166 
167 static int twl6030_pwm_remove(struct platform_device *pdev)
168 {
169  struct twl6030_pwm_chip *twl6030 = platform_get_drvdata(pdev);
170 
171  return pwmchip_remove(&twl6030->chip);
172 }
173 
174 static struct platform_driver twl6030_pwm_driver = {
175  .driver = {
176  .name = "twl6030-pwm",
177  },
178  .probe = twl6030_pwm_probe,
179  .remove = __devexit_p(twl6030_pwm_remove),
180 };
181 module_platform_driver(twl6030_pwm_driver);
182 
183 MODULE_ALIAS("platform:twl6030-pwm");
184 MODULE_LICENSE("GPL");