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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 <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); |
| 164 | |
| 165 | MODULE_LICENSE("GPL"); |
| 166 |
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Tags:
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v2.6.34-rc5
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