drivers/pwm/pwm-twl6030.c

   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/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
  49 struct twl6030_pwm_chip {
  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 */
  59         val = PWM_CTRL2_DIS_PD | PWM_CTRL2_CURR_02 | PWM_CTRL2_SRC_VAC |
  60               PWM_CTRL2_MODE_HW;
  61
  62         ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, val, LED_PWM_CTRL2);
  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
  78         ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, duty_cycle, LED_PWM_CTRL1);
  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
  93         ret = twl_i2c_read_u8(TWL6030_MODULE_ID1, &val, LED_PWM_CTRL2);
  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
 104         ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, val, LED_PWM_CTRL2);
 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
 111         twl_i2c_read_u8(TWL6030_MODULE_ID1, &val, LED_PWM_CTRL2);
 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
 120         ret = twl_i2c_read_u8(TWL6030_MODULE_ID1, &val, LED_PWM_CTRL2);
 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
 130         ret = twl_i2c_write_u8(TWL6030_MODULE_ID1, val, LED_PWM_CTRL2);
 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");