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Linux/drivers/pwm/pwm-ab8500.c

  1 /*
  2  * Copyright (C) ST-Ericsson SA 2010
  3  *
  4  * Author: Arun R Murthy <arun.murthy@stericsson.com>
  5  * License terms: GNU General Public License (GPL) version 2
  6  */
  7 #include <linux/err.h>
  8 #include <linux/platform_device.h>
  9 #include <linux/slab.h>
 10 #include <linux/pwm.h>
 11 #include <linux/mfd/abx500.h>
 12 #include <linux/mfd/abx500/ab8500.h>
 13 #include <linux/module.h>
 14 
 15 /*
 16  * PWM Out generators
 17  * Bank: 0x10
 18  */
 19 #define AB8500_PWM_OUT_CTRL1_REG        0x60
 20 #define AB8500_PWM_OUT_CTRL2_REG        0x61
 21 #define AB8500_PWM_OUT_CTRL7_REG        0x66
 22 
 23 struct ab8500_pwm_chip {
 24         struct pwm_chip chip;
 25 };
 26 
 27 static int ab8500_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
 28                              int duty_ns, int period_ns)
 29 {
 30         int ret = 0;
 31         unsigned int higher_val, lower_val;
 32         u8 reg;
 33 
 34         /*
 35          * get the first 8 bits that are be written to
 36          * AB8500_PWM_OUT_CTRL1_REG[0:7]
 37          */
 38         lower_val = duty_ns & 0x00FF;
 39         /*
 40          * get bits [9:10] that are to be written to
 41          * AB8500_PWM_OUT_CTRL2_REG[0:1]
 42          */
 43         higher_val = ((duty_ns & 0x0300) >> 8);
 44 
 45         reg = AB8500_PWM_OUT_CTRL1_REG + ((chip->base - 1) * 2);
 46 
 47         ret = abx500_set_register_interruptible(chip->dev, AB8500_MISC,
 48                         reg, (u8)lower_val);
 49         if (ret < 0)
 50                 return ret;
 51         ret = abx500_set_register_interruptible(chip->dev, AB8500_MISC,
 52                         (reg + 1), (u8)higher_val);
 53 
 54         return ret;
 55 }
 56 
 57 static int ab8500_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
 58 {
 59         int ret;
 60 
 61         ret = abx500_mask_and_set_register_interruptible(chip->dev,
 62                                 AB8500_MISC, AB8500_PWM_OUT_CTRL7_REG,
 63                                 1 << (chip->base - 1), 1 << (chip->base - 1));
 64         if (ret < 0)
 65                 dev_err(chip->dev, "%s: Failed to enable PWM, Error %d\n",
 66                                                         pwm->label, ret);
 67         return ret;
 68 }
 69 
 70 static void ab8500_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
 71 {
 72         int ret;
 73 
 74         ret = abx500_mask_and_set_register_interruptible(chip->dev,
 75                                 AB8500_MISC, AB8500_PWM_OUT_CTRL7_REG,
 76                                 1 << (chip->base - 1), 0);
 77         if (ret < 0)
 78                 dev_err(chip->dev, "%s: Failed to disable PWM, Error %d\n",
 79                                                         pwm->label, ret);
 80 }
 81 
 82 static const struct pwm_ops ab8500_pwm_ops = {
 83         .config = ab8500_pwm_config,
 84         .enable = ab8500_pwm_enable,
 85         .disable = ab8500_pwm_disable,
 86         .owner = THIS_MODULE,
 87 };
 88 
 89 static int ab8500_pwm_probe(struct platform_device *pdev)
 90 {
 91         struct ab8500_pwm_chip *ab8500;
 92         int err;
 93 
 94         /*
 95          * Nothing to be done in probe, this is required to get the
 96          * device which is required for ab8500 read and write
 97          */
 98         ab8500 = devm_kzalloc(&pdev->dev, sizeof(*ab8500), GFP_KERNEL);
 99         if (ab8500 == NULL)
100                 return -ENOMEM;
101 
102         ab8500->chip.dev = &pdev->dev;
103         ab8500->chip.ops = &ab8500_pwm_ops;
104         ab8500->chip.base = pdev->id;
105         ab8500->chip.npwm = 1;
106 
107         err = pwmchip_add(&ab8500->chip);
108         if (err < 0)
109                 return err;
110 
111         dev_dbg(&pdev->dev, "pwm probe successful\n");
112         platform_set_drvdata(pdev, ab8500);
113 
114         return 0;
115 }
116 
117 static int ab8500_pwm_remove(struct platform_device *pdev)
118 {
119         struct ab8500_pwm_chip *ab8500 = platform_get_drvdata(pdev);
120         int err;
121 
122         err = pwmchip_remove(&ab8500->chip);
123         if (err < 0)
124                 return err;
125 
126         dev_dbg(&pdev->dev, "pwm driver removed\n");
127 
128         return 0;
129 }
130 
131 static struct platform_driver ab8500_pwm_driver = {
132         .driver = {
133                 .name = "ab8500-pwm",
134                 .owner = THIS_MODULE,
135         },
136         .probe = ab8500_pwm_probe,
137         .remove = ab8500_pwm_remove,
138 };
139 module_platform_driver(ab8500_pwm_driver);
140 
141 MODULE_AUTHOR("Arun MURTHY <arun.murthy@stericsson.com>");
142 MODULE_DESCRIPTION("AB8500 Pulse Width Modulation Driver");
143 MODULE_ALIAS("platform:ab8500-pwm");
144 MODULE_LICENSE("GPL v2");
145 

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