152 lines
3.5 KiB
C
152 lines
3.5 KiB
C
/*
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* Copyright (C) ST-Ericsson SA 2010
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*
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* Author: Arun R Murthy <arun.murthy@stericsson.com>
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* License terms: GNU General Public License (GPL) version 2
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*/
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#include <linux/err.h>
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#include <linux/platform_device.h>
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#include <linux/slab.h>
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#include <linux/pwm.h>
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#include <linux/mfd/abx500.h>
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#include <linux/mfd/abx500/ab8500.h>
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#include <linux/module.h>
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/*
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* PWM Out generators
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* Bank: 0x10
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*/
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#define AB8500_PWM_OUT_CTRL1_REG 0x60
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#define AB8500_PWM_OUT_CTRL2_REG 0x61
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#define AB8500_PWM_OUT_CTRL7_REG 0x66
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/* backlight driver constants */
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#define ENABLE_PWM 1
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#define DISABLE_PWM 0
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struct ab8500_pwm_chip {
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struct pwm_chip chip;
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};
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static int ab8500_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
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int duty_ns, int period_ns)
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{
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int ret = 0;
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unsigned int higher_val, lower_val;
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u8 reg;
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/*
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* get the first 8 bits that are be written to
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* AB8500_PWM_OUT_CTRL1_REG[0:7]
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*/
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lower_val = duty_ns & 0x00FF;
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/*
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* get bits [9:10] that are to be written to
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* AB8500_PWM_OUT_CTRL2_REG[0:1]
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*/
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higher_val = ((duty_ns & 0x0300) >> 8);
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reg = AB8500_PWM_OUT_CTRL1_REG + ((chip->base - 1) * 2);
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ret = abx500_set_register_interruptible(chip->dev, AB8500_MISC,
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reg, (u8)lower_val);
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if (ret < 0)
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return ret;
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ret = abx500_set_register_interruptible(chip->dev, AB8500_MISC,
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(reg + 1), (u8)higher_val);
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return ret;
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}
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static int ab8500_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
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{
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int ret;
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ret = abx500_mask_and_set_register_interruptible(chip->dev,
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AB8500_MISC, AB8500_PWM_OUT_CTRL7_REG,
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1 << (chip->base - 1), ENABLE_PWM);
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if (ret < 0)
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dev_err(chip->dev, "%s: Failed to enable PWM, Error %d\n",
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pwm->label, ret);
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return ret;
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}
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static void ab8500_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
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{
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int ret;
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ret = abx500_mask_and_set_register_interruptible(chip->dev,
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AB8500_MISC, AB8500_PWM_OUT_CTRL7_REG,
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1 << (chip->base - 1), DISABLE_PWM);
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if (ret < 0)
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dev_err(chip->dev, "%s: Failed to disable PWM, Error %d\n",
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pwm->label, ret);
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return;
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}
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static const struct pwm_ops ab8500_pwm_ops = {
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.config = ab8500_pwm_config,
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.enable = ab8500_pwm_enable,
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.disable = ab8500_pwm_disable,
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.owner = THIS_MODULE,
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};
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static int ab8500_pwm_probe(struct platform_device *pdev)
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{
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struct ab8500_pwm_chip *ab8500;
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int err;
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/*
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* Nothing to be done in probe, this is required to get the
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* device which is required for ab8500 read and write
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*/
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ab8500 = devm_kzalloc(&pdev->dev, sizeof(*ab8500), GFP_KERNEL);
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if (ab8500 == NULL) {
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dev_err(&pdev->dev, "failed to allocate memory\n");
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return -ENOMEM;
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}
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ab8500->chip.dev = &pdev->dev;
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ab8500->chip.ops = &ab8500_pwm_ops;
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ab8500->chip.base = pdev->id;
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ab8500->chip.npwm = 1;
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err = pwmchip_add(&ab8500->chip);
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if (err < 0)
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return err;
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dev_dbg(&pdev->dev, "pwm probe successful\n");
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platform_set_drvdata(pdev, ab8500);
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return 0;
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}
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static int ab8500_pwm_remove(struct platform_device *pdev)
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{
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struct ab8500_pwm_chip *ab8500 = platform_get_drvdata(pdev);
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int err;
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err = pwmchip_remove(&ab8500->chip);
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if (err < 0)
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return err;
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dev_dbg(&pdev->dev, "pwm driver removed\n");
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return 0;
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}
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static struct platform_driver ab8500_pwm_driver = {
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.driver = {
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.name = "ab8500-pwm",
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.owner = THIS_MODULE,
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},
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.probe = ab8500_pwm_probe,
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.remove = ab8500_pwm_remove,
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};
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module_platform_driver(ab8500_pwm_driver);
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MODULE_AUTHOR("Arun MURTHY <arun.murthy@stericsson.com>");
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MODULE_DESCRIPTION("AB8500 Pulse Width Modulation Driver");
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MODULE_ALIAS("platform:ab8500-pwm");
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MODULE_LICENSE("GPL v2");
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