linux/drivers/pwm/pwm-tipwmss.c
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   1/*
   2 * TI PWM Subsystem driver
   3 *
   4 * Copyright (C) 2012 Texas Instruments Incorporated - http://www.ti.com/
   5 *
   6 * This program is free software; you can redistribute it and/or modify
   7 * it under the terms of the GNU General Public License as published by
   8 * the Free Software Foundation; either version 2 of the License, or
   9 * (at your option) any later version.
  10 *
  11 * This program is distributed in the hope that it will be useful,
  12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  14 * GNU General Public License for more details.
  15 *
  16 */
  17
  18#include <linux/module.h>
  19#include <linux/platform_device.h>
  20#include <linux/io.h>
  21#include <linux/err.h>
  22#include <linux/pm_runtime.h>
  23#include <linux/of_device.h>
  24
  25#include "pwm-tipwmss.h"
  26
  27#define PWMSS_CLKCONFIG         0x8     /* Clock gating reg */
  28#define PWMSS_CLKSTATUS         0xc     /* Clock gating status reg */
  29
  30struct pwmss_info {
  31        void __iomem    *mmio_base;
  32        struct mutex    pwmss_lock;
  33        u16             pwmss_clkconfig;
  34};
  35
  36u16 pwmss_submodule_state_change(struct device *dev, int set)
  37{
  38        struct pwmss_info *info = dev_get_drvdata(dev);
  39        u16 val;
  40
  41        mutex_lock(&info->pwmss_lock);
  42        val = readw(info->mmio_base + PWMSS_CLKCONFIG);
  43        val |= set;
  44        writew(val , info->mmio_base + PWMSS_CLKCONFIG);
  45        mutex_unlock(&info->pwmss_lock);
  46
  47        return readw(info->mmio_base + PWMSS_CLKSTATUS);
  48}
  49EXPORT_SYMBOL(pwmss_submodule_state_change);
  50
  51static const struct of_device_id pwmss_of_match[] = {
  52        { .compatible   = "ti,am33xx-pwmss" },
  53        {},
  54};
  55MODULE_DEVICE_TABLE(of, pwmss_of_match);
  56
  57static int pwmss_probe(struct platform_device *pdev)
  58{
  59        int ret;
  60        struct resource *r;
  61        struct pwmss_info *info;
  62        struct device_node *node = pdev->dev.of_node;
  63
  64        info = devm_kzalloc(&pdev->dev, sizeof(*info), GFP_KERNEL);
  65        if (!info) {
  66                dev_err(&pdev->dev, "failed to allocate memory\n");
  67                return -ENOMEM;
  68        }
  69
  70        mutex_init(&info->pwmss_lock);
  71
  72        r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  73        if (!r) {
  74                dev_err(&pdev->dev, "no memory resource defined\n");
  75                return -ENODEV;
  76        }
  77
  78        info->mmio_base = devm_ioremap_resource(&pdev->dev, r);
  79        if (IS_ERR(info->mmio_base))
  80                return PTR_ERR(info->mmio_base);
  81
  82        pm_runtime_enable(&pdev->dev);
  83        pm_runtime_get_sync(&pdev->dev);
  84        platform_set_drvdata(pdev, info);
  85
  86        /* Populate all the child nodes here... */
  87        ret = of_platform_populate(node, NULL, NULL, &pdev->dev);
  88        if (ret)
  89                dev_err(&pdev->dev, "no child node found\n");
  90
  91        return ret;
  92}
  93
  94static int pwmss_remove(struct platform_device *pdev)
  95{
  96        struct pwmss_info *info = platform_get_drvdata(pdev);
  97
  98        pm_runtime_put_sync(&pdev->dev);
  99        pm_runtime_disable(&pdev->dev);
 100        mutex_destroy(&info->pwmss_lock);
 101        return 0;
 102}
 103
 104static int pwmss_suspend(struct device *dev)
 105{
 106        struct pwmss_info *info = dev_get_drvdata(dev);
 107
 108        info->pwmss_clkconfig = readw(info->mmio_base + PWMSS_CLKCONFIG);
 109        pm_runtime_put_sync(dev);
 110        return 0;
 111}
 112
 113static int pwmss_resume(struct device *dev)
 114{
 115        struct pwmss_info *info = dev_get_drvdata(dev);
 116
 117        pm_runtime_get_sync(dev);
 118        writew(info->pwmss_clkconfig, info->mmio_base + PWMSS_CLKCONFIG);
 119        return 0;
 120}
 121
 122static SIMPLE_DEV_PM_OPS(pwmss_pm_ops, pwmss_suspend, pwmss_resume);
 123
 124static struct platform_driver pwmss_driver = {
 125        .driver = {
 126                .name   = "pwmss",
 127                .owner  = THIS_MODULE,
 128                .pm     = &pwmss_pm_ops,
 129                .of_match_table = pwmss_of_match,
 130        },
 131        .probe  = pwmss_probe,
 132        .remove = pwmss_remove,
 133};
 134
 135module_platform_driver(pwmss_driver);
 136
 137MODULE_DESCRIPTION("PWM Subsystem driver");
 138MODULE_AUTHOR("Texas Instruments");
 139MODULE_LICENSE("GPL");
 140
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