drivers/pwm/pwm-tipwmss.c

   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
  30 struct pwmss_info {
  31         void __iomem    *mmio_base;
  32         struct mutex    pwmss_lock;
  33         u16             pwmss_clkconfig;
  34 };
  35
  36 u16 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 }
  49 EXPORT_SYMBOL(pwmss_submodule_state_change);
  50
  51 static const struct of_device_id pwmss_of_match[] = {
  52         { .compatible   = "ti,am33xx-pwmss" },
  53         {},
  54 };
  55 MODULE_DEVICE_TABLE(of, pwmss_of_match);
  56
  57 static 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                 return -ENOMEM;
  67
  68         mutex_init(&info->pwmss_lock);
  69
  70         r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  71         info->mmio_base = devm_ioremap_resource(&pdev->dev, r);
  72         if (IS_ERR(info->mmio_base))
  73                 return PTR_ERR(info->mmio_base);
  74
  75         pm_runtime_enable(&pdev->dev);
  76         pm_runtime_get_sync(&pdev->dev);
  77         platform_set_drvdata(pdev, info);
  78
  79         /* Populate all the child nodes here... */
  80         ret = of_platform_populate(node, NULL, NULL, &pdev->dev);
  81         if (ret)
  82                 dev_err(&pdev->dev, "no child node found\n");
  83
  84         return ret;
  85 }
  86
  87 static int pwmss_remove(struct platform_device *pdev)
  88 {
  89         struct pwmss_info *info = platform_get_drvdata(pdev);
  90
  91         pm_runtime_put_sync(&pdev->dev);
  92         pm_runtime_disable(&pdev->dev);
  93         mutex_destroy(&info->pwmss_lock);
  94         return 0;
  95 }
  96
  97 #ifdef CONFIG_PM_SLEEP
  98 static int pwmss_suspend(struct device *dev)
  99 {
 100         struct pwmss_info *info = dev_get_drvdata(dev);
 101
 102         info->pwmss_clkconfig = readw(info->mmio_base + PWMSS_CLKCONFIG);
 103         pm_runtime_put_sync(dev);
 104         return 0;
 105 }
 106
 107 static int pwmss_resume(struct device *dev)
 108 {
 109         struct pwmss_info *info = dev_get_drvdata(dev);
 110
 111         pm_runtime_get_sync(dev);
 112         writew(info->pwmss_clkconfig, info->mmio_base + PWMSS_CLKCONFIG);
 113         return 0;
 114 }
 115 #endif
 116
 117 static SIMPLE_DEV_PM_OPS(pwmss_pm_ops, pwmss_suspend, pwmss_resume);
 118
 119 static struct platform_driver pwmss_driver = {
 120         .driver = {
 121                 .name   = "pwmss",
 122                 .pm     = &pwmss_pm_ops,
 123                 .of_match_table = pwmss_of_match,
 124         },
 125         .probe  = pwmss_probe,
 126         .remove = pwmss_remove,
 127 };
 128
 129 module_platform_driver(pwmss_driver);
 130
 131 MODULE_DESCRIPTION("PWM Subsystem driver");
 132 MODULE_AUTHOR("Texas Instruments");
 133 MODULE_LICENSE("GPL");