drivers/misc/atmel-ssc.c

   1 /*
   2  * Atmel SSC driver
   3  *
   4  * Copyright (C) 2007 Atmel Corporation
   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 version 2 as
   8  * published by the Free Software Foundation.
   9  */
  10
  11 #include <linux/platform_device.h>
  12 #include <linux/list.h>
  13 #include <linux/clk.h>
  14 #include <linux/err.h>
  15 #include <linux/io.h>
  16 #include <linux/spinlock.h>
  17 #include <linux/atmel-ssc.h>
  18 #include <linux/slab.h>
  19 #include <linux/module.h>
  20
  21 #include <linux/of.h>
  22 #include <linux/pinctrl/consumer.h>
  23
  24 /* Serialize access to ssc_list and user count */
  25 static DEFINE_SPINLOCK(user_lock);
  26 static LIST_HEAD(ssc_list);
  27
  28 struct ssc_device *ssc_request(unsigned int ssc_num)
  29 {
  30         int ssc_valid = 0;
  31         struct ssc_device *ssc;
  32
  33         spin_lock(&user_lock);
  34         list_for_each_entry(ssc, &ssc_list, list) {
  35                 if (ssc->pdev->dev.of_node) {
  36                         if (of_alias_get_id(ssc->pdev->dev.of_node, "ssc")
  37                                 == ssc_num) {
  38                                 ssc_valid = 1;
  39                                 break;
  40                         }
  41                 } else if (ssc->pdev->id == ssc_num) {
  42                         ssc_valid = 1;
  43                         break;
  44                 }
  45         }
  46
  47         if (!ssc_valid) {
  48                 spin_unlock(&user_lock);
  49                 pr_err("ssc: ssc%d platform device is missing\n", ssc_num);
  50                 return ERR_PTR(-ENODEV);
  51         }
  52
  53         if (ssc->user) {
  54                 spin_unlock(&user_lock);
  55                 dev_dbg(&ssc->pdev->dev, "module busy\n");
  56                 return ERR_PTR(-EBUSY);
  57         }
  58         ssc->user++;
  59         spin_unlock(&user_lock);
  60
  61         clk_enable(ssc->clk);
  62
  63         return ssc;
  64 }
  65 EXPORT_SYMBOL(ssc_request);
  66
  67 void ssc_free(struct ssc_device *ssc)
  68 {
  69         spin_lock(&user_lock);
  70         if (ssc->user) {
  71                 ssc->user--;
  72                 clk_disable(ssc->clk);
  73         } else {
  74                 dev_dbg(&ssc->pdev->dev, "device already free\n");
  75         }
  76         spin_unlock(&user_lock);
  77 }
  78 EXPORT_SYMBOL(ssc_free);
  79
  80 static struct atmel_ssc_platform_data at91rm9200_config = {
  81         .use_dma = 0,
  82 };
  83
  84 static struct atmel_ssc_platform_data at91sam9g45_config = {
  85         .use_dma = 1,
  86 };
  87
  88 static const struct platform_device_id atmel_ssc_devtypes[] = {
  89         {
  90                 .name = "at91rm9200_ssc",
  91                 .driver_data = (unsigned long) &at91rm9200_config,
  92         }, {
  93                 .name = "at91sam9g45_ssc",
  94                 .driver_data = (unsigned long) &at91sam9g45_config,
  95         }, {
  96                 /* sentinel */
  97         }
  98 };
  99
 100 #ifdef CONFIG_OF
 101 static const struct of_device_id atmel_ssc_dt_ids[] = {
 102         {
 103                 .compatible = "atmel,at91rm9200-ssc",
 104                 .data = &at91rm9200_config,
 105         }, {
 106                 .compatible = "atmel,at91sam9g45-ssc",
 107                 .data = &at91sam9g45_config,
 108         }, {
 109                 /* sentinel */
 110         }
 111 };
 112 MODULE_DEVICE_TABLE(of, atmel_ssc_dt_ids);
 113 #endif
 114
 115 static inline const struct atmel_ssc_platform_data * __init
 116         atmel_ssc_get_driver_data(struct platform_device *pdev)
 117 {
 118         if (pdev->dev.of_node) {
 119                 const struct of_device_id *match;
 120                 match = of_match_node(atmel_ssc_dt_ids, pdev->dev.of_node);
 121                 if (match == NULL)
 122                         return NULL;
 123                 return match->data;
 124         }
 125
 126         return (struct atmel_ssc_platform_data *)
 127                 platform_get_device_id(pdev)->driver_data;
 128 }
 129
 130 static int ssc_probe(struct platform_device *pdev)
 131 {
 132         struct resource *regs;
 133         struct ssc_device *ssc;
 134         const struct atmel_ssc_platform_data *plat_dat;
 135         struct pinctrl *pinctrl;
 136
 137         pinctrl = devm_pinctrl_get_select_default(&pdev->dev);
 138         if (IS_ERR(pinctrl)) {
 139                 dev_err(&pdev->dev, "Failed to request pinctrl\n");
 140                 return PTR_ERR(pinctrl);
 141         }
 142
 143         ssc = devm_kzalloc(&pdev->dev, sizeof(struct ssc_device), GFP_KERNEL);
 144         if (!ssc) {
 145                 dev_dbg(&pdev->dev, "out of memory\n");
 146                 return -ENOMEM;
 147         }
 148
 149         ssc->pdev = pdev;
 150
 151         plat_dat = atmel_ssc_get_driver_data(pdev);
 152         if (!plat_dat)
 153                 return -ENODEV;
 154         ssc->pdata = (struct atmel_ssc_platform_data *)plat_dat;
 155
 156         regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 157         ssc->regs = devm_ioremap_resource(&pdev->dev, regs);
 158         if (IS_ERR(ssc->regs))
 159                 return PTR_ERR(ssc->regs);
 160
 161         ssc->phybase = regs->start;
 162
 163         ssc->clk = devm_clk_get(&pdev->dev, "pclk");
 164         if (IS_ERR(ssc->clk)) {
 165                 dev_dbg(&pdev->dev, "no pclk clock defined\n");
 166                 return -ENXIO;
 167         }
 168
 169         /* disable all interrupts */
 170         clk_enable(ssc->clk);
 171         ssc_writel(ssc->regs, IDR, -1);
 172         ssc_readl(ssc->regs, SR);
 173         clk_disable(ssc->clk);
 174
 175         ssc->irq = platform_get_irq(pdev, 0);
 176         if (!ssc->irq) {
 177                 dev_dbg(&pdev->dev, "could not get irq\n");
 178                 return -ENXIO;
 179         }
 180
 181         spin_lock(&user_lock);
 182         list_add_tail(&ssc->list, &ssc_list);
 183         spin_unlock(&user_lock);
 184
 185         platform_set_drvdata(pdev, ssc);
 186
 187         dev_info(&pdev->dev, "Atmel SSC device at 0x%p (irq %d)\n",
 188                         ssc->regs, ssc->irq);
 189
 190         return 0;
 191 }
 192
 193 static int ssc_remove(struct platform_device *pdev)
 194 {
 195         struct ssc_device *ssc = platform_get_drvdata(pdev);
 196
 197         spin_lock(&user_lock);
 198         list_del(&ssc->list);
 199         spin_unlock(&user_lock);
 200
 201         return 0;
 202 }
 203
 204 static struct platform_driver ssc_driver = {
 205         .driver         = {
 206                 .name           = "ssc",
 207                 .owner          = THIS_MODULE,
 208                 .of_match_table = of_match_ptr(atmel_ssc_dt_ids),
 209         },
 210         .id_table       = atmel_ssc_devtypes,
 211         .probe          = ssc_probe,
 212         .remove         = ssc_remove,
 213 };
 214 module_platform_driver(ssc_driver);
 215
 216 MODULE_AUTHOR("Hans-Christian Egtvedt <hcegtvedt@atmel.com>");
 217 MODULE_DESCRIPTION("SSC driver for Atmel AVR32 and AT91");
 218 MODULE_LICENSE("GPL");
 219 MODULE_ALIAS("platform:ssc");