drivers/spi/dw_spi_mmio.c

   1 /*
   2  * dw_spi_mmio.c - Memory-mapped interface driver for DW SPI Core
   3  *
   4  * Copyright (c) 2010, Octasic semiconductor.
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms and conditions of the GNU General Public License,
   8  * version 2, as published by the Free Software Foundation.
   9  */
  10
  11 #include <linux/clk.h>
  12 #include <linux/interrupt.h>
  13 #include <linux/platform_device.h>
  14 #include <linux/slab.h>
  15 #include <linux/spi/dw_spi.h>
  16 #include <linux/spi/spi.h>
  17
  18 #define DRIVER_NAME "dw_spi_mmio"
  19
  20 struct dw_spi_mmio {
  21         struct dw_spi  dws;
  22         struct clk     *clk;
  23 };
  24
  25 static int __devinit dw_spi_mmio_probe(struct platform_device *pdev)
  26 {
  27         struct dw_spi_mmio *dwsmmio;
  28         struct dw_spi *dws;
  29         struct resource *mem, *ioarea;
  30         int ret;
  31
  32         dwsmmio = kzalloc(sizeof(struct dw_spi_mmio), GFP_KERNEL);
  33         if (!dwsmmio) {
  34                 ret = -ENOMEM;
  35                 goto err_end;
  36         }
  37
  38         dws = &dwsmmio->dws;
  39
  40         /* Get basic io resource and map it */
  41         mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  42         if (!mem) {
  43                 dev_err(&pdev->dev, "no mem resource?\n");
  44                 ret = -EINVAL;
  45                 goto err_kfree;
  46         }
  47
  48         ioarea = request_mem_region(mem->start, resource_size(mem),
  49                         pdev->name);
  50         if (!ioarea) {
  51                 dev_err(&pdev->dev, "SPI region already claimed\n");
  52                 ret = -EBUSY;
  53                 goto err_kfree;
  54         }
  55
  56         dws->regs = ioremap_nocache(mem->start, resource_size(mem));
  57         if (!dws->regs) {
  58                 dev_err(&pdev->dev, "SPI region already mapped\n");
  59                 ret = -ENOMEM;
  60                 goto err_release_reg;
  61         }
  62
  63         dws->irq = platform_get_irq(pdev, 0);
  64         if (dws->irq < 0) {
  65                 dev_err(&pdev->dev, "no irq resource?\n");
  66                 ret = dws->irq; /* -ENXIO */
  67                 goto err_unmap;
  68         }
  69
  70         dwsmmio->clk = clk_get(&pdev->dev, NULL);
  71         if (!dwsmmio->clk) {
  72                 ret = -ENODEV;
  73                 goto err_irq;
  74         }
  75         clk_enable(dwsmmio->clk);
  76
  77         dws->parent_dev = &pdev->dev;
  78         dws->bus_num = 0;
  79         dws->num_cs = 4;
  80         dws->max_freq = clk_get_rate(dwsmmio->clk);
  81
  82         ret = dw_spi_add_host(dws);
  83         if (ret)
  84                 goto err_clk;
  85
  86         platform_set_drvdata(pdev, dwsmmio);
  87         return 0;
  88
  89 err_clk:
  90         clk_disable(dwsmmio->clk);
  91         clk_put(dwsmmio->clk);
  92         dwsmmio->clk = NULL;
  93 err_irq:
  94         free_irq(dws->irq, dws);
  95 err_unmap:
  96         iounmap(dws->regs);
  97 err_release_reg:
  98         release_mem_region(mem->start, resource_size(mem));
  99 err_kfree:
 100         kfree(dwsmmio);
 101 err_end:
 102         return ret;
 103 }
 104
 105 static int __devexit dw_spi_mmio_remove(struct platform_device *pdev)
 106 {
 107         struct dw_spi_mmio *dwsmmio = platform_get_drvdata(pdev);
 108         struct resource *mem;
 109
 110         platform_set_drvdata(pdev, NULL);
 111
 112         clk_disable(dwsmmio->clk);
 113         clk_put(dwsmmio->clk);
 114         dwsmmio->clk = NULL;
 115
 116         free_irq(dwsmmio->dws.irq, &dwsmmio->dws);
 117         dw_spi_remove_host(&dwsmmio->dws);
 118         iounmap(dwsmmio->dws.regs);
 119         kfree(dwsmmio);
 120
 121         mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 122         release_mem_region(mem->start, resource_size(mem));
 123         return 0;
 124 }
 125
 126 static struct platform_driver dw_spi_mmio_driver = {
 127         .remove         = __devexit_p(dw_spi_mmio_remove),
 128         .driver         = {
 129                 .name   = DRIVER_NAME,
 130                 .owner  = THIS_MODULE,
 131         },
 132 };
 133
 134 static int __init dw_spi_mmio_init(void)
 135 {
 136         return platform_driver_probe(&dw_spi_mmio_driver, dw_spi_mmio_probe);
 137 }
 138 module_init(dw_spi_mmio_init);
 139
 140 static void __exit dw_spi_mmio_exit(void)
 141 {
 142         platform_driver_unregister(&dw_spi_mmio_driver);
 143 }
 144 module_exit(dw_spi_mmio_exit);
 145
 146 MODULE_AUTHOR("Jean-Hugues Deschenes <jean-hugues.deschenes@octasic.com>");
 147 MODULE_DESCRIPTION("Memory-mapped I/O interface driver for DW SPI Core");
 148 MODULE_LICENSE("GPL v2");