drivers/spi/spi-dw-mmio.c

   1 /*
   2  * 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/err.h>
  13 #include <linux/interrupt.h>
  14 #include <linux/platform_device.h>
  15 #include <linux/slab.h>
  16 #include <linux/spi/spi.h>
  17 #include <linux/scatterlist.h>
  18 #include <linux/module.h>
  19
  20 #include "spi-dw.h"
  21
  22 #define DRIVER_NAME "dw_spi_mmio"
  23
  24 struct dw_spi_mmio {
  25         struct dw_spi  dws;
  26         struct clk     *clk;
  27 };
  28
  29 static int dw_spi_mmio_probe(struct platform_device *pdev)
  30 {
  31         struct dw_spi_mmio *dwsmmio;
  32         struct dw_spi *dws;
  33         struct resource *mem, *ioarea;
  34         int ret;
  35
  36         dwsmmio = kzalloc(sizeof(struct dw_spi_mmio), GFP_KERNEL);
  37         if (!dwsmmio) {
  38                 ret = -ENOMEM;
  39                 goto err_end;
  40         }
  41
  42         dws = &dwsmmio->dws;
  43
  44         /* Get basic io resource and map it */
  45         mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  46         if (!mem) {
  47                 dev_err(&pdev->dev, "no mem resource?\n");
  48                 ret = -EINVAL;
  49                 goto err_kfree;
  50         }
  51
  52         ioarea = request_mem_region(mem->start, resource_size(mem),
  53                         pdev->name);
  54         if (!ioarea) {
  55                 dev_err(&pdev->dev, "SPI region already claimed\n");
  56                 ret = -EBUSY;
  57                 goto err_kfree;
  58         }
  59
  60         dws->regs = ioremap_nocache(mem->start, resource_size(mem));
  61         if (!dws->regs) {
  62                 dev_err(&pdev->dev, "SPI region already mapped\n");
  63                 ret = -ENOMEM;
  64                 goto err_release_reg;
  65         }
  66
  67         dws->irq = platform_get_irq(pdev, 0);
  68         if (dws->irq < 0) {
  69                 dev_err(&pdev->dev, "no irq resource?\n");
  70                 ret = dws->irq; /* -ENXIO */
  71                 goto err_unmap;
  72         }
  73
  74         dwsmmio->clk = clk_get(&pdev->dev, NULL);
  75         if (IS_ERR(dwsmmio->clk)) {
  76                 ret = PTR_ERR(dwsmmio->clk);
  77                 goto err_unmap;
  78         }
  79         clk_enable(dwsmmio->clk);
  80
  81         dws->parent_dev = &pdev->dev;
  82         dws->bus_num = 0;
  83         dws->num_cs = 4;
  84         dws->max_freq = clk_get_rate(dwsmmio->clk);
  85
  86         ret = dw_spi_add_host(dws);
  87         if (ret)
  88                 goto err_clk;
  89
  90         platform_set_drvdata(pdev, dwsmmio);
  91         return 0;
  92
  93 err_clk:
  94         clk_disable(dwsmmio->clk);
  95         clk_put(dwsmmio->clk);
  96         dwsmmio->clk = NULL;
  97 err_unmap:
  98         iounmap(dws->regs);
  99 err_release_reg:
 100         release_mem_region(mem->start, resource_size(mem));
 101 err_kfree:
 102         kfree(dwsmmio);
 103 err_end:
 104         return ret;
 105 }
 106
 107 static int dw_spi_mmio_remove(struct platform_device *pdev)
 108 {
 109         struct dw_spi_mmio *dwsmmio = platform_get_drvdata(pdev);
 110         struct resource *mem;
 111
 112         clk_disable(dwsmmio->clk);
 113         clk_put(dwsmmio->clk);
 114         dwsmmio->clk = NULL;
 115
 116         dw_spi_remove_host(&dwsmmio->dws);
 117         iounmap(dwsmmio->dws.regs);
 118         kfree(dwsmmio);
 119
 120         mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 121         release_mem_region(mem->start, resource_size(mem));
 122         return 0;
 123 }
 124
 125 static struct platform_driver dw_spi_mmio_driver = {
 126         .probe          = dw_spi_mmio_probe,
 127         .remove         = dw_spi_mmio_remove,
 128         .driver         = {
 129                 .name   = DRIVER_NAME,
 130                 .owner  = THIS_MODULE,
 131         },
 132 };
 133 module_platform_driver(dw_spi_mmio_driver);
 134
 135 MODULE_AUTHOR("Jean-Hugues Deschenes <jean-hugues.deschenes@octasic.com>");
 136 MODULE_DESCRIPTION("Memory-mapped I/O interface driver for DW SPI Core");
 137 MODULE_LICENSE("GPL v2");