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 #include <linux/of_gpio.h>
  20
  21 #include "spi-dw.h"
  22
  23 #define DRIVER_NAME "dw_spi_mmio"
  24
  25 struct dw_spi_mmio {
  26         struct dw_spi  dws;
  27         struct clk     *clk;
  28 };
  29
  30 static int dw_spi_mmio_probe(struct platform_device *pdev)
  31 {
  32         struct dw_spi_mmio *dwsmmio;
  33         struct dw_spi *dws;
  34         struct resource *mem;
  35         int ret;
  36
  37         dwsmmio = devm_kzalloc(&pdev->dev, sizeof(struct dw_spi_mmio),
  38                         GFP_KERNEL);
  39         if (!dwsmmio)
  40                 return -ENOMEM;
  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                 return -EINVAL;
  49         }
  50
  51         dws->regs = devm_ioremap_resource(&pdev->dev, mem);
  52         if (IS_ERR(dws->regs)) {
  53                 dev_err(&pdev->dev, "SPI region map failed\n");
  54                 return PTR_ERR(dws->regs);
  55         }
  56
  57         dws->irq = platform_get_irq(pdev, 0);
  58         if (dws->irq < 0) {
  59                 dev_err(&pdev->dev, "no irq resource?\n");
  60                 return dws->irq; /* -ENXIO */
  61         }
  62
  63         dwsmmio->clk = devm_clk_get(&pdev->dev, NULL);
  64         if (IS_ERR(dwsmmio->clk))
  65                 return PTR_ERR(dwsmmio->clk);
  66         ret = clk_prepare_enable(dwsmmio->clk);
  67         if (ret)
  68                 return ret;
  69
  70         dws->bus_num = pdev->id;
  71         dws->num_cs = 4;
  72         dws->max_freq = clk_get_rate(dwsmmio->clk);
  73
  74         if (pdev->dev.of_node) {
  75                 int i;
  76
  77                 for (i = 0; i < dws->num_cs; i++) {
  78                         int cs_gpio = of_get_named_gpio(pdev->dev.of_node,
  79                                         "cs-gpios", i);
  80
  81                         if (cs_gpio == -EPROBE_DEFER) {
  82                                 ret = cs_gpio;
  83                                 goto out;
  84                         }
  85
  86                         if (gpio_is_valid(cs_gpio)) {
  87                                 ret = devm_gpio_request(&pdev->dev, cs_gpio,
  88                                                 dev_name(&pdev->dev));
  89                                 if (ret)
  90                                         goto out;
  91                         }
  92                 }
  93         }
  94
  95         ret = dw_spi_add_host(&pdev->dev, dws);
  96         if (ret)
  97                 goto out;
  98
  99         platform_set_drvdata(pdev, dwsmmio);
 100         return 0;
 101
 102 out:
 103         clk_disable_unprepare(dwsmmio->clk);
 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
 111         clk_disable_unprepare(dwsmmio->clk);
 112         dw_spi_remove_host(&dwsmmio->dws);
 113
 114         return 0;
 115 }
 116
 117 static struct platform_driver dw_spi_mmio_driver = {
 118         .probe          = dw_spi_mmio_probe,
 119         .remove         = dw_spi_mmio_remove,
 120         .driver         = {
 121                 .name   = DRIVER_NAME,
 122                 .owner  = THIS_MODULE,
 123         },
 124 };
 125 module_platform_driver(dw_spi_mmio_driver);
 126
 127 MODULE_AUTHOR("Jean-Hugues Deschenes <jean-hugues.deschenes@octasic.com>");
 128 MODULE_DESCRIPTION("Memory-mapped I/O interface driver for DW SPI Core");
 129 MODULE_LICENSE("GPL v2");