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.h>
  20 #include <linux/of_gpio.h>
  21 #include <linux/of_platform.h>
  22
  23 #include "spi-dw.h"
  24
  25 #define DRIVER_NAME "dw_spi_mmio"
  26
  27 struct dw_spi_mmio {
  28         struct dw_spi  dws;
  29         struct clk     *clk;
  30 };
  31
  32 static int dw_spi_mmio_probe(struct platform_device *pdev)
  33 {
  34         struct dw_spi_mmio *dwsmmio;
  35         struct dw_spi *dws;
  36         struct resource *mem;
  37         int ret;
  38         int num_cs;
  39
  40         dwsmmio = devm_kzalloc(&pdev->dev, sizeof(struct dw_spi_mmio),
  41                         GFP_KERNEL);
  42         if (!dwsmmio)
  43                 return -ENOMEM;
  44
  45         dws = &dwsmmio->dws;
  46
  47         /* Get basic io resource and map it */
  48         mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  49         if (!mem) {
  50                 dev_err(&pdev->dev, "no mem resource?\n");
  51                 return -EINVAL;
  52         }
  53
  54         dws->regs = devm_ioremap_resource(&pdev->dev, mem);
  55         if (IS_ERR(dws->regs)) {
  56                 dev_err(&pdev->dev, "SPI region map failed\n");
  57                 return PTR_ERR(dws->regs);
  58         }
  59
  60         dws->irq = platform_get_irq(pdev, 0);
  61         if (dws->irq < 0) {
  62                 dev_err(&pdev->dev, "no irq resource?\n");
  63                 return dws->irq; /* -ENXIO */
  64         }
  65
  66         dwsmmio->clk = devm_clk_get(&pdev->dev, NULL);
  67         if (IS_ERR(dwsmmio->clk))
  68                 return PTR_ERR(dwsmmio->clk);
  69         ret = clk_prepare_enable(dwsmmio->clk);
  70         if (ret)
  71                 return ret;
  72
  73         dws->bus_num = pdev->id;
  74
  75         dws->max_freq = clk_get_rate(dwsmmio->clk);
  76
  77         num_cs = 4;
  78
  79         if (pdev->dev.of_node)
  80                 of_property_read_u32(pdev->dev.of_node, "num-cs", &num_cs);
  81
  82         dws->num_cs = num_cs;
  83
  84         if (pdev->dev.of_node) {
  85                 int i;
  86
  87                 for (i = 0; i < dws->num_cs; i++) {
  88                         int cs_gpio = of_get_named_gpio(pdev->dev.of_node,
  89                                         "cs-gpios", i);
  90
  91                         if (cs_gpio == -EPROBE_DEFER) {
  92                                 ret = cs_gpio;
  93                                 goto out;
  94                         }
  95
  96                         if (gpio_is_valid(cs_gpio)) {
  97                                 ret = devm_gpio_request(&pdev->dev, cs_gpio,
  98                                                 dev_name(&pdev->dev));
  99                                 if (ret)
 100                                         goto out;
 101                         }
 102                 }
 103         }
 104
 105         ret = dw_spi_add_host(&pdev->dev, dws);
 106         if (ret)
 107                 goto out;
 108
 109         platform_set_drvdata(pdev, dwsmmio);
 110         return 0;
 111
 112 out:
 113         clk_disable_unprepare(dwsmmio->clk);
 114         return ret;
 115 }
 116
 117 static int dw_spi_mmio_remove(struct platform_device *pdev)
 118 {
 119         struct dw_spi_mmio *dwsmmio = platform_get_drvdata(pdev);
 120
 121         clk_disable_unprepare(dwsmmio->clk);
 122         dw_spi_remove_host(&dwsmmio->dws);
 123
 124         return 0;
 125 }
 126
 127 static const struct of_device_id dw_spi_mmio_of_match[] = {
 128         { .compatible = "snps,dw-apb-ssi", },
 129         { /* end of table */}
 130 };
 131 MODULE_DEVICE_TABLE(of, dw_spi_mmio_of_match);
 132
 133 static struct platform_driver dw_spi_mmio_driver = {
 134         .probe          = dw_spi_mmio_probe,
 135         .remove         = dw_spi_mmio_remove,
 136         .driver         = {
 137                 .name   = DRIVER_NAME,
 138                 .owner  = THIS_MODULE,
 139                 .of_match_table = dw_spi_mmio_of_match,
 140         },
 141 };
 142 module_platform_driver(dw_spi_mmio_driver);
 143
 144 MODULE_AUTHOR("Jean-Hugues Deschenes <jean-hugues.deschenes@octasic.com>");
 145 MODULE_DESCRIPTION("Memory-mapped I/O interface driver for DW SPI Core");
 146 MODULE_LICENSE("GPL v2");