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 #include <linux/property.h>
  23
  24 #include "spi-dw.h"
  25
  26 #define DRIVER_NAME "dw_spi_mmio"
  27
  28 struct dw_spi_mmio {
  29         struct dw_spi  dws;
  30         struct clk     *clk;
  31 };
  32
  33 static int dw_spi_mmio_probe(struct platform_device *pdev)
  34 {
  35         struct dw_spi_mmio *dwsmmio;
  36         struct dw_spi *dws;
  37         struct resource *mem;
  38         int ret;
  39         int num_cs;
  40
  41         dwsmmio = devm_kzalloc(&pdev->dev, sizeof(struct dw_spi_mmio),
  42                         GFP_KERNEL);
  43         if (!dwsmmio)
  44                 return -ENOMEM;
  45
  46         dws = &dwsmmio->dws;
  47
  48         /* Get basic io resource and map it */
  49         mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  50         dws->regs = devm_ioremap_resource(&pdev->dev, mem);
  51         if (IS_ERR(dws->regs)) {
  52                 dev_err(&pdev->dev, "SPI region map failed\n");
  53                 return PTR_ERR(dws->regs);
  54         }
  55
  56         dws->irq = platform_get_irq(pdev, 0);
  57         if (dws->irq < 0) {
  58                 dev_err(&pdev->dev, "no irq resource?\n");
  59                 return dws->irq; /* -ENXIO */
  60         }
  61
  62         dwsmmio->clk = devm_clk_get(&pdev->dev, NULL);
  63         if (IS_ERR(dwsmmio->clk))
  64                 return PTR_ERR(dwsmmio->clk);
  65         ret = clk_prepare_enable(dwsmmio->clk);
  66         if (ret)
  67                 return ret;
  68
  69         dws->bus_num = pdev->id;
  70
  71         dws->max_freq = clk_get_rate(dwsmmio->clk);
  72
  73         device_property_read_u32(&pdev->dev, "reg-io-width", &dws->reg_io_width);
  74
  75         num_cs = 4;
  76
  77         device_property_read_u32(&pdev->dev, "num-cs", &num_cs);
  78
  79         dws->num_cs = num_cs;
  80
  81         if (pdev->dev.of_node) {
  82                 int i;
  83
  84                 for (i = 0; i < dws->num_cs; i++) {
  85                         int cs_gpio = of_get_named_gpio(pdev->dev.of_node,
  86                                         "cs-gpios", i);
  87
  88                         if (cs_gpio == -EPROBE_DEFER) {
  89                                 ret = cs_gpio;
  90                                 goto out;
  91                         }
  92
  93                         if (gpio_is_valid(cs_gpio)) {
  94                                 ret = devm_gpio_request(&pdev->dev, cs_gpio,
  95                                                 dev_name(&pdev->dev));
  96                                 if (ret)
  97                                         goto out;
  98                         }
  99                 }
 100         }
 101
 102         ret = dw_spi_add_host(&pdev->dev, dws);
 103         if (ret)
 104                 goto out;
 105
 106         platform_set_drvdata(pdev, dwsmmio);
 107         return 0;
 108
 109 out:
 110         clk_disable_unprepare(dwsmmio->clk);
 111         return ret;
 112 }
 113
 114 static int dw_spi_mmio_remove(struct platform_device *pdev)
 115 {
 116         struct dw_spi_mmio *dwsmmio = platform_get_drvdata(pdev);
 117
 118         clk_disable_unprepare(dwsmmio->clk);
 119         dw_spi_remove_host(&dwsmmio->dws);
 120
 121         return 0;
 122 }
 123
 124 static const struct of_device_id dw_spi_mmio_of_match[] = {
 125         { .compatible = "snps,dw-apb-ssi", },
 126         { /* end of table */}
 127 };
 128 MODULE_DEVICE_TABLE(of, dw_spi_mmio_of_match);
 129
 130 static struct platform_driver dw_spi_mmio_driver = {
 131         .probe          = dw_spi_mmio_probe,
 132         .remove         = dw_spi_mmio_remove,
 133         .driver         = {
 134                 .name   = DRIVER_NAME,
 135                 .of_match_table = dw_spi_mmio_of_match,
 136         },
 137 };
 138 module_platform_driver(dw_spi_mmio_driver);
 139
 140 MODULE_AUTHOR("Jean-Hugues Deschenes <jean-hugues.deschenes@octasic.com>");
 141 MODULE_DESCRIPTION("Memory-mapped I/O interface driver for DW SPI Core");
 142 MODULE_LICENSE("GPL v2");