kernel/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         of_property_read_u32(pdev->dev.of_node, "reg-io-width",
  78                              &dws->reg_io_width);
  79
  80         num_cs = 4;
  81
  82         if (pdev->dev.of_node)
  83                 of_property_read_u32(pdev->dev.of_node, "num-cs", &num_cs);
  84
  85         dws->num_cs = num_cs;
  86
  87         if (pdev->dev.of_node) {
  88                 int i;
  89
  90                 for (i = 0; i < dws->num_cs; i++) {
  91                         int cs_gpio = of_get_named_gpio(pdev->dev.of_node,
  92                                         "cs-gpios", i);
  93
  94                         if (cs_gpio == -EPROBE_DEFER) {
  95                                 ret = cs_gpio;
  96                                 goto out;
  97                         }
  98
  99                         if (gpio_is_valid(cs_gpio)) {
 100                                 ret = devm_gpio_request(&pdev->dev, cs_gpio,
 101                                                 dev_name(&pdev->dev));
 102                                 if (ret)
 103                                         goto out;
 104                         }
 105                 }
 106         }
 107
 108         ret = dw_spi_add_host(&pdev->dev, dws);
 109         if (ret)
 110                 goto out;
 111
 112         platform_set_drvdata(pdev, dwsmmio);
 113         return 0;
 114
 115 out:
 116         clk_disable_unprepare(dwsmmio->clk);
 117         return ret;
 118 }
 119
 120 static int dw_spi_mmio_remove(struct platform_device *pdev)
 121 {
 122         struct dw_spi_mmio *dwsmmio = platform_get_drvdata(pdev);
 123
 124         clk_disable_unprepare(dwsmmio->clk);
 125         dw_spi_remove_host(&dwsmmio->dws);
 126
 127         return 0;
 128 }
 129
 130 static const struct of_device_id dw_spi_mmio_of_match[] = {
 131         { .compatible = "snps,dw-apb-ssi", },
 132         { /* end of table */}
 133 };
 134 MODULE_DEVICE_TABLE(of, dw_spi_mmio_of_match);
 135
 136 static struct platform_driver dw_spi_mmio_driver = {
 137         .probe          = dw_spi_mmio_probe,
 138         .remove         = dw_spi_mmio_remove,
 139         .driver         = {
 140                 .name   = DRIVER_NAME,
 141                 .of_match_table = dw_spi_mmio_of_match,
 142         },
 143 };
 144 module_platform_driver(dw_spi_mmio_driver);
 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");