LXR linux/drivers/of/of

   1/*
   2 * SPI OF support routines
   3 * Copyright (C) 2008 Secret Lab Technologies Ltd.
   4 *
   5 * Support routines for deriving SPI device attachments from the device
   6 * tree.
   7 */
   8
   9#include <linux/module.h>
  10#include <linux/of.h>
  11#include <linux/device.h>
  12#include <linux/spi/spi.h>
  13#include <linux/of_irq.h>
  14#include <linux/of_spi.h>
  15
  16/**
  17 * of_register_spi_devices - Register child devices onto the SPI bus
  18 * @master:     Pointer to spi_master device
  19 *
  20 * Registers an spi_device for each child node of master node which has a 'reg'
  21 * property.
  22 */
  23void of_register_spi_devices(struct spi_master *master)
  24{
  25        struct spi_device *spi;
  26        struct device_node *nc;
  27        const __be32 *prop;
  28        int rc;
  29        int len;
  30
  31        if (!master->dev.of_node)
  32                return;
  33
  34        for_each_child_of_node(master->dev.of_node, nc) {
  35                /* Alloc an spi_device */
  36                spi = spi_alloc_device(master);
  37                if (!spi) {
  38                        dev_err(&master->dev, "spi_device alloc error for %s\n",
  39                                nc->full_name);
  40                        spi_dev_put(spi);
  41                        continue;
  42                }
  43
  44                /* Select device driver */
  45                if (of_modalias_node(nc, spi->modalias,
  46                                     sizeof(spi->modalias)) < 0) {
  47                        dev_err(&master->dev, "cannot find modalias for %s\n",
  48                                nc->full_name);
  49                        spi_dev_put(spi);
  50                        continue;
  51                }
  52
  53                /* Device address */
  54                prop = of_get_property(nc, "reg", &len);
  55                if (!prop || len < sizeof(*prop)) {
  56                        dev_err(&master->dev, "%s has no 'reg' property\n",
  57                                nc->full_name);
  58                        spi_dev_put(spi);
  59                        continue;
  60                }
  61                spi->chip_select = be32_to_cpup(prop);
  62
  63                /* Mode (clock phase/polarity/etc.) */
  64                if (of_find_property(nc, "spi-cpha", NULL))
  65                        spi->mode |= SPI_CPHA;
  66                if (of_find_property(nc, "spi-cpol", NULL))
  67                        spi->mode |= SPI_CPOL;
  68                if (of_find_property(nc, "spi-cs-high", NULL))
  69                        spi->mode |= SPI_CS_HIGH;
  70
  71                /* Device speed */
  72                prop = of_get_property(nc, "spi-max-frequency", &len);
  73                if (!prop || len < sizeof(*prop)) {
  74                        dev_err(&master->dev, "%s has no 'spi-max-frequency' property\n",
  75                                nc->full_name);
  76                        spi_dev_put(spi);
  77                        continue;
  78                }
  79                spi->max_speed_hz = be32_to_cpup(prop);
  80
  81                /* IRQ */
  82                spi->irq = irq_of_parse_and_map(nc, 0);
  83
  84                /* Store a pointer to the node in the device structure */
  85                of_node_get(nc);
  86                spi->dev.of_node = nc;
  87
  88                /* Register the new device */
  89                request_module(spi->modalias);
  90                rc = spi_add_device(spi);
  91                if (rc) {
  92                        dev_err(&master->dev, "spi_device register error %s\n",
  93                                nc->full_name);
  94                        spi_dev_put(spi);
  95                }
  96
  97        }
  98}
  99EXPORT_SYMBOL(of_register_spi_devices);
 100