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