Pileus Git - ~andy/linux/blob - drivers/of/of_spi.c

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