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 */
of_register_spi_devices(struct spi_master * master)22 void 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 }
98 EXPORT_SYMBOL(of_register_spi_devices);
99