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 */
of_register_spi_devices(struct spi_master * master)23 void 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 }
99 EXPORT_SYMBOL(of_register_spi_devices);
100