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_spi.h>
13
14 /**
15 * of_register_spi_devices - Register child devices onto the SPI bus
16 * @master: Pointer to spi_master device
17 * @np: parent node of SPI device nodes
18 *
19 * Registers an spi_device for each child node of 'np' which has a 'reg'
20 * property.
21 */
of_register_spi_devices(struct spi_master * master,struct device_node * np)22 void of_register_spi_devices(struct spi_master *master, struct device_node *np)
23 {
24 struct spi_device *spi;
25 struct device_node *nc;
26 const u32 *prop;
27 int rc;
28 int len;
29
30 for_each_child_of_node(np, nc) {
31 /* Alloc an spi_device */
32 spi = spi_alloc_device(master);
33 if (!spi) {
34 dev_err(&master->dev, "spi_device alloc error for %s\n",
35 nc->full_name);
36 spi_dev_put(spi);
37 continue;
38 }
39
40 /* Select device driver */
41 if (of_modalias_node(nc, spi->modalias,
42 sizeof(spi->modalias)) < 0) {
43 dev_err(&master->dev, "cannot find modalias for %s\n",
44 nc->full_name);
45 spi_dev_put(spi);
46 continue;
47 }
48
49 /* Device address */
50 prop = of_get_property(nc, "reg", &len);
51 if (!prop || len < sizeof(*prop)) {
52 dev_err(&master->dev, "%s has no 'reg' property\n",
53 nc->full_name);
54 spi_dev_put(spi);
55 continue;
56 }
57 spi->chip_select = *prop;
58
59 /* Mode (clock phase/polarity/etc.) */
60 if (of_find_property(nc, "spi-cpha", NULL))
61 spi->mode |= SPI_CPHA;
62 if (of_find_property(nc, "spi-cpol", NULL))
63 spi->mode |= SPI_CPOL;
64 if (of_find_property(nc, "spi-cs-high", NULL))
65 spi->mode |= SPI_CS_HIGH;
66
67 /* Device speed */
68 prop = of_get_property(nc, "spi-max-frequency", &len);
69 if (!prop || len < sizeof(*prop)) {
70 dev_err(&master->dev, "%s has no 'spi-max-frequency' property\n",
71 nc->full_name);
72 spi_dev_put(spi);
73 continue;
74 }
75 spi->max_speed_hz = *prop;
76
77 /* IRQ */
78 spi->irq = irq_of_parse_and_map(nc, 0);
79
80 /* Store a pointer to the node in the device structure */
81 of_node_get(nc);
82 spi->dev.archdata.of_node = nc;
83
84 /* Register the new device */
85 request_module(spi->modalias);
86 rc = spi_add_device(spi);
87 if (rc) {
88 dev_err(&master->dev, "spi_device register error %s\n",
89 nc->full_name);
90 spi_dev_put(spi);
91 }
92
93 }
94 }
95 EXPORT_SYMBOL(of_register_spi_devices);
96