99 lines
2.3 KiB
C
99 lines
2.3 KiB
C
/*
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* SPI OF support routines
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* Copyright (C) 2008 Secret Lab Technologies Ltd.
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*
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* Support routines for deriving SPI device attachments from the device
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* tree.
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*/
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#include <linux/of.h>
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#include <linux/device.h>
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#include <linux/spi/spi.h>
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#include <linux/of_irq.h>
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#include <linux/of_spi.h>
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/**
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* of_register_spi_devices - Register child devices onto the SPI bus
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* @master: Pointer to spi_master device
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*
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* Registers an spi_device for each child node of master node which has a 'reg'
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* property.
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*/
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void of_register_spi_devices(struct spi_master *master)
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{
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struct spi_device *spi;
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struct device_node *nc;
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const __be32 *prop;
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int rc;
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int len;
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if (!master->dev.of_node)
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return;
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for_each_child_of_node(master->dev.of_node, nc) {
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/* Alloc an spi_device */
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spi = spi_alloc_device(master);
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if (!spi) {
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dev_err(&master->dev, "spi_device alloc error for %s\n",
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nc->full_name);
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spi_dev_put(spi);
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continue;
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}
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/* Select device driver */
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if (of_modalias_node(nc, spi->modalias,
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sizeof(spi->modalias)) < 0) {
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dev_err(&master->dev, "cannot find modalias for %s\n",
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nc->full_name);
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spi_dev_put(spi);
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continue;
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}
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/* Device address */
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prop = of_get_property(nc, "reg", &len);
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if (!prop || len < sizeof(*prop)) {
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dev_err(&master->dev, "%s has no 'reg' property\n",
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nc->full_name);
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spi_dev_put(spi);
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continue;
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}
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spi->chip_select = be32_to_cpup(prop);
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/* Mode (clock phase/polarity/etc.) */
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if (of_find_property(nc, "spi-cpha", NULL))
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spi->mode |= SPI_CPHA;
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if (of_find_property(nc, "spi-cpol", NULL))
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spi->mode |= SPI_CPOL;
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if (of_find_property(nc, "spi-cs-high", NULL))
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spi->mode |= SPI_CS_HIGH;
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/* Device speed */
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prop = of_get_property(nc, "spi-max-frequency", &len);
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if (!prop || len < sizeof(*prop)) {
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dev_err(&master->dev, "%s has no 'spi-max-frequency' property\n",
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nc->full_name);
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spi_dev_put(spi);
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continue;
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}
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spi->max_speed_hz = be32_to_cpup(prop);
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/* IRQ */
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spi->irq = irq_of_parse_and_map(nc, 0);
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/* Store a pointer to the node in the device structure */
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of_node_get(nc);
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spi->dev.of_node = nc;
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/* Register the new device */
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request_module(spi->modalias);
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rc = spi_add_device(spi);
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if (rc) {
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dev_err(&master->dev, "spi_device register error %s\n",
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nc->full_name);
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spi_dev_put(spi);
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}
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}
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}
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EXPORT_SYMBOL(of_register_spi_devices);
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