first (partly) running spi support

1 files changed, 187 insertions, 4 deletions

diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 765e34d5e2..cba12552b6 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -1,14 +1,197 @@
+/*
+ * Copyright (C) 2008 Sascha Hauer, Pengutronix
+ *
+ * Derived from Linux SPI Framework
+ *
+ * Copyright (C) 2005 David Brownell
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ *
+ */
+
 #include <common.h>
 #include <spi/spi.h>
+#include <xfuncs.h>
+#include <malloc.h>
+#include <errno.h>
+
+/* SPI devices should normally not be created by SPI device drivers; that
+ * would make them board-specific.  Similarly with SPI master drivers.
+ * Device registration normally goes into like arch/.../mach.../board-YYY.c
+ * with other readonly (flashable) information about mainboard devices.
+ */
+
+struct boardinfo {
+	struct list_head	list;
+	unsigned		n_board_info;
+	struct spi_board_info	board_info[0];
+};
+
+static LIST_HEAD(board_list);
 
-int spi_register_boardinfo(struct spi_board_info *info, int num)
+/**
+ * spi_new_device - instantiate one new SPI device
+ * @master: Controller to which device is connected
+ * @chip: Describes the SPI device
+ * Context: can sleep
+ *
+ * On typical mainboards, this is purely internal; and it's not needed
+ * after board init creates the hard-wired devices.  Some development
+ * platforms may not be able to use spi_register_board_info though, and
+ * this is exported so that for example a USB or parport based adapter
+ * driver could add devices (which it would learn about out-of-band).
+ *
+ * Returns the new device, or NULL.
+ */
+struct spi_device *spi_new_device(struct spi_master *master,
+				  struct spi_board_info *chip)
 {
-	printf("%s\n", __FUNCTION__);
+	struct spi_device	*proxy;
+	int			status;
+
+	/* Chipselects are numbered 0..max; validate. */
+	if (chip->chip_select >= master->num_chipselect) {
+		debug("cs%d > max %d\n",
+			chip->chip_select,
+			master->num_chipselect);
+		return NULL;
+	}
+
+	proxy = xzalloc(sizeof *proxy);
+	proxy->master = master;
+	proxy->chip_select = chip->chip_select;
+	proxy->max_speed_hz = chip->max_speed_hz;
+	proxy->mode = chip->mode;
+	strcpy(proxy->dev.name, chip->name);
+	strcpy(proxy->dev.id, "pmic");
+	proxy->dev.type_data = proxy;
+	status = register_device(&proxy->dev);
+
+	/* drivers may modify this initial i/o setup */
+	status = master->setup(proxy);
+	if (status < 0) {
+		printf("can't %s %s, status %d\n",
+				"setup", proxy->dev.id, status);
+		goto fail;
+	}
+
+	return proxy;
+
+fail:
+	free(proxy);
+	return NULL;
+}
+EXPORT_SYMBOL(spi_new_device);
+
+/**
+ * spi_register_board_info - register SPI devices for a given board
+ * @info: array of chip descriptors
+ * @n: how many descriptors are provided
+ * Context: can sleep
+ *
+ * Board-specific early init code calls this (probably during arch_initcall)
+ * with segments of the SPI device table.  Any device nodes are created later,
+ * after the relevant parent SPI controller (bus_num) is defined.  We keep
+ * this table of devices forever, so that reloading a controller driver will
+ * not make Linux forget about these hard-wired devices.
+ *
+ * Other code can also call this, e.g. a particular add-on board might provide
+ * SPI devices through its expansion connector, so code initializing that board
+ * would naturally declare its SPI devices.
+ *
+ * The board info passed can safely be __initdata ... but be careful of
+ * any embedded pointers (platform_data, etc), they're copied as-is.
+ */
+int
+spi_register_board_info(struct spi_board_info const *info, int n)
+{
+	struct boardinfo	*bi;
+
+	bi = xmalloc(sizeof(*bi) + n * sizeof *info);
+
+	bi->n_board_info = n;
+	memcpy(bi->board_info, info, n * sizeof *info);
+
+	list_add_tail(&bi->list, &board_list);
+
 	return 0;
 }
 
+static void scan_boardinfo(struct spi_master *master)
+{
+	struct boardinfo	*bi;
+
+	list_for_each_entry(bi, &board_list, list) {
+		struct spi_board_info	*chip = bi->board_info;
+		unsigned		n;
+
+		for (n = bi->n_board_info; n > 0; n--, chip++) {
+			debug("%s %d %d\n", __FUNCTION__, chip->bus_num, master->bus_num);
+			if (chip->bus_num != master->bus_num)
+				continue;
+			/* NOTE: this relies on spi_new_device to
+			 * issue diagnostics when given bogus inputs
+			 */
+			(void) spi_new_device(master, chip);
+		}
+	}
+}
+
+/**
+ * spi_register_master - register SPI master controller
+ * @master: initialized master, originally from spi_alloc_master()
+ * Context: can sleep
+ *
+ * SPI master controllers connect to their drivers using some non-SPI bus,
+ * such as the platform bus.  The final stage of probe() in that code
+ * includes calling spi_register_master() to hook up to this SPI bus glue.
+ *
+ * SPI controllers use board specific (often SOC specific) bus numbers,
+ * and board-specific addressing for SPI devices combines those numbers
+ * with chip select numbers.  Since SPI does not directly support dynamic
+ * device identification, boards need configuration tables telling which
+ * chip is at which address.
+ *
+ * This must be called from context that can sleep.  It returns zero on
+ * success, else a negative error code (dropping the master's refcount).
+ * After a successful return, the caller is responsible for calling
+ * spi_unregister_master().
+ */
 int spi_register_master(struct spi_master *master)
 {
-	printf("%s\n", __FUNCTION__);
-	return 0;
+	int			status = -ENODEV;
+
+	debug("%s: %s:%s\n", __FUNCTION__, master->dev->name, master->dev->id);
+
+	/* even if it's just one always-selected device, there must
+	 * be at least one chipselect
+	 */
+	if (master->num_chipselect == 0)
+		return -EINVAL;
+
+	/* populate children from any spi device tables */
+	scan_boardinfo(master);
+	status = 0;
+
+	return status;
 }
+EXPORT_SYMBOL(spi_register_master);
+
+int spi_sync(struct spi_device *spi, struct spi_message *message)
+{
+	return spi->master->transfer(spi, message);
+}
+