Hi Jean,
Sorry for the late response, but I was pretty busy the last couple of weeks.
I'm thinking about something like this (based on
http://patchwork.ozlabs.org/linuxppc/patch?id=16282 to 16284):
This patch implements various helpers to support OF bindings for
the i2c API.
Signed-off-by: Jochen Friedrich <jochen@scram.de>
---
drivers/of/Kconfig | 6 +++
drivers/of/Makefile | 1 +
drivers/of/i2c.c | 113 ++++++++++++++++++++++++++++++++++++++++++++++++
include/linux/of_i2c.h | 24 ++++++++++
4 files changed, 144 insertions(+), 0 deletions(-)
create mode 100644 drivers/of/i2c.c
create mode 100644 include/linux/of_i2c.h
diff --git a/drivers/of/Kconfig b/drivers/of/Kconfig
index c03072b..3cff449 100644
--- a/drivers/of/Kconfig
+++ b/drivers/of/Kconfig
@@ -1,3 +1,9 @@
config OF_DEVICE
def_bool y
depends on OF && (SPARC || PPC_OF)
+
+config OF_I2C
+ def_bool y
+ depends on OF && PPC_OF && I2C
+ help
+ OpenFirmware I2C accessors
diff --git a/drivers/of/Makefile b/drivers/of/Makefile
index ab9be5d..655b982 100644
--- a/drivers/of/Makefile
+++ b/drivers/of/Makefile
@@ -1,2 +1,3 @@
obj-y = base.o
obj-$(CONFIG_OF_DEVICE) += device.o platform.o
+obj-$(CONFIG_OF_I2C) += i2c.o
diff --git a/drivers/of/i2c.c b/drivers/of/i2c.c
new file mode 100644
index 0000000..d3d1e9e
--- /dev/null
+++ b/drivers/of/i2c.c
@@ -0,0 +1,113 @@
+/*
+ * OF helpers for the I2C API
+ *
+ * Copyright (c) 2008 Jochen Friedrich <jochen@scram.de>
+ *
+ * Based on a previous patch from Jon Smirl <jonsmirl@gmail.com>
+ *
+ * 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.
+ */
+
+#include <linux/i2c.h>
+#include <asm/prom.h>
+
+struct i2c_driver_device {
+ char *of_device;
+ char *i2c_type;
+};
+
+static struct i2c_driver_device i2c_devices[] = {
+ {"dallas,ds1374", "rtc-ds1374",},
+};
+
+static int of_find_i2c_driver(struct device_node *node,
+ struct i2c_board_info *info)
+{
+ int i, cplen;
+ const char *compatible;
+ const char *p;
+
+ /* 1. search for exception list entry */
+ for (i = 0; i < ARRAY_SIZE(i2c_devices); i++) {
+ if (!of_device_is_compatible(node, i2c_devices[i].of_device))
+ continue;
+ if (strlcpy(info->type, i2c_devices[i].i2c_type,
+ I2C_NAME_SIZE) >= I2C_NAME_SIZE)
+ return -ENOMEM;
+
+ return 0;
+ }
+
+ compatible = of_get_property(node, "compatible", &cplen);
+ if (!compatible)
+ return -ENODEV;
+
+ /* 2. search for linux,<i2c-type> entry */
+ p = compatible;
+ while (cplen > 0) {
+ if (!strncmp(p, "linux,", 6)) {
+ p += 6;
+ if (strlcpy(info->type, p,
+ I2C_NAME_SIZE) >= I2C_NAME_SIZE)
+ return -ENOMEM;
+ return 0;
+ }
+
+ i = strlen(p) + 1;
+ p += i;
+ cplen -= i;
+ }
+
+ /* 3. take fist compatible entry and strip manufacturer */
+ p = strchr(compatible, ',');
+ if (!p)
+ return -ENODEV;
+ p++;
+ if (strlcpy(info->type, p, I2C_NAME_SIZE) >= I2C_NAME_SIZE)
+ return -ENOMEM;
+ return 0;
+}
+
+void of_register_i2c_devices(struct i2c_adapter *adap,
+ struct device_node *adap_node)
+{
+ void *result;
+ struct device_node *node = NULL;
+
+ while ((node = of_get_next_child(adap_node, node))) {
+ struct i2c_board_info info = {};
+ const u32 *addr;
+ int len;
+
+ addr = of_get_property(node, "reg", &len);
+ if (!addr || len < sizeof(int) || *addr > (1 << 10) - 1) {
+ printk(KERN_ERR
+ "of-i2c: invalid i2c device entry\n");
+ continue;
+ }
+
+ info.irq = irq_of_parse_and_map(node, 0);
+ if (info.irq == NO_IRQ)
+ info.irq = -1;
+
+ if (of_find_i2c_driver(node, &info) < 0)
+ continue;
+
+ info.addr = *addr;
+
+ request_module(info.type);
+
+ result = i2c_new_device(adap, &info);
+ if (result == NULL) {
+ printk(KERN_ERR
+ "of-i2c: Failed to load driver for %s\n",
+ info.type);
+ irq_dispose_mapping(info.irq);
+ continue;
+ }
+ }
+}
+EXPORT_SYMBOL(of_register_i2c_devices);
diff --git a/include/linux/of_i2c.h b/include/linux/of_i2c.h
new file mode 100644
index 0000000..2e5a967
--- /dev/null
+++ b/include/linux/of_i2c.h
@@ -0,0 +1,24 @@
+/*
+ * Generic I2C API implementation for PowerPC.
+ *
+ * Copyright (c) 2008 Jochen Friedrich <jochen@scram.de>
+ *
+ * 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.
+ */
+
+#ifndef __LINUX_OF_I2C_H
+#define __LINUX_OF_I2C_H
+
+#include <linux/i2c.h>
+
+#ifdef CONFIG_OF_I2C
+
+void of_register_i2c_devices(struct i2c_adapter *adap,
+ struct device_node *adap_node);
+
+#endif /* CONFIG_OF_I2C */
+
+#endif /* __LINUX_OF_I2C_H */
--
1.5.4.4
--
