[POWERPC] i2c: OF helpers for the i2c API

This implements various helpers to support OF bindings for the i2c
API.

Signed-off-by: Jochen Friedrich <jochen@scram.de>
Acked-by: David S. Miller <davem@davemloft.net>
Acked-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>

4 files changed, 146 insertions, 0 deletions

diff --git a/drivers/of/Kconfig b/drivers/of/Kconfig
index 3354ad766a49..7c305317f372 100644
--- a/drivers/of/Kconfig
+++ b/drivers/of/Kconfig
@@ -7,3 +7,9 @@ config OF_GPIO
         depends on OF && PPC_OF && HAVE_GPIO_LIB
         help
           OpenFirmware GPIO accessors
+
+config OF_I2C
+        def_bool y
+        depends on OF && I2C
+        help
+          OpenFirmware I2C accessors
diff --git a/drivers/of/Makefile b/drivers/of/Makefile
index 5a61f70b4027..a07b95362c53 100644
--- a/drivers/of/Makefile
+++ b/drivers/of/Makefile
@@ -1,3 +1,4 @@
 obj-y = base.o
 obj-$(CONFIG_OF_DEVICE) += device.o platform.o
 obj-$(CONFIG_OF_GPIO)   += gpio.o
+obj-$(CONFIG_OF_I2C)    += i2c.o
diff --git a/drivers/of/i2c.c b/drivers/of/i2c.c
new file mode 100644
index 000000000000..631689171159
--- /dev/null
+++ b/drivers/of/i2c.c
@@ -0,0 +1,115 @@
+/*
+ * 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 <linux/of.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;
+
+        for_each_child_of_node(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) {
+                        irq_dispose_mapping(info.irq);
+                        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 000000000000..2e5a96732042
--- /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 */