[POWERPC] i2c: OF helpers for the i2c API
Jochen Friedrich [Fri, 11 Apr 2008 19:22:35 +0000 (05:22 +1000)]
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>

drivers/of/Kconfig
drivers/of/Makefile
drivers/of/i2c.c [new file with mode: 0644]
include/linux/of_i2c.h [new file with mode: 0644]

index 3354ad7..7c30531 100644 (file)
@@ -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
index 5a61f70..a07b953 100644 (file)
@@ -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 (file)
index 0000000..6316891
--- /dev/null
@@ -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 (file)
index 0000000..2e5a967
--- /dev/null
@@ -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 */