[PATCH] 2/5 powerpc: Rework PowerMac i2c part 2

This is the continuation of the previous patch. This one removes the old
PowerMac i2c drivers (i2c-keywest and i2c-pmac-smu) and replaces them
both with a single stub driver that uses the new PowerMac low i2c layer.

Now that i2c-keywest is gone, the low-i2c code is extended to support
interrupt driver transfers. All i2c busses now appear as platform
devices. Compatibility with existing drivers should be maintained as the
i2c bus names have been kept identical, except for the SMU bus but in
that later case, all users has been fixed.

With that patch added, matching a device node to an i2c_adapter becomes
trivial.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 290 insertions, 0 deletions

diff --git a/drivers/i2c/busses/i2c-powermac.c b/drivers/i2c/busses/i2c-powermac.c
new file mode 100644
index 00000000000..df786eb5529
--- /dev/null
+++ b/drivers/i2c/busses/i2c-powermac.c
@@ -0,0 +1,290 @@
+/*
+    i2c Support for Apple SMU Controller
+
+    Copyright (c) 2005 Benjamin Herrenschmidt, IBM Corp.
+                       <benh@kernel.crashing.org>
+
+    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., 675 Mass Ave, Cambridge, MA 02139, USA.
+
+*/
+
+#include <linux/config.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/types.h>
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/completion.h>
+#include <linux/device.h>
+#include <linux/platform_device.h>
+#include <asm/prom.h>
+#include <asm/pmac_low_i2c.h>
+
+MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
+MODULE_DESCRIPTION("I2C driver for Apple PowerMac");
+MODULE_LICENSE("GPL");
+
+/*
+ * SMBUS-type transfer entrypoint
+ */
+static s32 i2c_powermac_smbus_xfer(	struct i2c_adapter*	adap,
+					u16			addr,
+					unsigned short		flags,
+					char			read_write,
+					u8			command,
+					int			size,
+					union i2c_smbus_data*	data)
+{
+	struct pmac_i2c_bus	*bus = i2c_get_adapdata(adap);
+	int			rc = 0;
+	int			read = (read_write == I2C_SMBUS_READ);
+	int			addrdir = (addr << 1) | read;
+	u8			local[2];
+
+	rc = pmac_i2c_open(bus, 0);
+	if (rc)
+		return rc;
+
+	switch (size) {
+        case I2C_SMBUS_QUICK:
+		rc = pmac_i2c_setmode(bus, pmac_i2c_mode_std);
+		if (rc)
+			goto bail;
+		rc = pmac_i2c_xfer(bus, addrdir, 0, 0, NULL, 0);
+	    	break;
+        case I2C_SMBUS_BYTE:
+		rc = pmac_i2c_setmode(bus, pmac_i2c_mode_std);
+		if (rc)
+			goto bail;
+		rc = pmac_i2c_xfer(bus, addrdir, 0, 0, &data->byte, 1);
+	    	break;
+        case I2C_SMBUS_BYTE_DATA:
+		rc = pmac_i2c_setmode(bus, read ?
+				      pmac_i2c_mode_combined :
+				      pmac_i2c_mode_stdsub);
+		if (rc)
+			goto bail;
+		rc = pmac_i2c_xfer(bus, addrdir, 1, command, &data->byte, 1);
+	    	break;
+        case I2C_SMBUS_WORD_DATA:
+		rc = pmac_i2c_setmode(bus, read ?
+				      pmac_i2c_mode_combined :
+				      pmac_i2c_mode_stdsub);
+		if (rc)
+			goto bail;
+		if (!read) {
+			local[0] = data->word & 0xff;
+			local[1] = (data->word >> 8) & 0xff;
+		}
+		rc = pmac_i2c_xfer(bus, addrdir, 1, command, local, 2);
+		if (rc == 0 && read) {
+			data->word = ((u16)local[1]) << 8;
+			data->word |= local[0];
+		}
+	    	break;
+
+	/* Note that these are broken vs. the expected smbus API where
+	 * on reads, the lenght is actually returned from the function,
+	 * but I think the current API makes no sense and I don't want
+	 * any driver that I haven't verified for correctness to go
+	 * anywhere near a pmac i2c bus anyway ...
+	 *
+	 * I'm also not completely sure what kind of phases to do between
+	 * the actual command and the data (what I am _supposed_ to do that
+	 * is). For now, I assume writes are a single stream and reads have
+	 * a repeat start/addr phase (but not stop in between)
+	 */
+        case I2C_SMBUS_BLOCK_DATA:
+		rc = pmac_i2c_setmode(bus, read ?
+				      pmac_i2c_mode_combined :
+				      pmac_i2c_mode_stdsub);
+		if (rc)
+			goto bail;
+		rc = pmac_i2c_xfer(bus, addrdir, 1, command, data->block,
+				   data->block[0] + 1);
+
+		break;
+	case I2C_SMBUS_I2C_BLOCK_DATA:
+		rc = pmac_i2c_setmode(bus, read ?
+				      pmac_i2c_mode_combined :
+				      pmac_i2c_mode_stdsub);
+		if (rc)
+			goto bail;
+		rc = pmac_i2c_xfer(bus, addrdir, 1, command,
+				   read ? data->block : &data->block[1],
+				   data->block[0]);
+		break;
+
+        default:
+	    	rc = -EINVAL;
+	}
+ bail:
+	pmac_i2c_close(bus);
+	return rc;
+}
+
+/*
+ * Generic i2c master transfer entrypoint. This driver only support single
+ * messages (for "lame i2c" transfers). Anything else should use the smbus
+ * entry point
+ */
+static int i2c_powermac_master_xfer(	struct i2c_adapter *adap,
+					struct i2c_msg *msgs,
+					int num)
+{
+	struct pmac_i2c_bus	*bus = i2c_get_adapdata(adap);
+	int			rc = 0;
+	int			read;
+	int			addrdir;
+
+	if (num != 1)
+		return -EINVAL;
+	if (msgs->flags & I2C_M_TEN)
+		return -EINVAL;
+	read = (msgs->flags & I2C_M_RD) != 0;
+	addrdir = (msgs->addr << 1) | read;
+	if (msgs->flags & I2C_M_REV_DIR_ADDR)
+		addrdir ^= 1;
+
+	rc = pmac_i2c_open(bus, 0);
+	if (rc)
+		return rc;
+	rc = pmac_i2c_setmode(bus, pmac_i2c_mode_std);
+	if (rc)
+		goto bail;
+	rc = pmac_i2c_xfer(bus, addrdir, 0, 0, msgs->buf, msgs->len);
+ bail:
+	pmac_i2c_close(bus);
+	return rc < 0 ? rc : msgs->len;
+}
+
+static u32 i2c_powermac_func(struct i2c_adapter * adapter)
+{
+	return I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
+		I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA |
+		I2C_FUNC_SMBUS_BLOCK_DATA | I2C_FUNC_I2C;
+}
+
+/* For now, we only handle smbus */
+static struct i2c_algorithm i2c_powermac_algorithm = {
+	.smbus_xfer	= i2c_powermac_smbus_xfer,
+	.master_xfer	= i2c_powermac_master_xfer,
+	.functionality	= i2c_powermac_func,
+};
+
+
+static int i2c_powermac_remove(struct device *dev)
+{
+	struct i2c_adapter	*adapter = dev_get_drvdata(dev);
+	struct pmac_i2c_bus	*bus = i2c_get_adapdata(adapter);
+	int			rc;
+
+	rc = i2c_del_adapter(adapter);
+	pmac_i2c_detach_adapter(bus, adapter);
+	i2c_set_adapdata(adapter, NULL);
+	/* We aren't that prepared to deal with this... */
+	if (rc)
+		printk("i2c-powermac.c: Failed to remove bus %s !\n",
+		       adapter->name);
+	dev_set_drvdata(dev, NULL);
+	kfree(adapter);
+
+	return 0;
+}
+
+
+static int i2c_powermac_probe(struct device *dev)
+{
+	struct pmac_i2c_bus *bus = dev->platform_data;
+	struct device_node *parent = NULL;
+	struct i2c_adapter *adapter;
+	char name[32], *basename;
+	int rc;
+
+	if (bus == NULL)
+		return -EINVAL;
+
+	/* Ok, now we need to make up a name for the interface that will
+	 * match what we used to do in the past, that is basically the
+	 * controller's parent device node for keywest. PMU didn't have a
+	 * naming convention and SMU has a different one
+	 */
+	switch(pmac_i2c_get_type(bus)) {
+	case pmac_i2c_bus_keywest:
+		parent = of_get_parent(pmac_i2c_get_controller(bus));
+		if (parent == NULL)
+			return -EINVAL;
+		basename = parent->name;
+		break;
+	case pmac_i2c_bus_pmu:
+		basename = "pmu";
+		break;
+	case pmac_i2c_bus_smu:
+		/* This is not what we used to do but I'm fixing drivers at
+		 * the same time as this change
+		 */
+		basename = "smu";
+		break;
+	default:
+		return -EINVAL;
+	}
+	snprintf(name, 32, "%s %d", basename, pmac_i2c_get_channel(bus));
+	of_node_put(parent);
+
+	adapter = kzalloc(sizeof(struct i2c_adapter), GFP_KERNEL);
+	if (adapter == NULL) {
+		printk(KERN_ERR "i2c-powermac: can't allocate inteface !\n");
+		return -ENOMEM;
+	}
+	dev_set_drvdata(dev, adapter);
+	strcpy(adapter->name, name);
+	adapter->algo = &i2c_powermac_algorithm;
+	i2c_set_adapdata(adapter, bus);
+	adapter->dev.parent = dev;
+	pmac_i2c_attach_adapter(bus, adapter);
+	rc = i2c_add_adapter(adapter);
+	if (rc) {
+		printk(KERN_ERR "i2c-powermac: Adapter %s registration "
+		       "failed\n", name);
+		i2c_set_adapdata(adapter, NULL);
+		pmac_i2c_detach_adapter(bus, adapter);
+	}
+
+	printk(KERN_INFO "PowerMac i2c bus %s registered\n", name);
+	return rc;
+}
+
+
+static struct device_driver i2c_powermac_driver = {
+	.name = "i2c-powermac",
+	.bus = &platform_bus_type,
+	.probe = i2c_powermac_probe,
+	.remove = i2c_powermac_remove,
+};
+
+static int __init i2c_powermac_init(void)
+{
+	driver_register(&i2c_powermac_driver);
+	return 0;
+}
+
+
+static void __exit i2c_powermac_cleanup(void)
+{
+	driver_unregister(&i2c_powermac_driver);
+}
+
+module_init(i2c_powermac_init);
+module_exit(i2c_powermac_cleanup);