![Jean Delvare](/assets/img/avatar_default.png)
Let the drivers specify how many bytes they want to read with i2c_smbus_read_i2c_block_data(). So far, the block count was hard-coded to I2C_SMBUS_BLOCK_MAX (32), which did not make much sense. Many driver authors complained about this before, and I believe it's about time to fix it. Right now, authors have to do technically stupid things, such as individual byte reads or full-fledged I2C messaging, to work around the problem. We do not want to encourage that. I even found that some bus drivers (e.g. i2c-amd8111) already implemented I2C block read the "right" way, that is, they didn't follow the old, broken standard. The fact that it was never noticed before just shows how little i2c_smbus_read_i2c_block_data() was used, which isn't that surprising given how broken its prototype was so far. There are some obvious compatiblity considerations: * This changes the i2c_smbus_read_i2c_block_data() prototype. Users outside the kernel tree will notice at compilation time, and will have to update their code. * User-space has access to i2c_smbus_xfer() directly using i2c-dev, so the changed expectations would affect tools such as i2cdump. In order to preserve binary compatibility, we give I2C_SMBUS_I2C_BLOCK_DATA a new numeric value, and define I2C_SMBUS_I2C_BLOCK_BROKEN with the old numeric value. When i2c-dev receives a transaction with the old value, it can convert it to the new format on the fly. Signed-off-by: Jean Delvare <khali@linux-fr.org>
289 lines
7.7 KiB
C
289 lines
7.7 KiB
C
/*
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i2c Support for Apple SMU Controller
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Copyright (c) 2005 Benjamin Herrenschmidt, IBM Corp.
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<benh@kernel.crashing.org>
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/types.h>
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#include <linux/i2c.h>
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#include <linux/init.h>
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#include <linux/device.h>
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#include <linux/platform_device.h>
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#include <asm/prom.h>
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#include <asm/pmac_low_i2c.h>
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MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
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MODULE_DESCRIPTION("I2C driver for Apple PowerMac");
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MODULE_LICENSE("GPL");
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/*
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* SMBUS-type transfer entrypoint
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*/
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static s32 i2c_powermac_smbus_xfer( struct i2c_adapter* adap,
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u16 addr,
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unsigned short flags,
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char read_write,
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u8 command,
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int size,
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union i2c_smbus_data* data)
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{
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struct pmac_i2c_bus *bus = i2c_get_adapdata(adap);
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int rc = 0;
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int read = (read_write == I2C_SMBUS_READ);
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int addrdir = (addr << 1) | read;
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u8 local[2];
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rc = pmac_i2c_open(bus, 0);
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if (rc)
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return rc;
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switch (size) {
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case I2C_SMBUS_QUICK:
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rc = pmac_i2c_setmode(bus, pmac_i2c_mode_std);
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if (rc)
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goto bail;
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rc = pmac_i2c_xfer(bus, addrdir, 0, 0, NULL, 0);
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break;
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case I2C_SMBUS_BYTE:
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rc = pmac_i2c_setmode(bus, pmac_i2c_mode_std);
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if (rc)
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goto bail;
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rc = pmac_i2c_xfer(bus, addrdir, 0, 0, &data->byte, 1);
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break;
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case I2C_SMBUS_BYTE_DATA:
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rc = pmac_i2c_setmode(bus, read ?
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pmac_i2c_mode_combined :
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pmac_i2c_mode_stdsub);
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if (rc)
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goto bail;
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rc = pmac_i2c_xfer(bus, addrdir, 1, command, &data->byte, 1);
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break;
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case I2C_SMBUS_WORD_DATA:
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rc = pmac_i2c_setmode(bus, read ?
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pmac_i2c_mode_combined :
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pmac_i2c_mode_stdsub);
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if (rc)
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goto bail;
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if (!read) {
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local[0] = data->word & 0xff;
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local[1] = (data->word >> 8) & 0xff;
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}
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rc = pmac_i2c_xfer(bus, addrdir, 1, command, local, 2);
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if (rc == 0 && read) {
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data->word = ((u16)local[1]) << 8;
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data->word |= local[0];
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}
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break;
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/* Note that these are broken vs. the expected smbus API where
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* on reads, the lenght is actually returned from the function,
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* but I think the current API makes no sense and I don't want
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* any driver that I haven't verified for correctness to go
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* anywhere near a pmac i2c bus anyway ...
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*
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* I'm also not completely sure what kind of phases to do between
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* the actual command and the data (what I am _supposed_ to do that
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* is). For now, I assume writes are a single stream and reads have
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* a repeat start/addr phase (but not stop in between)
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*/
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case I2C_SMBUS_BLOCK_DATA:
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rc = pmac_i2c_setmode(bus, read ?
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pmac_i2c_mode_combined :
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pmac_i2c_mode_stdsub);
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if (rc)
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goto bail;
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rc = pmac_i2c_xfer(bus, addrdir, 1, command, data->block,
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data->block[0] + 1);
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break;
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case I2C_SMBUS_I2C_BLOCK_DATA:
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rc = pmac_i2c_setmode(bus, read ?
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pmac_i2c_mode_combined :
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pmac_i2c_mode_stdsub);
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if (rc)
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goto bail;
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rc = pmac_i2c_xfer(bus, addrdir, 1, command,
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&data->block[1], data->block[0]);
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break;
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default:
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rc = -EINVAL;
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}
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bail:
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pmac_i2c_close(bus);
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return rc;
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}
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/*
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* Generic i2c master transfer entrypoint. This driver only support single
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* messages (for "lame i2c" transfers). Anything else should use the smbus
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* entry point
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*/
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static int i2c_powermac_master_xfer( struct i2c_adapter *adap,
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struct i2c_msg *msgs,
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int num)
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{
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struct pmac_i2c_bus *bus = i2c_get_adapdata(adap);
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int rc = 0;
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int read;
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int addrdir;
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if (msgs->flags & I2C_M_TEN)
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return -EINVAL;
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read = (msgs->flags & I2C_M_RD) != 0;
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addrdir = (msgs->addr << 1) | read;
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if (msgs->flags & I2C_M_REV_DIR_ADDR)
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addrdir ^= 1;
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rc = pmac_i2c_open(bus, 0);
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if (rc)
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return rc;
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rc = pmac_i2c_setmode(bus, pmac_i2c_mode_std);
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if (rc)
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goto bail;
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rc = pmac_i2c_xfer(bus, addrdir, 0, 0, msgs->buf, msgs->len);
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bail:
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pmac_i2c_close(bus);
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return rc < 0 ? rc : 1;
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}
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static u32 i2c_powermac_func(struct i2c_adapter * adapter)
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{
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return I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
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I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA |
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I2C_FUNC_SMBUS_BLOCK_DATA | I2C_FUNC_I2C;
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}
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/* For now, we only handle smbus */
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static const struct i2c_algorithm i2c_powermac_algorithm = {
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.smbus_xfer = i2c_powermac_smbus_xfer,
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.master_xfer = i2c_powermac_master_xfer,
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.functionality = i2c_powermac_func,
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};
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static int i2c_powermac_remove(struct platform_device *dev)
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{
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struct i2c_adapter *adapter = platform_get_drvdata(dev);
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struct pmac_i2c_bus *bus = i2c_get_adapdata(adapter);
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int rc;
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rc = i2c_del_adapter(adapter);
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pmac_i2c_detach_adapter(bus, adapter);
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i2c_set_adapdata(adapter, NULL);
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/* We aren't that prepared to deal with this... */
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if (rc)
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printk("i2c-powermac.c: Failed to remove bus %s !\n",
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adapter->name);
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platform_set_drvdata(dev, NULL);
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kfree(adapter);
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return 0;
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}
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static int __devexit i2c_powermac_probe(struct platform_device *dev)
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{
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struct pmac_i2c_bus *bus = dev->dev.platform_data;
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struct device_node *parent = NULL;
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struct i2c_adapter *adapter;
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char name[32];
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const char *basename;
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int rc;
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if (bus == NULL)
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return -EINVAL;
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/* Ok, now we need to make up a name for the interface that will
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* match what we used to do in the past, that is basically the
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* controller's parent device node for keywest. PMU didn't have a
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* naming convention and SMU has a different one
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*/
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switch(pmac_i2c_get_type(bus)) {
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case pmac_i2c_bus_keywest:
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parent = of_get_parent(pmac_i2c_get_controller(bus));
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if (parent == NULL)
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return -EINVAL;
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basename = parent->name;
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break;
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case pmac_i2c_bus_pmu:
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basename = "pmu";
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break;
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case pmac_i2c_bus_smu:
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/* This is not what we used to do but I'm fixing drivers at
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* the same time as this change
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*/
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basename = "smu";
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break;
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default:
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return -EINVAL;
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}
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snprintf(name, 32, "%s %d", basename, pmac_i2c_get_channel(bus));
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of_node_put(parent);
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adapter = kzalloc(sizeof(struct i2c_adapter), GFP_KERNEL);
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if (adapter == NULL) {
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printk(KERN_ERR "i2c-powermac: can't allocate inteface !\n");
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return -ENOMEM;
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}
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platform_set_drvdata(dev, adapter);
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strcpy(adapter->name, name);
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adapter->algo = &i2c_powermac_algorithm;
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i2c_set_adapdata(adapter, bus);
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adapter->dev.parent = &dev->dev;
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pmac_i2c_attach_adapter(bus, adapter);
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rc = i2c_add_adapter(adapter);
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if (rc) {
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printk(KERN_ERR "i2c-powermac: Adapter %s registration "
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"failed\n", name);
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i2c_set_adapdata(adapter, NULL);
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pmac_i2c_detach_adapter(bus, adapter);
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}
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printk(KERN_INFO "PowerMac i2c bus %s registered\n", name);
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return rc;
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}
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static struct platform_driver i2c_powermac_driver = {
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.probe = i2c_powermac_probe,
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.remove = __devexit_p(i2c_powermac_remove),
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.driver = {
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.name = "i2c-powermac",
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.bus = &platform_bus_type,
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},
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};
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static int __init i2c_powermac_init(void)
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{
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platform_driver_register(&i2c_powermac_driver);
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return 0;
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}
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static void __exit i2c_powermac_cleanup(void)
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{
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platform_driver_unregister(&i2c_powermac_driver);
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}
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module_init(i2c_powermac_init);
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module_exit(i2c_powermac_cleanup);
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