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i2c-algo-pca: Extend for future drivers

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The separation between algorithm and adapter was unsharp at places. This was
partly hidden by the fact, that the ISA-driver allowed just one instance and
had all private data in static variables. This patch makes neccessary
preparations to add a platform driver on top of the algorithm, while still
supporting ISA. Note: Due to lack of hardware, the ISA-driver could not be
tested except that it builds.

Concerning the core struct i2c_algo_pca_data:

- A private data field was added, all hardware dependant data may go here.
  Similar to other algorithms, now a pointer to this data is passed to the
  adapter's functions. In order to make as less changes as possible to the
  ISA-driver, it leaves the private data empty and still only uses its static
  variables.

- A "reset_chip" function pointer was added; such a functionality must come
  from the adapter, not the algorithm.

- use a variable "i2c_clock" instead of a function pointer "get_clock",
  allowing for write access to a default in case a wrong value was supplied.

In the algorithm-file:

- move "i2c-pca-algo.h" into "linux/i2c-algo-pca.h"
- now using per_instance timeout values (i2c_adap->timeout)
- error messages specify the device, not only the driver name
- restructure initialization to easily support "i2c_add_numbered_adapter"
- drop "retries" and "own" (i2c address) as they were unused

(The state-machine for I2C-communication was not touched.)

In the ISA-driver:

- adapt to new algorithm

Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
This commit is contained in:
Wolfram Sang
2008-04-22 22:16:46 +02:00
committed by Jean Delvare
parent 3d4382913f
commit c01b083105
4 changed files with 101 additions and 113 deletions
Download Patch File Download Diff File Expand all files Collapse all files

100
drivers/i2c/algos/i2c-algo-pca.c
View File

@@ -1,6 +1,7 @@
/*
* i2c-algo-pca.c i2c driver algorithms for PCA9564 adapters
* Copyright (C) 2004 Arcom Control Systems
* Copyright (C) 2008 Pengutronix
*
* 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
@@ -21,14 +22,10 @@
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/errno.h>
#include <linux/i2c.h>
#include <linux/i2c-algo-pca.h>
#include "i2c-algo-pca.h"
#define DRIVER "i2c-algo-pca"
#define DEB1(fmt, args...) do { if (i2c_debug>=1) printk(fmt, ## args); } while(0)
#define DEB2(fmt, args...) do { if (i2c_debug>=2) printk(fmt, ## args); } while(0)
@@ -36,15 +33,15 @@
static int i2c_debug;
#define pca_outw(adap, reg, val) adap->write_byte(adap, reg, val)
#define pca_inw(adap, reg) adap->read_byte(adap, reg)
#define pca_outw(adap, reg, val) adap->write_byte(adap->data, reg, val)
#define pca_inw(adap, reg) adap->read_byte(adap->data, reg)
#define pca_status(adap) pca_inw(adap, I2C_PCA_STA)
#define pca_clock(adap) adap->get_clock(adap)
#define pca_own(adap) adap->get_own(adap)
#define pca_clock(adap) adap->i2c_clock
#define pca_set_con(adap, val) pca_outw(adap, I2C_PCA_CON, val)
#define pca_get_con(adap) pca_inw(adap, I2C_PCA_CON)
#define pca_wait(adap) adap->wait_for_interrupt(adap)
#define pca_wait(adap) adap->wait_for_completion(adap->data)
#define pca_reset(adap) adap->reset_chip(adap->data)
/*
* Generate a start condition on the i2c bus.
@@ -168,15 +165,6 @@ static void pca_rx_ack(struct i2c_algo_pca_data *adap,
pca_wait(adap);
}
/*
* Reset the i2c bus / SIO
*/
static void pca_reset(struct i2c_algo_pca_data *adap)
{
/* apparently only an external reset will do it. not a lot can be done */
printk(KERN_ERR DRIVER ": Haven't figured out how to do a reset yet\n");
}
static int pca_xfer(struct i2c_adapter *i2c_adap,
struct i2c_msg *msgs,
int num)
@@ -187,7 +175,7 @@ static int pca_xfer(struct i2c_adapter *i2c_adap,
int numbytes = 0;
int state;
int ret;
int timeout = 100;
int timeout = i2c_adap->timeout;
while ((state = pca_status(adap)) != 0xf8 && timeout--) {
msleep(10);
@@ -317,7 +305,7 @@ static int pca_xfer(struct i2c_adapter *i2c_adap,
pca_reset(adap);
goto out;
default:
printk(KERN_ERR DRIVER ": unhandled SIO state 0x%02x\n", state);
dev_err(&i2c_adap->dev, "unhandled SIO state 0x%02x\n", state);
break;
}
@@ -337,53 +325,65 @@ static u32 pca_func(struct i2c_adapter *adap)
return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
}
static int pca_init(struct i2c_algo_pca_data *adap)
{
static int freqs[] = {330,288,217,146,88,59,44,36};
int own, clock;
own = pca_own(adap);
clock = pca_clock(adap);
DEB1(KERN_INFO DRIVER ": own address is %#04x\n", own);
DEB1(KERN_INFO DRIVER ": clock freqeuncy is %dkHz\n", freqs[clock]);
pca_outw(adap, I2C_PCA_ADR, own << 1);
pca_set_con(adap, I2C_PCA_CON_ENSIO | clock);
udelay(500); /* 500 us for oscilator to stabilise */
return 0;
}
static const struct i2c_algorithm pca_algo = {
.master_xfer = pca_xfer,
.functionality = pca_func,
};
static int pca_init(struct i2c_adapter *adap)
{
static int freqs[] = {330,288,217,146,88,59,44,36};
int clock;
struct i2c_algo_pca_data *pca_data = adap->algo_data;
if (pca_data->i2c_clock > 7) {
printk(KERN_WARNING "%s: Invalid I2C clock speed selected. Trying default.\n",
adap->name);
pca_data->i2c_clock = I2C_PCA_CON_59kHz;
}
adap->algo = &pca_algo;
pca_reset(pca_data);
clock = pca_clock(pca_data);
DEB1(KERN_INFO "%s: Clock frequency is %dkHz\n", adap->name, freqs[clock]);
pca_set_con(pca_data, I2C_PCA_CON_ENSIO | clock);
udelay(500); /* 500 us for oscilator to stabilise */
return 0;
}
/*
* registering functions to load algorithms at runtime
*/
int i2c_pca_add_bus(struct i2c_adapter *adap)
{
struct i2c_algo_pca_data *pca_adap = adap->algo_data;
int rval;
/* register new adapter to i2c module... */
adap->algo = &pca_algo;
adap->timeout = 100; /* default values, should */
adap->retries = 3; /* be replaced by defines */
if ((rval = pca_init(pca_adap)))
rval = pca_init(adap);
if (rval)
return rval;
rval = i2c_add_adapter(adap);
return rval;
return i2c_add_adapter(adap);
}
EXPORT_SYMBOL(i2c_pca_add_bus);
MODULE_AUTHOR("Ian Campbell <icampbell@arcom.com>");
int i2c_pca_add_numbered_bus(struct i2c_adapter *adap)
{
int rval;
rval = pca_init(adap);
if (rval)
return rval;
return i2c_add_numbered_adapter(adap);
}
EXPORT_SYMBOL(i2c_pca_add_numbered_bus);
MODULE_AUTHOR("Ian Campbell <icampbell@arcom.com>, "
"Wolfram Sang <w.sang@pengutronix.de>");
MODULE_DESCRIPTION("I2C-Bus PCA9564 algorithm");
MODULE_LICENSE("GPL");

26
drivers/i2c/algos/i2c-algo-pca.h
View File

@@ -1,26 +0,0 @@
#ifndef I2C_PCA9564_H
#define I2C_PCA9564_H 1
#define I2C_PCA_STA 0x00 /* STATUS Read Only */
#define I2C_PCA_TO 0x00 /* TIMEOUT Write Only */
#define I2C_PCA_DAT 0x01 /* DATA Read/Write */
#define I2C_PCA_ADR 0x02 /* OWN ADR Read/Write */
#define I2C_PCA_CON 0x03 /* CONTROL Read/Write */
#define I2C_PCA_CON_AA 0x80 /* Assert Acknowledge */
#define I2C_PCA_CON_ENSIO 0x40 /* Enable */
#define I2C_PCA_CON_STA 0x20 /* Start */
#define I2C_PCA_CON_STO 0x10 /* Stop */
#define I2C_PCA_CON_SI 0x08 /* Serial Interrupt */
#define I2C_PCA_CON_CR 0x07 /* Clock Rate (MASK) */
#define I2C_PCA_CON_330kHz 0x00
#define I2C_PCA_CON_288kHz 0x01
#define I2C_PCA_CON_217kHz 0x02
#define I2C_PCA_CON_146kHz 0x03
#define I2C_PCA_CON_88kHz 0x04
#define I2C_PCA_CON_59kHz 0x05
#define I2C_PCA_CON_44kHz 0x06
#define I2C_PCA_CON_36kHz 0x07
#endif /* I2C_PCA9564_H */