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i2c-algo-pca: Extend for future drivers 

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
Show Stats 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 * i2c-algo-pca.c i2c driver algorithms for PCA9564 adapters
* Copyright (C) 2004 Arcom Control Systems * Copyright (C) 2004 Arcom Control Systems
* Copyright (C) 2008 Pengutronix
* *
* This program is free software; you can redistribute it and/or modify * 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 * it under the terms of the GNU General Public License as published by
@ -21,14 +22,10 @@
#include <linux/module.h> #include <linux/module.h>
#include <linux/moduleparam.h> #include <linux/moduleparam.h>
#include <linux/delay.h> #include <linux/delay.h>
#include <linux/slab.h>
#include <linux/init.h> #include <linux/init.h>
#include <linux/errno.h> #include <linux/errno.h>
#include <linux/i2c.h> #include <linux/i2c.h>
#include <linux/i2c-algo-pca.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 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) #define DEB2(fmt, args...) do { if (i2c_debug>=2) printk(fmt, ## args); } while(0)
@ -36,15 +33,15 @@
static int i2c_debug; static int i2c_debug;
#define pca_outw(adap, reg, val) adap->write_byte(adap, reg, val) #define pca_outw(adap, reg, val) adap->write_byte(adap->data, reg, val)
#define pca_inw(adap, reg) adap->read_byte(adap, reg) #define pca_inw(adap, reg) adap->read_byte(adap->data, reg)
#define pca_status(adap) pca_inw(adap, I2C_PCA_STA) #define pca_status(adap) pca_inw(adap, I2C_PCA_STA)
#define pca_clock(adap) adap->get_clock(adap) #define pca_clock(adap) adap->i2c_clock
#define pca_own(adap) adap->get_own(adap)
#define pca_set_con(adap, val) pca_outw(adap, I2C_PCA_CON, val) #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_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. * 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); 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, static int pca_xfer(struct i2c_adapter *i2c_adap,
struct i2c_msg *msgs, struct i2c_msg *msgs,
int num) int num)
@ -187,7 +175,7 @@ static int pca_xfer(struct i2c_adapter *i2c_adap,
int numbytes = 0; int numbytes = 0;
int state; int state;
int ret; int ret;
int timeout = 100; int timeout = i2c_adap->timeout;
while ((state = pca_status(adap)) != 0xf8 && timeout--) { while ((state = pca_status(adap)) != 0xf8 && timeout--) {
msleep(10); msleep(10);
@ -317,7 +305,7 @@ static int pca_xfer(struct i2c_adapter *i2c_adap,
pca_reset(adap); pca_reset(adap);
goto out; goto out;
default: 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; break;
} }
@ -337,53 +325,65 @@ static u32 pca_func(struct i2c_adapter *adap)
return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL; 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 = { static const struct i2c_algorithm pca_algo = {
.master_xfer = pca_xfer, .master_xfer = pca_xfer,
.functionality = pca_func, .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 * registering functions to load algorithms at runtime
*/ */
int i2c_pca_add_bus(struct i2c_adapter *adap) int i2c_pca_add_bus(struct i2c_adapter *adap)
{ {
struct i2c_algo_pca_data *pca_adap = adap->algo_data;
int rval; int rval;
/* register new adapter to i2c module... */ rval = pca_init(adap);
adap->algo = &pca_algo; if (rval)
adap->timeout = 100; /* default values, should */
adap->retries = 3; /* be replaced by defines */
if ((rval = pca_init(pca_adap)))
return rval; return rval;
rval = i2c_add_adapter(adap); return i2c_add_adapter(adap);
return rval;
} }
EXPORT_SYMBOL(i2c_pca_add_bus); 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_DESCRIPTION("I2C-Bus PCA9564 algorithm");
MODULE_LICENSE("GPL"); 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 */

51
drivers/i2c/busses/i2c-pca-isa.c
View File

@ -1,6 +1,7 @@
/* /*
* i2c-pca-isa.c driver for PCA9564 on ISA boards * i2c-pca-isa.c driver for PCA9564 on ISA boards
* Copyright (C) 2004 Arcom Control Systems * Copyright (C) 2004 Arcom Control Systems
* Copyright (C) 2008 Pengutronix
* *
* This program is free software; you can redistribute it and/or modify * 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 * it under the terms of the GNU General Public License as published by
@ -22,11 +23,9 @@
#include <linux/module.h> #include <linux/module.h>
#include <linux/moduleparam.h> #include <linux/moduleparam.h>
#include <linux/delay.h> #include <linux/delay.h>
#include <linux/slab.h>
#include <linux/init.h> #include <linux/init.h>
#include <linux/interrupt.h> #include <linux/interrupt.h>
#include <linux/wait.h> #include <linux/wait.h>
#include <linux/isa.h> #include <linux/isa.h>
#include <linux/i2c.h> #include <linux/i2c.h>
#include <linux/i2c-algo-pca.h> #include <linux/i2c-algo-pca.h>
@ -34,13 +33,9 @@
#include <asm/io.h> #include <asm/io.h>
#include <asm/irq.h> #include <asm/irq.h>
#include "../algos/i2c-algo-pca.h" #define DRIVER "i2c-pca-isa"
#define IO_SIZE 4 #define IO_SIZE 4
#undef DEBUG_IO
//#define DEBUG_IO
static unsigned long base = 0x330; static unsigned long base = 0x330;
static int irq = 10; static int irq = 10;
@ -48,22 +43,9 @@ static int irq = 10;
* in the actual clock rate */ * in the actual clock rate */
static int clock = I2C_PCA_CON_59kHz; static int clock = I2C_PCA_CON_59kHz;
static int own = 0x55;
static wait_queue_head_t pca_wait; static wait_queue_head_t pca_wait;
static int pca_isa_getown(struct i2c_algo_pca_data *adap) static void pca_isa_writebyte(void *pd, int reg, int val)
{
return (own);
}
static int pca_isa_getclock(struct i2c_algo_pca_data *adap)
{
return (clock);
}
static void
pca_isa_writebyte(struct i2c_algo_pca_data *adap, int reg, int val)
{ {
#ifdef DEBUG_IO #ifdef DEBUG_IO
static char *names[] = { "T/O", "DAT", "ADR", "CON" }; static char *names[] = { "T/O", "DAT", "ADR", "CON" };
@ -72,8 +54,7 @@ pca_isa_writebyte(struct i2c_algo_pca_data *adap, int reg, int val)
outb(val, base+reg); outb(val, base+reg);
} }
static int static int pca_isa_readbyte(void *pd, int reg)
pca_isa_readbyte(struct i2c_algo_pca_data *adap, int reg)
{ {
int res = inb(base+reg); int res = inb(base+reg);
#ifdef DEBUG_IO #ifdef DEBUG_IO
@ -85,31 +66,37 @@ pca_isa_readbyte(struct i2c_algo_pca_data *adap, int reg)
return res; return res;
} }
static int pca_isa_waitforinterrupt(struct i2c_algo_pca_data *adap) static int pca_isa_waitforcompletion(void *pd)
{ {
int ret = 0; int ret = 0;
if (irq > -1) { if (irq > -1) {
ret = wait_event_interruptible(pca_wait, ret = wait_event_interruptible(pca_wait,
pca_isa_readbyte(adap, I2C_PCA_CON) & I2C_PCA_CON_SI); pca_isa_readbyte(pd, I2C_PCA_CON) & I2C_PCA_CON_SI);
} else { } else {
while ((pca_isa_readbyte(adap, I2C_PCA_CON) & I2C_PCA_CON_SI) == 0) while ((pca_isa_readbyte(pd, I2C_PCA_CON) & I2C_PCA_CON_SI) == 0)
udelay(100); udelay(100);
} }
return ret; return ret;
} }
static void pca_isa_resetchip(void *pd)
{
/* apparently only an external reset will do it. not a lot can be done */
printk(KERN_WARNING DRIVER ": Haven't figured out how to do a reset yet\n");
}
static irqreturn_t pca_handler(int this_irq, void *dev_id) { static irqreturn_t pca_handler(int this_irq, void *dev_id) {
wake_up_interruptible(&pca_wait); wake_up_interruptible(&pca_wait);
return IRQ_HANDLED; return IRQ_HANDLED;
} }
static struct i2c_algo_pca_data pca_isa_data = { static struct i2c_algo_pca_data pca_isa_data = {
.get_own = pca_isa_getown, /* .data intentionally left NULL, not needed with ISA */
.get_clock = pca_isa_getclock,
.write_byte = pca_isa_writebyte, .write_byte = pca_isa_writebyte,
.read_byte = pca_isa_readbyte, .read_byte = pca_isa_readbyte,
.wait_for_interrupt = pca_isa_waitforinterrupt, .wait_for_completion = pca_isa_waitforcompletion,
.reset_chip = pca_isa_resetchip,
}; };
static struct i2c_adapter pca_isa_ops = { static struct i2c_adapter pca_isa_ops = {
@ -117,6 +104,7 @@ static struct i2c_adapter pca_isa_ops = {
.id = I2C_HW_A_ISA, .id = I2C_HW_A_ISA,
.algo_data = &pca_isa_data, .algo_data = &pca_isa_data,
.name = "PCA9564 ISA Adapter", .name = "PCA9564 ISA Adapter",
.timeout = 100,
}; };
static int __devinit pca_isa_probe(struct device *dev, unsigned int id) static int __devinit pca_isa_probe(struct device *dev, unsigned int id)
@ -144,6 +132,7 @@ static int __devinit pca_isa_probe(struct device *dev, unsigned int id)
} }
} }
pca_isa_data.i2c_clock = clock;
if (i2c_pca_add_bus(&pca_isa_ops) < 0) { if (i2c_pca_add_bus(&pca_isa_ops) < 0) {
dev_err(dev, "Failed to add i2c bus\n"); dev_err(dev, "Failed to add i2c bus\n");
goto out_irq; goto out_irq;
@ -178,7 +167,7 @@ static struct isa_driver pca_isa_driver = {
.remove = __devexit_p(pca_isa_remove), .remove = __devexit_p(pca_isa_remove),
.driver = { .driver = {
.owner = THIS_MODULE, .owner = THIS_MODULE,
.name = "i2c-pca-isa", .name = DRIVER,
} }
}; };
@ -204,7 +193,5 @@ MODULE_PARM_DESC(irq, "IRQ");
module_param(clock, int, 0); module_param(clock, int, 0);
MODULE_PARM_DESC(clock, "Clock rate as described in table 1 of PCA9564 datasheet"); MODULE_PARM_DESC(clock, "Clock rate as described in table 1 of PCA9564 datasheet");
module_param(own, int, 0); /* the driver can't do slave mode, so there's no real point in this */
module_init(pca_isa_init); module_init(pca_isa_init);
module_exit(pca_isa_exit); module_exit(pca_isa_exit);

37
include/linux/i2c-algo-pca.h
View File

@ -1,14 +1,41 @@
#ifndef _LINUX_I2C_ALGO_PCA_H #ifndef _LINUX_I2C_ALGO_PCA_H
#define _LINUX_I2C_ALGO_PCA_H #define _LINUX_I2C_ALGO_PCA_H
/* Clock speeds for the bus */
#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
/* PCA9564 registers */
#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) */
struct i2c_algo_pca_data { struct i2c_algo_pca_data {
int (*get_own) (struct i2c_algo_pca_data *adap); /* Obtain own address */ void *data; /* private low level data */
int (*get_clock) (struct i2c_algo_pca_data *adap); void (*write_byte) (void *data, int reg, int val);
void (*write_byte) (struct i2c_algo_pca_data *adap, int reg, int val); int (*read_byte) (void *data, int reg);
int (*read_byte) (struct i2c_algo_pca_data *adap, int reg); int (*wait_for_completion) (void *data);
int (*wait_for_interrupt) (struct i2c_algo_pca_data *adap); void (*reset_chip) (void *data);
/* i2c_clock values are defined in linux/i2c-algo-pca.h */
unsigned int i2c_clock;
}; };
int i2c_pca_add_bus(struct i2c_adapter *); int i2c_pca_add_bus(struct i2c_adapter *);
int i2c_pca_add_numbered_bus(struct i2c_adapter *);
#endif /* _LINUX_I2C_ALGO_PCA_H */ #endif /* _LINUX_I2C_ALGO_PCA_H */