Commit 9ffc1699 authored by Linus Torvalds's avatar Linus Torvalds

Merge branch 'i2c-for-linus' of git://aeryn.fluff.org.uk/bjdooks/linux

* 'i2c-for-linus' of git://aeryn.fluff.org.uk/bjdooks/linux:
  i2c: Blackfin I2C Driver: Functional power management support
  i2c: Documentation: upgrading clients HOWTO
  i2c: S3C24XX I2C frequency scaling support.
  i2c: i2c_gpio: keep probe resident for hotplugged devices.
  i2c: S3C2410: Pass the I2C bus number via drivers platform data
parents a0138692 958585f5
Upgrading I2C Drivers to the new 2.6 Driver Model
=================================================
Ben Dooks <ben-linux@fluff.org>
Introduction
------------
This guide outlines how to alter existing Linux 2.6 client drivers from
the old to the new new binding methods.
Example old-style driver
------------------------
struct example_state {
struct i2c_client client;
....
};
static struct i2c_driver example_driver;
static unsigned short ignore[] = { I2C_CLIENT_END };
static unsigned short normal_addr[] = { OUR_ADDR, I2C_CLIENT_END };
I2C_CLIENT_INSMOD;
static int example_attach(struct i2c_adapter *adap, int addr, int kind)
{
struct example_state *state;
struct device *dev = &adap->dev; /* to use for dev_ reports */
int ret;
state = kzalloc(sizeof(struct example_state), GFP_KERNEL);
if (state == NULL) {
dev_err(dev, "failed to create our state\n");
return -ENOMEM;
}
example->client.addr = addr;
example->client.flags = 0;
example->client.adapter = adap;
i2c_set_clientdata(&state->i2c_client, state);
strlcpy(client->i2c_client.name, "example", I2C_NAME_SIZE);
ret = i2c_attach_client(&state->i2c_client);
if (ret < 0) {
dev_err(dev, "failed to attach client\n");
kfree(state);
return ret;
}
dev = &state->i2c_client.dev;
/* rest of the initialisation goes here. */
dev_info(dev, "example client created\n");
return 0;
}
static int __devexit example_detach(struct i2c_client *client)
{
struct example_state *state = i2c_get_clientdata(client);
i2c_detach_client(client);
kfree(state);
return 0;
}
static int example_attach_adapter(struct i2c_adapter *adap)
{
return i2c_probe(adap, &addr_data, example_attach);
}
static struct i2c_driver example_driver = {
.driver = {
.owner = THIS_MODULE,
.name = "example",
},
.attach_adapter = example_attach_adapter,
.detach_client = __devexit_p(example_detach),
.suspend = example_suspend,
.resume = example_resume,
};
Updating the client
-------------------
The new style binding model will check against a list of supported
devices and their associated address supplied by the code registering
the busses. This means that the driver .attach_adapter and
.detach_adapter methods can be removed, along with the addr_data,
as follows:
- static struct i2c_driver example_driver;
- static unsigned short ignore[] = { I2C_CLIENT_END };
- static unsigned short normal_addr[] = { OUR_ADDR, I2C_CLIENT_END };
- I2C_CLIENT_INSMOD;
- static int example_attach_adapter(struct i2c_adapter *adap)
- {
- return i2c_probe(adap, &addr_data, example_attach);
- }
static struct i2c_driver example_driver = {
- .attach_adapter = example_attach_adapter,
- .detach_client = __devexit_p(example_detach),
}
Add the probe and remove methods to the i2c_driver, as so:
static struct i2c_driver example_driver = {
+ .probe = example_probe,
+ .remove = __devexit_p(example_remove),
}
Change the example_attach method to accept the new parameters
which include the i2c_client that it will be working with:
- static int example_attach(struct i2c_adapter *adap, int addr, int kind)
+ static int example_probe(struct i2c_client *client,
+ const struct i2c_device_id *id)
Change the name of example_attach to example_probe to align it with the
i2c_driver entry names. The rest of the probe routine will now need to be
changed as the i2c_client has already been setup for use.
The necessary client fields have already been setup before
the probe function is called, so the following client setup
can be removed:
- example->client.addr = addr;
- example->client.flags = 0;
- example->client.adapter = adap;
-
- strlcpy(client->i2c_client.name, "example", I2C_NAME_SIZE);
The i2c_set_clientdata is now:
- i2c_set_clientdata(&state->client, state);
+ i2c_set_clientdata(client, state);
The call to i2c_attach_client is no longer needed, if the probe
routine exits successfully, then the driver will be automatically
attached by the core. Change the probe routine as so:
- ret = i2c_attach_client(&state->i2c_client);
- if (ret < 0) {
- dev_err(dev, "failed to attach client\n");
- kfree(state);
- return ret;
- }
Remove the storage of 'struct i2c_client' from the 'struct example_state'
as we are provided with the i2c_client in our example_probe. Instead we
store a pointer to it for when it is needed.
struct example_state {
- struct i2c_client client;
+ struct i2c_client *client;
the new i2c client as so:
- struct device *dev = &adap->dev; /* to use for dev_ reports */
+ struct device *dev = &i2c_client->dev; /* to use for dev_ reports */
And remove the change after our client is attached, as the driver no
longer needs to register a new client structure with the core:
- dev = &state->i2c_client.dev;
In the probe routine, ensure that the new state has the client stored
in it:
static int example_probe(struct i2c_client *i2c_client,
const struct i2c_device_id *id)
{
struct example_state *state;
struct device *dev = &i2c_client->dev;
int ret;
state = kzalloc(sizeof(struct example_state), GFP_KERNEL);
if (state == NULL) {
dev_err(dev, "failed to create our state\n");
return -ENOMEM;
}
+ state->client = i2c_client;
Update the detach method, by changing the name to _remove and
to delete the i2c_detach_client call. It is possible that you
can also remove the ret variable as it is not not needed for
any of the core functions.
- static int __devexit example_detach(struct i2c_client *client)
+ static int __devexit example_remove(struct i2c_client *client)
{
struct example_state *state = i2c_get_clientdata(client);
- i2c_detach_client(client);
And finally ensure that we have the correct ID table for the i2c-core
and other utilities:
+ struct i2c_device_id example_idtable[] = {
+ { "example", 0 },
+ { }
+};
+
+MODULE_DEVICE_TABLE(i2c, example_idtable);
static struct i2c_driver example_driver = {
.driver = {
.owner = THIS_MODULE,
.name = "example",
},
+ .id_table = example_ids,
Our driver should now look like this:
struct example_state {
struct i2c_client *client;
....
};
static int example_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct example_state *state;
struct device *dev = &client->dev;
state = kzalloc(sizeof(struct example_state), GFP_KERNEL);
if (state == NULL) {
dev_err(dev, "failed to create our state\n");
return -ENOMEM;
}
state->client = client;
i2c_set_clientdata(client, state);
/* rest of the initialisation goes here. */
dev_info(dev, "example client created\n");
return 0;
}
static int __devexit example_remove(struct i2c_client *client)
{
struct example_state *state = i2c_get_clientdata(client);
kfree(state);
return 0;
}
static struct i2c_device_id example_idtable[] = {
{ "example", 0 },
{ }
};
MODULE_DEVICE_TABLE(i2c, example_idtable);
static struct i2c_driver example_driver = {
.driver = {
.owner = THIS_MODULE,
.name = "example",
},
.id_table = example_idtable,
.probe = example_probe,
.remove = __devexit_p(example_remove),
.suspend = example_suspend,
.resume = example_resume,
};
......@@ -49,6 +49,8 @@ struct bfin_twi_iface {
struct i2c_msg *pmsg;
int msg_num;
int cur_msg;
u16 saved_clkdiv;
u16 saved_control;
void __iomem *regs_base;
};
......@@ -565,32 +567,43 @@ static u32 bfin_twi_functionality(struct i2c_adapter *adap)
I2C_FUNC_I2C;
}
static struct i2c_algorithm bfin_twi_algorithm = {
.master_xfer = bfin_twi_master_xfer,
.smbus_xfer = bfin_twi_smbus_xfer,
.functionality = bfin_twi_functionality,
};
static int i2c_bfin_twi_suspend(struct platform_device *dev, pm_message_t state)
static int i2c_bfin_twi_suspend(struct platform_device *pdev, pm_message_t state)
{
struct bfin_twi_iface *iface = platform_get_drvdata(dev);
struct bfin_twi_iface *iface = platform_get_drvdata(pdev);
iface->saved_clkdiv = read_CLKDIV(iface);
iface->saved_control = read_CONTROL(iface);
free_irq(iface->irq, iface);
/* Disable TWI */
write_CONTROL(iface, read_CONTROL(iface) & ~TWI_ENA);
SSYNC();
write_CONTROL(iface, iface->saved_control & ~TWI_ENA);
return 0;
}
static int i2c_bfin_twi_resume(struct platform_device *dev)
static int i2c_bfin_twi_resume(struct platform_device *pdev)
{
struct bfin_twi_iface *iface = platform_get_drvdata(dev);
struct bfin_twi_iface *iface = platform_get_drvdata(pdev);
/* Enable TWI */
write_CONTROL(iface, read_CONTROL(iface) | TWI_ENA);
SSYNC();
int rc = request_irq(iface->irq, bfin_twi_interrupt_entry,
IRQF_DISABLED, pdev->name, iface);
if (rc) {
dev_err(&pdev->dev, "Can't get IRQ %d !\n", iface->irq);
return -ENODEV;
}
/* Resume TWI interface clock as specified */
write_CLKDIV(iface, iface->saved_clkdiv);
/* Resume TWI */
write_CONTROL(iface, iface->saved_control);
return 0;
}
......
......@@ -77,7 +77,7 @@ static int i2c_gpio_getscl(void *data)
return gpio_get_value(pdata->scl_pin);
}
static int __init i2c_gpio_probe(struct platform_device *pdev)
static int __devinit i2c_gpio_probe(struct platform_device *pdev)
{
struct i2c_gpio_platform_data *pdata;
struct i2c_algo_bit_data *bit_data;
......@@ -174,7 +174,7 @@ static int __init i2c_gpio_probe(struct platform_device *pdev)
return ret;
}
static int __exit i2c_gpio_remove(struct platform_device *pdev)
static int __devexit i2c_gpio_remove(struct platform_device *pdev)
{
struct i2c_gpio_platform_data *pdata;
struct i2c_adapter *adap;
......@@ -196,14 +196,15 @@ static struct platform_driver i2c_gpio_driver = {
.name = "i2c-gpio",
.owner = THIS_MODULE,
},
.remove = __exit_p(i2c_gpio_remove),
.probe = i2c_gpio_probe,
.remove = __devexit_p(i2c_gpio_remove),
};
static int __init i2c_gpio_init(void)
{
int ret;
ret = platform_driver_probe(&i2c_gpio_driver, i2c_gpio_probe);
ret = platform_driver_register(&i2c_gpio_driver);
if (ret)
printk(KERN_ERR "i2c-gpio: probe failed: %d\n", ret);
......
......@@ -33,6 +33,7 @@
#include <linux/err.h>
#include <linux/platform_device.h>
#include <linux/clk.h>
#include <linux/cpufreq.h>
#include <asm/hardware.h>
#include <asm/irq.h>
......@@ -64,6 +65,7 @@ struct s3c24xx_i2c {
unsigned int tx_setup;
enum s3c24xx_i2c_state state;
unsigned long clkrate;
void __iomem *regs;
struct clk *clk;
......@@ -71,6 +73,10 @@ struct s3c24xx_i2c {
struct resource *irq;
struct resource *ioarea;
struct i2c_adapter adap;
#ifdef CONFIG_CPU_FREQ
struct notifier_block freq_transition;
#endif
};
/* default platform data to use if not supplied in the platform_device
......@@ -501,6 +507,9 @@ static int s3c24xx_i2c_doxfer(struct s3c24xx_i2c *i2c, struct i2c_msg *msgs, int
unsigned long timeout;
int ret;
if (!readl(i2c->regs + S3C2410_IICCON) & S3C2410_IICCON_IRQEN)
return -EIO;
ret = s3c24xx_i2c_set_master(i2c);
if (ret != 0) {
dev_err(i2c->dev, "cannot get bus (error %d)\n", ret);
......@@ -636,27 +645,28 @@ static inline int freq_acceptable(unsigned int freq, unsigned int wanted)
return (diff >= -2 && diff <= 2);
}
/* s3c24xx_i2c_getdivisor
/* s3c24xx_i2c_clockrate
*
* work out a divisor for the user requested frequency setting,
* either by the requested frequency, or scanning the acceptable
* range of frequencies until something is found
*/
static int s3c24xx_i2c_getdivisor(struct s3c24xx_i2c *i2c,
struct s3c2410_platform_i2c *pdata,
unsigned long *iicon,
unsigned int *got)
static int s3c24xx_i2c_clockrate(struct s3c24xx_i2c *i2c, unsigned int *got)
{
struct s3c2410_platform_i2c *pdata;
unsigned long clkin = clk_get_rate(i2c->clk);
unsigned int divs, div1;
u32 iiccon;
int freq;
int start, end;
i2c->clkrate = clkin;
pdata = s3c24xx_i2c_get_platformdata(i2c->adap.dev.parent);
clkin /= 1000; /* clkin now in KHz */
dev_dbg(i2c->dev, "pdata %p, freq %lu %lu..%lu\n",
dev_dbg(i2c->dev, "pdata %p, freq %lu %lu..%lu\n",
pdata, pdata->bus_freq, pdata->min_freq, pdata->max_freq);
if (pdata->bus_freq != 0) {
......@@ -688,11 +698,79 @@ static int s3c24xx_i2c_getdivisor(struct s3c24xx_i2c *i2c,
found:
*got = freq;
*iicon |= (divs-1);
*iicon |= (div1 == 512) ? S3C2410_IICCON_TXDIV_512 : 0;
iiccon = readl(i2c->regs + S3C2410_IICCON);
iiccon &= ~(S3C2410_IICCON_SCALEMASK | S3C2410_IICCON_TXDIV_512);
iiccon |= (divs-1);
if (div1 == 512)
iiccon |= S3C2410_IICCON_TXDIV_512;
writel(iiccon, i2c->regs + S3C2410_IICCON);
return 0;
}
#ifdef CONFIG_CPU_FREQ
#define freq_to_i2c(_n) container_of(_n, struct s3c24xx_i2c, freq_transition)
static int s3c24xx_i2c_cpufreq_transition(struct notifier_block *nb,
unsigned long val, void *data)
{
struct s3c24xx_i2c *i2c = freq_to_i2c(nb);
unsigned long flags;
unsigned int got;
int delta_f;
int ret;
delta_f = clk_get_rate(i2c->clk) - i2c->clkrate;
/* if we're post-change and the input clock has slowed down
* or at pre-change and the clock is about to speed up, then
* adjust our clock rate. <0 is slow, >0 speedup.
*/
if ((val == CPUFREQ_POSTCHANGE && delta_f < 0) ||
(val == CPUFREQ_PRECHANGE && delta_f > 0)) {
spin_lock_irqsave(&i2c->lock, flags);
ret = s3c24xx_i2c_clockrate(i2c, &got);
spin_unlock_irqrestore(&i2c->lock, flags);
if (ret < 0)
dev_err(i2c->dev, "cannot find frequency\n");
else
dev_info(i2c->dev, "setting freq %d\n", got);
}
return 0;
}
static inline int s3c24xx_i2c_register_cpufreq(struct s3c24xx_i2c *i2c)
{
i2c->freq_transition.notifier_call = s3c24xx_i2c_cpufreq_transition;
return cpufreq_register_notifier(&i2c->freq_transition,
CPUFREQ_TRANSITION_NOTIFIER);
}
static inline void s3c24xx_i2c_deregister_cpufreq(struct s3c24xx_i2c *i2c)
{
cpufreq_unregister_notifier(&i2c->freq_transition,
CPUFREQ_TRANSITION_NOTIFIER);
}
#else
static inline int s3c24xx_i2c_register_cpufreq(struct s3c24xx_i2c *i2c)
{
return 0;
}
static inline void s3c24xx_i2c_deregister_cpufreq(struct s3c24xx_i2c *i2c)
{
}
#endif
/* s3c24xx_i2c_init
*
* initialise the controller, set the IO lines and frequency
......@@ -719,9 +797,12 @@ static int s3c24xx_i2c_init(struct s3c24xx_i2c *i2c)
dev_info(i2c->dev, "slave address 0x%02x\n", pdata->slave_addr);
writel(iicon, i2c->regs + S3C2410_IICCON);
/* we need to work out the divisors for the clock... */
if (s3c24xx_i2c_getdivisor(i2c, pdata, &iicon, &freq) != 0) {
if (s3c24xx_i2c_clockrate(i2c, &freq) != 0) {
writel(0, i2c->regs + S3C2410_IICCON);
dev_err(i2c->dev, "cannot meet bus frequency required\n");
return -EINVAL;
}
......@@ -730,8 +811,6 @@ static int s3c24xx_i2c_init(struct s3c24xx_i2c *i2c)
dev_info(i2c->dev, "bus frequency set to %d KHz\n", freq);
dev_dbg(i2c->dev, "S3C2410_IICCON=0x%02lx\n", iicon);
writel(iicon, i2c->regs + S3C2410_IICCON);
/* check for s3c2440 i2c controller */
......@@ -752,9 +831,12 @@ static int s3c24xx_i2c_init(struct s3c24xx_i2c *i2c)
static int s3c24xx_i2c_probe(struct platform_device *pdev)
{
struct s3c24xx_i2c *i2c = &s3c24xx_i2c;
struct s3c2410_platform_i2c *pdata;
struct resource *res;
int ret;
pdata = s3c24xx_i2c_get_platformdata(&pdev->dev);
/* find the clock and enable it */
i2c->dev = &pdev->dev;
......@@ -832,17 +914,34 @@ static int s3c24xx_i2c_probe(struct platform_device *pdev)
dev_dbg(&pdev->dev, "irq resource %p (%lu)\n", res,
(unsigned long)res->start);
ret = i2c_add_adapter(&i2c->adap);
ret = s3c24xx_i2c_register_cpufreq(i2c);
if (ret < 0) {
dev_err(&pdev->dev, "failed to add bus to i2c core\n");
dev_err(&pdev->dev, "failed to register cpufreq notifier\n");
goto err_irq;
}
/* Note, previous versions of the driver used i2c_add_adapter()
* to add the bus at any number. We now pass the bus number via
* the platform data, so if unset it will now default to always
* being bus 0.
*/
i2c->adap.nr = pdata->bus_num;
ret = i2c_add_numbered_adapter(&i2c->adap);
if (ret < 0) {
dev_err(&pdev->dev, "failed to add bus to i2c core\n");
goto err_cpufreq;
}
platform_set_drvdata(pdev, i2c);
dev_info(&pdev->dev, "%s: S3C I2C adapter\n", i2c->adap.dev.bus_id);
return 0;
err_cpufreq:
s3c24xx_i2c_deregister_cpufreq(i2c);
err_irq:
free_irq(i2c->irq->start, i2c);
......@@ -870,6 +969,8 @@ static int s3c24xx_i2c_remove(struct platform_device *pdev)
{
struct s3c24xx_i2c *i2c = platform_get_drvdata(pdev);
s3c24xx_i2c_deregister_cpufreq(i2c);
i2c_del_adapter(&i2c->adap);
free_irq(i2c->irq->start, i2c);
......
......@@ -21,6 +21,7 @@
*/
struct s3c2410_platform_i2c {
int bus_num; /* bus number to use */
unsigned int flags;
unsigned int slave_addr; /* slave address for controller */
unsigned long bus_freq; /* standard bus frequency */
......
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