diff --git a/Documentation/i2c/upgrading-clients b/Documentation/i2c/upgrading-clients new file mode 100644 index 00000000000..9a45f9bb6a2 --- /dev/null +++ b/Documentation/i2c/upgrading-clients @@ -0,0 +1,281 @@ +Upgrading I2C Drivers to the new 2.6 Driver Model +================================================= + +Ben Dooks + +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, +}; diff --git a/drivers/i2c/busses/i2c-bfin-twi.c b/drivers/i2c/busses/i2c-bfin-twi.c index 48d084bdf7c..3c855ff2992 100644 --- a/drivers/i2c/busses/i2c-bfin-twi.c +++ b/drivers/i2c/busses/i2c-bfin-twi.c @@ -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; } diff --git a/drivers/i2c/busses/i2c-gpio.c b/drivers/i2c/busses/i2c-gpio.c index 79b455a1f09..32104eac8d3 100644 --- a/drivers/i2c/busses/i2c-gpio.c +++ b/drivers/i2c/busses/i2c-gpio.c @@ -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 @@ err_alloc_adap: 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); diff --git a/drivers/i2c/busses/i2c-s3c2410.c b/drivers/i2c/busses/i2c-s3c2410.c index 007390ad981..4864723c742 100644 --- a/drivers/i2c/busses/i2c-s3c2410.c +++ b/drivers/i2c/busses/i2c-s3c2410.c @@ -33,6 +33,7 @@ #include #include #include +#include #include #include @@ -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; @@ -832,10 +914,24 @@ 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 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_irq; + goto err_cpufreq; } platform_set_drvdata(pdev, i2c); @@ -843,6 +939,9 @@ static int s3c24xx_i2c_probe(struct platform_device *pdev) 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); diff --git a/include/asm-arm/plat-s3c/iic.h b/include/asm-arm/plat-s3c/iic.h index 71211c8b538..d08a1f2863e 100644 --- a/include/asm-arm/plat-s3c/iic.h +++ b/include/asm-arm/plat-s3c/iic.h @@ -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 */