linux驱动：i2c驱动（二）

3、驱动源码分析

IPNC_RDK_V3.8.0.1/Source/ti_tools/ipnc_psp_arago/kernel/sound/soc/codecs/tlv320aic3x.c

3.1 注册模块

module_init(aic3x_modinit);

3.2 在初始化函数中添加i2c驱动

static int __init aic3x_modinit(void)

{

intret = 0;

#if defined(CONFIG_I2C) ||defined(CONFIG_I2C_MODULE)

ret= i2c_add_driver(&aic3x_i2c_driver);

if(ret != 0) {

printk(KERN_ERR "Failed to registerTLV320AIC3x I2C driver: %d\n",

ret);

}

#endif

returnret;

}

3.3 【驱动】

static struct i2c_driver aic3x_i2c_driver = {

.driver= {

.name = "tlv320aic3x-codec",

.owner = THIS_MODULE,

},

.probe     = aic3x_i2c_probe,

.remove= aic3x_i2c_remove,

.id_table= aic3x_i2c_id,

};

3.4 probe

static int aic3x_i2c_probe(structi2c_client *i2c,

const struct i2c_device_id *id)

{

structaic3x_pdata *pdata = i2c->dev.platform_data;

structaic3x_priv *aic3x;

intret;

conststruct i2c_device_id *tbl;

aic3x= kzalloc(sizeof(struct aic3x_priv), GFP_KERNEL);

if(aic3x == NULL) {

dev_err(&i2c->dev, "failed tocreate private data\n");

return -ENOMEM;

}

aic3x->control_data= i2c;

aic3x->control_type= SND_SOC_I2C;

i2c_set_clientdata(i2c, aic3x);

if(pdata) {

aic3x->gpio_reset =pdata->gpio_reset;

aic3x->setup = pdata->setup;

}else {

aic3x->gpio_reset = -1;

}

for(tbl = aic3x_i2c_id; tbl->name[0]; tbl++) {

if (!strcmp(tbl->name, id->name))

break;

}

aic3x->model= tbl - aic3x_i2c_id;

ret= snd_soc_register_codec(&i2c->dev,

&soc_codec_dev_aic3x,&aic3x_dai, 1);

if(ret < 0)

kfree(aic3x);

returnret;

}

3.5 remove

static int aic3x_i2c_remove(structi2c_client *client)

{

snd_soc_unregister_codec(&client->dev);

kfree(i2c_get_clientdata(client));

return0;

}

3.6 i2c_device_id

static const struct i2c_device_id aic3x_i2c_id[] = {

[AIC3X_MODEL_3X]= { "tlv320aic3x", 0 },

[AIC3X_MODEL_33]= { "tlv320aic33", 0 },

[AIC3X_MODEL_3007]= { "tlv320aic3007", 0 },

[AIC3X_MODEL_3104]= { "tlv320aic3104", 0 },

{}

};

3.7 模块注销

static void __exit aic3x_exit(void)

{

#if defined(CONFIG_I2C) ||defined(CONFIG_I2C_MODULE)

i2c_del_driver(&aic3x_i2c_driver);

#endif

}

module_exit(aic3x_exit);

3、与i2c相关的函数

Include/linux/i2c.h中

4.1 i2c_add_driver

static inline int i2c_add_driver(structi2c_driver *driver)

{

returni2c_register_driver(THIS_MODULE,driver);

}

Drivers/i2c/i2c-core.c中

4.2 i2c_del_driver

/**

*i2c_del_driver - unregister I2C driver

*@driver: the driver being unregistered

*Context: can sleep

*/

void i2c_del_driver(structi2c_driver *driver)

{

mutex_lock(&core_lock);

bus_for_each_dev(&i2c_bus_type,NULL, driver, __process_removed_driver);

mutex_unlock(&core_lock);

driver_unregister(&driver->driver);

pr_debug("i2c-core:driver [%s] unregistered\n", driver->driver.name);

}

Include/linux/i2c.h中

4.3 i2c_set_clientdata

static inline void i2c_set_clientdata(structi2c_client *dev, void *data)

{

dev_set_drvdata(&dev->dev,data);

}

4、【设备】

Arch/arm/mach-omap2/board-ti8148ipnc.c

5.1 static struct i2c_board_info __initdatati814x_i2c_boardinfo[] = {

#ifdef CONFIG_SND_SOC_TLV320AIC3X

{

I2C_BOARD_INFO("tlv320aic3104", 0x18),

.platform_data =&dm8148ipnc_aic3x_data,

},

#endif

{

I2C_BOARD_INFO("tps65911", 0x2D),

.platform_data = &tps65911_pdata,

},

};

static void __init ti814x_evm_i2c_init(void)

{

/*There are 4 instances of I2C in TI814X but currently only one

* instance is being used on the TI8148 EVM

*/

#ifndef CONFIG_TI8148_EVM_OPTIMIZED

omap_register_i2c_bus(1,100, ti814x_i2c_boardinfo,

ARRAY_SIZE(ti814x_i2c_boardinfo));

#else

omap_register_i2c_bus(1,100, ti814x_i2c_boardinfo,

ARRAY_SIZE(ti814x_i2c_boardinfo));

#endif

}

5.2 int __init omap_register_i2c_bus(int bus_id, u32clkrate,

struct i2c_board_info const *info,

unsigned len)

{

interr;

BUG_ON(bus_id< 1 || bus_id > omap_i2c_nr_ports());

if(info) {

err = i2c_register_board_info(bus_id,info, len);

if (err)

returnerr;

}

if(!i2c_pdata[bus_id - 1].clkrate)

i2c_pdata[bus_id - 1].clkrate = clkrate;

i2c_pdata[bus_id- 1].clkrate &= ~OMAP_I2C_CMDLINE_SETUP;

returnomap_i2c_add_bus(bus_id);

【TI i2c适配器驱动】

Arch/arm/plat-omap/i2c.c中

1、static int __init omap_i2c_add_bus(intbus_id)

{

if(cpu_class_is_omap1())

return omap1_i2c_add_bus(bus_id);

else

return omap2_i2c_add_bus(bus_id);

}

Arch/arm/plat-omap/i2c.c中

2、static inline int omap2_i2c_add_bus(intbus_id)

{

intl;

structomap_hwmod *oh;

structomap_device *od;

charoh_name[MAX_OMAP_I2C_HWMOD_NAME_LEN];

structomap_i2c_bus_platform_data *pdata;

omap2_i2c_mux_pins(bus_id);

l= snprintf(oh_name, MAX_OMAP_I2C_HWMOD_NAME_LEN, "i2c%d", bus_id);

WARN(l>= MAX_OMAP_I2C_HWMOD_NAME_LEN,

"String buffer overflow in I2C%ddevice setup\n", bus_id);

oh= omap_hwmod_lookup(oh_name);

if(!oh) {

pr_err("Couldnot look up %s\n", oh_name);

return-EEXIST;

}

pdata= &i2c_pdata[bus_id - 1];

/*

* When waiting for completion of a i2ctransfer, we need to

* set a wake up latency constraint for theMPU. This is to

* ensure quick enough wakeup from idle, whentransfer

* completes.

* Only omap3 has support for constraints

*/

if(cpu_is_omap34xx())

pdata->set_mpu_wkup_lat =omap_pm_set_max_mpu_wakeup_lat_compat;

od= omap_device_build(name, bus_id, oh, pdata,

sizeof(structomap_i2c_bus_platform_data),

omap_i2c_latency,ARRAY_SIZE(omap_i2c_latency), 0);

WARN(IS_ERR(od),"Could not build omap_device for %s\n", name);

returnPTR_ERR(od);

}

3、omap_hwmod_lookup(oh_name) 获取之前注册到omap_hwmod_list中的“i2c1”

Arch/arm/plat-omap/omap_device.c中

4、struct omap_device *omap_device_build(constchar *pdev_name, int pdev_id,

struct omap_hwmod *oh, void *pdata,

int pdata_len,

struct omap_device_pm_latency *pm_lats,

int pm_lats_cnt, int is_early_device)

{

structomap_hwmod *ohs[] = { oh };

if(!oh)

return ERR_PTR(-EINVAL);

returnomap_device_build_ss(pdev_name,pdev_id, ohs, 1, pdata,

pdata_len, pm_lats, pm_lats_cnt,

is_early_device);

}

5、struct omap_device *omap_device_build_ss(const char *pdev_name, int pdev_id,

struct omap_hwmod **ohs, int oh_cnt,

void *pdata, int pdata_len,

struct omap_device_pm_latency *pm_lats,

int pm_lats_cnt, int is_early_device)

｛。。。。。。

ret = omap_device_register(od);

。。。。。。｝

6、int omap_device_register(structomap_device *od)

{

pr_debug("omap_device:%s: registering\n", od->pdev.name);

od->pdev.dev.parent= &omap_device_parent;

returnplatform_device_register(&od->pdev);

}

7、int platform_device_register(structplatform_device *pdev)

{

device_initialize(&pdev->dev);

returnplatform_device_add(pdev);

}

8、int platform_device_add(struct platform_device *pdev)

｛。。。。。。

ret = device_add(&pdev->dev);

。。。。。。｝