linux ad7606 驱动解读
本文记录阅读linux ad7606驱动的笔记。
主要文件
drivers/staging/iio/adc/ad7606_spi.c
drivers/staging/iio/adc/ad7606_core.c
drivers/staging/iio/adc/ad7606_ring.c
drivers/staging/iio/adc/ad7606_spi.c
static int __init ad7606_spi_init(void)
{
return spi_register_driver(&ad7606_driver);
}
module_init(ad7606_spi_init);
static struct spi_driver ad7606_driver = {
.driver = {
.name = "ad7606",
.bus = &spi_bus_type,
.owner = THIS_MODULE,
.pm = AD7606_SPI_PM_OPS,
},
.probe = ad7606_spi_probe,
.remove = __devexit_p(ad7606_spi_remove),
.id_table = ad7606_id,
};
static int __devinit ad7606_spi_probe(struct spi_device *spi)
{
struct iio_dev *indio_dev;
indio_dev = ad7606_probe(&spi->dev, spi->irq, NULL, ------+
spi_get_device_id(spi)->driver_data, |
&ad7606_spi_bops); ---------+ |
| |
if (IS_ERR(indio_dev)) | |
return PTR_ERR(indio_dev); | |
| |
| |
spi_set_drvdata(spi, indio_dev); | |
| |
return 0; | |
} | |
V |
static const struct ad7606_bus_ops ad7606_spi_bops = { |
.read_block = ad7606_spi_read_block, |
}; |
|
drivers/staging/iio/adc/ad7606_core.c |
struct iio_dev *ad7606_probe(struct device *dev, int irq, <---+
void __iomem *base_address,
unsigned id,
const struct ad7606_bus_ops *bops)
{
struct ad7606_platform_data *pdata = dev->platform_data;
struct ad7606_state *st;
int ret, regdone = 0;
struct iio_dev *indio_dev = iio_allocate_device(sizeof(*st));
if (indio_dev == NULL) {
ret = -ENOMEM;
goto error_ret;
}
st = iio_priv(indio_dev);
st->dev = dev;
st->id = id;
st->irq = irq;
st->bops = bops;
st->base_address = base_address;
// 默认的模拟通道输入电压范围, 10V/5V
st->range = pdata->default_range == 10000 ? 10000 : 5000;
// 过采样率
ret = ad7606_oversampling_get_index(pdata->default_os);
if (ret < 0) {
dev_warn(dev, "oversampling %d is not supported\n",
pdata->default_os);
st->oversampling = 0;
} else {
st->oversampling = pdata->default_os;
}
st->reg = regulator_get(dev, "vcc");
if (!IS_ERR(st->reg)) {
ret = regulator_enable(st->reg);
if (ret)
goto error_put_reg;
}
st->pdata = pdata;
st->chip_info = &ad7606_chip_info_tbl[id]; -----------------------------+
|
indio_dev->dev.parent = dev; |
indio_dev->info = &ad7606_info; |
indio_dev->modes = INDIO_DIRECT_MODE; |
indio_dev->name = st->chip_info->name; |
indio_dev->channels = st->chip_info->channels; |
indio_dev->num_channels = st->chip_info->num_channels; |
|
init_waitqueue_head(&st->wq_data_avail); |
|
ret = ad7606_request_gpios(st); -------------------------------+ |
if (ret) | |
goto error_disable_reg; | |
| |
| |
ret = ad7606_reset(st); | |
if (ret) | |
dev_warn(st->dev, "failed to RESET: no RESET GPIO specified\n"); | |
// ad7606中断，我使用的是busy引脚作为中断输入。 | |
ret = request_irq(st->irq, ad7606_interrupt, -------+ | |
IRQF_TRIGGER_FALLING, st->chip_info->name, indio_dev); | | |
if (ret) | | |
goto error_free_gpios; | | |
| | |
ret = ad7606_register_ring_funcs_and_init(indio_dev); | | |
if (ret) | | |
goto error_free_irq; | | |
| | |
ret = iio_device_register(indio_dev); | | |
if (ret) | | |
goto error_free_irq; | | |
regdone = 1; | | |
| | |
ret = iio_ring_buffer_register_ex(indio_dev->ring, 0, | | |
indio_dev->channels, | | |
indio_dev->num_channels); | | |
if (ret) | | |
goto error_cleanup_ring; | | |
| | |
return indio_dev; | | |
| | |
error_cleanup_ring: | | |
ad7606_ring_cleanup(indio_dev); | | |
| | |
error_free_irq: | | |
free_irq(st->irq, indio_dev); | | |
| | |
error_free_gpios: | | |
ad7606_free_gpios(st); | | |
| | |
error_disable_reg: | | |
if (!IS_ERR(st->reg)) | | |
regulator_disable(st->reg); | | |
error_put_reg: | | |
if (!IS_ERR(st->reg)) | | |
regulator_put(st->reg); | | |
if (regdone) | | |
iio_device_unregister(indio_dev); | | |
else | | |
iio_free_device(indio_dev); | | |
error_ret: | | |
return ERR_PTR(ret); | | |
} | | |
| | |
// 中断处理函数 | | |
static irqreturn_t ad7606_interrupt(int irq, void *dev_id) <---+ | |
{ | |
struct iio_dev *indio_dev = dev_id; | |
struct ad7606_state *st = iio_priv(indio_dev); | |
| |
if (iio_ring_enabled(indio_dev)) { | |
if (!work_pending(&st->poll_work)) | |
schedule_work(&st->poll_work); | |
} else { | |
st->done = true; | |
// 唤醒中断 | |
wake_up_interruptible(&st->wq_data_avail); | |
} | |
| |
return IRQ_HANDLED; | |
}; | |
static int ad7606_request_gpios(struct ad7606_state *st) <----------+ |
{ |
struct gpio gpio_array[3] = { |
[0] = { |
.gpio = st->pdata->gpio_os0, |
.flags = GPIOF_DIR_OUT | ((st->oversampling & 1) ? |
GPIOF_INIT_HIGH : GPIOF_INIT_LOW), |
.label = "AD7606_OS0", |
}, |
[1] = { |
.gpio = st->pdata->gpio_os1, |
.flags = GPIOF_DIR_OUT | ((st->oversampling & 2) ? |
GPIOF_INIT_HIGH : GPIOF_INIT_LOW), |
.label = "AD7606_OS1", |
}, |
[2] = { |
.gpio = st->pdata->gpio_os2, |
.flags = GPIOF_DIR_OUT | ((st->oversampling & 4) ? |
GPIOF_INIT_HIGH : GPIOF_INIT_LOW), |
.label = "AD7606_OS2", |
}, |
}; |
int ret; |
|
ret = gpio_request_one(st->pdata->gpio_convst, GPIOF_OUT_INIT_LOW, |
"AD7606_CONVST"); |
if (ret) { |
dev_err(st->dev, "failed to request GPIO CONVST\n"); |
return ret; |
} |
|
ret = gpio_request_array(gpio_array, ARRAY_SIZE(gpio_array)); |
if (!ret) { |
st->have_os = true; |
} |
|
ret = gpio_request_one(st->pdata->gpio_reset, GPIOF_OUT_INIT_LOW, |
"AD7606_RESET"); |
if (!ret) |
st->have_reset = true; |
|
ret = gpio_request_one(st->pdata->gpio_range, GPIOF_DIR_OUT | |
((st->range == 10000) ? GPIOF_INIT_HIGH : |
GPIOF_INIT_LOW), "AD7606_RANGE"); |
if (!ret) |
st->have_range = true; |
|
ret = gpio_request_one(st->pdata->gpio_stby, GPIOF_OUT_INIT_HIGH, |
"AD7606_STBY"); |
if (!ret) |
st->have_stby = true; |
// 是否定义了gpio_frstdata,没有定义就是-1. |
// 我调试的时候这个信号有问题，所以就设置成-1.st->have_frstdata=false |
if (gpio_is_valid(st->pdata->gpio_frstdata)) { |
ret = gpio_request_one(st->pdata->gpio_frstdata, GPIOF_IN, |
"AD7606_FRSTDATA"); |
if (!ret) |
st->have_frstdata = true; |
} |
|
return 0; |
} |
|
static const struct ad7606_chip_info ad7606_chip_info_tbl[] = { <------+
/*
* More devices added in future
*/
[ID_AD7606_8] = {
.name = "ad7606",
.int_vref_mv = 2500,
.channels = ad7606_8_channels,
.num_channels = 8,
},
[ID_AD7606_6] = {
.name = "ad7606-6",
.int_vref_mv = 2500,
.channels = ad7606_6_channels,
.num_channels = 6,
},
[ID_AD7606_4] = {
.name = "ad7606-4",
.int_vref_mv = 2500,
.channels = ad7606_4_channels,
.num_channels = 4,
},
};
static int ad7606_oversampling_get_index(unsigned val)
{
unsigned char supported[] = {0, 2, 4, 8, 16, 32, 64};
int i;
for (i = 0; i < ARRAY_SIZE(supported); i++)
if (val == supported[i])
return i;
return -EINVAL;
}
//应用层读取的时候会调用这个函数。
static int ad7606_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int *val,
int *val2,
long m)
{
int ret;
struct ad7606_state *st = iio_priv(indio_dev);
unsigned int scale_uv;
switch (m) {
case 0:
mutex_lock(&indio_dev->mlock);
if (iio_ring_enabled(indio_dev))
ret = ad7606_scan_from_ring(indio_dev, chan->address);
else
ret = ad7606_scan_direct(indio_dev, chan->address); ------+
mutex_unlock(&indio_dev->mlock); |
|
if (ret < 0) |
return ret; |
*val = (short) ret; |
return IIO_VAL_INT; |
case (1 << IIO_CHAN_INFO_SCALE_SHARED): |
scale_uv = (st->range * 1000 * 2) |
>> st->chip_info->channels[0].scan_type.realbits; |
*val = scale_uv / 1000; |
*val2 = (scale_uv % 1000) * 1000; |
return IIO_VAL_INT_PLUS_MICRO; |
} |
return -EINVAL; |
} |
|
static int ad7606_scan_direct(struct iio_dev *indio_dev, unsigned ch) <----+
{
struct ad7606_state *st = iio_priv(indio_dev);
int ret;
st->done = false;
gpio_set_value(st->pdata->gpio_convst, 1);
// 此处中断, 等待中断调用ad7606_interrupt函数唤醒中断。
ret = wait_event_interruptible(st->wq_data_avail, st->done);
if (ret)
goto error_ret;
// 判断have_frstdata是否为true
if (st->have_frstdata) {
ret = st->bops->read_block(st->dev, 1, st->data);
if (ret)
goto error_ret;
if (!gpio_get_value(st->pdata->gpio_frstdata)) {
/* This should never happen */
ad7606_reset(st);
ret = -EIO;
goto error_ret;
}
ret = st->bops->read_block(st->dev,
st->chip_info->num_channels - 1, &st->data[1]);
if (ret){
goto error_ret;
} else {
ret = st->bops->read_block(st->dev,
st->chip_info->num_channels, st->data);
if (ret)
goto error_ret;
}
ret = st->data[ch];
error_ret:
gpio_set_value(st->pdata->gpio_convst, 0);
return ret;
}
static int ad7606_spi_read_block(struct device *dev,
int count, void *buf)
{
struct spi_device *spi = to_spi_device(dev);
int i, ret;
unsigned short *data = buf;
ret = spi_read(spi, (u8 *)buf, count * 2);
if (ret < 0) {
dev_err(&spi->dev, "SPI read error\n");
return ret;
}
for (i = 0; i < count; i++) {
data[i] = be16_to_cpu(data[i]);
}
return 0;
}
include/linux/spi/spi.h
static inline int
spi_read(struct spi_device *spi, void *buf, size_t len)
{
struct spi_transfer t = {
.rx_buf = buf,
.len = len,
};
struct spi_message m;
spi_message_init(&m);
spi_message_add_tail(&t, &m);
return spi_sync(spi, &m);
}
Tony Liu
2017-1-13, Shenzhen
