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iio: adc: rockchip_saradc: Add support iio buffers
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Add the ability to also support access via (triggered) buffers
next to the existing direct mode.

Device in question is the Odroid Go Advance that connects a joystick
to two of the saradc channels for X and Y axis and the new (and still
pending) adc joystick driver of course wants to use triggered buffers
from the iio subsystem.

Signed-off-by: Simon Xue <xxm@rock-chips.com>
[some simplifications and added commit description]
Signed-off-by: Heiko Stuebner <heiko.stuebner@theobroma-systems.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
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Simon Xue authored and Jonathan Cameron committed Jun 27, 2020
1 parent 71eb7c8 commit 4e130dc
Showing 1 changed file with 110 additions and 35 deletions.
145 changes: 110 additions & 35 deletions drivers/iio/adc/rockchip_saradc.c
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Original file line number Diff line number Diff line change
Expand Up @@ -15,7 +15,10 @@
#include <linux/delay.h>
#include <linux/reset.h>
#include <linux/regulator/consumer.h>
#include <linux/iio/buffer.h>
#include <linux/iio/iio.h>
#include <linux/iio/trigger_consumer.h>
#include <linux/iio/triggered_buffer.h>

#define SARADC_DATA 0x00

Expand All @@ -32,9 +35,9 @@
#define SARADC_DLY_PU_SOC_MASK 0x3f

#define SARADC_TIMEOUT msecs_to_jiffies(100)
#define SARADC_MAX_CHANNELS 6

struct rockchip_saradc_data {
int num_bits;
const struct iio_chan_spec *channels;
int num_channels;
unsigned long clk_rate;
Expand All @@ -49,8 +52,37 @@ struct rockchip_saradc {
struct reset_control *reset;
const struct rockchip_saradc_data *data;
u16 last_val;
const struct iio_chan_spec *last_chan;
};

static void rockchip_saradc_power_down(struct rockchip_saradc *info)
{
/* Clear irq & power down adc */
writel_relaxed(0, info->regs + SARADC_CTRL);
}

static int rockchip_saradc_conversion(struct rockchip_saradc *info,
struct iio_chan_spec const *chan)
{
reinit_completion(&info->completion);

/* 8 clock periods as delay between power up and start cmd */
writel_relaxed(8, info->regs + SARADC_DLY_PU_SOC);

info->last_chan = chan;

/* Select the channel to be used and trigger conversion */
writel(SARADC_CTRL_POWER_CTRL
| (chan->channel & SARADC_CTRL_CHN_MASK)
| SARADC_CTRL_IRQ_ENABLE,
info->regs + SARADC_CTRL);

if (!wait_for_completion_timeout(&info->completion, SARADC_TIMEOUT))
return -ETIMEDOUT;

return 0;
}

static int rockchip_saradc_read_raw(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int *val, int *val2, long mask)
Expand All @@ -62,22 +94,11 @@ static int rockchip_saradc_read_raw(struct iio_dev *indio_dev,
case IIO_CHAN_INFO_RAW:
mutex_lock(&indio_dev->mlock);

reinit_completion(&info->completion);

/* 8 clock periods as delay between power up and start cmd */
writel_relaxed(8, info->regs + SARADC_DLY_PU_SOC);

/* Select the channel to be used and trigger conversion */
writel(SARADC_CTRL_POWER_CTRL
| (chan->channel & SARADC_CTRL_CHN_MASK)
| SARADC_CTRL_IRQ_ENABLE,
info->regs + SARADC_CTRL);

if (!wait_for_completion_timeout(&info->completion,
SARADC_TIMEOUT)) {
writel_relaxed(0, info->regs + SARADC_CTRL);
ret = rockchip_saradc_conversion(info, chan);
if (ret) {
rockchip_saradc_power_down(info);
mutex_unlock(&indio_dev->mlock);
return -ETIMEDOUT;
return ret;
}

*val = info->last_val;
Expand All @@ -91,7 +112,7 @@ static int rockchip_saradc_read_raw(struct iio_dev *indio_dev,
}

*val = ret / 1000;
*val2 = info->data->num_bits;
*val2 = chan->scan_type.realbits;
return IIO_VAL_FRACTIONAL_LOG2;
default:
return -EINVAL;
Expand All @@ -104,10 +125,9 @@ static irqreturn_t rockchip_saradc_isr(int irq, void *dev_id)

/* Read value */
info->last_val = readl_relaxed(info->regs + SARADC_DATA);
info->last_val &= GENMASK(info->data->num_bits - 1, 0);
info->last_val &= GENMASK(info->last_chan->scan_type.realbits - 1, 0);

/* Clear irq & power down adc */
writel_relaxed(0, info->regs + SARADC_CTRL);
rockchip_saradc_power_down(info);

complete(&info->completion);

Expand All @@ -118,51 +138,55 @@ static const struct iio_info rockchip_saradc_iio_info = {
.read_raw = rockchip_saradc_read_raw,
};

#define SARADC_CHANNEL(_index, _id) { \
#define SARADC_CHANNEL(_index, _id, _res) { \
.type = IIO_VOLTAGE, \
.indexed = 1, \
.channel = _index, \
.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
.datasheet_name = _id, \
.scan_index = _index, \
.scan_type = { \
.sign = 'u', \
.realbits = _res, \
.storagebits = 16, \
.endianness = IIO_CPU, \
}, \
}

static const struct iio_chan_spec rockchip_saradc_iio_channels[] = {
SARADC_CHANNEL(0, "adc0"),
SARADC_CHANNEL(1, "adc1"),
SARADC_CHANNEL(2, "adc2"),
SARADC_CHANNEL(0, "adc0", 10),
SARADC_CHANNEL(1, "adc1", 10),
SARADC_CHANNEL(2, "adc2", 10),
};

static const struct rockchip_saradc_data saradc_data = {
.num_bits = 10,
.channels = rockchip_saradc_iio_channels,
.num_channels = ARRAY_SIZE(rockchip_saradc_iio_channels),
.clk_rate = 1000000,
};

static const struct iio_chan_spec rockchip_rk3066_tsadc_iio_channels[] = {
SARADC_CHANNEL(0, "adc0"),
SARADC_CHANNEL(1, "adc1"),
SARADC_CHANNEL(0, "adc0", 12),
SARADC_CHANNEL(1, "adc1", 12),
};

static const struct rockchip_saradc_data rk3066_tsadc_data = {
.num_bits = 12,
.channels = rockchip_rk3066_tsadc_iio_channels,
.num_channels = ARRAY_SIZE(rockchip_rk3066_tsadc_iio_channels),
.clk_rate = 50000,
};

static const struct iio_chan_spec rockchip_rk3399_saradc_iio_channels[] = {
SARADC_CHANNEL(0, "adc0"),
SARADC_CHANNEL(1, "adc1"),
SARADC_CHANNEL(2, "adc2"),
SARADC_CHANNEL(3, "adc3"),
SARADC_CHANNEL(4, "adc4"),
SARADC_CHANNEL(5, "adc5"),
SARADC_CHANNEL(0, "adc0", 10),
SARADC_CHANNEL(1, "adc1", 10),
SARADC_CHANNEL(2, "adc2", 10),
SARADC_CHANNEL(3, "adc3", 10),
SARADC_CHANNEL(4, "adc4", 10),
SARADC_CHANNEL(5, "adc5", 10),
};

static const struct rockchip_saradc_data rk3399_saradc_data = {
.num_bits = 10,
.channels = rockchip_rk3399_saradc_iio_channels,
.num_channels = ARRAY_SIZE(rockchip_rk3399_saradc_iio_channels),
.clk_rate = 1000000,
Expand Down Expand Up @@ -214,6 +238,46 @@ static void rockchip_saradc_regulator_disable(void *data)
regulator_disable(info->vref);
}

static irqreturn_t rockchip_saradc_trigger_handler(int irq, void *p)
{
struct iio_poll_func *pf = p;
struct iio_dev *i_dev = pf->indio_dev;
struct rockchip_saradc *info = iio_priv(i_dev);
/*
* @values: each channel takes an u16 value
* @timestamp: will be 8-byte aligned automatically
*/
struct {
u16 values[SARADC_MAX_CHANNELS];
int64_t timestamp;
} data;
int ret;
int i, j = 0;

mutex_lock(&i_dev->mlock);

for_each_set_bit(i, i_dev->active_scan_mask, i_dev->masklength) {
const struct iio_chan_spec *chan = &i_dev->channels[i];

ret = rockchip_saradc_conversion(info, chan);
if (ret) {
rockchip_saradc_power_down(info);
goto out;
}

data.values[j] = info->last_val;
j++;
}

iio_push_to_buffers_with_timestamp(i_dev, &data, iio_get_time_ns(i_dev));
out:
mutex_unlock(&i_dev->mlock);

iio_trigger_notify_done(i_dev->trig);

return IRQ_HANDLED;
}

static int rockchip_saradc_probe(struct platform_device *pdev)
{
struct rockchip_saradc *info = NULL;
Expand Down Expand Up @@ -242,6 +306,12 @@ static int rockchip_saradc_probe(struct platform_device *pdev)

info->data = match->data;

/* Sanity check for possible later IP variants with more channels */
if (info->data->num_channels > SARADC_MAX_CHANNELS) {
dev_err(&pdev->dev, "max channels exceeded");
return -EINVAL;
}

mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
info->regs = devm_ioremap_resource(&pdev->dev, mem);
if (IS_ERR(info->regs))
Expand Down Expand Up @@ -354,6 +424,11 @@ static int rockchip_saradc_probe(struct platform_device *pdev)

indio_dev->channels = info->data->channels;
indio_dev->num_channels = info->data->num_channels;
ret = devm_iio_triggered_buffer_setup(&indio_dev->dev, indio_dev, NULL,
rockchip_saradc_trigger_handler,
NULL);
if (ret)
return ret;

return devm_iio_device_register(&pdev->dev, indio_dev);
}
Expand Down

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