[PATCH v3] iio: adc: rockchip_saradc: Add support iio buffers

Heiko Stuebner
2020-04-13T10:38:03Z

From: Simon Xue <xxm@rock-chips.com>

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>
---
changes in v3:
- split buffer struct into values and timestamp area similar to dln2-adc
and make sure timestamp gets 8-byte aligned - ALIGN uses 4 as it aligns
u16 elements not bytes - hopefully I got it right this time ;-)
changes in v2:
- use devm_iio_triggered_buffer_setup
- calculate data array size from channel number (curtesy of at91-sama5d2_adc)

drivers/iio/adc/Kconfig | 2 +
drivers/iio/adc/rockchip_saradc.c | 146 ++++++++++++++++++++++--------
2 files changed, 112 insertions(+), 36 deletions(-)

diff --git a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig
index 12bb8b7ca1ff..8d2dd60614c6 100644
--- a/drivers/iio/adc/Kconfig
+++ b/drivers/iio/adc/Kconfig
@@ -809,6 +809,8 @@ config ROCKCHIP_SARADC
tristate "Rockchip SARADC driver"
depends on ARCH_ROCKCHIP || (ARM && COMPILE_TEST)
depends on RESET_CONTROLLER
+ select IIO_BUFFER
+ select IIO_TRIGGERED_BUFFER
help
Say yes here to build support for the SARADC found in SoCs from
Rockchip.
diff --git a/drivers/iio/adc/rockchip_saradc.c b/drivers/iio/adc/rockchip_saradc.c
index 582ba047c4a6..0713363a4b43 100644
--- a/drivers/iio/adc/rockchip_saradc.c
+++ b/drivers/iio/adc/rockchip_saradc.c
@@ -15,7 +15,11 @@
#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.h>
+#include <linux/iio/trigger_consumer.h>
+#include <linux/iio/triggered_buffer.h>

#define SARADC_DATA 0x00

@@ -32,9 +36,12 @@
#define SARADC_DLY_PU_SOC_MASK 0x3f

#define SARADC_TIMEOUT msecs_to_jiffies(100)
+#define SARADC_MAX_CHANNELS 6
+
+/* buffer elements are u16, timestamp needs to be 8-byte aligned */
+#define SARADC_BUFFER_NUM_U16 ALIGN(SARADC_MAX_CHANNELS, 4)

struct rockchip_saradc_data {
- int num_bits;
const struct iio_chan_spec *channels;
int num_channels;
unsigned long clk_rate;
@@ -49,8 +56,37 @@ 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)
@@ -62,24 +98,12 @@ 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;
mutex_unlock(&indio_dev->mlock);
return IIO_VAL_INT;
@@ -91,7 +115,7 @@ 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;
@@ -104,10 +128,9 @@ 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);

@@ -118,51 +141,55 @@ static const struct iio_info rockchip_saradc_iio_info = {
.read_raw = rockchip_saradc_read_raw,
};

-#define ADC_CHANNEL(_index, _id) { \
+#define ADC_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_LE, \
+ }, \
}

static const struct iio_chan_spec rockchip_saradc_iio_channels[] = {
- ADC_CHANNEL(0, "adc0"),
- ADC_CHANNEL(1, "adc1"),
- ADC_CHANNEL(2, "adc2"),
+ ADC_CHANNEL(0, "adc0", 10),
+ ADC_CHANNEL(1, "adc1", 10),
+ ADC_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[] = {
- ADC_CHANNEL(0, "adc0"),
- ADC_CHANNEL(1, "adc1"),
+ ADC_CHANNEL(0, "adc0", 12),
+ ADC_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[] = {
- ADC_CHANNEL(0, "adc0"),
- ADC_CHANNEL(1, "adc1"),
- ADC_CHANNEL(2, "adc2"),
- ADC_CHANNEL(3, "adc3"),
- ADC_CHANNEL(4, "adc4"),
- ADC_CHANNEL(5, "adc5"),
+ ADC_CHANNEL(0, "adc0", 10),
+ ADC_CHANNEL(1, "adc1", 10),
+ ADC_CHANNEL(2, "adc2", 10),
+ ADC_CHANNEL(3, "adc3", 10),
+ ADC_CHANNEL(4, "adc4", 10),
+ ADC_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,
@@ -193,6 +220,42 @@ static void rockchip_saradc_reset_controller(struct reset_control *reset)
reset_control_deassert(reset);
}

+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);
+ struct {
+ u16 values[SARADC_BUFFER_NUM_U16];
+ 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;
@@ -221,6 +284,11 @@ static int rockchip_saradc_probe(struct platform_device *pdev)

info->data = match->data;

+ 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))
@@ -315,6 +383,12 @@ 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)
+ goto err_clk;
+
ret = iio_device_register(indio_dev);
if (ret)
goto err_clk;
--
2.24.1