[PATCH 04/15] iio: mfd: input: ti_am335x_adc:Add support for continuous mode

From: Zubair Lutfullah
Date: Thu Jul 18 2013 - 18:21:45 EST

From: "Patil, Rachna" <rachna@xxxxxx>

Current ADC driver supports only one shot mode.
Now ADC driver is enhanced to capture data continuously
from /dev/iio:deviceX interface.

ADC is now IRQ based, on interrupt ADC copies data onto
a software buffer, which is exposed to user.

Signed-off-by: Patil, Rachna <rachna@xxxxxx>
Signed-off-by: Zubair Lutfullah <zubair.lutfullah@xxxxxxxxx>
---
drivers/iio/adc/ti_am335x_adc.c | 350 +++++++++++++++++++++++++----
drivers/input/touchscreen/ti_am335x_tsc.c | 9 +-
drivers/mfd/ti_am335x_tscadc.c | 12 +-
include/linux/mfd/ti_am335x_tscadc.h | 10 +
4 files changed, 322 insertions(+), 59 deletions(-)

diff --git a/drivers/iio/adc/ti_am335x_adc.c b/drivers/iio/adc/ti_am335x_adc.c
index f73fee1..c1b051c 100644
--- a/drivers/iio/adc/ti_am335x_adc.c
+++ b/drivers/iio/adc/ti_am335x_adc.c
@@ -26,14 +26,24 @@
#include <linux/of_device.h>
#include <linux/iio/machine.h>
#include <linux/iio/driver.h>
-
#include <linux/mfd/ti_am335x_tscadc.h>
+#include <linux/stat.h>
+#include <linux/sched.h>
+#include <linux/iio/buffer.h>
+#include <linux/iio/trigger_consumer.h>
+#include <linux/iio/kfifo_buf.h>
+#include <linux/iio/sysfs.h>

struct tiadc_device {
struct ti_tscadc_dev *mfd_tscadc;
int channels;
u8 channel_line[8];
u8 channel_step[8];
+ struct work_struct poll_work;
+ wait_queue_head_t wq_data_avail;
+ int irq;
+ bool is_continuous_mode;
+ u16 *buffer;
};

static unsigned int tiadc_readl(struct tiadc_device *adc, unsigned int reg)
@@ -56,7 +66,7 @@ static u32 get_adc_step_mask(struct tiadc_device *adc_dev)
return step_en;
}

-static void tiadc_step_config(struct tiadc_device *adc_dev)
+static void tiadc_step_config(struct tiadc_device *adc_dev, bool mode)
{
unsigned int stepconfig;
int i, steps;
@@ -72,7 +82,11 @@ static void tiadc_step_config(struct tiadc_device *adc_dev)
*/

steps = TOTAL_STEPS - adc_dev->channels;
- stepconfig = STEPCONFIG_AVG_16 | STEPCONFIG_FIFO1;
+ if (mode == false)
+ stepconfig = STEPCONFIG_AVG_16 | STEPCONFIG_FIFO1;
+ else
+ stepconfig = STEPCONFIG_AVG_16 | STEPCONFIG_FIFO1
+ | STEPCONFIG_MODE_SWCNT;

for (i = 0; i < adc_dev->channels; i++) {
int chan;
@@ -88,6 +102,213 @@ static void tiadc_step_config(struct tiadc_device *adc_dev)

}

+static ssize_t tiadc_show_mode(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct iio_dev *indio_dev = dev_get_drvdata(dev);
+ struct tiadc_device *adc_dev = iio_priv(indio_dev);
+ unsigned int tmp;
+
+ tmp = tiadc_readl(adc_dev, REG_STEPCONFIG(TOTAL_STEPS));
+ tmp &= STEPCONFIG_MODE(1);
+
+ if (tmp == 0x00)
+ return sprintf(buf, "oneshot\n");
+ else if (tmp == 0x01)
+ return sprintf(buf, "continuous\n");
+ else
+ return sprintf(buf, "Operation mode unknown\n");
+}
+
+static ssize_t tiadc_set_mode(struct device *dev,
+ struct device_attribute *attr, const char *buf, size_t count)
+{
+ struct iio_dev *indio_dev = dev_get_drvdata(dev);
+ struct tiadc_device *adc_dev = iio_priv(indio_dev);
+ unsigned config;
+
+ config = tiadc_readl(adc_dev, REG_CTRL);
+ config &= ~(CNTRLREG_TSCSSENB);
+ tiadc_writel(adc_dev, REG_CTRL, config);
+
+ if (!strncmp(buf, "oneshot", 7))
+ adc_dev->is_continuous_mode = false;
+ else if (!strncmp(buf, "continuous", 10))
+ adc_dev->is_continuous_mode = true;
+ else {
+ dev_err(dev, "Operational mode unknown\n");
+ return -EINVAL;
+ }
+
+ tiadc_step_config(adc_dev, adc_dev->is_continuous_mode);
+
+ config = tiadc_readl(adc_dev, REG_CTRL);
+ tiadc_writel(adc_dev, REG_CTRL,
+ (config | CNTRLREG_TSCSSENB));
+ return count;
+}
+
+static IIO_DEVICE_ATTR(mode, S_IRUGO | S_IWUSR, tiadc_show_mode,
+ tiadc_set_mode, 0);
+
+static struct attribute *tiadc_attributes[] = {
+ &iio_dev_attr_mode.dev_attr.attr,
+ NULL,
+};
+
+static const struct attribute_group tiadc_attribute_group = {
+ .attrs = tiadc_attributes,
+};
+
+static irqreturn_t tiadc_irq(int irq, void *private)
+{
+ struct iio_dev *idev = private;
+ struct tiadc_device *adc_dev = iio_priv(idev);
+ unsigned int status, config;
+
+ status = tiadc_readl(adc_dev, REG_IRQSTATUS);
+ if (status & IRQENB_FIFO1THRES) {
+ tiadc_writel(adc_dev, REG_IRQCLR,
+ IRQENB_FIFO1THRES);
+
+ if (iio_buffer_enabled(idev)) {
+ if (!work_pending(&adc_dev->poll_work))
+ schedule_work(&adc_dev->poll_work);
+ } else {
+ wake_up_interruptible(&adc_dev->wq_data_avail);
+ }
+ tiadc_writel(adc_dev, REG_IRQSTATUS,
+ (status | IRQENB_FIFO1THRES));
+ return IRQ_HANDLED;
+ } else if ((status & IRQENB_FIFO1OVRRUN) ||
+ (status & IRQENB_FIFO1UNDRFLW)) {
+ config = tiadc_readl(adc_dev, REG_CTRL);
+ config &= ~(CNTRLREG_TSCSSENB);
+ tiadc_writel(adc_dev, REG_CTRL, config);
+
+ if (status & IRQENB_FIFO1UNDRFLW)
+ tiadc_writel(adc_dev, REG_IRQSTATUS,
+ (status | IRQENB_FIFO1UNDRFLW));
+ else
+ tiadc_writel(adc_dev, REG_IRQSTATUS,
+ (status | IRQENB_FIFO1OVRRUN));
+
+ tiadc_writel(adc_dev, REG_CTRL,
+ (config | CNTRLREG_TSCSSENB));
+ return IRQ_HANDLED;
+ } else {
+ return IRQ_NONE;
+ }
+}
+
+static void tiadc_poll_handler(struct work_struct *work_s)
+{
+ struct tiadc_device *adc_dev =
+ container_of(work_s, struct tiadc_device, poll_work);
+ struct iio_dev *idev = iio_priv_to_dev(adc_dev);
+ struct iio_buffer *buffer = idev->buffer;
+ unsigned int fifo1count, readx1, status;
+ int i;
+ u32 *inputbuffer;
+
+ fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
+ inputbuffer = kmalloc((fifo1count + 1) * sizeof(u32), GFP_KERNEL);
+ if (inputbuffer == NULL)
+ return;
+
+ for (i = 0; i < fifo1count; i++) {
+ readx1 = tiadc_readl(adc_dev, REG_FIFO1);
+ readx1 &= FIFOREAD_DATA_MASK;
+ inputbuffer[i] = readx1;
+ }
+
+ buffer->access->store_to(buffer, (u8 *) inputbuffer);
+ status = tiadc_readl(adc_dev, REG_IRQENABLE);
+ tiadc_writel(adc_dev, REG_IRQENABLE,
+ (status | IRQENB_FIFO1THRES));
+
+ kfree(inputbuffer);
+}
+
+static int tiadc_buffer_preenable(struct iio_dev *idev)
+{
+ struct iio_buffer *buffer = idev->buffer;
+
+ buffer->access->set_bytes_per_datum(buffer, 16);
+ return 0;
+}
+
+static int tiadc_buffer_postenable(struct iio_dev *idev)
+{
+ struct tiadc_device *adc_dev = iio_priv(idev);
+ struct iio_buffer *buffer = idev->buffer;
+ unsigned int enb, status, fifo1count;
+ int stepnum, i;
+ u8 bit;
+
+ if (!adc_dev->is_continuous_mode) {
+ pr_info("Data cannot be read continuously in one shot mode\n");
+ return -EINVAL;
+ } else {
+ status = tiadc_readl(adc_dev, REG_IRQENABLE);
+ tiadc_writel(adc_dev, REG_IRQENABLE,
+ (status | IRQENB_FIFO1THRES)|
+ IRQENB_FIFO1OVRRUN |
+ IRQENB_FIFO1UNDRFLW);
+
+ fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
+ for (i = 0; i < fifo1count; i++)
+ tiadc_readl(adc_dev, REG_FIFO1);
+
+ tiadc_writel(adc_dev, REG_SE, 0x00);
+ for_each_set_bit(bit, buffer->scan_mask,
+ adc_dev->channels) {
+ struct iio_chan_spec const *chan = idev->channels + bit;
+ /*
+ * There are a total of 16 steps available
+ * that are shared between ADC and touchscreen.
+ * We start configuring from step 16 to 0 incase of
+ * ADC. Hence the relation between input channel
+ * and step for ADC would be as below.
+ */
+ stepnum = chan->channel + 9;
+ enb = tiadc_readl(adc_dev, REG_SE);
+ enb |= (1 << stepnum);
+ tiadc_writel(adc_dev, REG_SE, enb);
+ }
+ return 0;
+ }
+}
+
+static int tiadc_buffer_postdisable(struct iio_dev *idev)
+{
+ struct tiadc_device *adc_dev = iio_priv(idev);
+
+ tiadc_writel(adc_dev, REG_IRQCLR, (IRQENB_FIFO1THRES |
+ IRQENB_FIFO1OVRRUN |
+ IRQENB_FIFO1UNDRFLW));
+ tiadc_writel(adc_dev, REG_SE, STPENB_STEPENB_TC);
+ return 0;
+}
+
+static const struct iio_buffer_setup_ops tiadc_buffer_setup_ops = {
+ .preenable = &tiadc_buffer_preenable,
+ .postenable = &tiadc_buffer_postenable,
+ .postdisable = &tiadc_buffer_postdisable,
+};
+
+static int tiadc_config_buffer(struct iio_dev *idev)
+{
+ struct tiadc_device *adc_dev = iio_priv(idev);
+ idev->buffer = iio_kfifo_allocate(idev);
+ if (!idev->buffer)
+ return -ENOMEM;
+ idev->setup_ops = &tiadc_buffer_setup_ops;
+ INIT_WORK(&adc_dev->poll_work, &tiadc_poll_handler);
+ idev->modes |= INDIO_BUFFER_HARDWARE;
+ return 0;
+}
+
static const char * const chan_name_ain[] = {
"AIN0",
"AIN1",
@@ -120,6 +341,7 @@ static int tiadc_channel_init(struct iio_dev *indio_dev, int channels)
chan->channel = adc_dev->channel_line[i];
chan->info_mask_separate = BIT(IIO_CHAN_INFO_RAW);
chan->datasheet_name = chan_name_ain[chan->channel];
+ chan->scan_index = i;
chan->scan_type.sign = 'u';
chan->scan_type.realbits = 12;
chan->scan_type.storagebits = 32;
@@ -147,56 +369,62 @@ static int tiadc_read_raw(struct iio_dev *indio_dev,
u32 step_en;
unsigned long timeout = jiffies + usecs_to_jiffies
(IDLE_TIMEOUT * adc_dev->channels);
- step_en = get_adc_step_mask(adc_dev);
- am335x_tsc_se_set(adc_dev->mfd_tscadc, step_en);

- /* Wait for ADC sequencer to complete sampling */
- while (tiadc_readl(adc_dev, REG_ADCFSM) & SEQ_STATUS) {
- if (time_after(jiffies, timeout))
- return -EAGAIN;
- }
- map_val = chan->channel + TOTAL_CHANNELS;
-
- /*
- * When the sub-system is first enabled,
- * the sequencer will always start with the
- * lowest step (1) and continue until step (16).
- * For ex: If we have enabled 4 ADC channels and
- * currently use only 1 out of them, the
- * sequencer still configures all the 4 steps,
- * leading to 3 unwanted data.
- * Hence we need to flush out this data.
- */
-
- for (i = 0; i < ARRAY_SIZE(adc_dev->channel_step); i++) {
- if (chan->channel == adc_dev->channel_line[i]) {
- step = adc_dev->channel_step[i];
- break;
- }
- }
- if (WARN_ON_ONCE(step == UINT_MAX))
+ if (adc_dev->is_continuous_mode) {
+ pr_info("One shot mode not enabled\n");
return -EINVAL;
-
- fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
- for (i = 0; i < fifo1count; i++) {
- read = tiadc_readl(adc_dev, REG_FIFO1);
- stepid = read & FIFOREAD_CHNLID_MASK;
- stepid = stepid >> 0x10;
-
- if (stepid == map_val) {
- read = read & FIFOREAD_DATA_MASK;
- found = true;
- *val = read;
+ } else {
+ step_en = get_adc_step_mask(adc_dev);
+ am335x_tsc_se_set(adc_dev->mfd_tscadc, step_en);
+
+ /* Wait for ADC sequencer to complete sampling */
+ while (tiadc_readl(adc_dev, REG_ADCFSM) & SEQ_STATUS) {
+ if (time_after(jiffies, timeout))
+ return -EAGAIN;
+ }
+ map_val = chan->channel + TOTAL_CHANNELS;
+
+ /*
+ * When the sub-system is first enabled,
+ * the sequencer will always start with the
+ * lowest step (1) and continue until step (16).
+ * For ex: If we have enabled 4 ADC channels and
+ * currently use only 1 out of them, the
+ * sequencer still configures all the 4 steps,
+ * leading to 3 unwanted data.
+ * Hence we need to flush out this data.
+ */
+
+ for (i = 0; i < ARRAY_SIZE(adc_dev->channel_step); i++) {
+ if (chan->channel == adc_dev->channel_line[i]) {
+ step = adc_dev->channel_step[i];
+ break;
+ }
}
+ if (WARN_ON_ONCE(step == UINT_MAX))
+ return -EINVAL;
+
+ fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
+ for (i = 0; i < fifo1count; i++) {
+ read = tiadc_readl(adc_dev, REG_FIFO1);
+ stepid = read & FIFOREAD_CHNLID_MASK;
+ stepid = stepid >> 0x10;
+
+ if (stepid == map_val) {
+ read = read & FIFOREAD_DATA_MASK;
+ found = true;
+ *val = read;
+ }
+ }
+ if (found == false)
+ return -EBUSY;
+ return IIO_VAL_INT;
}
-
- if (found == false)
- return -EBUSY;
- return IIO_VAL_INT;
}

static const struct iio_info tiadc_info = {
.read_raw = &tiadc_read_raw,
+ .attrs = &tiadc_attribute_group,
};

static int tiadc_probe(struct platform_device *pdev)
@@ -230,18 +458,38 @@ static int tiadc_probe(struct platform_device *pdev)
channels++;
}
adc_dev->channels = channels;
+ adc_dev->irq = adc_dev->mfd_tscadc->irq;

indio_dev->dev.parent = &pdev->dev;
indio_dev->name = dev_name(&pdev->dev);
indio_dev->modes = INDIO_DIRECT_MODE;
indio_dev->info = &tiadc_info;

- tiadc_step_config(adc_dev);
+ /* by default driver comes up with oneshot mode */
+ tiadc_step_config(adc_dev, adc_dev->is_continuous_mode);
+ /* program FIFO threshold to value minus 1 */
+ tiadc_writel(adc_dev, REG_FIFO1THR, FIFO1_THRESHOLD);

err = tiadc_channel_init(indio_dev, adc_dev->channels);
if (err < 0)
goto err_free_device;

+ init_waitqueue_head(&adc_dev->wq_data_avail);
+
+ err = request_irq(adc_dev->irq, tiadc_irq, IRQF_SHARED,
+ indio_dev->name, indio_dev);
+ if (err)
+ goto err_free_irq;
+
+ err = tiadc_config_buffer(indio_dev);
+ if (err < 0)
+ goto err_unregister;
+
+ err = iio_buffer_register(indio_dev,
+ indio_dev->channels, indio_dev->num_channels);
+ if (err < 0)
+ goto err_unregister;
+
err = iio_device_register(indio_dev);
if (err)
goto err_free_channels;
@@ -250,6 +498,10 @@ static int tiadc_probe(struct platform_device *pdev)

return 0;

+err_unregister:
+ iio_buffer_unregister(indio_dev);
+err_free_irq:
+ free_irq(adc_dev->irq, indio_dev);
err_free_channels:
tiadc_channels_remove(indio_dev);
err_free_device:
@@ -264,7 +516,9 @@ static int tiadc_remove(struct platform_device *pdev)
struct tiadc_device *adc_dev = iio_priv(indio_dev);
u32 step_en;

+ free_irq(adc_dev->irq, indio_dev);
iio_device_unregister(indio_dev);
+ iio_buffer_unregister(indio_dev);
tiadc_channels_remove(indio_dev);

step_en = get_adc_step_mask(adc_dev);
@@ -300,13 +554,13 @@ static int tiadc_resume(struct device *dev)
struct tiadc_device *adc_dev = iio_priv(indio_dev);
unsigned int restore;

+ tiadc_writel(adc_dev, REG_FIFO1THR, FIFO1_THRESHOLD);
+ tiadc_step_config(adc_dev, adc_dev->is_continuous_mode);
/* Make sure ADC is powered up */
restore = tiadc_readl(adc_dev, REG_CTRL);
restore &= ~(CNTRLREG_POWERDOWN);
tiadc_writel(adc_dev, REG_CTRL, restore);

- tiadc_step_config(adc_dev);
-
return 0;
}

diff --git a/drivers/input/touchscreen/ti_am335x_tsc.c b/drivers/input/touchscreen/ti_am335x_tsc.c
index edc3d03..ba7abfe 100644
--- a/drivers/input/touchscreen/ti_am335x_tsc.c
+++ b/drivers/input/touchscreen/ti_am335x_tsc.c
@@ -263,11 +263,14 @@ static irqreturn_t titsc_irq(int irq, void *dev)

/*
* ADC and touchscreen share the IRQ line.
- * FIFO1 threshold interrupt is used by ADC,
+ * FIFO1 threshold, FIFO1 Overrun and FIFO1 underflow
+ * interrupts are used by ADC,
* hence return from touchscreen IRQ handler if FIFO1
- * threshold interrupt occurred.
+ * related interrupts occurred.
*/
- if (status & IRQENB_FIFO1THRES)
+ if ((status & IRQENB_FIFO1THRES) ||
+ (status & IRQENB_FIFO1OVRRUN) ||
+ (status & IRQENB_FIFO1UNDRFLW))
return IRQ_NONE;
else if (status & IRQENB_FIFO0THRES) {
titsc_read_coordinates(ts_dev, &x, &y, &z1, &z2);
diff --git a/drivers/mfd/ti_am335x_tscadc.c b/drivers/mfd/ti_am335x_tscadc.c
index d72001c..9f5c326 100644
--- a/drivers/mfd/ti_am335x_tscadc.c
+++ b/drivers/mfd/ti_am335x_tscadc.c
@@ -282,6 +282,8 @@ static int tscadc_suspend(struct device *dev)
struct ti_tscadc_dev *tscadc_dev = dev_get_drvdata(dev);

tscadc_writel(tscadc_dev, REG_SE, 0x00);
+ tscadc_dev->irqstat = tscadc_readl(tscadc_dev, REG_IRQENABLE);
+ tscadc_dev->ctrl = tscadc_readl(tscadc_dev, REG_CTRL);
pm_runtime_put_sync(dev);

return 0;
@@ -290,22 +292,16 @@ static int tscadc_suspend(struct device *dev)
static int tscadc_resume(struct device *dev)
{
struct ti_tscadc_dev *tscadc_dev = dev_get_drvdata(dev);
- unsigned int restore, ctrl;

pm_runtime_get_sync(dev);

/* context restore */
- ctrl = CNTRLREG_STEPCONFIGWRT | CNTRLREG_STEPID;
- if (tscadc_dev->tsc_cell != -1)
- ctrl |= CNTRLREG_TSCENB | CNTRLREG_4WIRE;
- tscadc_writel(tscadc_dev, REG_CTRL, ctrl);
+ tscadc_writel(tscadc_dev, REG_IRQENABLE, tscadc_dev->irqstat);

if (tscadc_dev->tsc_cell != -1)
tscadc_idle_config(tscadc_dev);
am335x_tsc_se_update(tscadc_dev);
- restore = tscadc_readl(tscadc_dev, REG_CTRL);
- tscadc_writel(tscadc_dev, REG_CTRL,
- (restore | CNTRLREG_TSCSSENB));
+ tscadc_writel(tscadc_dev, REG_CTRL, tscadc_dev->ctrl);

return 0;
}
diff --git a/include/linux/mfd/ti_am335x_tscadc.h b/include/linux/mfd/ti_am335x_tscadc.h
index db1791b..3058aef 100644
--- a/include/linux/mfd/ti_am335x_tscadc.h
+++ b/include/linux/mfd/ti_am335x_tscadc.h
@@ -46,17 +46,23 @@
/* Step Enable */
#define STEPENB_MASK (0x1FFFF << 0)
#define STEPENB(val) ((val) << 0)
+#define ENB(val) (1 << (val))
+#define STPENB_STEPENB STEPENB(0x1FFFF)
+#define STPENB_STEPENB_TC STEPENB(0x1FFF)

/* IRQ enable */
#define IRQENB_HW_PEN BIT(0)
#define IRQENB_FIFO0THRES BIT(2)
#define IRQENB_FIFO1THRES BIT(5)
#define IRQENB_PENUP BIT(9)
+#define IRQENB_FIFO1OVRRUN BIT(6)
+#define IRQENB_FIFO1UNDRFLW BIT(7)

/* Step Configuration */
#define STEPCONFIG_MODE_MASK (3 << 0)
#define STEPCONFIG_MODE(val) ((val) << 0)
#define STEPCONFIG_MODE_HWSYNC STEPCONFIG_MODE(2)
+#define STEPCONFIG_MODE_SWCNT STEPCONFIG_MODE(1)
#define STEPCONFIG_AVG_MASK (7 << 2)
#define STEPCONFIG_AVG(val) ((val) << 2)
#define STEPCONFIG_AVG_16 STEPCONFIG_AVG(4)
@@ -124,6 +130,7 @@
#define MAX_CLK_DIV 7
#define TOTAL_STEPS 16
#define TOTAL_CHANNELS 8
+#define FIFO1_THRESHOLD 19

/*
* ADC runs at 3MHz, and it takes
@@ -153,6 +160,9 @@ struct ti_tscadc_dev {

/* adc device */
struct adc_device *adc;
+ /* Context save */
+ unsigned int irqstat;
+ unsigned int ctrl;
};

static inline struct ti_tscadc_dev *ti_tscadc_dev_get(struct platform_device *p)
--
1.7.9.5

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