Merge tag 'iio-fixes-for-3.11b' of git://git.kernel.org/pub/scm/linux/kernel/git...

Jonathan writes:

Second round of IIO fixes for the 3.11 cycle.

1) Fix a long term race in the IIO trigger handling.
   This only effects cases where a single trigger is in use
   by multiple devices.
2) ti_am335x fix an issue with incorrect data due to reading before
   the sequencer is finished.

diff --git a/drivers/iio/adc/ti_am335x_adc.c b/drivers/iio/adc/ti_am335x_adc.c
index 0ad208a69c298aef50bb4b0ff6744b60753e9a08..3ceac3e91dde4cd30339bc3c61feb4ad570a03c7 100644 (file)
--- a/drivers/iio/adc/ti_am335x_adc.c
+++ b/drivers/iio/adc/ti_am335x_adc.c
@@ -60,7 +60,6 @@ static void tiadc_step_config(struct tiadc_device *adc_dev)
 {
        unsigned int stepconfig;
        int i, steps;
-       u32 step_en;
 
        /*
         * There are 16 configurable steps and 8 analog input
@@ -86,8 +85,7 @@ static void tiadc_step_config(struct tiadc_device *adc_dev)
                adc_dev->channel_step[i] = steps;
                steps++;
        }
-       step_en = get_adc_step_mask(adc_dev);
-       am335x_tsc_se_set(adc_dev->mfd_tscadc, step_en);
+
 }
 
 static const char * const chan_name_ain[] = {
@@ -142,10 +140,22 @@ static int tiadc_read_raw(struct iio_dev *indio_dev,
                int *val, int *val2, long mask)
 {
        struct tiadc_device *adc_dev = iio_priv(indio_dev);
-       int i;
-       unsigned int fifo1count, read;
+       int i, map_val;
+       unsigned int fifo1count, read, stepid;
        u32 step = UINT_MAX;
        bool found = false;
+       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,
@@ -170,12 +180,16 @@ static int tiadc_read_raw(struct iio_dev *indio_dev,
        fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT);
        for (i = 0; i < fifo1count; i++) {
                read = tiadc_readl(adc_dev, REG_FIFO1);
-               if (read >> 16 == step) {
-                       *val = read & 0xfff;
+               stepid = read & FIFOREAD_CHNLID_MASK;
+               stepid = stepid >> 0x10;
+
+               if (stepid == map_val) {
+                       read = read & FIFOREAD_DATA_MASK;
                        found = true;
+                       *val = read;
                }
        }
-       am335x_tsc_se_update(adc_dev->mfd_tscadc);
+
        if (found == false)
                return -EBUSY;
        return IIO_VAL_INT;

diff --git a/drivers/iio/industrialio-trigger.c b/drivers/iio/industrialio-trigger.c
index ea8a4146620de5c6ad551644facb278654ab1c1c..0dd9bb8731301e755dc29ef2851371f70deb819d 100644 (file)
--- a/drivers/iio/industrialio-trigger.c
+++ b/drivers/iio/industrialio-trigger.c
@@ -127,12 +127,17 @@ static struct iio_trigger *iio_trigger_find_by_name(const char *name,
 void iio_trigger_poll(struct iio_trigger *trig, s64 time)
 {
        int i;
-       if (!trig->use_count)
-               for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++)
-                       if (trig->subirqs[i].enabled) {
-                               trig->use_count++;
+
+       if (!atomic_read(&trig->use_count)) {
+               atomic_set(&trig->use_count, CONFIG_IIO_CONSUMERS_PER_TRIGGER);
+
+               for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++) {
+                       if (trig->subirqs[i].enabled)
                                generic_handle_irq(trig->subirq_base + i);
-                       }
+                       else
+                               iio_trigger_notify_done(trig);
+               }
+       }
 }
 EXPORT_SYMBOL(iio_trigger_poll);
 
@@ -146,19 +151,24 @@ EXPORT_SYMBOL(iio_trigger_generic_data_rdy_poll);
 void iio_trigger_poll_chained(struct iio_trigger *trig, s64 time)
 {
        int i;
-       if (!trig->use_count)
-               for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++)
-                       if (trig->subirqs[i].enabled) {
-                               trig->use_count++;
+
+       if (!atomic_read(&trig->use_count)) {
+               atomic_set(&trig->use_count, CONFIG_IIO_CONSUMERS_PER_TRIGGER);
+
+               for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++) {
+                       if (trig->subirqs[i].enabled)
                                handle_nested_irq(trig->subirq_base + i);
-                       }
+                       else
+                               iio_trigger_notify_done(trig);
+               }
+       }
 }
 EXPORT_SYMBOL(iio_trigger_poll_chained);
 
 void iio_trigger_notify_done(struct iio_trigger *trig)
 {
-       trig->use_count--;
-       if (trig->use_count == 0 && trig->ops && trig->ops->try_reenable)
+       if (atomic_dec_and_test(&trig->use_count) && trig->ops &&
+               trig->ops->try_reenable)
                if (trig->ops->try_reenable(trig))
                        /* Missed an interrupt so launch new poll now */
                        iio_trigger_poll(trig, 0);

diff --git a/include/linux/iio/trigger.h b/include/linux/iio/trigger.h
index 3869c525b052171fff8bbe3000d61d5999bae7ee..369cf2cd51448b690cb812e6310cbd450ab83386 100644 (file)
--- a/include/linux/iio/trigger.h
+++ b/include/linux/iio/trigger.h
@@ -8,6 +8,7 @@
  */
 #include <linux/irq.h>
 #include <linux/module.h>
+#include <linux/atomic.h>
 
 #ifndef _IIO_TRIGGER_H_
 #define _IIO_TRIGGER_H_
@@ -61,7 +62,7 @@ struct iio_trigger {
 
        struct list_head                list;
        struct list_head                alloc_list;
-       int use_count;
+       atomic_t                        use_count;
 
        struct irq_chip                 subirq_chip;
        int                             subirq_base;

diff --git a/include/linux/mfd/ti_am335x_tscadc.h b/include/linux/mfd/ti_am335x_tscadc.h
index 8d73fe29796a9bc1ce8687c9e18e6963cc278c62..db1791bb997ae495d65637e506b6f13ab4945b6d 100644 (file)
--- a/include/linux/mfd/ti_am335x_tscadc.h
+++ b/include/linux/mfd/ti_am335x_tscadc.h
@@ -113,11 +113,27 @@
 #define CNTRLREG_8WIRE         CNTRLREG_AFE_CTRL(3)
 #define CNTRLREG_TSCENB                BIT(7)
 
+/* FIFO READ Register */
+#define FIFOREAD_DATA_MASK (0xfff << 0)
+#define FIFOREAD_CHNLID_MASK (0xf << 16)
+
+/* Sequencer Status */
+#define SEQ_STATUS BIT(5)
+
 #define ADC_CLK                        3000000
 #define        MAX_CLK_DIV             7
 #define TOTAL_STEPS            16
 #define TOTAL_CHANNELS         8
 
+/*
+* ADC runs at 3MHz, and it takes
+* 15 cycles to latch one data output.
+* Hence the idle time for ADC to
+* process one sample data would be
+* around 5 micro seconds.
+*/
+#define IDLE_TIMEOUT 5 /* microsec */
+
 #define TSCADC_CELLS           2
 
 struct ti_tscadc_dev {