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authorSebastian Andrzej Siewior <bigeasy@linutronix.de>2013-05-29 19:39:02 +0400
committerSebastian Andrzej Siewior <bigeasy@linutronix.de>2013-06-12 20:50:23 +0400
commit18926edebcb82ca325abf843293801d4ff43436a (patch)
tree17b4966968b04bc4e61a8ca87ed21642e472f583 /drivers/iio
parent9a28b8834c55f7315fb1a7c487f836472fd37bf9 (diff)
downloadlinux-18926edebcb82ca325abf843293801d4ff43436a.tar.xz
iio: ti_am335x_adc: Allow to specify input line
The TSC part allows to specify the input lines. The IIO part assumes that it usues always the last few, that means if IIO has adc-channels set to 2 it will use channel 6 and 7. However it might make sense to use only 6. This patch changes the device property (which was introduced recently and was never in an official release) in a way that the user can specify which of the AIN lines should be used. In Addition to this, the name is now AINx where x is the channel number i.e. for AIN6 we would have 6. Prior this, it always started counting at 0 which is confusing. In addition to this, it also checks for correct step number during reading and does not rely on proper FIFO depth. Acked-by: Jonathan Cameron <jic23@kernel.org> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Diffstat (limited to 'drivers/iio')
-rw-r--r--drivers/iio/adc/ti_am335x_adc.c57
1 files changed, 37 insertions, 20 deletions
diff --git a/drivers/iio/adc/ti_am335x_adc.c b/drivers/iio/adc/ti_am335x_adc.c
index 307a7c07be47..8ffe52d58829 100644
--- a/drivers/iio/adc/ti_am335x_adc.c
+++ b/drivers/iio/adc/ti_am335x_adc.c
@@ -32,6 +32,8 @@
struct tiadc_device {
struct ti_tscadc_dev *mfd_tscadc;
int channels;
+ u8 channel_line[8];
+ u8 channel_step[8];
};
static unsigned int tiadc_readl(struct tiadc_device *adc, unsigned int reg)
@@ -57,7 +59,7 @@ static u32 get_adc_step_mask(struct tiadc_device *adc_dev)
static void tiadc_step_config(struct tiadc_device *adc_dev)
{
unsigned int stepconfig;
- int i, channels = 0, steps;
+ int i, steps;
u32 step_en;
/*
@@ -71,16 +73,18 @@ static void tiadc_step_config(struct tiadc_device *adc_dev)
*/
steps = TOTAL_STEPS - adc_dev->channels;
- channels = TOTAL_CHANNELS - adc_dev->channels;
-
stepconfig = STEPCONFIG_AVG_16 | STEPCONFIG_FIFO1;
- for (i = steps; i < TOTAL_STEPS; i++) {
- tiadc_writel(adc_dev, REG_STEPCONFIG(i),
- stepconfig | STEPCONFIG_INP(channels));
- tiadc_writel(adc_dev, REG_STEPDELAY(i),
+ for (i = 0; i < adc_dev->channels; i++) {
+ int chan;
+
+ chan = adc_dev->channel_line[i];
+ tiadc_writel(adc_dev, REG_STEPCONFIG(steps),
+ stepconfig | STEPCONFIG_INP(chan));
+ tiadc_writel(adc_dev, REG_STEPDELAY(steps),
STEPCONFIG_OPENDLY);
- channels++;
+ 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);
@@ -115,9 +119,9 @@ static int tiadc_channel_init(struct iio_dev *indio_dev, int channels)
chan->type = IIO_VOLTAGE;
chan->indexed = 1;
- chan->channel = i;
+ chan->channel = adc_dev->channel_line[i];
chan->info_mask_separate = BIT(IIO_CHAN_INFO_RAW);
- chan->datasheet_name = chan_name_ain[i];
+ chan->datasheet_name = chan_name_ain[chan->channel];
chan->scan_type.sign = 'u';
chan->scan_type.realbits = 12;
chan->scan_type.storagebits = 32;
@@ -139,7 +143,8 @@ static int tiadc_read_raw(struct iio_dev *indio_dev,
{
struct tiadc_device *adc_dev = iio_priv(indio_dev);
int i;
- unsigned int fifo1count, readx1;
+ unsigned int fifo1count, read;
+ u32 step = UINT_MAX;
/*
* When the sub-system is first enabled,
@@ -152,11 +157,20 @@ static int tiadc_read_raw(struct iio_dev *indio_dev,
* 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++) {
- readx1 = tiadc_readl(adc_dev, REG_FIFO1);
- if (i == chan->channel)
- *val = readx1 & 0xfff;
+ read = tiadc_readl(adc_dev, REG_FIFO1);
+ if (read >> 16 == step)
+ *val = read & 0xfff;
}
am335x_tsc_se_update(adc_dev->mfd_tscadc);
@@ -172,8 +186,11 @@ static int tiadc_probe(struct platform_device *pdev)
struct iio_dev *indio_dev;
struct tiadc_device *adc_dev;
struct device_node *node = pdev->dev.of_node;
+ struct property *prop;
+ const __be32 *cur;
int err;
- u32 val32;
+ u32 val;
+ int channels = 0;
if (!node) {
dev_err(&pdev->dev, "Could not find valid DT data.\n");
@@ -190,11 +207,11 @@ static int tiadc_probe(struct platform_device *pdev)
adc_dev->mfd_tscadc = ti_tscadc_dev_get(pdev);
- err = of_property_read_u32(node,
- "ti,adc-channels", &val32);
- if (err < 0)
- goto err_free_device;
- adc_dev->channels = val32;
+ of_property_for_each_u32(node, "ti,adc-channels", prop, cur, val) {
+ adc_dev->channel_line[channels] = val;
+ channels++;
+ }
+ adc_dev->channels = channels;
indio_dev->dev.parent = &pdev->dev;
indio_dev->name = dev_name(&pdev->dev);