[PATCH v10 09/18] counter: stm32-lptimer: add counter device

From: William Breathitt Gray
Date: Tue Apr 02 2019 - 02:31:46 EST

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From: Fabrice Gasnier <fabrice.gasnier@xxxxxx>

Add support for new counter device to stm32-lptimer.

Signed-off-by: Fabrice Gasnier <fabrice.gasnier@xxxxxx>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
Signed-off-by: William Breathitt Gray <vilhelm.gray@xxxxxxxxx>
---
drivers/counter/Kconfig | 10 +
drivers/counter/Makefile | 1 +
drivers/{iio => }/counter/stm32-lptimer-cnt.c | 361 ++++++++++++++++--
drivers/iio/Kconfig | 1 -
drivers/iio/Makefile | 1 -
drivers/iio/counter/Kconfig | 17 -
drivers/iio/counter/Makefile | 7 -
7 files changed, 350 insertions(+), 48 deletions(-)
rename drivers/{iio => }/counter/stm32-lptimer-cnt.c (51%)
delete mode 100644 drivers/iio/counter/Kconfig
delete mode 100644 drivers/iio/counter/Makefile

diff --git a/drivers/counter/Kconfig b/drivers/counter/Kconfig
index 0bb2340d6087..87c491a19c63 100644
--- a/drivers/counter/Kconfig
+++ b/drivers/counter/Kconfig
@@ -38,4 +38,14 @@ config STM32_TIMER_CNT
To compile this driver as a module, choose M here: the
module will be called stm32-timer-cnt.

+config STM32_LPTIMER_CNT
+ tristate "STM32 LP Timer encoder counter driver"
+ depends on (MFD_STM32_LPTIMER || COMPILE_TEST) && IIO
+ help
+ Select this option to enable STM32 Low-Power Timer quadrature encoder
+ and counter driver.
+
+ To compile this driver as a module, choose M here: the
+ module will be called stm32-lptimer-cnt.
+
endif # COUNTER
diff --git a/drivers/counter/Makefile b/drivers/counter/Makefile
index 6b4a5be21b00..5589976d37f8 100644
--- a/drivers/counter/Makefile
+++ b/drivers/counter/Makefile
@@ -6,3 +6,4 @@ obj-$(CONFIG_COUNTER) += counter.o

obj-$(CONFIG_104_QUAD_8) += 104-quad-8.o
obj-$(CONFIG_STM32_TIMER_CNT) += stm32-timer-cnt.o
+obj-$(CONFIG_STM32_LPTIMER_CNT) += stm32-lptimer-cnt.o
diff --git a/drivers/iio/counter/stm32-lptimer-cnt.c b/drivers/counter/stm32-lptimer-cnt.c
similarity index 51%
rename from drivers/iio/counter/stm32-lptimer-cnt.c
rename to drivers/counter/stm32-lptimer-cnt.c
index 2a49cce0edb4..bbc930a5962c 100644
--- a/drivers/iio/counter/stm32-lptimer-cnt.c
+++ b/drivers/counter/stm32-lptimer-cnt.c
@@ -11,6 +11,7 @@
*/

#include <linux/bitfield.h>
+#include <linux/counter.h>
#include <linux/iio/iio.h>
#include <linux/mfd/stm32-lptimer.h>
#include <linux/module.h>
@@ -18,10 +19,11 @@
#include <linux/platform_device.h>

struct stm32_lptim_cnt {
+ struct counter_device counter;
struct device *dev;
struct regmap *regmap;
struct clk *clk;
- u32 preset;
+ u32 ceiling;
u32 polarity;
u32 quadrature_mode;
bool enabled;
@@ -57,7 +59,7 @@ static int stm32_lptim_set_enable_state(struct stm32_lptim_cnt *priv,
}

/* LP timer must be enabled before writing CMP & ARR */
- ret = regmap_write(priv->regmap, STM32_LPTIM_ARR, priv->preset);
+ ret = regmap_write(priv->regmap, STM32_LPTIM_ARR, priv->ceiling);
if (ret)
return ret;

@@ -251,44 +253,57 @@ static const struct iio_enum stm32_lptim_cnt_polarity_en = {
.set = stm32_lptim_cnt_set_polarity,
};

-static ssize_t stm32_lptim_cnt_get_preset(struct iio_dev *indio_dev,
- uintptr_t private,
- const struct iio_chan_spec *chan,
- char *buf)
+static ssize_t stm32_lptim_cnt_get_ceiling(struct stm32_lptim_cnt *priv,
+ char *buf)
{
- struct stm32_lptim_cnt *priv = iio_priv(indio_dev);
-
- return snprintf(buf, PAGE_SIZE, "%u\n", priv->preset);
+ return snprintf(buf, PAGE_SIZE, "%u\n", priv->ceiling);
}

-static ssize_t stm32_lptim_cnt_set_preset(struct iio_dev *indio_dev,
- uintptr_t private,
- const struct iio_chan_spec *chan,
- const char *buf, size_t len)
+static ssize_t stm32_lptim_cnt_set_ceiling(struct stm32_lptim_cnt *priv,
+ const char *buf, size_t len)
{
- struct stm32_lptim_cnt *priv = iio_priv(indio_dev);
int ret;

if (stm32_lptim_is_enabled(priv))
return -EBUSY;

- ret = kstrtouint(buf, 0, &priv->preset);
+ ret = kstrtouint(buf, 0, &priv->ceiling);
if (ret)
return ret;

- if (priv->preset > STM32_LPTIM_MAX_ARR)
+ if (priv->ceiling > STM32_LPTIM_MAX_ARR)
return -EINVAL;

return len;
}

+static ssize_t stm32_lptim_cnt_get_preset_iio(struct iio_dev *indio_dev,
+ uintptr_t private,
+ const struct iio_chan_spec *chan,
+ char *buf)
+{
+ struct stm32_lptim_cnt *priv = iio_priv(indio_dev);
+
+ return stm32_lptim_cnt_get_ceiling(priv, buf);
+}
+
+static ssize_t stm32_lptim_cnt_set_preset_iio(struct iio_dev *indio_dev,
+ uintptr_t private,
+ const struct iio_chan_spec *chan,
+ const char *buf, size_t len)
+{
+ struct stm32_lptim_cnt *priv = iio_priv(indio_dev);
+
+ return stm32_lptim_cnt_set_ceiling(priv, buf, len);
+}
+
/* LP timer with encoder */
static const struct iio_chan_spec_ext_info stm32_lptim_enc_ext_info[] = {
{
.name = "preset",
.shared = IIO_SEPARATE,
- .read = stm32_lptim_cnt_get_preset,
- .write = stm32_lptim_cnt_set_preset,
+ .read = stm32_lptim_cnt_get_preset_iio,
+ .write = stm32_lptim_cnt_set_preset_iio,
},
IIO_ENUM("polarity", IIO_SEPARATE, &stm32_lptim_cnt_polarity_en),
IIO_ENUM_AVAILABLE("polarity", &stm32_lptim_cnt_polarity_en),
@@ -313,8 +328,8 @@ static const struct iio_chan_spec_ext_info stm32_lptim_cnt_ext_info[] = {
{
.name = "preset",
.shared = IIO_SEPARATE,
- .read = stm32_lptim_cnt_get_preset,
- .write = stm32_lptim_cnt_set_preset,
+ .read = stm32_lptim_cnt_get_preset_iio,
+ .write = stm32_lptim_cnt_set_preset_iio,
},
IIO_ENUM("polarity", IIO_SEPARATE, &stm32_lptim_cnt_polarity_en),
IIO_ENUM_AVAILABLE("polarity", &stm32_lptim_cnt_polarity_en),
@@ -331,11 +346,293 @@ static const struct iio_chan_spec stm32_lptim_cnt_channels = {
.indexed = 1,
};

+/**
+ * stm32_lptim_cnt_function - enumerates stm32 LPTimer counter & encoder modes
+ * @STM32_LPTIM_COUNTER_INCREASE: up count on IN1 rising, falling or both edges
+ * @STM32_LPTIM_ENCODER_BOTH_EDGE: count on both edges (IN1 & IN2 quadrature)
+ */
+enum stm32_lptim_cnt_function {
+ STM32_LPTIM_COUNTER_INCREASE,
+ STM32_LPTIM_ENCODER_BOTH_EDGE,
+};
+
+static enum counter_count_function stm32_lptim_cnt_functions[] = {
+ [STM32_LPTIM_COUNTER_INCREASE] = COUNTER_COUNT_FUNCTION_INCREASE,
+ [STM32_LPTIM_ENCODER_BOTH_EDGE] = COUNTER_COUNT_FUNCTION_QUADRATURE_X4,
+};
+
+enum stm32_lptim_synapse_action {
+ STM32_LPTIM_SYNAPSE_ACTION_RISING_EDGE,
+ STM32_LPTIM_SYNAPSE_ACTION_FALLING_EDGE,
+ STM32_LPTIM_SYNAPSE_ACTION_BOTH_EDGES,
+ STM32_LPTIM_SYNAPSE_ACTION_NONE,
+};
+
+static enum counter_synapse_action stm32_lptim_cnt_synapse_actions[] = {
+ /* Index must match with stm32_lptim_cnt_polarity[] (priv->polarity) */
+ [STM32_LPTIM_SYNAPSE_ACTION_RISING_EDGE] = COUNTER_SYNAPSE_ACTION_RISING_EDGE,
+ [STM32_LPTIM_SYNAPSE_ACTION_FALLING_EDGE] = COUNTER_SYNAPSE_ACTION_FALLING_EDGE,
+ [STM32_LPTIM_SYNAPSE_ACTION_BOTH_EDGES] = COUNTER_SYNAPSE_ACTION_BOTH_EDGES,
+ [STM32_LPTIM_SYNAPSE_ACTION_NONE] = COUNTER_SYNAPSE_ACTION_NONE,
+};
+
+static int stm32_lptim_cnt_read(struct counter_device *counter,
+ struct counter_count *count,
+ struct counter_count_read_value *val)
+{
+ struct stm32_lptim_cnt *const priv = counter->priv;
+ u32 cnt;
+ int ret;
+
+ ret = regmap_read(priv->regmap, STM32_LPTIM_CNT, &cnt);
+ if (ret)
+ return ret;
+
+ counter_count_read_value_set(val, COUNTER_COUNT_POSITION, &cnt);
+
+ return 0;
+}
+
+static int stm32_lptim_cnt_function_get(struct counter_device *counter,
+ struct counter_count *count,
+ size_t *function)
+{
+ struct stm32_lptim_cnt *const priv = counter->priv;
+
+ if (!priv->quadrature_mode) {
+ *function = STM32_LPTIM_COUNTER_INCREASE;
+ return 0;
+ }
+
+ if (priv->polarity == STM32_LPTIM_SYNAPSE_ACTION_BOTH_EDGES) {
+ *function = STM32_LPTIM_ENCODER_BOTH_EDGE;
+ return 0;
+ }
+
+ return -EINVAL;
+}
+
+static int stm32_lptim_cnt_function_set(struct counter_device *counter,
+ struct counter_count *count,
+ size_t function)
+{
+ struct stm32_lptim_cnt *const priv = counter->priv;
+
+ if (stm32_lptim_is_enabled(priv))
+ return -EBUSY;
+
+ switch (function) {
+ case STM32_LPTIM_COUNTER_INCREASE:
+ priv->quadrature_mode = 0;
+ return 0;
+ case STM32_LPTIM_ENCODER_BOTH_EDGE:
+ priv->quadrature_mode = 1;
+ priv->polarity = STM32_LPTIM_SYNAPSE_ACTION_BOTH_EDGES;
+ return 0;
+ }
+
+ return -EINVAL;
+}
+
+static ssize_t stm32_lptim_cnt_enable_read(struct counter_device *counter,
+ struct counter_count *count,
+ void *private, char *buf)
+{
+ struct stm32_lptim_cnt *const priv = counter->priv;
+ int ret;
+
+ ret = stm32_lptim_is_enabled(priv);
+ if (ret < 0)
+ return ret;
+
+ return scnprintf(buf, PAGE_SIZE, "%u\n", ret);
+}
+
+static ssize_t stm32_lptim_cnt_enable_write(struct counter_device *counter,
+ struct counter_count *count,
+ void *private,
+ const char *buf, size_t len)
+{
+ struct stm32_lptim_cnt *const priv = counter->priv;
+ bool enable;
+ int ret;
+
+ ret = kstrtobool(buf, &enable);
+ if (ret)
+ return ret;
+
+ /* Check nobody uses the timer, or already disabled/enabled */
+ ret = stm32_lptim_is_enabled(priv);
+ if ((ret < 0) || (!ret && !enable))
+ return ret;
+ if (enable && ret)
+ return -EBUSY;
+
+ ret = stm32_lptim_setup(priv, enable);
+ if (ret)
+ return ret;
+
+ ret = stm32_lptim_set_enable_state(priv, enable);
+ if (ret)
+ return ret;
+
+ return len;
+}
+
+static ssize_t stm32_lptim_cnt_ceiling_read(struct counter_device *counter,
+ struct counter_count *count,
+ void *private, char *buf)
+{
+ struct stm32_lptim_cnt *const priv = counter->priv;
+
+ return stm32_lptim_cnt_get_ceiling(priv, buf);
+}
+
+static ssize_t stm32_lptim_cnt_ceiling_write(struct counter_device *counter,
+ struct counter_count *count,
+ void *private,
+ const char *buf, size_t len)
+{
+ struct stm32_lptim_cnt *const priv = counter->priv;
+
+ return stm32_lptim_cnt_set_ceiling(priv, buf, len);
+}
+
+static const struct counter_count_ext stm32_lptim_cnt_ext[] = {
+ {
+ .name = "enable",
+ .read = stm32_lptim_cnt_enable_read,
+ .write = stm32_lptim_cnt_enable_write
+ },
+ {
+ .name = "ceiling",
+ .read = stm32_lptim_cnt_ceiling_read,
+ .write = stm32_lptim_cnt_ceiling_write
+ },
+};
+
+static int stm32_lptim_cnt_action_get(struct counter_device *counter,
+ struct counter_count *count,
+ struct counter_synapse *synapse,
+ size_t *action)
+{
+ struct stm32_lptim_cnt *const priv = counter->priv;
+ size_t function;
+ int err;
+
+ err = stm32_lptim_cnt_function_get(counter, count, &function);
+ if (err)
+ return err;
+
+ switch (function) {
+ case STM32_LPTIM_COUNTER_INCREASE:
+ /* LP Timer acts as up-counter on input 1 */
+ if (synapse->signal->id == count->synapses[0].signal->id)
+ *action = priv->polarity;
+ else
+ *action = STM32_LPTIM_SYNAPSE_ACTION_NONE;
+ return 0;
+ case STM32_LPTIM_ENCODER_BOTH_EDGE:
+ *action = priv->polarity;
+ return 0;
+ }
+
+ return -EINVAL;
+}
+
+static int stm32_lptim_cnt_action_set(struct counter_device *counter,
+ struct counter_count *count,
+ struct counter_synapse *synapse,
+ size_t action)
+{
+ struct stm32_lptim_cnt *const priv = counter->priv;
+ size_t function;
+ int err;
+
+ if (stm32_lptim_is_enabled(priv))
+ return -EBUSY;
+
+ err = stm32_lptim_cnt_function_get(counter, count, &function);
+ if (err)
+ return err;
+
+ /* only set polarity when in counter mode (on input 1) */
+ if (function == STM32_LPTIM_COUNTER_INCREASE
+ && synapse->signal->id == count->synapses[0].signal->id) {
+ switch (action) {
+ case STM32_LPTIM_SYNAPSE_ACTION_RISING_EDGE:
+ case STM32_LPTIM_SYNAPSE_ACTION_FALLING_EDGE:
+ case STM32_LPTIM_SYNAPSE_ACTION_BOTH_EDGES:
+ priv->polarity = action;
+ return 0;
+ }
+ }
+
+ return -EINVAL;
+}
+
+static const struct counter_ops stm32_lptim_cnt_ops = {
+ .count_read = stm32_lptim_cnt_read,
+ .function_get = stm32_lptim_cnt_function_get,
+ .function_set = stm32_lptim_cnt_function_set,
+ .action_get = stm32_lptim_cnt_action_get,
+ .action_set = stm32_lptim_cnt_action_set,
+};
+
+static struct counter_signal stm32_lptim_cnt_signals[] = {
+ {
+ .id = 0,
+ .name = "Channel 1 Quadrature A"
+ },
+ {
+ .id = 1,
+ .name = "Channel 1 Quadrature B"
+ }
+};
+
+static struct counter_synapse stm32_lptim_cnt_synapses[] = {
+ {
+ .actions_list = stm32_lptim_cnt_synapse_actions,
+ .num_actions = ARRAY_SIZE(stm32_lptim_cnt_synapse_actions),
+ .signal = &stm32_lptim_cnt_signals[0]
+ },
+ {
+ .actions_list = stm32_lptim_cnt_synapse_actions,
+ .num_actions = ARRAY_SIZE(stm32_lptim_cnt_synapse_actions),
+ .signal = &stm32_lptim_cnt_signals[1]
+ }
+};
+
+/* LP timer with encoder */
+static struct counter_count stm32_lptim_enc_counts = {
+ .id = 0,
+ .name = "LPTimer Count",
+ .functions_list = stm32_lptim_cnt_functions,
+ .num_functions = ARRAY_SIZE(stm32_lptim_cnt_functions),
+ .synapses = stm32_lptim_cnt_synapses,
+ .num_synapses = ARRAY_SIZE(stm32_lptim_cnt_synapses),
+ .ext = stm32_lptim_cnt_ext,
+ .num_ext = ARRAY_SIZE(stm32_lptim_cnt_ext)
+};
+
+/* LP timer without encoder (counter only) */
+static struct counter_count stm32_lptim_in1_counts = {
+ .id = 0,
+ .name = "LPTimer Count",
+ .functions_list = stm32_lptim_cnt_functions,
+ .num_functions = 1,
+ .synapses = stm32_lptim_cnt_synapses,
+ .num_synapses = 1,
+ .ext = stm32_lptim_cnt_ext,
+ .num_ext = ARRAY_SIZE(stm32_lptim_cnt_ext)
+};
+
static int stm32_lptim_cnt_probe(struct platform_device *pdev)
{
struct stm32_lptimer *ddata = dev_get_drvdata(pdev->dev.parent);
struct stm32_lptim_cnt *priv;
struct iio_dev *indio_dev;
+ int ret;

if (IS_ERR_OR_NULL(ddata))
return -EINVAL;
@@ -348,8 +645,9 @@ static int stm32_lptim_cnt_probe(struct platform_device *pdev)
priv->dev = &pdev->dev;
priv->regmap = ddata->regmap;
priv->clk = ddata->clk;
- priv->preset = STM32_LPTIM_MAX_ARR;
+ priv->ceiling = STM32_LPTIM_MAX_ARR;

+ /* Initialize IIO device */
indio_dev->name = dev_name(&pdev->dev);
indio_dev->dev.parent = &pdev->dev;
indio_dev->dev.of_node = pdev->dev.of_node;
@@ -360,9 +658,28 @@ static int stm32_lptim_cnt_probe(struct platform_device *pdev)
indio_dev->channels = &stm32_lptim_cnt_channels;
indio_dev->num_channels = 1;

+ /* Initialize Counter device */
+ priv->counter.name = dev_name(&pdev->dev);
+ priv->counter.parent = &pdev->dev;
+ priv->counter.ops = &stm32_lptim_cnt_ops;
+ if (ddata->has_encoder) {
+ priv->counter.counts = &stm32_lptim_enc_counts;
+ priv->counter.num_signals = ARRAY_SIZE(stm32_lptim_cnt_signals);
+ } else {
+ priv->counter.counts = &stm32_lptim_in1_counts;
+ priv->counter.num_signals = 1;
+ }
+ priv->counter.num_counts = 1;
+ priv->counter.signals = stm32_lptim_cnt_signals;
+ priv->counter.priv = priv;
+
platform_set_drvdata(pdev, priv);

- return devm_iio_device_register(&pdev->dev, indio_dev);
+ ret = devm_iio_device_register(&pdev->dev, indio_dev);
+ if (ret)
+ return ret;
+
+ return devm_counter_register(&pdev->dev, &priv->counter);
}

#ifdef CONFIG_PM_SLEEP
diff --git a/drivers/iio/Kconfig b/drivers/iio/Kconfig
index 014006d1cbb6..4243e35c25e9 100644
--- a/drivers/iio/Kconfig
+++ b/drivers/iio/Kconfig
@@ -74,7 +74,6 @@ source "drivers/iio/afe/Kconfig"
source "drivers/iio/amplifiers/Kconfig"
source "drivers/iio/chemical/Kconfig"
source "drivers/iio/common/Kconfig"
-source "drivers/iio/counter/Kconfig"
source "drivers/iio/dac/Kconfig"
source "drivers/iio/dummy/Kconfig"
source "drivers/iio/frequency/Kconfig"
diff --git a/drivers/iio/Makefile b/drivers/iio/Makefile
index cb5993251381..bff682ad1cfb 100644
--- a/drivers/iio/Makefile
+++ b/drivers/iio/Makefile
@@ -20,7 +20,6 @@ obj-y += amplifiers/
obj-y += buffer/
obj-y += chemical/
obj-y += common/
-obj-y += counter/
obj-y += dac/
obj-y += dummy/
obj-y += gyro/
diff --git a/drivers/iio/counter/Kconfig b/drivers/iio/counter/Kconfig
deleted file mode 100644
index eeb358122cbe..000000000000
--- a/drivers/iio/counter/Kconfig
+++ /dev/null
@@ -1,17 +0,0 @@
-#
-# Counter devices
-#
-# When adding new entries keep the list in alphabetical order
-
-menu "Counters"
-
-config STM32_LPTIMER_CNT
- tristate "STM32 LP Timer encoder counter driver"
- depends on MFD_STM32_LPTIMER || COMPILE_TEST
- help
- Select this option to enable STM32 Low-Power Timer quadrature encoder
- and counter driver.
-
- To compile this driver as a module, choose M here: the
- module will be called stm32-lptimer-cnt.
-endmenu
diff --git a/drivers/iio/counter/Makefile b/drivers/iio/counter/Makefile
deleted file mode 100644
index 93933ba49280..000000000000
--- a/drivers/iio/counter/Makefile
+++ /dev/null
@@ -1,7 +0,0 @@
-#
-# Makefile for IIO counter devices
-#
-
-# When adding new entries keep the list in alphabetical order
-
-obj-$(CONFIG_STM32_LPTIMER_CNT) += stm32-lptimer-cnt.o
--
2.21.0

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