[PATCH 2/2] counter: microchip-tcb-capture: Add support for RC Compare

[William Breathitt Gray <wbg@kernel.org>]

In Capture mode, the RC register serves as a compare register for the
Timer Counter Channel. When a the Counter Value reaches the RC value, a
RC Compare event occurs (COUNTER_EVENT_THRESHOLD). This patch exposes
the RC register to userspace as the 'compare' Count extension, thus
allowing users to configure the threshold condition for these events.

Signed-off-by: William Breathitt Gray <wbg@kernel.org>
---
 drivers/counter/microchip-tcb-capture.c | 33 +++++++++++++++++++++++++++++++++
 1 file changed, 33 insertions(+)

diff --git a/drivers/counter/microchip-tcb-capture.c b/drivers/counter/microchip-tcb-capture.c
index 2f096a5b973d18edf5de5a2b33f2f72571deefb7..e32f8d324cb373909e0a093b14d742fa0a93e07e 100644
--- a/drivers/counter/microchip-tcb-capture.c
+++ b/drivers/counter/microchip-tcb-capture.c
@@ -247,6 +247,37 @@ static int mchp_tc_count_read(struct counter_device *counter,
 	return 0;
 }
 
+static int mchp_tc_count_compare_read(struct counter_device *counter, struct counter_count *count,
+				      u64 *val)
+{
+	struct mchp_tc_data *const priv = counter_priv(counter);
+	u32 cnt;
+	int ret;
+
+	ret = regmap_read(priv->regmap, ATMEL_TC_REG(priv->channel[0], RC), &cnt);
+	if (ret < 0)
+		return ret;
+
+	*val = cnt;
+
+	return 0;
+}
+
+static int mchp_tc_count_compare_write(struct counter_device *counter, struct counter_count *count,
+				       u64 val)
+{
+	struct mchp_tc_data *const priv = counter_priv(counter);
+
+	if (val > U32_MAX)
+		return -ERANGE;
+
+	return regmap_write(priv->regmap, ATMEL_TC_REG(priv->channel[0], RC), val);
+}
+
+static struct counter_comp mchp_tc_count_ext[] = {
+	COUNTER_COMP_COMPARE(mchp_tc_count_compare_read, mchp_tc_count_compare_write),
+};
+
 static struct counter_count mchp_tc_counts[] = {
 	{
 		.id = 0,
@@ -255,6 +286,8 @@ static struct counter_count mchp_tc_counts[] = {
 		.num_functions = ARRAY_SIZE(mchp_tc_count_functions),
 		.synapses = mchp_tc_count_synapses,
 		.num_synapses = ARRAY_SIZE(mchp_tc_count_synapses),
+		.ext = mchp_tc_count_ext,
+		.num_ext = ARRAY_SIZE(mchp_tc_count_ext),
 	},
 };
 

-- 
2.48.1