The CYTTSP TMA340 chips have two supplies: VCPIN and
VDD for analog and digital voltage respectively.
Add some minimal code to obtain and enable these
regulators if need be.

Reviewed-by: Javier Martinez Canillas <javier@dowhile0.org>
Signed-off-by: Linus Walleij <redacted>
---
ChangeLog v3->v5:
- Rebase on v5.13-rc1
ChangeLog v1->v3:
- Collect Javier's reviewed-by.
---
 drivers/input/touchscreen/cyttsp_core.c | 30 +++++++++++++++++++++++--
 drivers/input/touchscreen/cyttsp_core.h |  2 ++
 2 files changed, 30 insertions(+), 2 deletions(-)

diff --git a/drivers/input/touchscreen/cyttsp_core.c b/drivers/input/touchscreen/cyttsp_core.c
index 106dd4962785..5af4d034b36b 100644
--- a/drivers/input/touchscreen/cyttsp_core.c
+++ b/drivers/input/touchscreen/cyttsp_core.c

@@ -22,6 +22,7 @@
 #include <linux/slab.h>
 #include <linux/property.h>
 #include <linux/gpio/consumer.h>
+#include <linux/regulator/consumer.h>
 
 #include "cyttsp_core.h"
 

@@ -628,6 +629,19 @@ struct cyttsp *cyttsp_probe(const struct cyttsp_bus_ops *bus_ops,
 	ts->bus_ops = bus_ops;
 	ts->irq = irq;
 
+	/*
+	 * VCPIN is the analog voltage supply
+	 * VDD is the digital voltage supply
+	 */
+	ts->regulators[0].supply = "vcpin";
+	ts->regulators[1].supply = "vdd";
+	error = devm_regulator_bulk_get(dev, ARRAY_SIZE(ts->regulators),
+					ts->regulators);
+	if (error) {
+		dev_err(dev, "Failed to get regulators: %d\n", error);
+		return ERR_PTR(error);
+	}
+
 	ts->reset_gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_LOW);
 	if (IS_ERR(ts->reset_gpio)) {
 		error = PTR_ERR(ts->reset_gpio);

@@ -673,20 +687,32 @@ struct cyttsp *cyttsp_probe(const struct cyttsp_bus_ops *bus_ops,
 		return ERR_PTR(error);
 	}
 
+	error = regulator_bulk_enable(ARRAY_SIZE(ts->regulators),
+				      ts->regulators);
+	if (error) {
+		dev_err(dev, "Cannot enable regulators: %d\n", error);
+		return ERR_PTR(error);
+	}