Input: cyttsp - obtain regulators

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 <linus.walleij@linaro.org>
Link: https://lore.kernel.org/r/20210526230352.1433537-3-linus.walleij@linaro.orgSigned-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

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"
 
@@ -608,6 +609,14 @@ static int cyttsp_parse_properties(struct cyttsp *ts)
 	return 0;
 }
 
+static void cyttsp_disable_regulators(void *_ts)
+{
+	struct cyttsp *ts = _ts;
+
+	regulator_bulk_disable(ARRAY_SIZE(ts->regulators),
+			       ts->regulators);
+}
+
 struct cyttsp *cyttsp_probe(const struct cyttsp_bus_ops *bus_ops,
 			    struct device *dev, int irq, size_t xfer_buf_size)
 {
@@ -628,6 +637,32 @@ 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);
+	}
+
+	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);
+	}
+
+	error = devm_add_action_or_reset(dev, cyttsp_disable_regulators, ts);
+	if (error) {
+		dev_err(dev, "failed to install chip disable handler\n");
+		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);

drivers/input/touchscreen/cyttsp_core.h

@@ -23,6 +23,7 @@
 #include <linux/types.h>
 #include <linux/device.h>
 #include <linux/input/cyttsp.h>
+#include <linux/regulator/consumer.h>
 
 #define CY_NUM_RETRY		16 /* max number of retries for read ops */
 
@@ -122,6 +123,7 @@ struct cyttsp {
 	enum cyttsp_state state;
 	bool suspended;
 
+	struct regulator_bulk_data regulators[2];
 	struct gpio_desc *reset_gpio;
 	bool use_hndshk;
 	u8 act_dist;