From f237cf1914e24ebba88670ecc36e8209c888c9a2 Mon Sep 17 00:00:00 2001
From: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Date: Tue, 15 Nov 2022 10:55:17 +0100
Subject: [PATCH] iio: addac: ad74413r: add support for reset-gpio
We have a board where the reset pin of the ad74412 is connected to a
gpio, but also pulled low (i.e., asserted) by default. Hence to get
the chip out of reset, the driver needs to know about that gpio and
deassert the reset signal before attempting to communicate with the
chip.
When a reset-gpio is given in device tree, use that instead of the
software reset. According to the data sheet, the two methods are
functionally equivalent.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Link: https://lore.kernel.org/r/20221115095517.1008632-4-linux@rasmusvillemoes.dk
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
---
drivers/iio/addac/ad74413r.c | 12 ++++++++++++
1 file changed, 12 insertions(+)
diff --git a/drivers/iio/addac/ad74413r.c b/drivers/iio/addac/ad74413r.c
index 29b3a5775f236..61030053cbeaa 100644
--- a/drivers/iio/addac/ad74413r.c
+++ b/drivers/iio/addac/ad74413r.c
@@ -71,6 +71,7 @@ struct ad74413r_state {
struct regmap *regmap;
struct device *dev;
struct iio_trigger *trig;
+ struct gpio_desc *reset_gpio;
size_t adc_active_channels;
struct spi_message adc_samples_msg;
@@ -393,6 +394,13 @@ static int ad74413r_reset(struct ad74413r_state *st)
{
int ret;
+ if (st->reset_gpio) {
+ gpiod_set_value_cansleep(st->reset_gpio, 1);
+ fsleep(50);
+ gpiod_set_value_cansleep(st->reset_gpio, 0);
+ return 0;
+ }
+
ret = regmap_write(st->regmap, AD74413R_REG_CMD_KEY,
AD74413R_CMD_KEY_RESET1);
if (ret)
@@ -1322,6 +1330,10 @@ static int ad74413r_probe(struct spi_device *spi)
if (IS_ERR(st->regmap))
return PTR_ERR(st->regmap);
+ st->reset_gpio = devm_gpiod_get_optional(st->dev, "reset", GPIOD_OUT_LOW);
+ if (IS_ERR(st->reset_gpio))
+ return PTR_ERR(st->reset_gpio);
+
st->refin_reg = devm_regulator_get(st->dev, "refin");
if (IS_ERR(st->refin_reg))
return dev_err_probe(st->dev, PTR_ERR(st->refin_reg),
--
2.30.2