linux-kernel - [PATCH v3 03/12] mfd: pm8008: Deassert reset on probe

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Date: Sat,  8 Jun 2024 17:55:17 +0200
From: Johan Hovold <johan+linaro@...nel.org>
To: Lee Jones <lee@...nel.org>,
	Mark Brown <broonie@...nel.org>,
	Bjorn Andersson <andersson@...nel.org>
Cc: Rob Herring <robh@...nel.org>,
	Krzysztof Kozlowski <krzk+dt@...nel.org>,
	Conor Dooley <conor+dt@...nel.org>,
	Konrad Dybcio <konrad.dybcio@...aro.org>,
	Liam Girdwood <lgirdwood@...il.com>,
	Das Srinagesh <quic_gurus@...cinc.com>,
	Satya Priya Kakitapalli <quic_skakitap@...cinc.com>,
	Linus Walleij <linus.walleij@...aro.org>,
	Stephen Boyd <swboyd@...omium.org>,
	Bryan O'Donoghue <bryan.odonoghue@...aro.org>,
	Andy Shevchenko <andy.shevchenko@...il.com>,
	linux-arm-msm@...r.kernel.org,
	devicetree@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Johan Hovold <johan+linaro@...nel.org>
Subject: [PATCH v3 03/12] mfd: pm8008: Deassert reset on probe

Request and deassert any (optional) reset gpio during probe in case it
has been left asserted by the boot firmware.

Note the reset line is not asserted to avoid reverting to the default
I2C address in case the firmware has configured an alternate address.

Tested-by: Bryan O'Donoghue <bryan.odonoghue@...aro.org>
Reviewed-by: Linus Walleij <linus.walleij@...aro.org>
Signed-off-by: Johan Hovold <johan+linaro@...nel.org>
---
 drivers/mfd/qcom-pm8008.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/drivers/mfd/qcom-pm8008.c b/drivers/mfd/qcom-pm8008.c
index f71c490f25c8..5a77155a63d7 100644
--- a/drivers/mfd/qcom-pm8008.c
+++ b/drivers/mfd/qcom-pm8008.c
@@ -4,6 +4,7 @@
  */
 
 #include <linux/bitops.h>
+#include <linux/gpio/consumer.h>
 #include <linux/i2c.h>
 #include <linux/interrupt.h>
 #include <linux/irq.h>
@@ -156,6 +157,7 @@ static struct regmap_config qcom_mfd_regmap_cfg = {
 static int pm8008_probe(struct i2c_client *client)
 {
 	struct regmap_irq_chip_data *irq_data;
+	struct gpio_desc *reset;
 	int rc;
 	struct device *dev;
 	struct regmap *regmap;
@@ -167,6 +169,16 @@ static int pm8008_probe(struct i2c_client *client)
 
 	i2c_set_clientdata(client, regmap);
 
+	reset = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_LOW);
+	if (IS_ERR(reset))
+		return PTR_ERR(reset);
+
+	/*
+	 * The PMIC does not appear to require a post-reset delay, but wait
+	 * for a millisecond for now anyway.
+	 */
+	usleep_range(1000, 2000);
+
 	if (of_property_read_bool(dev->of_node, "interrupt-controller")) {
 		rc = devm_regmap_add_irq_chip(dev, regmap, client->irq,
 				IRQF_SHARED, 0, &pm8008_irq_chip, &irq_data);
-- 
2.44.1