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Date:   Tue, 06 Jun 2023 07:25:55 +0000
To:     linux-kernel@vger.kernel.org
From:   Raymond Hackley <raymondhackley@protonmail.com>
Cc:     Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>,
        "David S . Miller" <davem@davemloft.net>,
        Eric Dumazet <edumazet@google.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>,
        Rob Herring <robh+dt@kernel.org>,
        Liam Girdwood <lgirdwood@gmail.com>,
        Mark Brown <broonie@kernel.org>,
        Michael Walle <michael@walle.cc>,
        =?utf-8?Q?Uwe_Kleine-K=C3=B6nig?= <u.kleine-koenig@pengutronix.de>,
        Jeremy Kerr <jk@codeconstruct.com.au>,
        Raymond Hackley <raymondhackley@protonmail.com>,
        netdev@vger.kernel.org, devicetree@vger.kernel.org
Subject: [PATCH 2/2] NFC: nxp-nci: Add pad supply voltage pvdd-supply
Message-ID: <20230606072454.145106-1-raymondhackley@protonmail.com>
In-Reply-To: <20230606071824.144990-1-raymondhackley@protonmail.com>
References: <20230606071824.144990-1-raymondhackley@protonmail.com>
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PN547/553, QN310/330 chips on some devices require a pad supply voltage
(PVDD). Otherwise, the NFC won't power up.

Implement support for pad supply voltage pvdd-supply that is enabled by
the nxp-nci driver so that the regulator gets enabled when needed.

Signed-off-by: Raymond Hackley <raymondhackley@protonmail.com>
---
 drivers/nfc/nxp-nci/i2c.c | 47 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 47 insertions(+)

diff --git a/drivers/nfc/nxp-nci/i2c.c b/drivers/nfc/nxp-nci/i2c.c
index d4c299be7949..e2d16111daa4 100644
--- a/drivers/nfc/nxp-nci/i2c.c
+++ b/drivers/nfc/nxp-nci/i2c.c
@@ -35,6 +35,7 @@ struct nxp_nci_i2c_phy {
=20
 =09struct gpio_desc *gpiod_en;
 =09struct gpio_desc *gpiod_fw;
+=09struct regulator *pvdd;
=20
 =09int hard_fault; /*
 =09=09=09 * < 0 if hardware error occurred (e.g. i2c err)
@@ -263,6 +264,22 @@ static const struct acpi_gpio_mapping acpi_nxp_nci_gpi=
os[] =3D {
 =09{ }
 };
=20
+static void nxp_nci_i2c_poweroff(void *data)
+{
+=09struct nxp_nci_i2c_phy *phy =3D data;
+=09struct device *dev =3D &phy->i2c_dev->dev;
+=09struct regulator *pvdd =3D phy->pvdd;
+=09int r;
+
+=09if (!IS_ERR(pvdd) && regulator_is_enabled(pvdd)) {
+=09=09r =3D regulator_disable(pvdd);
+=09=09if (r < 0)
+=09=09=09dev_warn(dev,
+=09=09=09=09 "Failed to disable regulator pvdd: %d\n",
+=09=09=09=09 r);
+=09}
+}
+
 static int nxp_nci_i2c_probe(struct i2c_client *client)
 {
 =09struct device *dev =3D &client->dev;
@@ -298,6 +315,34 @@ static int nxp_nci_i2c_probe(struct i2c_client *client=
)
 =09=09return PTR_ERR(phy->gpiod_fw);
 =09}
=20
+=09phy->pvdd =3D devm_regulator_get_optional(dev, "pvdd");
+=09if (IS_ERR(phy->pvdd)) {
+=09=09r =3D PTR_ERR(phy->pvdd);
+=09=09if (r !=3D -ENODEV) {
+=09=09=09if (r !=3D -EPROBE_DEFER)
+=09=09=09=09dev_err(dev,
+=09=09=09=09=09"Failed to get regulator pvdd: %d\n",
+=09=09=09=09=09r);
+=09=09=09return r;
+=09=09}
+=09} else {
+=09=09r =3D regulator_enable(phy->pvdd);
+=09=09if (r < 0) {
+=09=09=09nfc_err(dev,
+=09=09=09=09"Failed to enable regulator pvdd: %d\n",
+=09=09=09=09r);
+=09=09=09return r;
+=09=09}
+=09}
+
+=09r =3D devm_add_action_or_reset(dev, nxp_nci_i2c_poweroff, phy);
+=09if (r < 0) {
+=09=09nfc_err(dev, "Failed to install poweroff handler: %d\n",
+=09=09=09r);
+=09=09nxp_nci_i2c_poweroff(phy);
+=09=09return r;
+=09}
+
 =09r =3D nxp_nci_probe(phy, &client->dev, &i2c_phy_ops,
 =09=09=09  NXP_NCI_I2C_MAX_PAYLOAD, &phy->ndev);
 =09if (r < 0)
@@ -319,6 +364,8 @@ static void nxp_nci_i2c_remove(struct i2c_client *clien=
t)
=20
 =09nxp_nci_remove(phy->ndev);
 =09free_irq(client->irq, phy);
+
+=09nxp_nci_i2c_poweroff(phy);
 }
=20
 static const struct i2c_device_id nxp_nci_i2c_id_table[] =3D {
--=20
2.30.2