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From:   Benjamin Bara <bbara93@gmail.com>
Date:   Thu, 27 Jul 2023 17:26:41 +0200
Subject: [PATCH 6/6] regulator: pca9450: register restart handlers
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Message-Id: <20230727-pca9450-reboot-v1-6-c8edb27bf404@skidata.com>
References: <20230727-pca9450-reboot-v1-0-c8edb27bf404@skidata.com>
In-Reply-To: <20230727-pca9450-reboot-v1-0-c8edb27bf404@skidata.com>
To:     Lee Jones <lee@kernel.org>,
        Thierry Reding <thierry.reding@gmail.com>,
        Jonathan Hunter <jonathanh@nvidia.com>,
        Tony Lindgren <tony@atomide.com>,
        Liam Girdwood <lgirdwood@gmail.com>,
        Mark Brown <broonie@kernel.org>,
        Dmitry Osipenko <dmitry.osipenko@collabora.com>,
        Robin Gong <yibin.gong@nxp.com>,
        Jerome Neanne <jneanne@baylibre.com>
Cc:     linux-kernel@vger.kernel.org, linux-tegra@vger.kernel.org,
        linux-omap@vger.kernel.org,
        Benjamin Bara <benjamin.bara@skidata.com>
Precedence: bulk

From: Benjamin Bara <benjamin.bara@skidata.com>

The PCA9450 supports both, a warm and a cold reset. Implement both and
register the respective handlers.

Signed-off-by: Benjamin Bara <benjamin.bara@skidata.com>
---
 drivers/regulator/pca9450-regulator.c | 59 +++++++++++++++++++++++++++++++++++
 include/linux/regulator/pca9450.h     |  7 +++++
 2 files changed, 66 insertions(+)

diff --git a/drivers/regulator/pca9450-regulator.c b/drivers/regulator/pca9450-regulator.c
index 2ab365d2749f..86903d677bf6 100644
--- a/drivers/regulator/pca9450-regulator.c
+++ b/drivers/regulator/pca9450-regulator.c
@@ -38,6 +38,11 @@ struct pca9450 {
 	int irq;
 };
 
+static inline struct pca9450 *dev_to_pca9450(struct device *dev)
+{
+	return dev_get_drvdata(dev);
+}
+
 static const struct regmap_range pca9450_status_range = {
 	.range_min = PCA9450_REG_INT1,
 	.range_max = PCA9450_REG_PWRON_STAT,
@@ -219,6 +224,42 @@ static int pca9450_set_dvs_levels(struct device_node *np,
 	return ret;
 }
 
+static int pca9450_cold_reset(struct pca9450 *pca9450)
+{
+	int ret;
+
+	ret = regmap_write(pca9450->regmap, PCA9450_REG_SWRST,
+			   SWRST_RESET_COLD_LDO12);
+	if (ret)
+		return ret;
+
+	/* t_RESTART is 250 ms. */
+	mdelay(500);
+	return -ETIME;
+}
+
+static int pca9450_warm_reset(struct pca9450 *pca9450)
+{
+	int ret;
+
+	ret = regmap_write(pca9450->regmap, PCA9450_REG_SWRST,
+			   SWRST_RESET_WARM);
+	if (ret)
+		return ret;
+
+	/* t_RESET is 20 ms. */
+	mdelay(50);
+	return -ETIME;
+}
+
+static int pca9450_restart_handler(struct sys_off_data *data)
+{
+	int (*handler)(struct pca9450 *) = data->cb_data;
+	struct pca9450 *pca9450 = dev_to_pca9450(data->dev);
+
+	return handler(pca9450);
+}
+
 static const struct pca9450_regulator_desc pca9450a_regulators[] = {
 	{
 		.desc = {
@@ -845,6 +886,24 @@ static int pca9450_i2c_probe(struct i2c_client *i2c)
 		return PTR_ERR(pca9450->sd_vsel_gpio);
 	}
 
+	ret = devm_register_cold_restart_handler(pca9450->dev,
+						 pca9450_restart_handler,
+						 pca9450_cold_reset);
+	if (ret) {
+		dev_err(&i2c->dev, "register cold restart handler failed: %d\n",
+			ret);
+		return ret;
+	}
+
+	ret = devm_register_warm_restart_handler(pca9450->dev,
+						 pca9450_restart_handler,
+						 pca9450_warm_reset);
+	if (ret) {
+		dev_err(&i2c->dev, "register warm restart handler failed: %d\n",
+			ret);
+		return ret;
+	}
+
 	dev_info(&i2c->dev, "%s probed.\n",
 		type == PCA9450_TYPE_PCA9450A ? "pca9450a" : "pca9450bc");
 
diff --git a/include/linux/regulator/pca9450.h b/include/linux/regulator/pca9450.h
index 505c908dbb81..a72fd4942d5f 100644
--- a/include/linux/regulator/pca9450.h
+++ b/include/linux/regulator/pca9450.h
@@ -93,6 +93,13 @@ enum {
 	PCA9450_MAX_REGISTER	    = 0x2F,
 };
 
+/* PCA9450 SW_RST bits */
+#define SWRST_NOACTION			0x00
+#define SWRST_RESET_REGS		0x05
+#define SWRST_RESET_COLD_LDO12		0x14
+#define SWRST_RESET_WARM		0x35
+#define SWRST_RESET_COLD		0x64
+
 /* PCA9450 BUCK ENMODE bits */
 #define BUCK_ENMODE_OFF			0x00
 #define BUCK_ENMODE_ONREQ		0x01

-- 
2.34.1