[PATCH 1/2] pmic: pca9450: enable system reset on WDOG_B assertion

[Heiko Thiery <heiko.thiery@gmail.com>]

By default the PCA9450 doesn't handle the assertion of the WDOG_B
signal, but this is required to guarantee that things like software
resets triggered by the watchdog work reliably.

This is a port of the same changes in the Linux kernel:
f7684f5a048f ("regulator: pca9450: Enable system reset on WDOG_B assertion")
2364a64d0673 ("regulator: pca9450: Make warm reset on WDOG_B assertion")

Cc: Frieder Schrempf <frieder.schrempf@kontron.de>
Signed-off-by: Heiko Thiery <heiko.thiery@gmail.com>
---
 drivers/power/pmic/Kconfig   |  4 ++++
 drivers/power/pmic/pca9450.c | 15 +++++++++++++++
 include/power/pca9450.h      |  7 +++++++
 3 files changed, 26 insertions(+)

diff --git a/drivers/power/pmic/Kconfig b/drivers/power/pmic/Kconfig
index bb3960020d..d30d6d25c4 100644
--- a/drivers/power/pmic/Kconfig
+++ b/drivers/power/pmic/Kconfig
@@ -158,6 +158,8 @@ config SPL_DM_PMIC_MP5416
 
 config DM_PMIC_PCA9450
 	bool "Enable Driver Model for PMIC PCA9450"
+	select REGMAP
+	select SYSCON
 	help
 	  This config enables implementation of driver-model pmic uclass features
 	  for PMIC PCA9450. The driver implements read/write operations.
@@ -165,6 +167,8 @@ config DM_PMIC_PCA9450
 config SPL_DM_PMIC_PCA9450
 	bool "Enable Driver Model for PMIC PCA9450"
 	depends on SPL_DM_PMIC
+	select SPL_REGMAP
+	select SPL_SYSCON
 	help
 	  This config enables implementation of driver-model pmic uclass features
 	  for PMIC PCA9450 in SPL. The driver implements read/write operations.
diff --git a/drivers/power/pmic/pca9450.c b/drivers/power/pmic/pca9450.c
index a186edc08d..fecab0496f 100644
--- a/drivers/power/pmic/pca9450.c
+++ b/drivers/power/pmic/pca9450.c
@@ -11,6 +11,8 @@
 #include <i2c.h>
 #include <linux/err.h>
 #include <log.h>
+#include <regmap.h>
+#include <syscon.h>
 #include <asm/global_data.h>
 #include <asm-generic/gpio.h>
 #include <power/pmic.h>
@@ -30,6 +32,7 @@ static const struct pmic_child_info pmic_children_info[] = {
 };
 
 struct pca9450_priv {
+	struct regmap *regmap;
 	struct gpio_desc *sd_vsel_gpio;
 };
 
@@ -86,8 +89,20 @@ static int pca9450_bind(struct udevice *dev)
 static int pca9450_probe(struct udevice *dev)
 {
 	struct pca9450_priv *priv = dev_get_priv(dev);
+	unsigned int reset_ctrl;
 	int ret = 0;
 
+	priv->regmap = syscon_node_to_regmap(dev_ofnode(dev));
+
+	if (dev_read_bool(dev, "nxp,wdog_b-warm-reset"))
+		reset_ctrl = WDOG_B_CFG_WARM;
+	else
+		reset_ctrl = WDOG_B_CFG_COLD_LDO12;
+
+	/* Set reset behavior on assertion of WDOG_B signal */
+	ret = regmap_update_bits(priv->regmap, PCA9450_RESET_CTRL,
+				 WDOG_B_CFG_MASK, reset_ctrl);
+
 	if (CONFIG_IS_ENABLED(DM_GPIO) && CONFIG_IS_ENABLED(DM_REGULATOR_PCA9450)) {
 		priv->sd_vsel_gpio = devm_gpiod_get_optional(dev, "sd-vsel",
 							     GPIOD_IS_OUT |
diff --git a/include/power/pca9450.h b/include/power/pca9450.h
index fa0405fcb8..bf9be7d6bb 100644
--- a/include/power/pca9450.h
+++ b/include/power/pca9450.h
@@ -67,4 +67,11 @@ enum {
 #define PCA9450_LDO34_MASK		0x1f
 #define PCA9450_LDO5_MASK		0x0f
 
+/* PCA9450_REG_RESET_CTRL bits */
+#define WDOG_B_CFG_MASK			0xC0
+#define WDOG_B_CFG_NONE			0x00
+#define WDOG_B_CFG_WARM			0x40
+#define WDOG_B_CFG_COLD_LDO12		0x80
+#define WDOG_B_CFG_COLD			0xC0
+
 #endif
-- 
2.30.2