Re: [PATCH] power: reset: Add MAX77620 support

From: Laxman Dewangan
Date: Thu Jan 12 2017 - 11:51:10 EST


On Thursday 12 January 2017 09:45 PM, Thierry Reding wrote:
From: Thierry Reding <treding@xxxxxxxxxx>

The Maxim MAX77620 PMIC has the ability to power off and restart the
system. Add a driver that supports power off (via pm_power_off()) and
restart (via arm_pm_restart() on 32-bit and 64-bit ARM).

Based on work by Chaitanya Bandi <bandik@xxxxxxxxxx>.

Cc: Chaitanya Bandi <bandik@xxxxxxxxxx>
Signed-off-by: Thierry Reding <treding@xxxxxxxxxx>
---
drivers/power/reset/Kconfig | 6 ++
drivers/power/reset/Makefile | 1 +
drivers/power/reset/max77620-poweroff.c | 146 ++++++++++++++++++++++++++++++++
3 files changed, 153 insertions(+)
create mode 100644 drivers/power/reset/max77620-poweroff.c

diff --git a/drivers/power/reset/Kconfig b/drivers/power/reset/Kconfig
index abeb77217a21..f0d0c20632f8 100644
--- a/drivers/power/reset/Kconfig
+++ b/drivers/power/reset/Kconfig
@@ -98,6 +98,12 @@ config POWER_RESET_IMX
say N here or disable in dts to make sure pm_power_off never be
overwrote wrongly by this driver.
+config POWER_RESET_MAX77620
+ bool "Maxim MAX77620 PMIC power-off driver"
+ depends on MFD_MAX77620
+ help
+ Power off and restart support for Maxim MAX77620 PMICs.
+
config POWER_RESET_MSM
bool "Qualcomm MSM power-off driver"
depends on ARCH_QCOM
diff --git a/drivers/power/reset/Makefile b/drivers/power/reset/Makefile
index 11dae3b56ff9..74511d2f037a 100644
--- a/drivers/power/reset/Makefile
+++ b/drivers/power/reset/Makefile
@@ -9,6 +9,7 @@ obj-$(CONFIG_POWER_RESET_GPIO) += gpio-poweroff.o
obj-$(CONFIG_POWER_RESET_GPIO_RESTART) += gpio-restart.o
obj-$(CONFIG_POWER_RESET_HISI) += hisi-reboot.o
obj-$(CONFIG_POWER_RESET_IMX) += imx-snvs-poweroff.o
+obj-$(CONFIG_POWER_RESET_MAX77620) += max77620-poweroff.o
obj-$(CONFIG_POWER_RESET_MSM) += msm-poweroff.o
obj-$(CONFIG_POWER_RESET_PIIX4_POWEROFF) += piix4-poweroff.o
obj-$(CONFIG_POWER_RESET_LTC2952) += ltc2952-poweroff.o
diff --git a/drivers/power/reset/max77620-poweroff.c b/drivers/power/reset/max77620-poweroff.c
new file mode 100644
index 000000000000..4f2682d10925
--- /dev/null
+++ b/drivers/power/reset/max77620-poweroff.c
@@ -0,0 +1,146 @@
+/*
+ * Power off driver for Maxim MAX77620 device.
+ *
+ * Copyright (c) 2014-2016, NVIDIA CORPORATION. All rights reserved.

Should we change year here?

+ *
+ * Based on work by Chaitanya Bandi <bandik@xxxxxxxxxx>.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation version 2.
+ *
+ * This program is distributed "as is" WITHOUT ANY WARRANTY of any kind,
+ * whether express or implied; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ */
+
+#include <linux/errno.h>
+#include <linux/mfd/max77620.h>
+#include <linux/module.h>
+#include <linux/notifier.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/reboot.h>
+#include <linux/regmap.h>
+#include <linux/slab.h>
+
+#if defined(CONFIG_ARM) || defined(CONFIG_ARM64)
+#include <asm/system_misc.h>
+#endif
+
+struct max77620_power {
+ struct regmap *regmap;
+ struct device *dev;
+};
+
+static struct max77620_power *system_power_controller = NULL;

As this is static and so already initialized as NULL. Hence we may not need to explicitly NULL initialization.
+
+static void max77620_pm_power_off(void)
+{
+ struct max77620_power *power = system_power_controller;
+ unsigned int value;
+ int err;
+
+ if (!power)
+ return;
+
+ /* clear power key interrupts */
+ err = regmap_read(power->regmap, MAX77620_REG_ONOFFIRQ, &value);
+ if (err < 0)
+ dev_err(power->dev, "failed to clear power key interrupts: %d\n", err);
+
+ /* clear RTC interrupts */
+ /*
+ err = regmap_read(power->regmap, MAX77620_REG_RTCINT, &value);
+ if (err < 0)
+ dev_err(power->dev, "failed to clear RTC interrupts: %d\n", err);
+ */
+
+ /* clear TOP interrupts */
+ err = regmap_read(power->regmap, MAX77620_REG_IRQTOP, &value);
+ if (err < 0)
+ dev_err(power->dev, "failed to clear interrupts: %d\n", err);
+
+ err = regmap_update_bits(power->regmap, MAX77620_REG_ONOFFCNFG2,
+ MAX77620_ONOFFCNFG2_SFT_RST_WK, 0);
+ if (err < 0)
+ dev_err(power->dev, "failed to clear SFT_RST_WK: %d\n", err);
+
+ err = regmap_update_bits(power->regmap, MAX77620_REG_ONOFFCNFG1,
+ MAX77620_ONOFFCNFG1_SFT_RST,
+ MAX77620_ONOFFCNFG1_SFT_RST);
+ if (err < 0)
+ dev_err(power->dev, "failed to set SFT_RST: %d\n", err);
+}
+
+#if defined(CONFIG_ARM) || defined(CONFIG_ARM64)
+static void max77620_pm_restart(enum reboot_mode mode, const char *cmd)
+{
+ struct max77620_power *power = system_power_controller;
+ int err;
+
+ if (!power)
+ return;
+
+ err = regmap_update_bits(power->regmap, MAX77620_REG_ONOFFCNFG2,
+ MAX77620_ONOFFCNFG2_SFT_RST_WK,
+ MAX77620_ONOFFCNFG2_SFT_RST_WK);
+ if (err < 0)
+ dev_err(power->dev, "failed to set SFT_RST_WK: %d\n", err);
+
+ err = regmap_update_bits(power->regmap, MAX77620_REG_ONOFFCNFG1,
+ MAX77620_ONOFFCNFG1_SFT_RST,
+ MAX77620_ONOFFCNFG1_SFT_RST);
+ if (err < 0)
+ dev_err(power->dev, "failed to set SFT_RST: %d\n", err);
+}
+#endif
+
+static int max77620_poweroff_probe(struct platform_device *pdev)
+{
+ struct max77620_chip *max77620 = dev_get_drvdata(pdev->dev.parent);
+ struct device_node *np = pdev->dev.parent->of_node;
+ struct max77620_power *power;
+ unsigned int value;
+ int err;
+
+ if (!of_property_read_bool(np, "system-power-controller"))
+ return 0;
+
+ power = devm_kzalloc(&pdev->dev, sizeof(*power), GFP_KERNEL);
+ if (!power)
+ return -ENOMEM;
+
+ power->regmap = max77620->rmap;

We can use the function info->regmap = dev_get_regmap(parent, NULL); to get the regmap. This will make this driver independent of max77620 chip and extend same for other Maxim Chips.

+ power->dev = &pdev->dev;
+
+ err = regmap_read(power->regmap, MAX77620_REG_NVERC, &value);
+ if (err < 0) {
+ dev_err(power->dev, "failed to read event recorder: %d\n", err);
+ return err;
+ }
+
+ dev_dbg(&pdev->dev, "event recorder: %#x\n", value);
+
+ system_power_controller = power;
+ pm_power_off = max77620_pm_power_off;
+#if defined(CONFIG_ARM) || defined(CONFIG_ARM64)
+ arm_pm_restart = max77620_pm_restart;

What if we want to reset via the Tegra and not through PMIC?
+#endif
+
+ return 0;
+}
+
+static struct platform_driver max77620_poweroff_driver = {
+ .driver = {
+ .name = "max77620-power",
+ },
+ .probe = max77620_poweroff_probe,
+};
+module_platform_driver(max77620_poweroff_driver);
+
+MODULE_DESCRIPTION("Maxim MAX77620 PMIC power off and restart driver");
+MODULE_AUTHOR("Thierry Reding <treding@xxxxxxxxxx>");
+MODULE_ALIAS("platform:max77620-power");
+MODULE_LICENSE("GPL v2");