Commit 94227b9c authored by Hans de Goede's avatar Hans de Goede
Browse files

platform/x86: Add intel_bytcrc_pwrsrc driver 



Add a new driver for the power-, wake- and reset-source functionality
of the Bay Trail (BYT) version of the Crystal Cove PMIC.

The main functionality here is detecting which power-sources (USB /
DC in / battery) are active. This is normally exposed to userspace as
a power_supply class charger device with an online sysfs attribute.

But if a charger is online or not is already exposed on BYT-CRC devices
through either an ACPI AC power_supply device, or through a native driver
for the battery charger chip (e.g. a BQ24292i).

So instead of adding duplicate info under the power_supply class this
driver exports the info through debugfs and likewise adds debugfs files
for the reset- and wake-source info / registers.

Despite this driver only exporting debugfs bits it is still useful to
have this driver because it clears the wake- and reset-source registers
after reading them. Not clearing these can have undesirable side-effects.

Specifically if the WAKESRC register contains 0x01 (wake by powerbutton)
on reboot then the firmware on some tablets turns the reboot into
a poweroff. I guess this may be necessary to make long power-presses turn
into a poweroff somehow?

Signed-off-by: default avatarHans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20230303221928.285477-1-hdegoede@redhat.com
parent de4fb5f5

drivers/platform/x86/intel/Kconfig

+10 −0
Original line number Diff line number Diff line
@@ -80,6 +80,16 @@ config INTEL_BXTWC_PMIC_TMU 
	  This driver enables the alarm wakeup functionality in the TMU unit of

	  Whiskey Cove PMIC.



config INTEL_BYTCRC_PWRSRC

	tristate "Intel Bay Trail Crystal Cove power source driver"

	depends on INTEL_SOC_PMIC

	help

	  This option adds a power source driver for Crystal Cove PMICs

	  on Intel Bay Trail devices.



	  To compile this driver as a module, choose M here: the module

	  will be called intel_bytcrc_pwrsrc.



config INTEL_CHTDC_TI_PWRBTN

	tristate "Intel Cherry Trail Dollar Cove TI power button driver"

	depends on INTEL_SOC_PMIC_CHTDC_TI

drivers/platform/x86/intel/Makefile

+2 −0
Original line number Diff line number Diff line
@@ -38,6 +38,8 @@ intel_bxtwc_tmu-y := bxtwc_tmu.o 
obj-$(CONFIG_INTEL_BXTWC_PMIC_TMU)	+= intel_bxtwc_tmu.o

intel_crystal_cove_charger-y		:= crystal_cove_charger.o

obj-$(CONFIG_X86_ANDROID_TABLETS)	+= intel_crystal_cove_charger.o

intel_bytcrc_pwrsrc-y			:= bytcrc_pwrsrc.o

obj-$(CONFIG_INTEL_BYTCRC_PWRSRC)	+= intel_bytcrc_pwrsrc.o

intel_chtdc_ti_pwrbtn-y			:= chtdc_ti_pwrbtn.o

obj-$(CONFIG_INTEL_CHTDC_TI_PWRBTN)	+= intel_chtdc_ti_pwrbtn.o

intel_chtwc_int33fe-y			:= chtwc_int33fe.o

drivers/platform/x86/intel/bytcrc_pwrsrc.c

0 → 100644
+181 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0

/*

 * Power-source driver for Bay Trail Crystal Cove PMIC

 *

 * Copyright (c) 2023 Hans de Goede <hdegoede@redhat.com>

 *

 * Based on intel_crystalcove_pwrsrc.c from Android kernel sources, which is:

 * Copyright (C) 2013 Intel Corporation

 */



#include <linux/debugfs.h>

#include <linux/mfd/intel_soc_pmic.h>

#include <linux/module.h>

#include <linux/platform_device.h>

#include <linux/regmap.h>



#define CRYSTALCOVE_SPWRSRC_REG		0x1E

#define CRYSTALCOVE_RESETSRC0_REG	0x20

#define CRYSTALCOVE_RESETSRC1_REG	0x21

#define CRYSTALCOVE_WAKESRC_REG		0x22



struct crc_pwrsrc_data {

	struct regmap *regmap;

	struct dentry *debug_dentry;

	unsigned int resetsrc0;

	unsigned int resetsrc1;

	unsigned int wakesrc;

};



static const char * const pwrsrc_pwrsrc_info[] = {

	/* bit 0 */ "USB",

	/* bit 1 */ "DC in",

	/* bit 2 */ "Battery",

	NULL,

};



static const char * const pwrsrc_resetsrc0_info[] = {

	/* bit 0 */ "SOC reporting a thermal event",

	/* bit 1 */ "critical PMIC temperature",

	/* bit 2 */ "critical system temperature",

	/* bit 3 */ "critical battery temperature",

	/* bit 4 */ "VSYS under voltage",

	/* bit 5 */ "VSYS over voltage",

	/* bit 6 */ "battery removal",

	NULL,

};



static const char * const pwrsrc_resetsrc1_info[] = {

	/* bit 0 */ "VCRIT threshold",

	/* bit 1 */ "BATID reporting battery removal",

	/* bit 2 */ "user pressing the power button",

	NULL,

};



static const char * const pwrsrc_wakesrc_info[] = {

	/* bit 0 */ "user pressing the power button",

	/* bit 1 */ "a battery insertion",

	/* bit 2 */ "a USB charger insertion",

	/* bit 3 */ "an adapter insertion",

	NULL,

};



static void crc_pwrsrc_log(struct seq_file *seq, const char *prefix,

			   const char * const *info, unsigned int reg_val)

{

	int i;



	for (i = 0; info[i]; i++) {

		if (reg_val & BIT(i))

			seq_printf(seq, "%s by %s\n", prefix, info[i]);

	}

}



static int pwrsrc_show(struct seq_file *seq, void *unused)

{

	struct crc_pwrsrc_data *data = seq->private;

	unsigned int reg_val;

	int ret;



	ret = regmap_read(data->regmap, CRYSTALCOVE_SPWRSRC_REG, &reg_val);

	if (ret)

		return ret;



	crc_pwrsrc_log(seq, "System powered", pwrsrc_pwrsrc_info, reg_val);

	return 0;

}



static int resetsrc_show(struct seq_file *seq, void *unused)

{

	struct crc_pwrsrc_data *data = seq->private;



	crc_pwrsrc_log(seq, "Last shutdown caused", pwrsrc_resetsrc0_info, data->resetsrc0);

	crc_pwrsrc_log(seq, "Last shutdown caused", pwrsrc_resetsrc1_info, data->resetsrc1);

	return 0;

}



static int wakesrc_show(struct seq_file *seq, void *unused)

{

	struct crc_pwrsrc_data *data = seq->private;



	crc_pwrsrc_log(seq, "Last wake caused", pwrsrc_wakesrc_info, data->wakesrc);

	return 0;

}



DEFINE_SHOW_ATTRIBUTE(pwrsrc);

DEFINE_SHOW_ATTRIBUTE(resetsrc);

DEFINE_SHOW_ATTRIBUTE(wakesrc);



static int crc_pwrsrc_read_and_clear(struct crc_pwrsrc_data *data,

				     unsigned int reg, unsigned int *val)

{

	int ret;



	ret = regmap_read(data->regmap, reg, val);

	if (ret)

		return ret;



	return regmap_write(data->regmap, reg, *val);

}



static int crc_pwrsrc_probe(struct platform_device *pdev)

{

	struct intel_soc_pmic *pmic = dev_get_drvdata(pdev->dev.parent);

	struct crc_pwrsrc_data *data;

	int ret;



	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);

	if (!data)

		return -ENOMEM;



	data->regmap = pmic->regmap;



	/*

	 * Read + clear resetsrc0/1 and wakesrc now, so that they get

	 * cleared even if the debugfs interface is never used.

	 *

	 * Properly clearing the wakesrc is important, leaving bit 0 of it

	 * set turns reboot into poweroff on some tablets.

	 */

	ret = crc_pwrsrc_read_and_clear(data, CRYSTALCOVE_RESETSRC0_REG, &data->resetsrc0);

	if (ret)

		return ret;



	ret = crc_pwrsrc_read_and_clear(data, CRYSTALCOVE_RESETSRC1_REG, &data->resetsrc1);

	if (ret)

		return ret;



	ret = crc_pwrsrc_read_and_clear(data, CRYSTALCOVE_WAKESRC_REG, &data->wakesrc);

	if (ret)

		return ret;



	data->debug_dentry = debugfs_create_dir(KBUILD_MODNAME, NULL);

	debugfs_create_file("pwrsrc", 0444, data->debug_dentry, data, &pwrsrc_fops);

	debugfs_create_file("resetsrc", 0444, data->debug_dentry, data, &resetsrc_fops);

	debugfs_create_file("wakesrc", 0444, data->debug_dentry, data, &wakesrc_fops);



	platform_set_drvdata(pdev, data);

	return 0;

}



static int crc_pwrsrc_remove(struct platform_device *pdev)

{

	struct crc_pwrsrc_data *data = platform_get_drvdata(pdev);



	debugfs_remove_recursive(data->debug_dentry);

	return 0;

}



static struct platform_driver crc_pwrsrc_driver = {

	.probe = crc_pwrsrc_probe,

	.remove = crc_pwrsrc_remove,

	.driver = {

		.name = "crystal_cove_pwrsrc",

	},

};

module_platform_driver(crc_pwrsrc_driver);



MODULE_ALIAS("platform:crystal_cove_pwrsrc");

MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");

MODULE_DESCRIPTION("Power-source driver for Bay Trail Crystal Cove PMIC");

MODULE_LICENSE("GPL");