mfd: Add Cherry Trail Whiskey Cove PMIC driver

Add mfd driver for Intel CHT Whiskey Cove PMIC, based on various non
upstreamed CHT Whiskey Cove PMIC patches.

This is a somewhat minimal version which adds irqchip support and cells
for: ACPI PMIC opregion support, the i2c-controller driving the external
charger irc and the pwrsrc/extcon block.

Further cells can be added in the future if/when drivers are upstreamed
for them.

[The above patch caused a build error on some archetectures]

From: Arnd Bergmann <arnd@arndb.de>

I ran into a build error on ARM with a platform that has a non-standard
clk implementation:

drivers/clk/clk.o: In function `clk_disable':
clk.c:(.text.clk_disable+0x0): multiple definition of `clk_disable'
arch/arm/mach-omap1/clock.o:clock.c:(.text.clk_disable+0x0): first defined here
drivers/clk/clk.o: In function `clk_enable':
clk.c:(.text.clk_enable+0x0): multiple definition of `clk_enable'
arch/arm/mach-omap1/clock.o:clock.c:(.text.clk_enable+0x0): first defined here

The problem is a device driver that uses 'select COMMON_CLK', which is
generally a bad idea: selecting a subsystem should only be done from
a platform, otherwise we run into circular dependencies. The same driver
also selects 'GPIOLIB' and 'I2C', which has a similar effect.

This turns all three into 'depends on', as it should be.

Finally, we can limit the build to x86, unless we are compile testing.

First patch:
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

Fix for first patch (squashed):
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

drivers/mfd/Kconfig

@@ -475,6 +475,22 @@ config INTEL_SOC_PMIC_BXTWC
 	  thermal, charger and related power management functions
 	  on these systems.
 
+config INTEL_SOC_PMIC_CHTWC
+	tristate "Support for Intel Cherry Trail Whiskey Cove PMIC"
+	depends on ACPI && HAS_IOMEM && I2C=y && COMMON_CLK
+	depends on X86 || COMPILE_TEST
+	select MFD_CORE
+	select REGMAP_I2C
+	select REGMAP_IRQ
+	select I2C_DESIGNWARE_PLATFORM
+	help
+	  Select this option to enable support for the Intel Cherry Trail
+	  Whiskey Cove PMIC found on some Intel Cherry Trail systems.
+
+	  This option is a bool as it provides an ACPI OpRegion which must be
+	  available before any devices using it are probed. This option also
+	  causes the designware-i2c driver to be builtin for the same reason.
+
 config MFD_INTEL_LPSS
 	tristate
 	select COMMON_CLK

drivers/mfd/Makefile

@@ -214,6 +214,7 @@ obj-$(CONFIG_MFD_SKY81452)	+= sky81452.o
 intel-soc-pmic-objs		:= intel_soc_pmic_core.o intel_soc_pmic_crc.o
 obj-$(CONFIG_INTEL_SOC_PMIC)	+= intel-soc-pmic.o
 obj-$(CONFIG_INTEL_SOC_PMIC_BXTWC)	+= intel_soc_pmic_bxtwc.o
+obj-$(CONFIG_INTEL_SOC_PMIC_CHTWC)	+= intel_soc_pmic_chtwc.o
 obj-$(CONFIG_MFD_MT6397)	+= mt6397-core.o
 
 obj-$(CONFIG_MFD_ALTERA_A10SR)	+= altera-a10sr.o

drivers/mfd/intel_soc_pmic_chtwc.c

+/*
+ * MFD core driver for Intel Cherrytrail Whiskey Cove PMIC
+ *
+ * Copyright (C) 2017 Hans de Goede <hdegoede@redhat.com>
+ *
+ * Based on various non upstream patches to support the CHT Whiskey Cove PMIC:
+ * Copyright (C) 2013-2015 Intel Corporation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/acpi.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/mfd/core.h>
+#include <linux/mfd/intel_soc_pmic.h>
+#include <linux/regmap.h>
+
+/* PMIC device registers */
+#define REG_OFFSET_MASK		GENMASK(7, 0)
+#define REG_ADDR_MASK		GENMASK(15, 8)
+#define REG_ADDR_SHIFT		8
+
+#define CHT_WC_IRQLVL1		0x6e02
+#define CHT_WC_IRQLVL1_MASK	0x6e0e
+
+/* Whiskey Cove PMIC share same ACPI ID between different platforms */
+#define CHT_WC_HRV		3
+
+/* Level 1 IRQs (level 2 IRQs are handled in the child device drivers) */
+enum {
+	CHT_WC_PWRSRC_IRQ = 0,
+	CHT_WC_THRM_IRQ,
+	CHT_WC_BCU_IRQ,
+	CHT_WC_ADC_IRQ,
+	CHT_WC_EXT_CHGR_IRQ,
+	CHT_WC_GPIO_IRQ,
+	/* There is no irq 6 */
+	CHT_WC_CRIT_IRQ = 7,
+};
+
+static struct resource cht_wc_pwrsrc_resources[] = {
+	DEFINE_RES_IRQ(CHT_WC_PWRSRC_IRQ),
+};
+
+static struct resource cht_wc_ext_charger_resources[] = {
+	DEFINE_RES_IRQ(CHT_WC_EXT_CHGR_IRQ),
+};
+
+static struct mfd_cell cht_wc_dev[] = {
+	{
+		.name = "cht_wcove_pwrsrc",
+		.num_resources = ARRAY_SIZE(cht_wc_pwrsrc_resources),
+		.resources = cht_wc_pwrsrc_resources,
+	}, {
+		.name = "cht_wcove_ext_chgr",
+		.num_resources = ARRAY_SIZE(cht_wc_ext_charger_resources),
+		.resources = cht_wc_ext_charger_resources,
+	},
+	{	.name = "cht_wcove_region", },
+};
+
+/*
+ * The CHT Whiskey Cove covers multiple I2C addresses, with a 1 Byte
+ * register address space per I2C address, so we use 16 bit register
+ * addresses where the high 8 bits contain the I2C client address.
+ */
+static int cht_wc_byte_reg_read(void *context, unsigned int reg,
+				unsigned int *val)
+{
+	struct i2c_client *client = context;
+	int ret, orig_addr = client->addr;
+
+	if (!(reg & REG_ADDR_MASK)) {
+		dev_err(&client->dev, "Error I2C address not specified\n");
+		return -EINVAL;
+	}
+
+	client->addr = (reg & REG_ADDR_MASK) >> REG_ADDR_SHIFT;
+	ret = i2c_smbus_read_byte_data(client, reg & REG_OFFSET_MASK);
+	client->addr = orig_addr;
+
+	if (ret < 0)
+		return ret;
+
+	*val = ret;
+	return 0;
+}
+
+static int cht_wc_byte_reg_write(void *context, unsigned int reg,
+				 unsigned int val)
+{
+	struct i2c_client *client = context;
+	int ret, orig_addr = client->addr;
+
+	if (!(reg & REG_ADDR_MASK)) {
+		dev_err(&client->dev, "Error I2C address not specified\n");
+		return -EINVAL;
+	}
+
+	client->addr = (reg & REG_ADDR_MASK) >> REG_ADDR_SHIFT;
+	ret = i2c_smbus_write_byte_data(client, reg & REG_OFFSET_MASK, val);
+	client->addr = orig_addr;
+
+	return ret;
+}
+
+static const struct regmap_config cht_wc_regmap_cfg = {
+	.reg_bits = 16,
+	.val_bits = 8,
+	.reg_write = cht_wc_byte_reg_write,
+	.reg_read = cht_wc_byte_reg_read,
+};
+
+static const struct regmap_irq cht_wc_regmap_irqs[] = {
+	REGMAP_IRQ_REG(CHT_WC_PWRSRC_IRQ, 0, BIT(CHT_WC_PWRSRC_IRQ)),
+	REGMAP_IRQ_REG(CHT_WC_THRM_IRQ, 0, BIT(CHT_WC_THRM_IRQ)),
+	REGMAP_IRQ_REG(CHT_WC_BCU_IRQ, 0, BIT(CHT_WC_BCU_IRQ)),
+	REGMAP_IRQ_REG(CHT_WC_ADC_IRQ, 0, BIT(CHT_WC_ADC_IRQ)),
+	REGMAP_IRQ_REG(CHT_WC_EXT_CHGR_IRQ, 0, BIT(CHT_WC_EXT_CHGR_IRQ)),
+	REGMAP_IRQ_REG(CHT_WC_GPIO_IRQ, 0, BIT(CHT_WC_GPIO_IRQ)),
+	REGMAP_IRQ_REG(CHT_WC_CRIT_IRQ, 0, BIT(CHT_WC_CRIT_IRQ)),
+};
+
+static const struct regmap_irq_chip cht_wc_regmap_irq_chip = {
+	.name = "cht_wc_irq_chip",
+	.status_base = CHT_WC_IRQLVL1,
+	.mask_base = CHT_WC_IRQLVL1_MASK,
+	.irqs = cht_wc_regmap_irqs,
+	.num_irqs = ARRAY_SIZE(cht_wc_regmap_irqs),
+	.num_regs = 1,
+};
+
+static int cht_wc_probe(struct i2c_client *client)
+{
+	struct device *dev = &client->dev;
+	struct intel_soc_pmic *pmic;
+	acpi_status status;
+	unsigned long long hrv;
+	int ret;
+
+	status = acpi_evaluate_integer(ACPI_HANDLE(dev), "_HRV", NULL, &hrv);
+	if (ACPI_FAILURE(status)) {
+		dev_err(dev, "Failed to get PMIC hardware revision\n");
+		return -ENODEV;
+	}
+	if (hrv != CHT_WC_HRV) {
+		dev_err(dev, "Invalid PMIC hardware revision: %llu\n", hrv);
+		return -ENODEV;
+	}
+	if (client->irq < 0) {
+		dev_err(dev, "Invalid IRQ\n");
+		return -EINVAL;
+	}
+
+	pmic = devm_kzalloc(dev, sizeof(*pmic), GFP_KERNEL);
+	if (!pmic)
+		return -ENOMEM;
+
+	pmic->irq = client->irq;
+	pmic->dev = dev;
+	i2c_set_clientdata(client, pmic);
+
+	pmic->regmap = devm_regmap_init(dev, NULL, client, &cht_wc_regmap_cfg);
+	if (IS_ERR(pmic->regmap))
+		return PTR_ERR(pmic->regmap);
+
+	ret = devm_regmap_add_irq_chip(dev, pmic->regmap, pmic->irq,
+				       IRQF_ONESHOT | IRQF_SHARED, 0,
+				       &cht_wc_regmap_irq_chip,
+				       &pmic->irq_chip_data);
+	if (ret)
+		return ret;
+
+	return devm_mfd_add_devices(dev, PLATFORM_DEVID_NONE,
+				cht_wc_dev, ARRAY_SIZE(cht_wc_dev), NULL, 0,
+				regmap_irq_get_domain(pmic->irq_chip_data));
+}
+
+static void cht_wc_shutdown(struct i2c_client *client)
+{
+	struct intel_soc_pmic *pmic = i2c_get_clientdata(client);
+
+	disable_irq(pmic->irq);
+}
+
+static int __maybe_unused cht_wc_suspend(struct device *dev)
+{
+	struct intel_soc_pmic *pmic = dev_get_drvdata(dev);
+
+	disable_irq(pmic->irq);
+
+	return 0;
+}
+
+static int __maybe_unused cht_wc_resume(struct device *dev)
+{
+	struct intel_soc_pmic *pmic = dev_get_drvdata(dev);
+
+	enable_irq(pmic->irq);
+
+	return 0;
+}
+static SIMPLE_DEV_PM_OPS(cht_wc_pm_ops, cht_wc_suspend, cht_wc_resume);
+
+static const struct i2c_device_id cht_wc_i2c_id[] = {
+	{ }
+};
+
+static const struct acpi_device_id cht_wc_acpi_ids[] = {
+	{ "INT34D3", },
+	{ }
+};
+
+static struct i2c_driver cht_wc_driver = {
+	.driver	= {
+		.name	= "CHT Whiskey Cove PMIC",
+		.pm     = &cht_wc_pm_ops,
+		.acpi_match_table = cht_wc_acpi_ids,
+	},
+	.probe_new = cht_wc_probe,
+	.shutdown = cht_wc_shutdown,
+	.id_table = cht_wc_i2c_id,
+};
+builtin_i2c_driver(cht_wc_driver);