[v2] i2c-cht-wc: Add Intel Cherry Trail Whiskey Cove SMBUS controller driver

The Intel Cherry Trail Whiskey Cove PMIC does not contain a builtin
battery charger, instead boards with this PMIC use an external TI
bq24292i charger IC, which is connected to a SMBUS controller built into
the PMIC.

This commit adds an i2c-bus driver for the PMIC's builtin SMBUS
controller. The probe function for this i2c-bus will also register an
i2c-client for the TI bq24292i charger after the i2c-bus has been
registered.

Note that several device-properties are set on the client-device to
tell the bq24190 power-supply driver to integrate the Whiskey Cove PMIC
and e.g. use the PMIC's BC1.2 detection (through extcon) to determine
the maximum input current.

Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
---
Changes in v2:
-Various style (mostly captialization and variable name) fixes
-Use device-properties instead of platform_data for the i2c_board_info
---
 drivers/i2c/busses/Kconfig      |   8 +
 drivers/i2c/busses/Makefile     |   1 +
 drivers/i2c/busses/i2c-cht-wc.c | 336 ++++++++++++++++++++++++++++++++++++++++
 3 files changed, 345 insertions(+)
 create mode 100644 drivers/i2c/busses/i2c-cht-wc.c

On Wed, 2017-06-21 at 16:12 +0200, Hans de Goede wrote:
> The Intel Cherry Trail Whiskey Cove PMIC does not contain a builtin
> battery charger, instead boards with this PMIC use an external TI
> bq24292i charger IC, which is connected to a SMBUS controller built
> into
> the PMIC.
> 
> This commit adds an i2c-bus driver for the PMIC's builtin SMBUS
> controller. The probe function for this i2c-bus will also register an
> i2c-client for the TI bq24292i charger after the i2c-bus has been
> registered.
> 
> Note that several device-properties are set on the client-device to
> tell the bq24190 power-supply driver to integrate the Whiskey Cove
> PMIC
> and e.g. use the PMIC's BC1.2 detection (through extcon) to determine
> the maximum input current.
> 

Looks good to me, FWIW, 

Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

(I suppose you might need to rebase it on top of i2c-next when it will
be opened)

> Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
> ---
> Changes in v2:
> -Various style (mostly captialization and variable name) fixes
> -Use device-properties instead of platform_data for the i2c_board_info
> ---
>  drivers/i2c/busses/Kconfig      |   8 +
>  drivers/i2c/busses/Makefile     |   1 +
>  drivers/i2c/busses/i2c-cht-wc.c | 336
> ++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 345 insertions(+)
>  create mode 100644 drivers/i2c/busses/i2c-cht-wc.c
> 
> diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
> index 144cbadc7c72..18c96178b177 100644
> --- a/drivers/i2c/busses/Kconfig
> +++ b/drivers/i2c/busses/Kconfig
> @@ -187,6 +187,14 @@ config I2C_PIIX4
>  	  This driver can also be built as a module.  If so, the
> module
>  	  will be called i2c-piix4.
>  
> +config I2C_CHT_WC
> +	tristate "Intel Cherry Trail Whiskey Cove PMIC smbus
> controller"
> +	depends on INTEL_SOC_PMIC_CHTWC
> +	help
> +	  If you say yes to this option, support will be included for
> the
> +	  SMBus controller found in the Intel Cherry Trail Whiskey
> Cove PMIC
> +	  found on some Intel Cherry Trail systems.
> +
>  config I2C_NFORCE2
>  	tristate "Nvidia nForce2, nForce3 and nForce4"
>  	depends on PCI
> diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
> index 30b60855fbcd..f6443fa44f61 100644
> --- a/drivers/i2c/busses/Makefile
> +++ b/drivers/i2c/busses/Makefile
> @@ -12,6 +12,7 @@ obj-$(CONFIG_I2C_ALI15X3)	+= i2c-ali15x3.o
>  obj-$(CONFIG_I2C_AMD756)	+= i2c-amd756.o
>  obj-$(CONFIG_I2C_AMD756_S4882)	+= i2c-amd756-s4882.o
>  obj-$(CONFIG_I2C_AMD8111)	+= i2c-amd8111.o
> +obj-$(CONFIG_I2C_CHT_WC)	+= i2c-cht-wc.o
>  obj-$(CONFIG_I2C_I801)		+= i2c-i801.o
>  obj-$(CONFIG_I2C_ISCH)		+= i2c-isch.o
>  obj-$(CONFIG_I2C_ISMT)		+= i2c-ismt.o
> diff --git a/drivers/i2c/busses/i2c-cht-wc.c b/drivers/i2c/busses/i2c-
> cht-wc.c
> new file mode 100644
> index 000000000000..ccf0785bcb75
> --- /dev/null
> +++ b/drivers/i2c/busses/i2c-cht-wc.c
> @@ -0,0 +1,336 @@
> +/*
> + * Intel CHT Whiskey Cove PMIC I2C Master driver
> + * Copyright (C) 2017 Hans de Goede <hdegoede@redhat.com>
> + *
> + * Based on various non upstream patches to support the CHT Whiskey
> Cove PMIC:
> + * Copyright (C) 2011 - 2014 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.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + */
> +
> +#include <linux/completion.h>
> +#include <linux/delay.h>
> +#include <linux/i2c.h>
> +#include <linux/interrupt.h>
> +#include <linux/irq.h>
> +#include <linux/irqdomain.h>
> +#include <linux/mfd/intel_soc_pmic.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/slab.h>
> +
> +#define CHT_WC_I2C_CTRL			0x5e24
> +#define CHT_WC_I2C_CTRL_WR		BIT(0)
> +#define CHT_WC_I2C_CTRL_RD		BIT(1)
> +#define CHT_WC_I2C_CLIENT_ADDR		0x5e25
> +#define CHT_WC_I2C_REG_OFFSET		0x5e26
> +#define CHT_WC_I2C_WRDATA		0x5e27
> +#define CHT_WC_I2C_RDDATA		0x5e28
> +
> +#define CHT_WC_EXTCHGRIRQ		0x6e0a
> +#define CHT_WC_EXTCHGRIRQ_CLIENT_IRQ	BIT(0)
> +#define CHT_WC_EXTCHGRIRQ_WRITE_IRQ	BIT(1)
> +#define CHT_WC_EXTCHGRIRQ_READ_IRQ	BIT(2)
> +#define CHT_WC_EXTCHGRIRQ_NACK_IRQ	BIT(3)
> +#define CHT_WC_EXTCHGRIRQ_ADAP_IRQMASK	((u8)GENMASK(3, 1))
> +#define CHT_WC_EXTCHGRIRQ_MSK		0x6e17
> +
> +struct cht_wc_i2c_adap {
> +	struct i2c_adapter adapter;
> +	wait_queue_head_t wait;
> +	struct irq_chip irqchip;
> +	struct mutex irqchip_lock;
> +	struct regmap *regmap;
> +	struct irq_domain *irq_domain;
> +	struct i2c_client *client;
> +	int client_irq;
> +	u8 irq_mask;
> +	u8 old_irq_mask;
> +	bool nack;
> +	bool done;
> +};
> +
> +static irqreturn_t cht_wc_i2c_adap_thread_handler(int id, void *data)
> +{
> +	struct cht_wc_i2c_adap *adap = data;
> +	int ret, reg;
> +
> +	/* Read IRQs */
> +	ret = regmap_read(adap->regmap, CHT_WC_EXTCHGRIRQ, &reg);
> +	if (ret) {
> +		dev_err(&adap->adapter.dev, "Error reading extchgrirq
> reg\n");
> +		return IRQ_NONE;
> +	}
> +
> +	reg &= ~adap->irq_mask;
> +
> +	/*
> +	 * Immediately ack IRQs, so that if new IRQs arrives while
> we're
> +	 * handling the previous ones our irq will re-trigger when
> we're done.
> +	 */
> +	ret = regmap_write(adap->regmap, CHT_WC_EXTCHGRIRQ, reg);
> +	if (ret)
> +		dev_err(&adap->adapter.dev, "Error writing extchgrirq
> reg\n");
> +
> +	/*
> +	 * Do NOT use handle_nested_irq here, the client irq handler
> will
> +	 * likely want to do i2c transfers and the i2c controller
> uses this
> +	 * interrupt handler as well, so running the client irq
> handler from
> +	 * this thread will cause things to lock up.
> +	 */
> +	if (reg & CHT_WC_EXTCHGRIRQ_CLIENT_IRQ) {
> +		/*
> +		 * generic_handle_irq expects local IRQs to be
> disabled
> +		 * as normally it is called from interrupt context.
> +		 */
> +		local_irq_disable();
> +		generic_handle_irq(adap->client_irq);
> +		local_irq_enable();
> +	}
> +
> +	if (reg & CHT_WC_EXTCHGRIRQ_ADAP_IRQMASK) {
> +		adap->nack = !!(reg & CHT_WC_EXTCHGRIRQ_NACK_IRQ);
> +		adap->done = true;
> +		wake_up(&adap->wait);
> +	}
> +
> +	return IRQ_HANDLED;
> +}
> +
> +static u32 cht_wc_i2c_adap_master_func(struct i2c_adapter *adap)
> +{
> +	/* This i2c adapter only supports SMBUS byte transfers */
> +	return I2C_FUNC_SMBUS_BYTE_DATA;
> +}
> +
> +static int cht_wc_i2c_adap_smbus_xfer(struct i2c_adapter *_adap, u16
> addr,
> +				      unsigned short flags, char
> read_write,
> +				      u8 command, int size,
> +				      union i2c_smbus_data *data)
> +{
> +	struct cht_wc_i2c_adap *adap = i2c_get_adapdata(_adap);
> +	int ret, reg;
> +
> +	adap->nack = false;
> +	adap->done = false;
> +
> +	ret = regmap_write(adap->regmap, CHT_WC_I2C_CLIENT_ADDR,
> addr);
> +	if (ret)
> +		return ret;
> +
> +	if (read_write == I2C_SMBUS_WRITE) {
> +		ret = regmap_write(adap->regmap, CHT_WC_I2C_WRDATA,
> data->byte);
> +		if (ret)
> +			return ret;
> +	}
> +
> +	ret = regmap_write(adap->regmap, CHT_WC_I2C_REG_OFFSET,
> command);
> +	if (ret)
> +		return ret;
> +
> +	ret = regmap_write(adap->regmap, CHT_WC_I2C_CTRL,
> +			   (read_write == I2C_SMBUS_WRITE) ?
> +			   CHT_WC_I2C_CTRL_WR : CHT_WC_I2C_CTRL_RD);
> +	if (ret)
> +		return ret;
> +
> +	/* 3 second timeout, during cable plug the PMIC responds
> quite slow */
> +	ret = wait_event_timeout(adap->wait, adap->done, 3 * HZ);
> +	if (ret == 0)
> +		return -ETIMEDOUT;
> +	if (adap->nack)
> +		return -EIO;
> +
> +	if (read_write == I2C_SMBUS_READ) {
> +		ret = regmap_read(adap->regmap, CHT_WC_I2C_RDDATA,
> &reg);
> +		if (ret)
> +			return ret;
> +
> +		data->byte = reg;
> +	}
> +
> +	return 0;
> +}
> +
> +static const struct i2c_algorithm cht_wc_i2c_adap_algo = {
> +	.functionality = cht_wc_i2c_adap_master_func,
> +	.smbus_xfer = cht_wc_i2c_adap_smbus_xfer,
> +};
> +
> +/**** irqchip for the client connected to the extchgr i2c adapter
> ****/
> +static void cht_wc_i2c_irq_lock(struct irq_data *data)
> +{
> +	struct cht_wc_i2c_adap *adap =
> irq_data_get_irq_chip_data(data);
> +
> +	mutex_lock(&adap->irqchip_lock);
> +}
> +
> +static void cht_wc_i2c_irq_sync_unlock(struct irq_data *data)
> +{
> +	struct cht_wc_i2c_adap *adap =
> irq_data_get_irq_chip_data(data);
> +	int ret;
> +
> +	if (adap->irq_mask != adap->old_irq_mask) {
> +		ret = regmap_write(adap->regmap,
> CHT_WC_EXTCHGRIRQ_MSK,
> +				   adap->irq_mask);
> +		if (ret == 0)
> +			adap->old_irq_mask = adap->irq_mask;
> +		else
> +			dev_err(&adap->adapter.dev, "Error writing
> EXTCHGRIRQ_MSK\n");
> +	}
> +
> +	mutex_unlock(&adap->irqchip_lock);
> +}
> +
> +static void cht_wc_i2c_irq_enable(struct irq_data *data)
> +{
> +	struct cht_wc_i2c_adap *adap =
> irq_data_get_irq_chip_data(data);
> +
> +	adap->irq_mask &= ~CHT_WC_EXTCHGRIRQ_CLIENT_IRQ;
> +}
> +
> +static void cht_wc_i2c_irq_disable(struct irq_data *data)
> +{
> +	struct cht_wc_i2c_adap *adap =
> irq_data_get_irq_chip_data(data);
> +
> +	adap->irq_mask |= CHT_WC_EXTCHGRIRQ_CLIENT_IRQ;
> +}
> +
> +static const struct irq_chip cht_wc_i2c_irq_chip = {
> +	.irq_bus_lock		= cht_wc_i2c_irq_lock,
> +	.irq_bus_sync_unlock	= cht_wc_i2c_irq_sync_unlock,
> +	.irq_disable		= cht_wc_i2c_irq_disable,
> +	.irq_enable		= cht_wc_i2c_irq_enable,
> +	.name			= "cht_wc_ext_chrg_irq_chip",
> +};
> +
> +static const struct property_entry bq24190_props[] = {
> +	PROPERTY_ENTRY_STRING("extcon-name", "cht_wcove_pwrsrc"),
> +	PROPERTY_ENTRY_BOOL("omit-battery-class"),
> +	PROPERTY_ENTRY_BOOL("disable-reset"),
> +	{ }
> +};
> +
> +static int cht_wc_i2c_adap_i2c_probe(struct platform_device *pdev)
> +{
> +	struct intel_soc_pmic *pmic = dev_get_drvdata(pdev-
> >dev.parent);
> +	struct cht_wc_i2c_adap *adap;
> +	struct i2c_board_info board_info = {
> +		.type = "bq24190",
> +		.addr = 0x6b,
> +		.properties = bq24190_props,
> +	};
> +	int ret, irq;
> +
> +	irq = platform_get_irq(pdev, 0);
> +	if (irq < 0) {
> +		dev_err(&pdev->dev, "Error missing irq resource\n");
> +		return -EINVAL;
> +	}
> +
> +	adap = devm_kzalloc(&pdev->dev, sizeof(*adap), GFP_KERNEL);
> +	if (!adap)
> +		return -ENOMEM;
> +
> +	init_waitqueue_head(&adap->wait);
> +	mutex_init(&adap->irqchip_lock);
> +	adap->irqchip = cht_wc_i2c_irq_chip;
> +	adap->regmap = pmic->regmap;
> +	adap->adapter.owner = THIS_MODULE;
> +	adap->adapter.class = I2C_CLASS_HWMON;
> +	adap->adapter.algo = &cht_wc_i2c_adap_algo;
> +	strlcpy(adap->adapter.name, "PMIC I2C Adapter",
> +		sizeof(adap->adapter.name));
> +	adap->adapter.dev.parent = &pdev->dev;
> +
> +	/* Clear and activate i2c-adapter interrupts, disable client
> IRQ */
> +	adap->old_irq_mask = adap->irq_mask =
> ~CHT_WC_EXTCHGRIRQ_ADAP_IRQMASK;
> +	ret = regmap_write(adap->regmap, CHT_WC_EXTCHGRIRQ, ~adap-
> >irq_mask);
> +	if (ret)
> +		return ret;
> +
> +	ret = regmap_write(adap->regmap, CHT_WC_EXTCHGRIRQ_MSK, adap-
> >irq_mask);
> +	if (ret)
> +		return ret;
> +
> +	/* Alloc and register client IRQ */
> +	adap->irq_domain = irq_domain_add_linear(pdev->dev.of_node,
> 1,
> +						 &irq_domain_simple_o
> ps, NULL);
> +	if (!adap->irq_domain)
> +		return -ENOMEM;
> +
> +	adap->client_irq = irq_create_mapping(adap->irq_domain, 0);
> +	if (!adap->client_irq) {
> +		ret = -ENOMEM;
> +		goto remove_irq_domain;
> +	}
> +
> +	irq_set_chip_data(adap->client_irq, adap);
> +	irq_set_chip_and_handler(adap->client_irq, &adap->irqchip,
> +				 handle_simple_irq);
> +
> +	ret = devm_request_threaded_irq(&pdev->dev, irq, NULL,
> +					cht_wc_i2c_adap_thread_handle
> r,
> +					IRQF_ONESHOT, "PMIC I2C
> Adapter", adap);
> +	if (ret)
> +		goto remove_irq_domain;
> +
> +	i2c_set_adapdata(&adap->adapter, adap);
> +	ret = i2c_add_adapter(&adap->adapter);
> +	if (ret)
> +		goto remove_irq_domain;
> +
> +	board_info.irq = adap->client_irq;
> +	adap->client = i2c_new_device(&adap->adapter, &board_info);
> +	if (!adap->client) {
> +		ret = -ENOMEM;
> +		goto del_adapter;
> +	}
> +
> +	platform_set_drvdata(pdev, adap);
> +	return 0;
> +
> +del_adapter:
> +	i2c_del_adapter(&adap->adapter);
> +remove_irq_domain:
> +	irq_domain_remove(adap->irq_domain);
> +	return ret;
> +}
> +
> +static int cht_wc_i2c_adap_i2c_remove(struct platform_device *pdev)
> +{
> +	struct cht_wc_i2c_adap *adap = platform_get_drvdata(pdev);
> +
> +	i2c_unregister_device(adap->client);
> +	i2c_del_adapter(&adap->adapter);
> +	irq_domain_remove(adap->irq_domain);
> +
> +	return 0;
> +}
> +
> +static struct platform_device_id cht_wc_i2c_adap_id_table[] = {
> +	{ .name = "cht_wcove_ext_chgr" },
> +	{},
> +};
> +MODULE_DEVICE_TABLE(platform, cht_wc_i2c_adap_id_table);
> +
> +struct platform_driver cht_wc_i2c_adap_driver = {
> +	.probe = cht_wc_i2c_adap_i2c_probe,
> +	.remove = cht_wc_i2c_adap_i2c_remove,
> +	.driver = {
> +		.name = "cht_wcove_ext_chgr",
> +	},
> +	.id_table = cht_wc_i2c_adap_id_table,
> +};
> +module_platform_driver(cht_wc_i2c_adap_driver);
> +
> +MODULE_DESCRIPTION("Intel CHT Whiskey Cove PMIC I2C Master driver");
> +MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
> +MODULE_LICENSE("GPL");