Date:	Tue, 20 Jan 2015 12:47:46 +0000
From:	Lee Jones <lee.jones@...aro.org>
To:	Raymond Tan <raymond.tan@...el.com>
Cc:	Mike Turquette <mturquette@...aro.org>,
	Samuel Ortiz <sameo@...ux.intel.com>,
	linux-kernel@...r.kernel.org, Alvin Chen <alvin.chen@...el.com>,
	Andriy Shevchenko <andriy.shevchenko@...el.com>
Subject: Re: [PATCH v3 1/1] mfd: intel_quark_i2c_gpio: Add Intel Quark X1000
 I2C-GPIO MFD Driver

On Thu, 11 Dec 2014, Raymond Tan wrote:

> In Quark X1000, there's a single PCI device that provides both
> an I2C controller and a GPIO controller. This MFD driver will
> split the 2 devices for their respective drivers.
> 
> This patch is based on Josef Ahmad's initial work for Quark enabling.
> 
> Reviewed-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
> Signed-off-by: Weike Chen <alvin.chen@...el.com>
> Signed-off-by: Raymond Tan <raymond.tan@...el.com>
> ---
>  drivers/mfd/Kconfig                |   12 ++
>  drivers/mfd/Makefile               |    1 +
>  drivers/mfd/intel_quark_i2c_gpio.c |  279 ++++++++++++++++++++++++++++++++++++
>  3 files changed, 292 insertions(+)
>  create mode 100644 drivers/mfd/intel_quark_i2c_gpio.c
> 
> diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
> index b7c74a7..2f2f62d 100644
> --- a/drivers/mfd/Kconfig
> +++ b/drivers/mfd/Kconfig
> @@ -219,6 +219,18 @@ config HTC_I2CPLD
>  	  This device provides input and output GPIOs through an I2C
>  	  interface to one or more sub-chips.
>  
> +config MFD_INTEL_QUARK_I2C_GPIO
> +	tristate "Intel Quark MFD I2C GPIO"
> +	depends on PCI
> +	depends on X86
> +	depends on COMMON_CLK
> +	select MFD_CORE
> +	help
> +	  This MFD provides support for I2C and GPIO that exist only
> +	  in a single PCI device. It splits the 2 IO devices to
> +	  their respective IO driver.
> +	  The GPIO exports a total amount of 8 interrupt-capable GPIOs.
> +
>  config LPC_ICH
>  	tristate "Intel ICH LPC"
>  	depends on PCI
> diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
> index 8a28dc9..d42652d 100644
> --- a/drivers/mfd/Makefile
> +++ b/drivers/mfd/Makefile
> @@ -133,6 +133,7 @@ obj-$(CONFIG_AB8500_CORE)	+= ab8500-core.o ab8500-sysctrl.o
>  obj-$(CONFIG_MFD_TIMBERDALE)    += timberdale.o
>  obj-$(CONFIG_PMIC_ADP5520)	+= adp5520.o
>  obj-$(CONFIG_MFD_KEMPLD)	+= kempld-core.o
> +obj-$(CONFIG_MFD_INTEL_QUARK_I2C_GPIO)	+= intel_quark_i2c_gpio.o
>  obj-$(CONFIG_LPC_SCH)		+= lpc_sch.o
>  obj-$(CONFIG_LPC_ICH)		+= lpc_ich.o
>  obj-$(CONFIG_MFD_RDC321X)	+= rdc321x-southbridge.o
> diff --git a/drivers/mfd/intel_quark_i2c_gpio.c b/drivers/mfd/intel_quark_i2c_gpio.c
> new file mode 100644
> index 0000000..a3a7043
> --- /dev/null
> +++ b/drivers/mfd/intel_quark_i2c_gpio.c
> @@ -0,0 +1,279 @@
> +/*
> + * Intel Quark MFD PCI driver for I2C & GPIO
> + *
> + * Copyright(c) 2014 Intel Corporation.
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms and conditions of the GNU General Public License,
> + * version 2, as published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope 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.
> + *
> + * Intel Quark PCI device for I2C and GPIO controller sharing the same
> + * PCI function. This PCI driver will split the 2 devices into their
> + * respective drivers.
> + */
> +
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/pci.h>
> +#include <linux/mfd/core.h>
> +#include <linux/clkdev.h>
> +#include <linux/clk-provider.h>
> +#include <linux/dmi.h>
> +#include <linux/platform_data/gpio-dwapb.h>
> +#include <linux/platform_data/i2c-designware.h>
> +
> +/* PCI BAR for register base address */
> +#define MFD_I2C_BAR		0
> +#define MFD_GPIO_BAR		1
> +
> +/* The base GPIO number under GPIOLIB framework */
> +#define INTEL_QUARK_MFD_GPIO_BASE	8
> +
> +/* The default number of South-Cluster GPIO on Quark. */
> +#define INTEL_QUARK_MFD_NGPIO		8
> +
> +/* The DesignWare GPIO ports on Quark. */
> +#define INTEL_QUARK_GPIO_NPORTS	1
> +
> +#define INTEL_QUARK_IORES_MEM	0
> +#define INTEL_QUARK_IORES_IRQ	1
> +
> +#define INTEL_QUARK_I2C_CONTROLLER_CLK "i2c_designware.0"
> +
> +/* The Quark I2C controller source clock */
> +#define INTEL_QUARK_I2C_CLK_HZ	33000000
> +
> +#define INTEL_QUARK_I2C_NCLK	1
> +
> +struct intel_quark_mfd {
> +	struct pci_dev		*pdev;
> +	struct clk			*i2c_clk;
> +	struct clk_lookup	*i2c_clk_lookup;
> +};
> +
> +struct i2c_mode_info {
> +	const char *name;
> +	unsigned int i2c_scl_freq;
> +};
> +
> +static const struct i2c_mode_info platform_i2c_mode_info[] = {
> +	{
> +		.name = "Galileo",
> +		.i2c_scl_freq = 100000,
> +	},
> +	{
> +		.name = "GalileoGen2",
> +		.i2c_scl_freq = 400000,
> +	},
> +};

We normally do not capitalise device names.

> +static struct resource intel_quark_i2c_res[] = {
> +	[INTEL_QUARK_IORES_MEM] = {
> +		.flags = IORESOURCE_MEM,
> +	},
> +	[INTEL_QUARK_IORES_IRQ] = {
> +		.flags = IORESOURCE_IRQ,
> +	},
> +};
> +
> +static struct resource intel_quark_gpio_res[] = {
> +	[INTEL_QUARK_IORES_MEM] = {
> +		.flags = IORESOURCE_MEM,
> +	},
> +};
> +
> +static struct mfd_cell intel_quark_mfd_cells[] = {
> +	{
> +		.id = MFD_I2C_BAR,
> +		.name = "i2c_designware",
> +		.num_resources = ARRAY_SIZE(intel_quark_i2c_res),
> +		.resources = intel_quark_i2c_res,
> +		.ignore_resource_conflicts = true,
> +	},
> +	{
> +		.id = MFD_GPIO_BAR,
> +		.name = "gpio-dwapb",
> +		.num_resources = ARRAY_SIZE(intel_quark_gpio_res),
> +		.resources = intel_quark_gpio_res,
> +		.ignore_resource_conflicts = true,
> +	},
> +};
> +
> +static const struct pci_device_id intel_quark_mfd_ids[] = {
> +	{ PCI_VDEVICE(INTEL, 0x0934), },
> +	{ 0,}

No need to populate this; just { }, will do fine.

> +};
> +MODULE_DEVICE_TABLE(pci, intel_quark_mfd_ids);
> +
> +static int intel_quark_register_i2c_clk(struct intel_quark_mfd *quark_mfd)
> +{
> +	struct pci_dev *pdev = quark_mfd->pdev;
> +	struct clk_lookup *i2c_clk_lookup;
> +	struct clk *i2c_clk;
> +	int retval;
> +
> +	i2c_clk_lookup = devm_kcalloc(
> +		&pdev->dev, INTEL_QUARK_I2C_NCLK,

Place this line back on the one above and line subsequent lines up
against the '('.

> +		sizeof(*i2c_clk_lookup), GFP_KERNEL);
> +

Rid this empty line.

> +	if (!i2c_clk_lookup)
> +		return -ENOMEM;
> +
> +	i2c_clk_lookup[0].dev_id = INTEL_QUARK_I2C_CONTROLLER_CLK;
> +
> +	i2c_clk = clk_register_fixed_rate(
> +		&pdev->dev, INTEL_QUARK_I2C_CONTROLLER_CLK, NULL,

Same here, put this back up on the line above.

> +		CLK_IS_ROOT, INTEL_QUARK_I2C_CLK_HZ);
> +
> +	quark_mfd->i2c_clk_lookup = i2c_clk_lookup;
> +	quark_mfd->i2c_clk = i2c_clk;
> +
> +	retval = clk_register_clkdevs(i2c_clk, i2c_clk_lookup,
> +				      INTEL_QUARK_I2C_NCLK);
> +	if (retval)
> +		dev_err(&pdev->dev, "Fixed clk register failed: %d\n", retval);
> +
> +	return retval;
> +}

I wouldn't mind a clk Ack on this.  Did you Cc Mike already?

> +static void intel_quark_unregister_i2c_clk(struct pci_dev *pdev)
> +{
> +	struct intel_quark_mfd *quark_mfd = dev_get_drvdata(&pdev->dev);
> +
> +	if (!quark_mfd->i2c_clk || !quark_mfd->i2c_clk_lookup)
> +		return;
> +
> +	clkdev_drop(quark_mfd->i2c_clk_lookup);
> +	clk_unregister(quark_mfd->i2c_clk);
> +}
> +
> +static int intel_quark_i2c_setup(struct pci_dev *pdev, struct mfd_cell *cell)
> +{
> +	const char *board_name = dmi_get_system_info(DMI_BOARD_NAME);
> +	struct dw_i2c_platform_data *pdata;
> +	struct resource *res = (struct resource *)cell->resources;
> +	struct device *dev = &pdev->dev;
> +	unsigned int i;
> +
> +	res[INTEL_QUARK_IORES_MEM].start =
> +		pci_resource_start(pdev, MFD_I2C_BAR);
> +	res[INTEL_QUARK_IORES_MEM].end =
> +		pci_resource_end(pdev, MFD_I2C_BAR);
> +
> +	res[INTEL_QUARK_IORES_IRQ].start = pdev->irq;
> +	res[INTEL_QUARK_IORES_IRQ].end = pdev->irq;
> +
> +	pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
> +	if (!pdata)
> +		return -ENOMEM;
> +
> +	/* Fast mode by default */
> +	pdata->i2c_scl_freq = 400000;
> +
> +	for (i = 0; i < ARRAY_SIZE(platform_i2c_mode_info); i++)
> +		if (!strcmp(board_name, platform_i2c_mode_info[i].name))
> +			pdata->i2c_scl_freq
> +				= platform_i2c_mode_info[i].i2c_scl_freq;
> +
> +	cell->platform_data = pdata;
> +	cell->pdata_size = sizeof(*pdata);
> +
> +	return 0;
> +}
> +
> +static int intel_quark_gpio_setup(struct pci_dev *pdev, struct mfd_cell *cell)
> +{
> +	struct dwapb_platform_data *pdata;
> +	struct resource *res = (struct resource *)cell->resources;
> +	struct device *dev = &pdev->dev;
> +
> +	res[INTEL_QUARK_IORES_MEM].start =
> +		pci_resource_start(pdev, MFD_GPIO_BAR);
> +	res[INTEL_QUARK_IORES_MEM].end =
> +		pci_resource_end(pdev, MFD_GPIO_BAR);
> +
> +	pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
> +	if (!pdata)
> +		return -ENOMEM;
> +
> +	/* For intel quark x1000, it has only one port: portA */
> +	pdata->nports = INTEL_QUARK_GPIO_NPORTS;
> +	pdata->properties = devm_kcalloc(dev, pdata->nports,
> +					 sizeof(*pdata->properties),
> +					 GFP_KERNEL);
> +	if (!pdata->properties)
> +		return -ENOMEM;
> +
> +	/* Set the properties for portA */
> +	pdata->properties->node	= NULL;
> +	pdata->properties->name	= "intel-quark-x1000-gpio-portA";
> +	pdata->properties->idx	= 0;
> +	pdata->properties->ngpio	= INTEL_QUARK_MFD_NGPIO;
> +	pdata->properties->gpio_base	= INTEL_QUARK_MFD_GPIO_BASE;
> +	pdata->properties->irq	= pdev->irq;
> +	pdata->properties->irq_shared	= true;

Nit: This looks untidy.  Either line up all of the '=' or don't do any
aligning at all.

> +	cell->platform_data = pdata;
> +	cell->pdata_size = sizeof(*pdata);
> +
> +	return 0;
> +}
> +
> +static int intel_quark_mfd_probe(struct pci_dev *pdev,
> +				 const struct pci_device_id *id)
> +{
> +	struct intel_quark_mfd *quark_mfd;
> +	int retval;

I prefer the use of 'ret' or 'err', as it's more consistent with the
rest of the kernel.

> +	retval = pcim_enable_device(pdev);
> +	if (retval)
> +		return retval;
> +
> +	quark_mfd = devm_kzalloc(&pdev->dev, sizeof(*quark_mfd), GFP_KERNEL);
> +	if (!quark_mfd)
> +		return -ENOMEM;
> +	quark_mfd->pdev = pdev;
> +
> +	retval = intel_quark_register_i2c_clk(quark_mfd);
> +	if (retval)
> +		return retval;
> +
> +	dev_set_drvdata(&pdev->dev, quark_mfd);
> +
> +	retval = intel_quark_i2c_setup(pdev,
> +				       &intel_quark_mfd_cells[MFD_I2C_BAR]);
> +	if (retval)
> +		return retval;
> +
> +	retval = intel_quark_gpio_setup(pdev,
> +					&intel_quark_mfd_cells[MFD_GPIO_BAR]);
> +	if (retval)
> +		return retval;
> +
> +	return mfd_add_devices(&pdev->dev, 0, intel_quark_mfd_cells,
> +		ARRAY_SIZE(intel_quark_mfd_cells), NULL, 0, NULL);

Odd alignment.  Please use the '('.

> +}
> +
> +static void intel_quark_mfd_remove(struct pci_dev *pdev)
> +{
> +	intel_quark_unregister_i2c_clk(pdev);
> +	mfd_remove_devices(&pdev->dev);
> +}
> +
> +static struct pci_driver intel_quark_mfd_driver = {
> +	.name		= "intel_quark_mfd_i2c_gpio",
> +	.id_table	= intel_quark_mfd_ids,
> +	.probe		= intel_quark_mfd_probe,
> +	.remove		= intel_quark_mfd_remove,
> +};
> +
> +module_pci_driver(intel_quark_mfd_driver);
> +
> +MODULE_AUTHOR("Raymond Tan <raymond.tan@...el.com>");
> +MODULE_DESCRIPTION("Intel Quark MFD PCI driver for I2C & GPIO");
> +MODULE_LICENSE("GPL v2");

-- 
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
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