Date:   Mon, 21 Nov 2016 10:32:40 +0000
From:   Lee Jones <lee.jones@...aro.org>
To:     Tan Jui Nee <jui.nee.tan@...el.com>
Cc:     mika.westerberg@...ux.intel.com, heikki.krogerus@...ux.intel.com,
        andriy.shevchenko@...ux.intel.com, tglx@...utronix.de,
        dvhart@...radead.org, mingo@...hat.com, hpa@...or.com,
        x86@...nel.org, ptyser@...-inc.com, linus.walleij@...aro.org,
        linux-gpio@...r.kernel.org, platform-driver-x86@...r.kernel.org,
        linux-kernel@...r.kernel.org, jonathan.yong@...el.com,
        ong.hock.yu@...el.com, tony.luck@...el.com,
        wan.ahmad.zainie.wan.mohamad@...el.com, yunying.sun@...el.com
Subject: Re: [PATCH v11 6/6] mfd: lpc_ich: Add support for Intel Apollo Lake
 GPIO pinctrl in non-ACPI system

On Fri, 18 Nov 2016, Tan Jui Nee wrote:

> This driver uses the P2SB hide/unhide mechanism cooperatively
> to pass the PCI BAR address to the gpio platform driver.
> 
> Signed-off-by: Tan Jui Nee <jui.nee.tan@...el.com>
> Reviewed-by: Mika Westerberg <mika.westerberg@...ux.intel.com>
> ---
> Changes in V11:
> 	- Remove duplicated object file lpc_ich-objs in Makefile.
> 	- Put p2sb.h header file in separate section in lpc_ich-apl.c, as asm stuff
> 	  is platform specific (suggested by Andy).
> 	- Rearrange variable declarations in lpc_ich_add_gpio() function
> 	  (suggested by Andy).
> 	- Move warn_continue label before if/else statement for the sake of
> 	  readability (suggested by Andy).
> 	- Add comment to #endif in lpc_ich_apl.h file.
> 
> Changes in V10:
> 	- No change
> 
> Changes in V9:
> 	- No change
> 
> Changes in V8:
> 	- Rename source file lpc_ich-apl.c to lpc_ich_apl.c (suggested by Mika).
> 
> Changes in V7:
> 	- Add author information and rewrite description of source file 
> 	  lpc_ich-apl.c and lpc_ich_apl.h.
> 	- Sort the header files by alphabetical order in lpc_ich-apl.c.
> 	- Rename header file lpc_ich-apl.h to lpc_ich_apl.h (suggested by Lee).
> 	- Remove unneeded pdata_size and platform_data from mfd_cell.
> 	  Also, remove unneeded apl_pinctrl_pdata.
> 	- Since variable apl_p2sb is only used once, hence switch it out for the
> 	  PCI_DEVFN macro (suggested by Lee).
> 	- Define APL_GPIO_COMMUNITY_MAX as total Apollo Lake GPIO communities
> 	  supported.
> 	- Set resources in mfd_cell for each GPIO community.
> 	- Call p2sb_bar() function once instead of four times inside the for loop.
> 	  And make p2sb_bar() function just to fill in the base address into a
> 	  scratch "struct resource" and have the loop do the additions to base/end.
> 	- Remove entire apl_pinctrl_pdata.name memory allocation since it is no
> 	  longer needed.
> 	- Return ret at the end of lpc_ich_add_gpio() function.
> 
> Changes in V6:
> 	- Rename CONFIG_X86_INTEL_APL to CONFIG_X86_INTEL_IVI so that it
> 	  relates to the actual product, as suggested by Mika.
> 	- Rework Makefile according Andy's comments.
> 	- Rename lpc_ich_misc() to lpc_ich_add_gpio() so that the name should not
> 	  be so generic, as suggested by Andy.
> 	- Call lpc_ich_add_gpio() via priv->chipset.
> 	- lpc_ich_add_gpio() function will be moved from 
> 	  .../include/linux/mfd/lpc_ich.h to
> 	  .../drivers/mfd/lpc_ich-apl.h
> 	  as this is a part of internal driver interface as suggested by Andy.
> 	- Move enum lpc_chipsets from 
> 	  .../drivers/mfd/lpc_ich-core.c to
> 	  .../include/linux/mfd/lpc_ich.h
> 	  as lpc_chipsets is also accessed by lpc_ich_add_gpio().
> 	- Check if kasprintf return value for all 4 gpio controllers before
> 	  proceed to add platform device by using mfd_add_devices().
> 
> Changes in V5:
> 	- Split lpc-ich driver into two parts (lpc_ich-core and lpc_ich-apl).
> 	  The file lpc_ich-apl.c introduces gpio platform driver in MFD.
> 	- Rename Kconfig option CONFIG_X86_INTEL_NON_ACPI to CONFIG_X86_INTEL_APL
> 	  so that it reflects actual product as suggested by Mika.
> 
> Changes in V4:
> 	- Move Kconfig option CONFIG_X86_INTEL_NON_ACPI from
> 	  [PATCH 2/3] x86/platform/p2sb: New Primary to Sideband bridge support driver for Intel SOC's
> 	  to
> 	  [PATCH 3/3] mfd: lpc_ich: Add support for Intel Apollo Lake GPIO pinctrl in non-ACPI system
> 	  since the config is used in latter patch.
> 	- Select CONFIG_P2SB when CONFIG_LPC_ICH is enabled.
> 	- Remove #ifdef CONFIG_X86_INTEL_NON_ACPI and use
> 	  #if defined(CONFIG_X86_INTEL_NON_ACPI) when lpc_ich_misc is called
> 	  as suggested by Lee Jones.
> 	- Use single dimensional array instead of 2D array for apl_gpio_io_res
> 	  structure and use DEFINE_RES_IRQ for its IRQ resource.
> 
> Changes in V3:
> 	- Simplify register addresses calculation and use DEFINE_RES_MEM_NAMED
> 	  defines for apl_gpio_io_res structure
> 	- Define magic number for P2SB PCI ID
> 	- Replace switch-case with if-else since currently we have only one
> 	  use case
> 	- Only call mfd_add_devices() once for all gpio communities
> 
> Changes in V2:
> 	- Add new config option CONFIG_X86_INTEL_NON_ACPI and "select PINCTRL"
> 	  to fix kbuildbot error
> 
>  drivers/mfd/Makefile       |   3 ++
>  drivers/mfd/lpc_ich_apl.c  | 121 +++++++++++++++++++++++++++++++++++++++++++++
>  drivers/mfd/lpc_ich_apl.h  |  28 +++++++++++
>  drivers/mfd/lpc_ich_core.c |   5 ++
>  4 files changed, 157 insertions(+)
>  create mode 100644 drivers/mfd/lpc_ich_apl.c
>  create mode 100644 drivers/mfd/lpc_ich_apl.h
> 
> diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
> index 06a91ea..b7fb703 100644
> --- a/drivers/mfd/Makefile
> +++ b/drivers/mfd/Makefile
> @@ -161,6 +161,9 @@ obj-$(CONFIG_MFD_INTEL_QUARK_I2C_GPIO)	+= intel_quark_i2c_gpio.o
>  obj-$(CONFIG_LPC_SCH)		+= lpc_sch.o
>  lpc_ich-objs		:= lpc_ich_core.o
>  obj-$(CONFIG_LPC_ICH)		+= lpc_ich.o
> +ifeq ($(CONFIG_X86_INTEL_IVI),y)
> +lpc_ich-objs += lpc_ich_apl.o
> +endif

What's with the iffery?

>  obj-$(CONFIG_MFD_RDC321X)	+= rdc321x-southbridge.o
>  obj-$(CONFIG_MFD_JANZ_CMODIO)	+= janz-cmodio.o
>  obj-$(CONFIG_MFD_JZ4740_ADC)	+= jz4740-adc.o
> diff --git a/drivers/mfd/lpc_ich_apl.c b/drivers/mfd/lpc_ich_apl.c
> new file mode 100644
> index 0000000..aef3c13
> --- /dev/null
> +++ b/drivers/mfd/lpc_ich_apl.c
> @@ -0,0 +1,121 @@
> +/*
> + * Intel Apollo Lake In-Vehicle Infotainment (IVI) systems used in cars support
> + *
> + * Copyright (C) 2016 Intel Corporation
> + *
> + * Author: Tan, Jui Nee <jui.nee.tan@...el.com>
> + *
> + * 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/mfd/core.h>
> +#include <linux/mfd/lpc_ich.h>
> +#include <linux/pci.h>
> +#include <linux/pinctrl/pinctrl.h>
> +
> +#include <asm/p2sb.h>
> +
> +#include "lpc_ich_apl.h"
> +
> +/* Offset data for Apollo Lake GPIO communities */
> +#define APL_GPIO_SOUTHWEST_OFFSET	0xc00000
> +#define APL_GPIO_NORTHWEST_OFFSET	0xc40000
> +#define APL_GPIO_NORTH_OFFSET		0xc50000
> +#define APL_GPIO_WEST_OFFSET		0xc70000
> +
> +#define APL_GPIO_SOUTHWEST_NPIN		43
> +#define APL_GPIO_NORTHWEST_NPIN		77
> +#define APL_GPIO_NORTH_NPIN		78
> +#define APL_GPIO_WEST_NPIN		47
> +
> +#define APL_GPIO_COMMUNITY_MAX		4
> +
> +#define APL_GPIO_IRQ 14
> +
> +#define PCI_IDSEL_P2SB	0x0d

Please tab all of these out, so they are in a single line. #OCD

> +static struct resource apl_gpio_io_res[] = {
> +	DEFINE_RES_MEM_NAMED(APL_GPIO_NORTH_OFFSET,
> +		APL_GPIO_NORTH_NPIN * SZ_8, "apl_pinctrl_n"),
> +	DEFINE_RES_MEM_NAMED(APL_GPIO_NORTHWEST_OFFSET,
> +		APL_GPIO_NORTHWEST_NPIN * SZ_8, "apl_pinctrl_nw"),
> +	DEFINE_RES_MEM_NAMED(APL_GPIO_WEST_OFFSET,
> +		APL_GPIO_WEST_NPIN * SZ_8, "apl_pinctrl_w"),
> +	DEFINE_RES_MEM_NAMED(APL_GPIO_SOUTHWEST_OFFSET,
> +		APL_GPIO_SOUTHWEST_NPIN * SZ_8, "apl_pinctrl_sw"),
> +	DEFINE_RES_IRQ(APL_GPIO_IRQ),
> +};
> +
> +static struct mfd_cell apl_gpio_devices[] = {
> +	{
> +		.name = "apl-pinctrl",
> +		.id = 0,

Are you using these IDs for anything specific?

> +		.num_resources = ARRAY_SIZE(apl_gpio_io_res),
> +		.resources = &apl_gpio_io_res[0],
> +		.ignore_resource_conflicts = true,
> +	},
> +	{
> +		.name = "apl-pinctrl",
> +		.id = 1,
> +		.num_resources = ARRAY_SIZE(apl_gpio_io_res),
> +		.resources = &apl_gpio_io_res[1],
> +		.ignore_resource_conflicts = true,
> +	},
> +	{
> +		.name = "apl-pinctrl",
> +		.id = 2,
> +		.num_resources = ARRAY_SIZE(apl_gpio_io_res),
> +		.resources = &apl_gpio_io_res[2],
> +		.ignore_resource_conflicts = true,
> +	},
> +	{
> +		.name = "apl-pinctrl",
> +		.id = 3,
> +		.num_resources = ARRAY_SIZE(apl_gpio_io_res),
> +		.resources = &apl_gpio_io_res[3],
> +		.ignore_resource_conflicts = true,
> +	},
> +};
> +
> +int lpc_ich_add_gpio(struct pci_dev *dev, enum lpc_chipsets chipset)

Why does these need to be in its own file?

> +{
> +	struct resource base;
> +	unsigned int i;
> +	int ret;
> +
> +	if (chipset != LPC_APL)
> +		return -ENODEV;
> +	/*
> +	 * Apollo lake has 4 gpio controllers,
> +	 * handle it a bit differently.
> +	 */
> +
> +	ret = p2sb_bar(dev, PCI_DEVFN(PCI_IDSEL_P2SB, 0), &base);
> +	if (ret)
> +		goto warn_continue;
> +
> +	for (i = 0; i < APL_GPIO_COMMUNITY_MAX; i++) {
> +		struct resource *res = &apl_gpio_io_res[i];
> +
> +		/* Fill MEM resource */
> +		res->start += base.start;
> +		res->end += base.start;
> +		res->flags = base.flags;
> +
> +		res++;
> +	}
> +
> +	ret = mfd_add_devices(&dev->dev, 0,
> +		apl_gpio_devices, ARRAY_SIZE(apl_gpio_devices),
> +			NULL, 0, NULL);
> +
> +warn_continue:
> +	if (ret)
> +		dev_warn(&dev->dev,
> +			"Failed to add Apollo Lake GPIO: %d\n",
> +				ret);

Incorrect tabbing.

> +	return ret;
> +}
> diff --git a/drivers/mfd/lpc_ich_apl.h b/drivers/mfd/lpc_ich_apl.h
> new file mode 100644
> index 0000000..6721621
> --- /dev/null
> +++ b/drivers/mfd/lpc_ich_apl.h
> @@ -0,0 +1,28 @@
> +/*
> + * Intel In-Vehicle Infotainment (IVI) systems used in cars support
> + *
> + * Copyright (C) 2016, Intel Corporation
> + *
> + * Author: Tan, Jui Nee <jui.nee.tan@...el.com>
> + *
> + * 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.
> + */
> +
> +#ifndef __LPC_ICH_APL_H__
> +#define __LPC_ICH_APL_H__
> +
> +#include <linux/pci.h>
> +
> +#if IS_ENABLED(CONFIG_X86_INTEL_IVI)
> +int lpc_ich_add_gpio(struct pci_dev *dev, enum lpc_chipsets chipset);
> +#else /* CONFIG_X86_INTEL_IVI is not set */
> +static inline int lpc_ich_add_gpio(struct pci_dev *dev,
> +	enum lpc_chipsets chipset)
> +{
> +	return -ENODEV;
> +}
> +#endif /* CONFIG_X86_INTEL_IVI */
> +
> +#endif /* __LPC_ICH_APL_H__ */
> diff --git a/drivers/mfd/lpc_ich_core.c b/drivers/mfd/lpc_ich_core.c
> index 3bb6334..25c4d99 100644
> --- a/drivers/mfd/lpc_ich_core.c
> +++ b/drivers/mfd/lpc_ich_core.c
> @@ -68,6 +68,8 @@
>  #include <linux/mfd/lpc_ich.h>
>  #include <linux/platform_data/itco_wdt.h>
>  
> +#include "lpc_ich_apl.h"
> +
>  #define ACPIBASE		0x40
>  #define ACPIBASE_GPE_OFF	0x28
>  #define ACPIBASE_GPE_END	0x2f
> @@ -1030,6 +1032,9 @@ static int lpc_ich_probe(struct pci_dev *dev,
>  			cell_added = true;
>  	}
>  
> +	if (!lpc_ich_add_gpio(dev, priv->chipset))

This is a non-traditional way of checking for errors.  Please use
'ret' instead.

Why isn't it an issue if this fails?

> +		cell_added = true;
> +
>  	/*
>  	 * We only care if at least one or none of the cells registered
>  	 * successfully.

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