Date:   Fri, 17 Feb 2023 10:24:35 +1100
From:   Orlando Chamberlain <orlandoch.dev@gmail.com>
To:     Hans de Goede <hdegoede@redhat.com>
Cc:     Mark Gross <markgross@kernel.org>,
        platform-driver-x86@vger.kernel.org, linux-kernel@vger.kernel.org,
        Lukas Wunner <lukas@wunner.de>,
        Seth Forshee <sforshee@kernel.org>,
        Aditya Garg <gargaditya08@live.com>,
        Aun-Ali Zaidi <admin@kodeit.net>,
        Kerem Karabay <kekrby@gmail.com>
Subject: Re: [PATCH v2 2/5] apple-gmux: refactor gmux types
Message-ID: <20230217102435.3fabf965@redecorated-mbp>
In-Reply-To: <bac7cf14-fa40-fddf-b19a-5333b86f3c70@redhat.com>
References: <20230216122342.5918-1-orlandoch.dev@gmail.com>
        <20230216122342.5918-3-orlandoch.dev@gmail.com>
        <bac7cf14-fa40-fddf-b19a-5333b86f3c70@redhat.com>
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On Thu, 16 Feb 2023 14:13:25 +0100
Hans de Goede <hdegoede@redhat.com> wrote:

> Hi,
> 
> One small nit below.
> 
> On 2/16/23 13:23, Orlando Chamberlain wrote:
> > Add apple_gmux_config struct containing operations and data
> > specific to each mux type.
> > 
> > This is in preparation for adding a third, MMIO based, gmux type.
> > 
> > Signed-off-by: Orlando Chamberlain <orlandoch.dev@gmail.com>
> > ---
> > v1->v2: Handle the two ways of reading the version as part of this
> > type system (read_version_as_u32).
> >  drivers/platform/x86/apple-gmux.c | 93
> > ++++++++++++++++++++----------- include/linux/apple-gmux.h        |
> > 18 ++++-- 2 files changed, 74 insertions(+), 37 deletions(-)
> > 
> > diff --git a/drivers/platform/x86/apple-gmux.c
> > b/drivers/platform/x86/apple-gmux.c index
> > ec99e05e532c..36208e93d745 100644 ---
> > a/drivers/platform/x86/apple-gmux.c +++
> > b/drivers/platform/x86/apple-gmux.c @@ -5,6 +5,7 @@
> >   *  Copyright (C) Canonical Ltd. <seth.forshee@canonical.com>
> >   *  Copyright (C) 2010-2012 Andreas Heider <andreas@meetr.de>
> >   *  Copyright (C) 2015 Lukas Wunner <lukas@wunner.de>
> > + *  Copyright (C) 2023 Orlando Chamberlain
> > <orlandoch.dev@gmail.com> */
> >  
> >  #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
> > @@ -43,10 +44,12 @@
> >   *
> > http://www.renesas.com/products/mpumcu/h8s/h8s2100/h8s2113/index.jsp
> > */ 
> > +struct apple_gmux_config;
> > +
> >  struct apple_gmux_data {
> >  	unsigned long iostart;
> >  	unsigned long iolen;
> > -	bool indexed;
> > +	const struct apple_gmux_config *config;
> >  	struct mutex index_lock;
> >  
> >  	struct backlight_device *bdev;
> > @@ -64,6 +67,18 @@ struct apple_gmux_data {
> >  
> >  static struct apple_gmux_data *apple_gmux_data;
> >  
> > +struct apple_gmux_config {
> > +	u8 (*read8)(struct apple_gmux_data *gmux_data, int port);
> > +	void (*write8)(struct apple_gmux_data *gmux_data, int
> > port, u8 val);
> > +	u32 (*read32)(struct apple_gmux_data *gmux_data, int port);
> > +	void (*write32)(struct apple_gmux_data *gmux_data, int
> > port, u32 val);
> > +	const struct vga_switcheroo_handler *gmux_handler;
> > +	enum vga_switcheroo_handler_flags_t handler_flags;
> > +	unsigned long resource_type;
> > +	bool read_version_as_u32;
> > +	char *name;
> > +};
> > +
> >  #define GMUX_INTERRUPT_ENABLE		0xff
> >  #define GMUX_INTERRUPT_DISABLE		0x00
> >  
> > @@ -195,35 +210,23 @@ static void gmux_index_write32(struct
> > apple_gmux_data *gmux_data, int port, 
> >  static u8 gmux_read8(struct apple_gmux_data *gmux_data, int port)
> >  {
> > -	if (gmux_data->indexed)
> > -		return gmux_index_read8(gmux_data, port);
> > -	else
> > -		return gmux_pio_read8(gmux_data, port);
> > +	return gmux_data->config->read8(gmux_data, port);
> >  }
> >  
> >  static void gmux_write8(struct apple_gmux_data *gmux_data, int
> > port, u8 val) {
> > -	if (gmux_data->indexed)
> > -		gmux_index_write8(gmux_data, port, val);
> > -	else
> > -		gmux_pio_write8(gmux_data, port, val);
> > +	return gmux_data->config->write8(gmux_data, port, val);
> >  }
> >  
> >  static u32 gmux_read32(struct apple_gmux_data *gmux_data, int port)
> >  {
> > -	if (gmux_data->indexed)
> > -		return gmux_index_read32(gmux_data, port);
> > -	else
> > -		return gmux_pio_read32(gmux_data, port);
> > +	return gmux_data->config->read32(gmux_data, port);
> >  }
> >  
> >  static void gmux_write32(struct apple_gmux_data *gmux_data, int
> > port, u32 val)
> >  {
> > -	if (gmux_data->indexed)
> > -		gmux_index_write32(gmux_data, port, val);
> > -	else
> > -		gmux_pio_write32(gmux_data, port, val);
> > +	return gmux_data->config->write32(gmux_data, port, val);
> >  }
> >  
> >  /**
> > @@ -463,19 +466,43 @@ static enum vga_switcheroo_client_id
> > gmux_get_client_id(struct pci_dev *pdev) return VGA_SWITCHEROO_DIS;
> >  }
> >  
> > -static const struct vga_switcheroo_handler gmux_handler_indexed = {
> > +static const struct vga_switcheroo_handler gmux_handler_no_ddc = {
> >  	.switchto = gmux_switchto,
> >  	.power_state = gmux_set_power_state,
> >  	.get_client_id = gmux_get_client_id,
> >  };
> >  
> > -static const struct vga_switcheroo_handler gmux_handler_classic = {
> > +static const struct vga_switcheroo_handler gmux_handler_ddc = {
> >  	.switchto = gmux_switchto,
> >  	.switch_ddc = gmux_switch_ddc,
> >  	.power_state = gmux_set_power_state,
> >  	.get_client_id = gmux_get_client_id,
> >  };
> >  
> > +static const struct apple_gmux_config apple_gmux_pio = {
> > +	.read8 = &gmux_pio_read8,
> > +	.write8 = &gmux_pio_write8,
> > +	.read32 = &gmux_pio_read32,
> > +	.write32 = &gmux_pio_write32,
> > +	.gmux_handler = &gmux_handler_ddc,
> > +	.handler_flags = VGA_SWITCHEROO_CAN_SWITCH_DDC,
> > +	.resource_type = IORESOURCE_IO,
> > +	.read_version_as_u32 = false,
> > +	.name = "classic"
> > +};
> > +
> > +static const struct apple_gmux_config apple_gmux_index = {
> > +	.read8 = &gmux_index_read8,
> > +	.write8 = &gmux_index_write8,
> > +	.read32 = &gmux_index_read32,
> > +	.write32 = &gmux_index_write32,
> > +	.gmux_handler = &gmux_handler_no_ddc,
> > +	.handler_flags = VGA_SWITCHEROO_NEEDS_EDP_CONFIG,
> > +	.resource_type = IORESOURCE_IO,
> > +	.read_version_as_u32 = true,
> > +	.name = "indexed"
> > +};
> > +
> >  /**
> >   * DOC: Interrupt
> >   *
> > @@ -565,13 +592,13 @@ static int gmux_probe(struct pnp_dev *pnp,
> > const struct pnp_device_id *id) int ret = -ENXIO;
> >  	acpi_status status;
> >  	unsigned long long gpe;
> > -	bool indexed = false;
> > +	enum apple_gmux_type type;
> >  	u32 version;
> >  
> >  	if (apple_gmux_data)
> >  		return -EBUSY;
> >  
> > -	if (!apple_gmux_detect(pnp, &indexed)) {
> > +	if (!apple_gmux_detect(pnp, &type)) {
> >  		pr_info("gmux device not present\n");
> >  		return -ENODEV;
> >  	}
> > @@ -581,6 +608,16 @@ static int gmux_probe(struct pnp_dev *pnp,
> > const struct pnp_device_id *id) return -ENOMEM;
> >  	pnp_set_drvdata(pnp, gmux_data);
> >  
> > +	switch (type) {
> > +	case APPLE_GMUX_TYPE_INDEXED:
> > +		gmux_data->config = &apple_gmux_index;
> > +		mutex_init(&gmux_data->index_lock);
> > +		break;
> > +	case APPLE_GMUX_TYPE_PIO:
> > +		gmux_data->config = &apple_gmux_pio;
> > +		break;
> > +	}
> > +
> >  	res = pnp_get_resource(pnp, IORESOURCE_IO, 0);
> >  	gmux_data->iostart = res->start;
> >  	gmux_data->iolen = resource_size(res);
> > @@ -591,9 +628,7 @@ static int gmux_probe(struct pnp_dev *pnp,
> > const struct pnp_device_id *id) goto err_free;
> >  	}
> >  
> > -	if (indexed) {
> > -		mutex_init(&gmux_data->index_lock);
> > -		gmux_data->indexed = true;
> > +	if (gmux_data->config->read_version_as_u32) {
> >  		version = gmux_read32(gmux_data,
> > GMUX_PORT_VERSION_MAJOR); ver_major = (version >> 24) & 0xff;
> >  		ver_minor = (version >> 16) & 0xff;
> > @@ -604,7 +639,7 @@ static int gmux_probe(struct pnp_dev *pnp,
> > const struct pnp_device_id *id) ver_release = gmux_read8(gmux_data,
> > GMUX_PORT_VERSION_RELEASE); }
> >  	pr_info("Found gmux version %d.%d.%d [%s]\n", ver_major,
> > ver_minor,
> > -		ver_release, (gmux_data->indexed ? "indexed" :
> > "classic"));
> > +		ver_release, gmux_data->config->name);
> >  
> >  	memset(&props, 0, sizeof(props));
> >  	props.type = BACKLIGHT_PLATFORM;
> > @@ -694,12 +729,8 @@ static int gmux_probe(struct pnp_dev *pnp,
> > const struct pnp_device_id *id) *
> >  	 * Pre-retina MacBook Pros can switch the panel's DDC
> > separately. */
> > -	if (gmux_data->indexed)
> > -		ret =
> > vga_switcheroo_register_handler(&gmux_handler_indexed,
> > -
> > VGA_SWITCHEROO_NEEDS_EDP_CONFIG);
> > -	else
> > -		ret =
> > vga_switcheroo_register_handler(&gmux_handler_classic,
> > -
> > VGA_SWITCHEROO_CAN_SWITCH_DDC);
> > +	ret =
> > vga_switcheroo_register_handler(gmux_data->config->gmux_handler,
> > +			gmux_data->config->handler_flags);
> >  	if (ret) {
> >  		pr_err("Failed to register vga_switcheroo
> > handler\n"); goto err_register_handler;
> > diff --git a/include/linux/apple-gmux.h b/include/linux/apple-gmux.h
> > index 1f68b49bcd68..5f658439f7f8 100644
> > --- a/include/linux/apple-gmux.h
> > +++ b/include/linux/apple-gmux.h
> > @@ -36,6 +36,11 @@
> >  
> >  #define GMUX_MIN_IO_LEN
> > (GMUX_PORT_BRIGHTNESS + 4) 
> > +enum apple_gmux_type {
> > +	APPLE_GMUX_TYPE_PIO,
> > +	APPLE_GMUX_TYPE_INDEXED  
> 
> In the kernel with things like enum "values" or array initializers we
> typically add a , at the end of the last entry, to avoid needless
> churn when adding more entry.
> 
> The one exception is this when there is a special entry which
> marks the end of the array / enum. But that is not the case here.
> 

Thanks, I'll fix that up in v3.

> 
> > +};
> > +
> >  #if IS_ENABLED(CONFIG_APPLE_GMUX)
> >  static inline bool apple_gmux_is_indexed(unsigned long iostart)
> >  {
> > @@ -65,13 +70,13 @@ static inline bool
> > apple_gmux_is_indexed(unsigned long iostart)
> >   * Return: %true if a supported gmux ACPI device is detected and
> > the kernel
> >   * was configured with CONFIG_APPLE_GMUX, %false otherwise.
> >   */
> > -static inline bool apple_gmux_detect(struct pnp_dev *pnp_dev, bool
> > *indexed_ret) +static inline bool apple_gmux_detect(struct pnp_dev
> > *pnp_dev, enum apple_gmux_type *type_ret) {
> >  	u8 ver_major, ver_minor, ver_release;
> >  	struct device *dev = NULL;
> >  	struct acpi_device *adev;
> >  	struct resource *res;
> > -	bool indexed = false;
> > +	enum apple_gmux_type type = APPLE_GMUX_TYPE_PIO;
> >  	bool ret = false;
> >  
> >  	if (!pnp_dev) {
> > @@ -99,13 +104,14 @@ static inline bool apple_gmux_detect(struct
> > pnp_dev *pnp_dev, bool *indexed_ret) ver_minor = inb(res->start +
> > GMUX_PORT_VERSION_MINOR); ver_release = inb(res->start +
> > GMUX_PORT_VERSION_RELEASE); if (ver_major == 0xff && ver_minor ==
> > 0xff && ver_release == 0xff) {
> > -		indexed = apple_gmux_is_indexed(res->start);
> > -		if (!indexed)
> > +		if (apple_gmux_is_indexed(res->start))
> > +			type = APPLE_GMUX_TYPE_INDEXED;
> > +		else
> >  			goto out;
> >  	}
> >  
> > -	if (indexed_ret)
> > -		*indexed_ret = indexed;
> > +	if (type_ret)
> > +		*type_ret = type;
> >  
> >  	ret = true;
> >  out:  
>