Re: [PATCH v2 2/5] apple-gmux: refactor gmux types

Hans de Goede
2023-02-16T13:14:38Z

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.

> +};
> +
> #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;