Allow reading gmux ports from userspace. When the unsafe module parameter allow_user_writes is true, writing 1 byte values is also allowed.
For example:
cd /sys/bus/acpi/devices/APP000B:00/physical_node/ echo 4 > gmux_selected_port cat gmux_selected_port_data | xxd -p
Will show the gmux version information (00000005 in this case)
Signed-off-by: Orlando Chamberlain orlandoch.dev@gmail.com --- drivers/platform/x86/apple-gmux.c | 129 ++++++++++++++++++++++++++++++ 1 file changed, 129 insertions(+)
diff --git a/drivers/platform/x86/apple-gmux.c b/drivers/platform/x86/apple-gmux.c index c38d6ef0c15a..756059d48393 100644 --- a/drivers/platform/x86/apple-gmux.c +++ b/drivers/platform/x86/apple-gmux.c @@ -66,6 +66,11 @@ struct apple_gmux_data { enum vga_switcheroo_client_id switch_state_external; enum vga_switcheroo_state power_state; struct completion powerchange_done; + +#ifdef CONFIG_SYSFS + /* sysfs data */ + int selected_port; +#endif /* CONFIG_SYSFS */ };
static struct apple_gmux_data *apple_gmux_data; @@ -651,6 +656,121 @@ static void gmux_notify_handler(acpi_handle device, u32 value, void *context) complete(&gmux_data->powerchange_done); }
+/** + * DOC: Sysfs Interface + * + * gmux ports can be read from userspace as a sysfs interface. For example: + * + * # echo 4 > /sys/bus/acpi/devices/APP000B:00/physical_node/gmux_selected_port + * # cat /sys/bus/acpi/devices/APP000B:00/physical_node/gmux_selected_port_data | xxd -p + * 00000005 + * + * Reads 4 bytes from port 4 (GMUX_PORT_VERSION_MAJOR). + * + * Single byte writes are also supported, however this must be enabled with the + * unsafe allow_user_writes module parameter. + * + */ + +#ifdef CONFIG_SYSFS + +static bool allow_user_writes; +module_param_unsafe(allow_user_writes, bool, 0); +MODULE_PARM_DESC(allow_user_writes, "Allow userspace to write to gmux ports (default: false) (bool)"); + +static ssize_t gmux_selected_port_store(struct device *dev, + struct device_attribute *attr, const char *sysfsbuf, size_t count) +{ + struct apple_gmux_data *gmux_data = dev_get_drvdata(dev); + u8 port; + + if (kstrtou8(sysfsbuf, 10, &port) < 0) + return -EINVAL; + + /* On pio gmux's, make sure the user doesn't access too high of a port. */ + if ((gmux_data->config == &apple_gmux_pio) && + port > (gmux_data->iolen - 4)) + return -EINVAL; + + gmux_data->selected_port = port; + return count; +} + +static ssize_t gmux_selected_port_show(struct device *dev, + struct device_attribute *attr, char *sysfsbuf) +{ + struct apple_gmux_data *gmux_data = dev_get_drvdata(dev); + + return sysfs_emit(sysfsbuf, "%d\n", gmux_data->selected_port); +} + +DEVICE_ATTR_RW(gmux_selected_port); + +static ssize_t gmux_selected_port_data_store(struct device *dev, + struct device_attribute *attr, const char *sysfsbuf, size_t count) +{ + struct apple_gmux_data *gmux_data = dev_get_drvdata(dev); + + if (count == 1) + gmux_write8(gmux_data, gmux_data->selected_port, *sysfsbuf); + else + return -EINVAL; + + return count; +} + +static ssize_t gmux_selected_port_data_show(struct device *dev, + struct device_attribute *attr, char *sysfsbuf) +{ + struct apple_gmux_data *gmux_data = dev_get_drvdata(dev); + u32 data; + + data = gmux_read32(gmux_data, gmux_data->selected_port); + memcpy(sysfsbuf, &data, sizeof(data)); + + return sizeof(data); +} + +struct device_attribute dev_attr_gmux_selected_port_data_rw = __ATTR_RW(gmux_selected_port_data); +struct device_attribute dev_attr_gmux_selected_port_data_ro = __ATTR_RO(gmux_selected_port_data); + +static int gmux_init_sysfs(struct pnp_dev *pnp) +{ + int ret; + + ret = device_create_file(&pnp->dev, &dev_attr_gmux_selected_port); + if (ret) + return ret; + if (allow_user_writes) + ret = device_create_file(&pnp->dev, &dev_attr_gmux_selected_port_data_rw); + else + ret = device_create_file(&pnp->dev, &dev_attr_gmux_selected_port_data_ro); + if (ret) + device_remove_file(&pnp->dev, &dev_attr_gmux_selected_port); + return ret; +} + +static void gmux_fini_sysfs(struct pnp_dev *pnp) +{ + device_remove_file(&pnp->dev, &dev_attr_gmux_selected_port); + if (allow_user_writes) + device_remove_file(&pnp->dev, &dev_attr_gmux_selected_port_data_rw); + else + device_remove_file(&pnp->dev, &dev_attr_gmux_selected_port_data_ro); +} + +#else + +static int gmux_init_sysfs(struct pnp_dev *pnp) +{ + return 0; +} +static void gmux_fini_sysfs(struct pnp_dev *pnp) +{ +} + +#endif /* CONFIG_SYSFS */ + static int gmux_suspend(struct device *dev) { struct pnp_dev *pnp = to_pnp_dev(dev); @@ -846,8 +966,16 @@ static int gmux_probe(struct pnp_dev *pnp, const struct pnp_device_id *id) goto err_register_handler; }
+ ret = gmux_init_sysfs(pnp); + if (ret) { + pr_err("Failed to register gmux sysfs entries\n"); + goto err_sysfs; + } + return 0;
+err_sysfs: + vga_switcheroo_unregister_handler(); err_register_handler: gmux_disable_interrupts(gmux_data); apple_gmux_data = NULL; @@ -877,6 +1005,7 @@ static void gmux_remove(struct pnp_dev *pnp) { struct apple_gmux_data *gmux_data = pnp_get_drvdata(pnp);
+ gmux_fini_sysfs(pnp); vga_switcheroo_unregister_handler(); gmux_disable_interrupts(gmux_data); if (gmux_data->gpe >= 0) {