时间戳

首页 > 解决方案 > 为什么我对 gpiod_set_value 的调用返回“无效 GPIO”错误？

linux - 为什么我对 gpiod_set_value 的调用返回“无效 GPIO”错误？

问题描述

我正在尝试为 OV2680 相机传感器编写驱动程序。我想打开一些 GPIO 引脚作为其->probe()功能中的步骤之一。这些 GpioIo() 引脚在 DSDT 表中声明，如下所示（对于 OV2680 所依赖的设备；请参阅完整的 DSDT 表：

        Device (PMI1)
        {
            Name (_ADR, Zero)  // _ADR: Address
            Name (_HID, "INT3472")  // _HID: Hardware ID
            Name (_CID, "INT3472")  // _CID: Compatible ID
            Name (_DDN, "INCL-CRDD")  // _DDN: DOS Device Name
            Name (_UID, One)  // _UID: Unique ID
            Method (_CRS, 0, NotSerialized)  // _CRS: Current Resource Settings
            {
                Name (SBUF, ResourceTemplate ()
                {
                    GpioIo (Exclusive, PullDefault, 0x0000, 0x0000, IoRestrictionOutputOnly,
                        "\\_SB.PCI0.GPI0", 0x00, ResourceConsumer, ,
                        )
                        {   // Pin list
                            0x0079
                        }
                    GpioIo (Exclusive, PullDefault, 0x0000, 0x0000, IoRestrictionOutputOnly,
                        "\\_SB.PCI0.GPI0", 0x00, ResourceConsumer, ,
                        )
                        {   // Pin list
                            0x007A
                        }
                    GpioIo (Exclusive, PullDefault, 0x0000, 0x0000, IoRestrictionOutputOnly,
                        "\\_SB.PCI0.GPI0", 0x00, ResourceConsumer, ,
                        )
                        {   // Pin list
                            0x008F
                        }
                })
                Return (SBUF) /* \_SB_.PCI0.PMI1._CRS.SBUF */
            }
        }

        Device (CAM1)
        {
            Name (_ADR, Zero)  // _ADR: Address
            Name (_HID, "OVTI2680")  // _HID: Hardware ID
            Name (_CID, "OVTI2680")  // _CID: Compatible ID
            Name (_DDN, "OV2680-CRDD")  // _DDN: DOS Device Name
            Name (_UID, One)  // _UID: Unique ID
            Name (_DEP, Package (0x02)  // _DEP: Dependencies
            {
                PMI1, 
                I2C2
            })
            Name (_PLD, Package (0x01)  // _PLD: Physical Location of Device
            {
                ToPLD (
                    PLD_Revision           = 0x2,
                    PLD_IgnoreColor        = 0x1,
                    PLD_Red                = 0x0,
                    PLD_Green              = 0x0,
                    PLD_Blue               = 0x0,
                    PLD_Width              = 0x0,
                    PLD_Height             = 0x0,
                    PLD_UserVisible        = 0x1,
                    PLD_Dock               = 0x0,
                    PLD_Lid                = 0x0,
                    PLD_Panel              = "FRONT",
                    PLD_VerticalPosition   = "CENTER",
                    PLD_HorizontalPosition = "RIGHT",
                    PLD_Shape              = "VERTICALRECTANGLE",
                    PLD_GroupOrientation   = 0x0,
                    PLD_GroupToken         = 0x0,
                    PLD_GroupPosition      = 0x0,
                    PLD_Bay                = 0x0,
                    PLD_Ejectable          = 0x1,
                    PLD_EjectRequired      = 0x1,
                    PLD_CabinetNumber      = 0x0,
                    PLD_CardCageNumber     = 0x0,
                    PLD_Reference          = 0x0,
                    PLD_Rotation           = 0x0,
                    PLD_Order              = 0x0,
                    PLD_VerticalOffset     = 0xFFFF,
                    PLD_HorizontalOffset   = 0xFFFF)

            })
            Method (_CRS, 0, NotSerialized)  // _CRS: Current Resource Settings
            {
                Name (SBUF, ResourceTemplate ()
                {
                    I2cSerialBusV2 (0x0010, ControllerInitiated, 0x00061A80,
                        AddressingMode7Bit, "\\_SB.PCI0.I2C2",
                        0x00, ResourceConsumer, , Exclusive,
                        )
                })
                Return (SBUF) /* \_SB_.PCI0.CAM1._CRS.SBUF */
            }
        }

请注意缺少 _DSD 段，这意味着我必须根据文档在驱动程序代码中明确声明它们。那没问题; 我有struct acpi_device这个 ACPI 设备的（通过抓取驱动程序匹配的 OV2680 设备的依赖项），所以我可以这样做并acpi_dev_add_driver_gpios()按照文档说明添加它们。我的问题出现在获取 GPIO 描述符阶段；文档说要使用gpiod_get_index()，哪个函数需要 astruct device而不是 a struct acpi_device。我试图通过传递struct acpi_device::dev成员来实现这一点，但是虽然这样做时我没有收到任何错误消息，但当我设置 GPIO 引脚时实际上似乎没有发生任何事情，所以我认为它不起作用。

鉴于这是特定于硬件的，我不确定 MRE 是否有用，但这里有一个应该编译并成功插入的驱动程序：

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/i2c.h>
#include <linux/acpi.h>
#include <linux/gpio/consumer.h>
#include <linux/platform_device.h>

static const struct acpi_gpio_params gpio1 = {0, 0, false};
static const struct acpi_gpio_params gpio2 = {1, 0, false};
static const struct acpi_gpio_params gpio3 = {2, 0, false};

static const struct acpi_gpio_mapping int3472_acpi_gpios[] = {
    {"gpio1", &gpio1, 1},
    {"gpio2", &gpio2, 1},
    {"gpio3", &gpio3, 1},
    {}
};

static int ov2680_probe(struct i2c_client *client)
{    
    /*
     * The driver will match the OV2680 device, but the GPIO
     * pins lie in its dependent INT3472, so we need to walk
     * up the dependencies to find that device.
    */
   struct acpi_device *int3472_device;

   /* get ACPI handle of OV2680 device */
   struct acpi_handle *dev_handle = ACPI_HANDLE(&client->dev);

   /* Get dependent devices */
   struct acpi_handle_list dep_devices;
   acpi_evaluate_reference(dev_handle, "_DEP", NULL, &dep_devices);

   int i;
   for (i=0; i < dep_devices.count; i++) {
       struct acpi_device_info *devinfo;
       acpi_get_object_info(dep_devices.handles[i], &devinfo);

       if (devinfo->valid & ACPI_VALID_HID && !strcmp(devinfo->hardware_id.string, "INT3472")) {
           acpi_bus_get_device(dep_devices.handles[i], &int3472_device);
       }
   }

   int ret;

   ret = acpi_dev_add_driver_gpios(int3472_device, int3472_acpi_gpios);

   struct gpio_desc *gpiod1, *gpiod2, *gpiod3;

   gpiod1 = gpiod_get_index(&int3472_device->dev, NULL, 0, GPIOD_ASIS);
   gpiod2 = gpiod_get_index(&int3472_device->dev, NULL, 1, GPIOD_ASIS);
   gpiod3 = gpiod_get_index(&int3472_device->dev, NULL, 2, GPIOD_ASIS);
   
   gpiod_set_value_cansleep(gpiod1, 1);
   gpiod_set_value_cansleep(gpiod2, 1);
   gpiod_set_value_cansleep(gpiod3, 1);

   return 0;
}

static int ov2680_remove(struct i2c_client *client)
{
    /*
     * Code goes here to get acpi_device, turn off all
     * the GPIO pins, remove them from the ACPI device
     * and whatnot
     */

    return 0;
}

static const struct acpi_device_id ov2680_acpi_match[] = {
    {"OVTI2680", 0},
    { }
};
MODULE_DEVICE_TABLE(acpi, ov2680_acpi_match);

static struct i2c_driver ov2680_driver = {
    .driver = {
        .name = "ov2680",
        .acpi_match_table = ov2680_acpi_match,
    },
    .probe_new = ov2680_probe,
    .remove = ov2680_remove,
};
module_i2c_driver(ov2680_driver);

MODULE_AUTHOR("Dan Scally");
MODULE_DESCRIPTION("A driver for OmniVision 2680 sensors");
MODULE_LICENSE("GPL");

dmesg报告添加引脚或任何内容没有问题，但调用在gpiod_set_value_cansleep()那里引发错误：

[4840.774633] gpiod_set_value_cansleep：无效的 GPIO（错误指针）

这是因为调用gpiod_get_index()失败，因此 GPIO 描述符无效。

问题：

  1. 我的使用&int3472->device作为gpiod_get_index()正确方法的参数吗？
  2. 如果是这样，什么可能导致调用gpiod_get_index()失败？

编辑：

的输出grep -H 15 /sys/bus/acpi/devices/*/status

/sys/bus/acpi/devices/ACPI000C:00/status:15
/sys/bus/acpi/devices/BOSC0200:00/status:15
/sys/bus/acpi/devices/device:16/status:15
/sys/bus/acpi/devices/device:17/status:15
/sys/bus/acpi/devices/device:32/status:15
/sys/bus/acpi/devices/INT33D3:00/status:15
/sys/bus/acpi/devices/INT33D6:00/status:15
/sys/bus/acpi/devices/INT3400:00/status:15
/sys/bus/acpi/devices/INT340E:00/status:15
/sys/bus/acpi/devices/INT344B:00/status:15
/sys/bus/acpi/devices/INT3472:08/status:15
/sys/bus/acpi/devices/INT3472:09/status:15
/sys/bus/acpi/devices/INT3F0D:00/status:15
/sys/bus/acpi/devices/MSFT0001:00/status:15
/sys/bus/acpi/devices/MSFT0101:00/status:15
/sys/bus/acpi/devices/OVTI2680:00/status:15
/sys/bus/acpi/devices/OVTI5648:00/status:15
/sys/bus/acpi/devices/PNP0103:00/status:15
/sys/bus/acpi/devices/PNP0401:01/status:15
/sys/bus/acpi/devices/PNP0A05:04/status:15
/sys/bus/acpi/devices/PNP0C09:00/status:15
/sys/bus/acpi/devices/PNP0C0C:00/status:15
/sys/bus/acpi/devices/PNP0C0D:00/status:15
/sys/bus/acpi/devices/VPC2004:00/status:15
/sys/bus/acpi/devices/WCOM508C:00/status:15

标签： linuxlinux-kernellinux-device-drivergpio

解决方案

（根据我之前给出的评论收集答案）

为了澄清起见，我不得不说，从您的 DSDT 我们可以得到以下信息。有 3 组 PMIC，DSCx即CLPx和PMIx。我相信它们是基于模型的，例如Desktop、Laptop、2-in-1。在每种情况下，同一组中的所有 PMIC 都有不同的_UID. 从提供的输出中，grep -H 15 ...我们只有十分之二的实例枚举了实例INT3472:08和INT3472:09（恰好是 DSDT 中最后定义的两个）。他们是PMIx，你可以检查一下grep -H . /sys/bus/acpi/devices/INT3472:*/path。

您的兴趣是PMI1消耗来自Intel GPIO 驱动程序的三个 GPIO 线，即引脚 121、122 和 143（相对于组引脚 1、2 和 23，您可以将它们解码为 Community #2、Group #5 或 GPP_F，这可能帮助您理解_INI通过 DSDT 中的其他方法接触这些线的方法），并根据其驱动程序提供3 + 7 = 10 个引脚。

现在到代码。ACPI 方法仅用于链接电源资源，Linux 内核还有其他方法可以劫持其他设备的_DEP资源，因为您试图做的是使用与您正在为其创建驱动程序的设备无关的资源。

方法是通过 ACPI HID 查找设备：

struct acpi_device *adev;
struct device *phys_dev;
struct gpio_desc *desc;

...

adev = acpi_dev_get_first_match_dev("INT3472", "1", -1);
if (!adev) {
  pr_err("Oops, we didn't find an ACPI device!\n");
  return -ENODEV;
}

phys_dev = get_device(acpi_get_first_physical_node(adev));
acpi_dev_put(adev);

if (!phys_dev) {
  pr_err("Oops, we didn't find a physical device!\n");
  return -ENODEV;
}

desc = gpiod_get_index(phys_dev, NULL, 0, GPIOD_ASIS);
if (IS_ERR(desc)) {
  pr_err("Something went wrong when retrieving GPIO\n");
  put_device(phys_dev);
  return PTR_ERR(desc);
}

...

gpiod_put(desc);
put_device(phys_dev);

简化这一点的黑客方法（因为您知道设备实例的总线类型和确切名称，但 Linux 不保证它在引导时保持相同）是：

struct device *phys_dev;
struct gpio_desc *desc;

...

phys_dev = bus_find_device_by_name(&i2c_bus_type, NULL, "i2c-INT3472:09");
if (!phys_dev) {
  pr_err("Oops, we didn't find a physical device!\n");
  return -ENODEV;
}

desc = gpiod_get_index(phys_dev, NULL, 0, GPIOD_ASIS);
if (IS_ERR(desc)) {
  pr_err("Something went wrong when retrieving GPIO\n");
  put_device(phys_dev);
  return PTR_ERR(desc);
}

...

gpiod_put(desc);
put_device(phys_dev);

旁注：

  1. OV2680 相机传感器已经存在驱动程序，扩展它而不是为 ACPI 案例创建特定的分支是有意义的。
  2. 正确的方法是使用可以在没有任何黑客攻击的情况下使用的资源，即在 PMIC MFD 驱动程序中。

推荐阅读