diff mbox series

dm: Use explicit numbers for all enum values

Message ID 2f8e786bf3a7dcd0518e5374d7b56c559b23c784.1648808022.git.michal.simek@xilinx.com
State Rejected
Delegated to: Simon Glass
Headers show
Series dm: Use explicit numbers for all enum values | expand

Commit Message

Michal Simek April 1, 2022, 10:13 a.m. UTC 
Based on discussion at
https://lore.kernel.org/r/20200318125003.GA2727094@kroah.com we got
recommendation to use explicit values for all enum values.
The patch is following this recommendation.

The same change was also done by commit 31431dd466e7 ("firmware: xilinx:
Use explicit values for all enum values").

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
---

I was doing some debug and got uclass ID but without values it is hard to
find out which uclass it is.
---
 include/dm/uclass-id.h | 240 ++++++++++++++++++++---------------------
 1 file changed, 120 insertions(+), 120 deletions(-)

Comments

Sean Anderson April 1, 2022, 5:22 p.m. UTC | #1 
Hi Michal,

On 4/1/22 6:13 AM, Michal Simek wrote:
> Based on discussion at
> https://lore.kernel.org/r/20200318125003.GA2727094@kroah.com we got
> recommendation to use explicit values for all enum values.
> The patch is following this recommendation.

To comment on Greg's comment

> Yes, but is that guaranteed by the compiler?  I keep getting
> conflicting advice with that.

It's guaranteed by the spec as far back as C89:

> Each subsequent enumerator with no = defines its enumeration constant
> as the value of the constant expression obtained by adding 1 to the
> value of the previous enumeration constant.

from http://port70.net/~nsz/c/c89/c89-draft.html#3.5.2.2

I prefer explicit enumerations when dealing with hardware (to
make it very clear what the value of the constant is). However, when
these enumerations are used only by software, they act as arbitrary
identifiers. They can be changed or rearranged at will without regard to
breaking hardware compatibility. This is especially the case if, like
uclass identifiers, they are entirely internal to U-Boot.

For example, the uclass list is sorted alphabetically. This helps reduce
merge conflicts, since multiple uclasses can be added without trampling
on each other's diff context. This patch would make it such that new
uclass identifiers could only be added to the end of the list, or each
identifier would need to be redefined. This would drastically increase
the incident of merge conflicts in this enum.  For this reason, I don't
think this patch should be applied.

> The same change was also done by commit 31431dd466e7 ("firmware: xilinx:
> Use explicit values for all enum values").
> 
> Signed-off-by: Michal Simek <michal.simek@xilinx.com>
> ---
> 
> I was doing some debug and got uclass ID but without values it is hard to
> find out which uclass it is.

You can get a list of all compiled-in uclasses along with their ids with
the "dm uclass" command.

--Sean
diff mbox series

Patch

diff --git a/include/dm/uclass-id.h b/include/dm/uclass-id.h
index 0e26e1d13824..30d120879a4e 100644
--- a/include/dm/uclass-id.h
+++ b/include/dm/uclass-id.h
@@ -13,129 +13,129 @@ 
 enum uclass_id {
 	/* These are used internally by driver model */
 	UCLASS_ROOT = 0,
-	UCLASS_DEMO,
-	UCLASS_TEST,
-	UCLASS_TEST_FDT,
-	UCLASS_TEST_FDT_MANUAL,
-	UCLASS_TEST_BUS,
-	UCLASS_TEST_PROBE,
-	UCLASS_TEST_DUMMY,
-	UCLASS_TEST_DEVRES,
-	UCLASS_TEST_ACPI,
-	UCLASS_SPI_EMUL,	/* sandbox SPI device emulator */
-	UCLASS_I2C_EMUL,	/* sandbox I2C device emulator */
-	UCLASS_I2C_EMUL_PARENT,	/* parent for I2C device emulators */
-	UCLASS_PCI_EMUL,	/* sandbox PCI device emulator */
-	UCLASS_PCI_EMUL_PARENT,	/* parent for PCI device emulators */
-	UCLASS_USB_EMUL,	/* sandbox USB bus device emulator */
-	UCLASS_AXI_EMUL,	/* sandbox AXI bus device emulator */
+	UCLASS_DEMO = 1,
+	UCLASS_TEST = 2,
+	UCLASS_TEST_FDT = 3,
+	UCLASS_TEST_FDT_MANUAL = 4,
+	UCLASS_TEST_BUS = 5,
+	UCLASS_TEST_PROBE = 6,
+	UCLASS_TEST_DUMMY = 7,
+	UCLASS_TEST_DEVRES = 8,
+	UCLASS_TEST_ACPI = 10,
+	UCLASS_SPI_EMUL = 11,	/* sandbox SPI device emulator */
+	UCLASS_I2C_EMUL = 12,	/* sandbox I2C device emulator */
+	UCLASS_I2C_EMUL_PARENT = 12, /* parent for I2C device emulators */
+	UCLASS_PCI_EMUL = 13,	/* sandbox PCI device emulator */
+	UCLASS_PCI_EMUL_PARENT = 14, /* parent for PCI device emulators */
+	UCLASS_USB_EMUL = 15,	/* sandbox USB bus device emulator */
+	UCLASS_AXI_EMUL = 16,	/* sandbox AXI bus device emulator */
 
 	/* U-Boot uclasses start here - in alphabetical order */
-	UCLASS_ACPI_PMC,	/* (x86) Power-management controller (PMC) */
-	UCLASS_ADC,		/* Analog-to-digital converter */
-	UCLASS_AHCI,		/* SATA disk controller */
-	UCLASS_AUDIO_CODEC,	/* Audio codec with control and data path */
-	UCLASS_AXI,		/* AXI bus */
-	UCLASS_BLK,		/* Block device */
-	UCLASS_BOOTCOUNT,       /* Bootcount backing store */
-	UCLASS_BUTTON,		/* Button */
-	UCLASS_CACHE,		/* Cache controller */
-	UCLASS_CLK,		/* Clock source, e.g. used by peripherals */
-	UCLASS_CPU,		/* CPU, typically part of an SoC */
-	UCLASS_CROS_EC,		/* Chrome OS EC */
-	UCLASS_DISPLAY,		/* Display (e.g. DisplayPort, HDMI) */
-	UCLASS_DSI_HOST,	/* Display Serial Interface host */
-	UCLASS_DMA,		/* Direct Memory Access */
-	UCLASS_DSA,		/* Distributed (Ethernet) Switch Architecture */
-	UCLASS_ECDSA,		/* Elliptic curve cryptographic device */
-	UCLASS_EFI_LOADER,	/* Devices created by UEFI applications */
-	UCLASS_EFI_MEDIA,	/* Devices provided by UEFI firmware */
-	UCLASS_ETH,		/* Ethernet device */
-	UCLASS_ETH_PHY,		/* Ethernet PHY device */
-	UCLASS_FIRMWARE,	/* Firmware */
-	UCLASS_FS_FIRMWARE_LOADER,		/* Generic loader */
-	UCLASS_GPIO,		/* Bank of general-purpose I/O pins */
-	UCLASS_HASH,		/* Hash device */
-	UCLASS_HWSPINLOCK,	/* Hardware semaphores */
-	UCLASS_I2C,		/* I2C bus */
-	UCLASS_I2C_EEPROM,	/* I2C EEPROM device */
-	UCLASS_I2C_GENERIC,	/* Generic I2C device */
-	UCLASS_I2C_MUX,		/* I2C multiplexer */
-	UCLASS_I2S,		/* I2S bus */
-	UCLASS_IDE,		/* IDE device */
-	UCLASS_IOMMU,		/* IOMMU */
-	UCLASS_IRQ,		/* Interrupt controller */
-	UCLASS_KEYBOARD,	/* Keyboard input device */
-	UCLASS_LED,		/* Light-emitting diode (LED) */
-	UCLASS_LPC,		/* x86 'low pin count' interface */
-	UCLASS_MAILBOX,		/* Mailbox controller */
-	UCLASS_MASS_STORAGE,	/* Mass storage device */
-	UCLASS_MDIO,		/* MDIO bus */
-	UCLASS_MDIO_MUX,	/* MDIO MUX/switch */
-	UCLASS_MISC,		/* Miscellaneous device */
-	UCLASS_MMC,		/* SD / MMC card or chip */
-	UCLASS_MOD_EXP,		/* RSA Mod Exp device */
-	UCLASS_MTD,		/* Memory Technology Device (MTD) device */
-	UCLASS_MUX,		/* Multiplexer device */
-	UCLASS_NOP,		/* No-op devices */
-	UCLASS_NORTHBRIDGE,	/* Intel Northbridge / SDRAM controller */
-	UCLASS_NVME,		/* NVM Express device */
-	UCLASS_P2SB,		/* (x86) Primary-to-Sideband Bus */
-	UCLASS_PANEL,		/* Display panel, such as an LCD */
-	UCLASS_PANEL_BACKLIGHT,	/* Backlight controller for panel */
-	UCLASS_PCH,		/* x86 platform controller hub */
-	UCLASS_PCI,		/* PCI bus */
-	UCLASS_PCI_EP,		/* PCI endpoint device */
-	UCLASS_PCI_GENERIC,	/* Generic PCI bus device */
-	UCLASS_PHY,		/* Physical Layer (PHY) device */
-	UCLASS_PINCONFIG,	/* Pin configuration node device */
-	UCLASS_PINCTRL,		/* Pinctrl (pin muxing/configuration) device */
-	UCLASS_PMIC,		/* PMIC I/O device */
-	UCLASS_POWER_DOMAIN,	/* (SoC) Power domains */
-	UCLASS_PWM,		/* Pulse-width modulator */
-	UCLASS_PWRSEQ,		/* Power sequence device */
-	UCLASS_QFW,		/* QEMU firmware config device */
-	UCLASS_RAM,		/* RAM controller */
-	UCLASS_REBOOT_MODE,	/* Reboot mode */
-	UCLASS_REGULATOR,	/* Regulator device */
-	UCLASS_REMOTEPROC,	/* Remote Processor device */
-	UCLASS_RESET,		/* Reset controller device */
-	UCLASS_RNG,		/* Random Number Generator */
-	UCLASS_RTC,		/* Real time clock device */
-	UCLASS_SCMI_AGENT,	/* Interface with an SCMI server */
-	UCLASS_SCSI,		/* SCSI device */
-	UCLASS_SERIAL,		/* Serial UART */
-	UCLASS_SIMPLE_BUS,	/* Bus with child devices */
-	UCLASS_SMEM,		/* Shared memory interface */
-	UCLASS_SOC,		/* SOC Device */
-	UCLASS_SOUND,		/* Playing simple sounds */
-	UCLASS_SPI,		/* SPI bus */
-	UCLASS_SPI_FLASH,	/* SPI flash */
-	UCLASS_SPI_GENERIC,	/* Generic SPI flash target */
-	UCLASS_SPMI,		/* System Power Management Interface bus */
-	UCLASS_SYSCON,		/* System configuration device */
-	UCLASS_SYSINFO,		/* Device information from hardware */
-	UCLASS_SYSRESET,	/* System reset device */
-	UCLASS_TEE,		/* Trusted Execution Environment device */
-	UCLASS_THERMAL,		/* Thermal sensor */
-	UCLASS_TIMER,		/* Timer device */
-	UCLASS_TPM,		/* Trusted Platform Module TIS interface */
-	UCLASS_UFS,		/* Universal Flash Storage */
-	UCLASS_USB,		/* USB bus */
-	UCLASS_USB_DEV_GENERIC,	/* USB generic device */
-	UCLASS_USB_HUB,		/* USB hub */
-	UCLASS_USB_GADGET_GENERIC,	/* USB generic device */
-	UCLASS_VIDEO,		/* Video or LCD device */
-	UCLASS_VIDEO_BRIDGE,	/* Video bridge, e.g. DisplayPort to LVDS */
-	UCLASS_VIDEO_CONSOLE,	/* Text console driver for video device */
-	UCLASS_VIDEO_OSD,	/* On-screen display */
-	UCLASS_VIRTIO,		/* VirtIO transport device */
-	UCLASS_W1,		/* Dallas 1-Wire bus */
-	UCLASS_W1_EEPROM,	/* one-wire EEPROMs */
-	UCLASS_WDT,		/* Watchdog Timer driver */
-	UCLASS_PVBLOCK,		/* Xen virtual block device */
+	UCLASS_ACPI_PMC = 17,	/* (x86) Power-management controller (PMC) */
+	UCLASS_ADC = 18,	/* Analog-to-digital converter */
+	UCLASS_AHCI = 19,	/* SATA disk controller */
+	UCLASS_AUDIO_CODEC = 20,/* Audio codec with control and data path */
+	UCLASS_AXI = 21,	/* AXI bus */
+	UCLASS_BLK = 22,	/* Block device */
+	UCLASS_BOOTCOUNT = 23,	/* Bootcount backing store */
+	UCLASS_BUTTON = 24,	/* Button */
+	UCLASS_CACHE = 25,	/* Cache controller */
+	UCLASS_CLK = 26,	/* Clock source, e.g. used by peripherals */
+	UCLASS_CPU = 27,	/* CPU, typically part of an SoC */
+	UCLASS_CROS_EC = 28,	/* Chrome OS EC */
+	UCLASS_DISPLAY = 29,	/* Display (e.g. DisplayPort, HDMI) */
+	UCLASS_DSI_HOST = 30,	/* Display Serial Interface host */
+	UCLASS_DMA = 31,	/* Direct Memory Access */
+	UCLASS_DSA = 32,	/* Distributed (Ethernet) Switch Architecture */
+	UCLASS_ECDSA = 33,	/* Elliptic curve cryptographic device */
+	UCLASS_EFI_LOADER = 34,	/* Devices created by UEFI applications */
+	UCLASS_EFI_MEDIA = 35,	/* Devices provided by UEFI firmware */
+	UCLASS_ETH = 36,	/* Ethernet device */
+	UCLASS_ETH_PHY = 37,	/* Ethernet PHY device */
+	UCLASS_FIRMWARE = 38,	/* Firmware */
+	UCLASS_FS_FIRMWARE_LOADER = 39, /* Generic loader */
+	UCLASS_GPIO = 40,	/* Bank of general-purpose I/O pins */
+	UCLASS_HASH = 41,	/* Hash device */
+	UCLASS_HWSPINLOCK = 42,	/* Hardware semaphores */
+	UCLASS_I2C = 43,	/* I2C bus */
+	UCLASS_I2C_EEPROM = 44,	/* I2C EEPROM device */
+	UCLASS_I2C_GENERIC = 45, /* Generic I2C device */
+	UCLASS_I2C_MUX = 46,	/* I2C multiplexer */
+	UCLASS_I2S = 47,	/* I2S bus */
+	UCLASS_IDE = 48,	/* IDE device */
+	UCLASS_IOMMU = 49,	/* IOMMU */
+	UCLASS_IRQ = 49,	/* Interrupt controller */
+	UCLASS_KEYBOARD = 50,	/* Keyboard input device */
+	UCLASS_LED = 51,	/* Light-emitting diode (LED) */
+	UCLASS_LPC = 52,	/* x86 'low pin count' interface */
+	UCLASS_MAILBOX = 53,	/* Mailbox controller */
+	UCLASS_MASS_STORAGE = 54, /* Mass storage device */
+	UCLASS_MDIO = 55,	/* MDIO bus */
+	UCLASS_MDIO_MUX = 56,	/* MDIO MUX/switch */
+	UCLASS_MISC = 57,	/* Miscellaneous device */
+	UCLASS_MMC = 58,	/* SD / MMC card or chip */
+	UCLASS_MOD_EXP = 59,	/* RSA Mod Exp device */
+	UCLASS_MTD = 60,	/* Memory Technology Device (MTD) device */
+	UCLASS_MUX = 61,	/* Multiplexer device */
+	UCLASS_NOP = 62,	/* No-op devices */
+	UCLASS_NORTHBRIDGE = 63, /* Intel Northbridge / SDRAM controller */
+	UCLASS_NVME = 64,	/* NVM Express device */
+	UCLASS_P2SB = 65,	/* (x86) Primary-to-Sideband Bus */
+	UCLASS_PANEL = 66,	/* Display panel, such as an LCD */
+	UCLASS_PANEL_BACKLIGHT = 67, /* Backlight controller for panel */
+	UCLASS_PCH = 68,	/* x86 platform controller hub */
+	UCLASS_PCI = 69,	/* PCI bus */
+	UCLASS_PCI_EP = 70,	/* PCI endpoint device */
+	UCLASS_PCI_GENERIC = 71,/* Generic PCI bus device */
+	UCLASS_PHY = 72,	/* Physical Layer (PHY) device */
+	UCLASS_PINCONFIG = 73,	/* Pin configuration node device */
+	UCLASS_PINCTRL = 74,	/* Pinctrl (pin muxing/configuration) device */
+	UCLASS_PMIC = 75,	/* PMIC I/O device */
+	UCLASS_POWER_DOMAIN = 76, /* (SoC) Power domains */
+	UCLASS_PWM = 77,	/* Pulse-width modulator */
+	UCLASS_PWRSEQ = 78,	/* Power sequence device */
+	UCLASS_QFW = 79,	/* QEMU firmware config device */
+	UCLASS_RAM = 80,	/* RAM controller */
+	UCLASS_REBOOT_MODE = 81,/* Reboot mode */
+	UCLASS_REGULATOR = 82,	/* Regulator device */
+	UCLASS_REMOTEPROC = 83,	/* Remote Processor device */
+	UCLASS_RESET = 84,	/* Reset controller device */
+	UCLASS_RNG = 85,	/* Random Number Generator */
+	UCLASS_RTC = 86,	/* Real time clock device */
+	UCLASS_SCMI_AGENT = 87,	/* Interface with an SCMI server */
+	UCLASS_SCSI = 88,	/* SCSI device */
+	UCLASS_SERIAL = 89,	/* Serial UART */
+	UCLASS_SIMPLE_BUS = 90,	/* Bus with child devices */
+	UCLASS_SMEM = 91,	/* Shared memory interface */
+	UCLASS_SOC = 92,	/* SOC Device */
+	UCLASS_SOUND = 93,	/* Playing simple sounds */
+	UCLASS_SPI = 94,	/* SPI bus */
+	UCLASS_SPI_FLASH = 95,	/* SPI flash */
+	UCLASS_SPI_GENERIC = 96, /* Generic SPI flash target */
+	UCLASS_SPMI = 97,	/* System Power Management Interface bus */
+	UCLASS_SYSCON = 98,	/* System configuration device */
+	UCLASS_SYSINFO = 99,	/* Device information from hardware */
+	UCLASS_SYSRESET = 100,	/* System reset device */
+	UCLASS_TEE = 101,	/* Trusted Execution Environment device */
+	UCLASS_THERMAL = 102,	/* Thermal sensor */
+	UCLASS_TIMER = 103,	/* Timer device */
+	UCLASS_TPM = 104,	/* Trusted Platform Module TIS interface */
+	UCLASS_UFS = 105,	/* Universal Flash Storage */
+	UCLASS_USB = 106,	/* USB bus */
+	UCLASS_USB_DEV_GENERIC = 107, /* USB generic device */
+	UCLASS_USB_HUB = 108,	/* USB hub */
+	UCLASS_USB_GADGET_GENERIC = 109, /* USB generic device */
+	UCLASS_VIDEO = 110,	/* Video or LCD device */
+	UCLASS_VIDEO_BRIDGE = 111, /* Video bridge, e.g. DisplayPort to LVDS */
+	UCLASS_VIDEO_CONSOLE = 112, /* Text console driver for video device */
+	UCLASS_VIDEO_OSD = 113,	/* On-screen display */
+	UCLASS_VIRTIO = 114,	/* VirtIO transport device */
+	UCLASS_W1 = 115,	/* Dallas 1-Wire bus */
+	UCLASS_W1_EEPROM = 116,	/* one-wire EEPROMs */
+	UCLASS_WDT = 117,	/* Watchdog Timer driver */
+	UCLASS_PVBLOCK = 118,	/* Xen virtual block device */
 
-	UCLASS_COUNT,
+	UCLASS_COUNT = 119,
 	UCLASS_INVALID = -1,
 };