[PATCH 1/1] i2c:aspeed:support ast2600 i2c new register mode driver

Simon Glass sjg at chromium.org
Mon Jan 9 20:47:28 CET 2023


  Hi Ryan_chen,

On Mon, 9 Jan 2023 at 01:30, ryan_chen <ryan_chen at aspeedtech.com> wrote:
>
> Add i2c new register mode driver to support AST2600 i2c
> new register mode. AST2600 i2c controller have legacy and
> new register mode. The new register mode have global register
> support 4 base clock for scl clock selection, and new clock
> divider mode.
>
> Signed-off-by: ryan_chen <ryan_chen at aspeedtech.com>
> ---
>  MAINTAINERS               |   6 +
>  drivers/i2c/Kconfig       |   7 +
>  drivers/i2c/Makefile      |   1 +
>  drivers/i2c/ast2600_i2c.c | 480 ++++++++++++++++++++++++++++++++++++++
>  4 files changed, 494 insertions(+)
>  create mode 100644 drivers/i2c/ast2600_i2c.c

This generally looks OK, but I have quite a few minor comments, and
one major one: could/should this driver be an update to the existing
one, instead? That is the short of thing that really should be in your
commit message.

>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 3fc4cd0f12..1cf54f0b4e 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -769,6 +769,12 @@ S: Maintained
>  F:     drivers/pci/pcie_phytium.c
>  F:     arch/arm/dts/phytium-durian.dts
>
> +ASPEED AST2600 I2C DRIVER
> +M:     Ryan Chen <ryan_chen at aspeedtech.com>
> +R:     Aspeed BMC SW team <BMC-SW at aspeedtech.com>
> +S:     Maintained
> +F:     drivers/i2c/ast2600_i2c.c
> +
>  ASPEED FMC SPI DRIVER
>  M:     Chin-Ting Kuo <chin-ting_kuo at aspeedtech.com>
>  M:     Cédric Le Goater <clg at kaod.org>
> diff --git a/drivers/i2c/Kconfig b/drivers/i2c/Kconfig
> index 08b6c7bdcc..34f507fb3b 100644
> --- a/drivers/i2c/Kconfig
> +++ b/drivers/i2c/Kconfig
> @@ -221,6 +221,13 @@ config SYS_I2C_DW
>           controller is used in various SoCs, e.g. the ST SPEAr, Altera
>           SoCFPGA, Synopsys ARC700 and some Intel x86 SoCs.
>
> +config SYS_I2C_AST2600
> +    bool "AST2600 I2C Controller"
> +    depends on DM_I2C && ARCH_ASPEED
> +    help
> +      Say yes here to select AST2600 I2C Host Controller. The driver
> +      support AST2600 I2C new mode register.

What speeds does it support? Please add at least 3 lines of info.

A link to the datasheet would help too, either here or in doc/

> +
>  config SYS_I2C_ASPEED
>         bool "Aspeed I2C Controller"
>         depends on DM_I2C && ARCH_ASPEED
> diff --git a/drivers/i2c/Makefile b/drivers/i2c/Makefile
> index 920aafb91c..89db2d8e37 100644
> --- a/drivers/i2c/Makefile
> +++ b/drivers/i2c/Makefile
> @@ -12,6 +12,7 @@ obj-$(CONFIG_$(SPL_)I2C_CROS_EC_LDO) += cros_ec_ldo.o
>
>  obj-$(CONFIG_$(SPL_)SYS_I2C_LEGACY) += i2c_core.o
>  obj-$(CONFIG_SYS_I2C_ASPEED) += ast_i2c.o
> +obj-$(CONFIG_SYS_I2C_AST2600) += ast2600_i2c.o
>  obj-$(CONFIG_SYS_I2C_AT91) += at91_i2c.o
>  obj-$(CONFIG_SYS_I2C_CADENCE) += i2c-cdns.o
>  obj-$(CONFIG_SYS_I2C_CA) += i2c-cortina.o
> diff --git a/drivers/i2c/ast2600_i2c.c b/drivers/i2c/ast2600_i2c.c
> new file mode 100644
> index 0000000000..52aea460ac
> --- /dev/null
> +++ b/drivers/i2c/ast2600_i2c.c
> @@ -0,0 +1,480 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Copyright ASPEED Technology Inc.
> + */
> +#include <linux/iopoll.h>

The ordering is off here. Please see

https://u-boot.readthedocs.io/en/latest/develop/codingstyle.html#include-files

> +#include <common.h>
> +#include <clk.h>
> +#include <dm.h>
> +#include <errno.h>
> +#include <fdtdec.h>
> +#include <i2c.h>
> +#include <asm/io.h>
> +#include <regmap.h>
> +#include <reset.h>
> +
> +struct ast2600_i2c_regs {
> +       u32 fun_ctrl;
> +       u32 ac_timing;
> +       u32 trx_buff;
> +       u32 icr;
> +       u32 ier;
> +       u32 isr;
> +       u32 cmd_sts;
> +};
> +
> +/* 0x00 : I2CC Master/Slave Function Control Register  */
> +#define AST2600_I2CC_SLAVE_ADDR_RX_EN  BIT(20)

Perhaps this should go in the .h file like the other drivers?

> +#define AST2600_I2CC_MASTER_RETRY_MASK GENMASK(19, 18)
> +#define AST2600_I2CC_MASTER_RETRY(x)   (((x) & GENMASK(1, 0)) << 18)

Can you drop unused things?

> +#define AST2600_I2CC_BUS_AUTO_RELEASE  BIT(17)
> +#define AST2600_I2CC_M_SDA_LOCK_EN             BIT(16)
> +#define AST2600_I2CC_MULTI_MASTER_DIS  BIT(15)
> +#define AST2600_I2CC_M_SCL_DRIVE_EN            BIT(14)
> +#define AST2600_I2CC_MSB_STS                   BIT(9)
> +#define AST2600_I2CC_SDA_DRIVE_1T_EN   BIT(8)
> +#define AST2600_I2CC_M_SDA_DRIVE_1T_EN BIT(7)
> +#define AST2600_I2CC_M_HIGH_SPEED_EN   BIT(6)
> +/* reserver 5 : 2 */

reserved?

> +#define AST2600_I2CC_SLAVE_EN                  BIT(1)
> +#define AST2600_I2CC_MASTER_EN                 BIT(0)
> +
> +/* 0x04 : I2CD Clock and AC Timing Control Register #1 */
> +/* Base register value. These bits are always set by the driver. */
> +#define I2CD_CACTC_BASE                0xfff00300
> +#define I2CD_TCKHIGH_SHIFT     16
> +#define I2CD_TCKLOW_SHIFT      12
> +#define I2CD_THDDAT_SHIFT      10
> +#define I2CD_TO_DIV_SHIFT      8
> +#define I2CD_BASE_DIV_SHIFT    0
> +
> +/* 0x08 : I2CC Master/Slave Transmit/Receive Byte Buffer Register */
> +#define AST2600_I2CC_TX_DIR_MASK               GENMASK(31, 29)
> +#define AST2600_I2CC_SDA_OE                            BIT(28)
> +#define AST2600_I2CC_SDA_O                             BIT(27)
> +#define AST2600_I2CC_SCL_OE                            BIT(26)
> +#define AST2600_I2CC_SCL_O                             BIT(25)
> +
> +#define AST2600_I2CC_SCL_LINE_STS              BIT(18)
> +#define AST2600_I2CC_SDA_LINE_STS              BIT(17)
> +#define AST2600_I2CC_BUS_BUSY_STS              BIT(16)
> +#define AST2600_I2CC_GET_RX_BUFF(x)            (((x) >> 8) & GENMASK(7, 0))

Can you drop the AST2600 prefix here? It is too long and we know it is
this driver.

> +
> +/* 0x10 : I2CM Master Interrupt Control Register */
> +/* 0x14 : I2CM Master Interrupt Status Register  */
> +#define AST2600_I2CM_PKT_TIMEOUT               BIT(18)
> +#define AST2600_I2CM_PKT_ERROR                 BIT(17)
> +#define AST2600_I2CM_PKT_DONE                  BIT(16)
> +
> +#define AST2600_I2CM_BUS_RECOVER_FAIL  BIT(15)
> +#define AST2600_I2CM_SDA_DL_TO                 BIT(14)
> +#define AST2600_I2CM_BUS_RECOVER               BIT(13)
> +#define AST2600_I2CM_SMBUS_ALT                 BIT(12)
> +
> +#define AST2600_I2CM_SCL_LOW_TO                        BIT(6)
> +#define AST2600_I2CM_ABNORMAL                  BIT(5)
> +#define AST2600_I2CM_NORMAL_STOP               BIT(4)
> +#define AST2600_I2CM_ARBIT_LOSS                        BIT(3)
> +#define AST2600_I2CM_RX_DONE                   BIT(2)
> +#define AST2600_I2CM_TX_NAK                            BIT(1)
> +#define AST2600_I2CM_TX_ACK                            BIT(0)
> +
> +/* 0x18 : I2CM Master Command/Status Register   */
> +#define AST2600_I2CM_PKT_ADDR(x)               (((x) & GENMASK(6, 0)) << 24)
> +#define AST2600_I2CM_PKT_EN                            BIT(16)
> +#define AST2600_I2CM_SDA_OE_OUT_DIR            BIT(15)
> +#define AST2600_I2CM_SDA_O_OUT_DIR             BIT(14)
> +#define AST2600_I2CM_SCL_OE_OUT_DIR            BIT(13)
> +#define AST2600_I2CM_SCL_O_OUT_DIR             BIT(12)
> +#define AST2600_I2CM_RECOVER_CMD_EN            BIT(11)
> +
> +#define AST2600_I2CM_RX_DMA_EN                 BIT(9)
> +#define AST2600_I2CM_TX_DMA_EN                 BIT(8)
> +/* Command Bit */
> +#define AST2600_I2CM_RX_BUFF_EN                        BIT(7)
> +#define AST2600_I2CM_TX_BUFF_EN                        BIT(6)
> +#define AST2600_I2CM_STOP_CMD                  BIT(5)
> +#define AST2600_I2CM_RX_CMD_LAST               BIT(4)
> +#define AST2600_I2CM_RX_CMD                            BIT(3)
> +
> +#define AST2600_I2CM_TX_CMD                            BIT(1)
> +#define AST2600_I2CM_START_CMD                 BIT(0)
> +
> +#define I2C_TIMEOUT_US 100000
> +/*
> + * Device private data
> + */

single-line comment style is

/* Device-private data */

> +struct ast2600_i2c_priv {
> +       struct clk clk;
> +       struct ast2600_i2c_regs *regs;
> +       void __iomem *global;
> +};
> +
> +static int ast2600_i2c_read_data(struct ast2600_i2c_priv *priv, u8 chip_addr,
> +                                u8 *buffer, size_t len, bool send_stop)

Please add a full comment for this one

> +{
> +       int rx_cnt, ret = 0;
> +       u32 cmd, isr;
> +
> +       for (rx_cnt = 0; rx_cnt < len; rx_cnt++, buffer++) {
> +               cmd = AST2600_I2CM_PKT_EN | AST2600_I2CM_PKT_ADDR(chip_addr) |
> +                     AST2600_I2CM_RX_CMD;
> +               if (!rx_cnt)
> +                       cmd |= AST2600_I2CM_START_CMD;
> +
> +               if ((len - 1) == rx_cnt)
> +                       cmd |= AST2600_I2CM_RX_CMD_LAST;
> +
> +               if (send_stop && ((len - 1) == rx_cnt))
> +                       cmd |= AST2600_I2CM_STOP_CMD;
> +
> +               writel(cmd, &priv->regs->cmd_sts);
> +
> +               ret = readl_poll_timeout(&priv->regs->isr, isr,
> +                                        isr & AST2600_I2CM_PKT_DONE,
> +                                        I2C_TIMEOUT_US);
> +               if (ret)
> +                       return -ETIMEDOUT;
> +
> +               *buffer =
> +                       AST2600_I2CC_GET_RX_BUFF(readl(&priv->regs->trx_buff));

^^ too long

> +
> +               writel(AST2600_I2CM_PKT_DONE, &priv->regs->isr);
> +
> +               if (isr & AST2600_I2CM_TX_NAK)
> +                       return -EREMOTEIO;
> +       }
> +
> +       return 0;
> +}
> +
> +static int ast2600_i2c_write_data(struct ast2600_i2c_priv *priv, u8 chip_addr,
> +                                 u8 *buffer, size_t len, bool send_stop)

and this

> +{
> +       int tx_cnt, ret = 0;
> +       u32 cmd, isr;
> +
> +       if (!len) {
> +               cmd = AST2600_I2CM_PKT_EN | AST2600_I2CM_PKT_ADDR(chip_addr) |
> +                     AST2600_I2CM_START_CMD;
> +               writel(cmd, &priv->regs->cmd_sts);
> +               ret = readl_poll_timeout(&priv->regs->isr, isr,
> +                                        isr & AST2600_I2CM_PKT_DONE,
> +                                        I2C_TIMEOUT_US);
> +               if (ret)
> +                       return -ETIMEDOUT;
> +
> +               writel(AST2600_I2CM_PKT_DONE, &priv->regs->isr);
> +
> +               if (isr & AST2600_I2CM_TX_NAK)
> +                       return -EREMOTEIO;
> +       }
> +
> +       for (tx_cnt = 0; tx_cnt < len; tx_cnt++, buffer++) {
> +               cmd = AST2600_I2CM_PKT_EN | AST2600_I2CM_PKT_ADDR(chip_addr);
> +               cmd |= AST2600_I2CM_TX_CMD;
> +
> +               if (!tx_cnt)
> +                       cmd |= AST2600_I2CM_START_CMD;
> +
> +               if (send_stop && ((len - 1) == tx_cnt))
> +                       cmd |= AST2600_I2CM_STOP_CMD;
> +
> +               writel(*buffer, &priv->regs->trx_buff);
> +               writel(cmd, &priv->regs->cmd_sts);
> +               ret = readl_poll_timeout(&priv->regs->isr, isr,
> +                                        isr & AST2600_I2CM_PKT_DONE,
> +                                        I2C_TIMEOUT_US);
> +               if (ret)
> +                       return -ETIMEDOUT;
> +
> +               writel(AST2600_I2CM_PKT_DONE, &priv->regs->isr);
> +
> +               if (isr & AST2600_I2CM_TX_NAK)
> +                       return -EREMOTEIO;
> +       }
> +
> +       return 0;
> +}
> +
> +static int ast2600_i2c_deblock(struct udevice *dev)
> +{
> +       struct ast2600_i2c_priv *priv = dev_get_priv(dev);
> +       u32 csr = readl(&priv->regs->cmd_sts);
> +       u32 isr;
> +       int ret;
> +
> +       //reinit

/* reinit */

> +       writel(0, &priv->regs->fun_ctrl);
> +       /* Enable Master Mode. Assuming single-master */
> +       writel(AST2600_I2CC_BUS_AUTO_RELEASE | AST2600_I2CC_MASTER_EN |
> +                      AST2600_I2CC_MULTI_MASTER_DIS,
> +              &priv->regs->fun_ctrl);
> +

[..]

> +static int ast2600_i2c_set_speed(struct udevice *dev, unsigned int speed)
> +{
> +       struct ast2600_i2c_priv *priv = dev_get_priv(dev);
> +       unsigned long base_clk1, base_clk2, base_clk3, base_clk4;
> +       int baseclk_idx;
> +       u32 clk_div_reg;
> +       u32 apb_clk;
> +       u32 scl_low;
> +       u32 scl_high;
> +       int divisor;
> +       int inc = 0;
> +       u32 data;
> +
> +       debug("Setting speed for I2C%d to <%u>\n", dev->seq_, speed);
> +       if (!speed) {
> +               debug("No valid speed specified\n");
> +               return -EINVAL;
> +       }
> +
> +       apb_clk = clk_get_rate(&priv->clk);
> +
> +       clk_div_reg = readl(priv->global + 0x10);
> +       base_clk1 = (apb_clk * 10) / ((((clk_div_reg & 0xff) + 2) * 10) / 2);

Can apb_clk * 10 go in a local var to reduce duplication?

> +       base_clk2 =
> +               (apb_clk * 10) / (((((clk_div_reg >> 8) & 0xff) + 2) * 10) / 2);
> +       base_clk3 = (apb_clk * 10) /
> +                   (((((clk_div_reg >> 16) & 0xff) + 2) * 10) / 2);
> +       base_clk4 = (apb_clk * 10) /
> +                   (((((clk_div_reg >> 24) & 0xff) + 2) * 10) / 2);

Normally we like to define these fields, like:

#define CLK1_DIV_SHIFT 0
#define CLK1_DIV_MASK (0xff >> CLK1_DIV_SHIFT)
#define CLK2_DIV_SHIFT 8
#define CLK2_DIV_MASK (0xff >> CLK2_DIV_SHIFT)

etc.

> +
> +       if ((apb_clk / speed) <= 32) {
> +               baseclk_idx = 0;
> +               divisor = DIV_ROUND_UP(apb_clk, speed);
> +       } else if ((base_clk1 / speed) <= 32) {
> +               baseclk_idx = 1;
> +               divisor = DIV_ROUND_UP(base_clk1, speed);
> +       } else if ((base_clk2 / speed) <= 32) {
> +               baseclk_idx = 2;
> +               divisor = DIV_ROUND_UP(base_clk2, speed);
> +       } else if ((base_clk3 / speed) <= 32) {
> +               baseclk_idx = 3;
> +               divisor = DIV_ROUND_UP(base_clk3, speed);
> +       } else {
> +               baseclk_idx = 4;
> +               divisor = DIV_ROUND_UP(base_clk4, speed);
> +               inc = 0;
> +               while ((divisor + inc) > 32) {
> +                       inc |= divisor & 0x1;
> +                       divisor >>= 1;
> +                       baseclk_idx++;
> +               }
> +               divisor += inc;
> +       }
> +       divisor = min_t(int, divisor, 32);
> +       baseclk_idx &= 0xf;

What happens if baseclk_idx is >= 16 ?

> +       scl_low = ((divisor * 9) / 16) - 1;
> +       scl_low = min_t(u32, scl_low, 0xf);
> +       scl_high = (divisor - scl_low - 2) & 0xf;
> +       /* Divisor : Base Clock : tCKHighMin : tCK High : tCK Low  */
> +       data = ((scl_high - 1) << 20) | (scl_high << 16) | (scl_low << 12) |
> +              (baseclk_idx);

drop extra () around baseclk_idx

> +       /* Set AC Timing */
> +       writel(data, &priv->regs->ac_timing);
> +
> +       return 0;
> +}
> +
> +static int ast2600_i2c_probe(struct udevice *dev)
> +{
> +       struct ast2600_i2c_priv *priv = dev_get_priv(dev);
> +       struct udevice *misc_dev;
> +       int ret;
> +
> +       /* find global base address */
> +       ret = uclass_get_device_by_driver(UCLASS_MISC,
> +                                         DM_DRIVER_GET(aspeed_i2c_global),
> +                                         &misc_dev);

But isn't this the parent device of this one? Just use device_get_parent(dev)

Also misc_dev is not a great name. How about glob_dev ?

> +       if (ret) {
> +               debug("i2c global not defined\n");
> +               return ret;
> +       }
> +
> +       priv->global = devfdt_get_addr_ptr(misc_dev);

dev_read_addr()

> +       if (IS_ERR(priv->global)) {
> +               debug("%s(): can't get global\n", __func__);
> +               return PTR_ERR(priv->global);
> +       }
> +
> +       /* Reset device */
> +       writel(0, &priv->regs->fun_ctrl);

When you have functions with a lot of priv->regs things it makes sense
to add a local 'regs' variable.

> +       /* Enable Master Mode. Assuming single-master */
> +       writel(AST2600_I2CC_BUS_AUTO_RELEASE | AST2600_I2CC_MASTER_EN |
> +                      AST2600_I2CC_MULTI_MASTER_DIS,
> +              &priv->regs->fun_ctrl);
> +
> +       writel(0, &priv->regs->ier);
> +       /* Clear Interrupt */
> +       writel(~0, &priv->regs->isr);
> +
> +       return 0;
> +}
> +
> +static int ast2600_i2c_of_to_plat(struct udevice *dev)
> +{
> +       struct ast2600_i2c_priv *priv = dev_get_priv(dev);
> +       int ret;
> +
> +       priv->regs = dev_read_addr_ptr(dev);
> +       if (!(priv->regs))

Drop extra ()

> +               return -EINVAL;
> +
> +       ret = clk_get_by_index(dev, 0, &priv->clk);
> +       if (ret < 0) {
> +               debug("%s: Can't get clock for %s: %d\n", __func__, dev->name,
> +                     ret);
> +               return ret;
> +       }
> +
> +       return 0;
> +}
> +
> +static const struct dm_i2c_ops ast2600_i2c_ops = {
> +       .xfer = ast2600_i2c_xfer,
> +       .deblock = ast2600_i2c_deblock,
> +       .set_bus_speed = ast2600_i2c_set_speed,
> +};
> +
> +static const struct udevice_id ast2600_i2c_ids[] = {
> +       { .compatible = "aspeed,ast2600-i2c" },
> +       {},
> +};
> +
> +U_BOOT_DRIVER(ast2600_i2c) = {
> +       .name = "ast2600_i2c",
> +       .id = UCLASS_I2C,
> +       .of_match = ast2600_i2c_ids,
> +       .probe = ast2600_i2c_probe,
> +       .of_to_plat = ast2600_i2c_of_to_plat,
> +       .priv_auto = sizeof(struct ast2600_i2c_priv),
> +       .ops = &ast2600_i2c_ops,
> +};
> +
> +#define AST2600_I2CG_ISR                       0x00
> +#define AST2600_I2CG_SLAVE_ISR         0x04
> +#define AST2600_I2CG_OWNER                 0x08
> +#define AST2600_I2CG_CTRL                  0x0C
> +#define AST2600_I2CG_CLK_DIV_CTRL      0x10
> +
> +#define AST2600_I2CG_SLAVE_PKT_NAK         BIT(4)
> +#define AST2600_I2CG_M_S_SEPARATE_INTR BIT(3)
> +#define AST2600_I2CG_CTRL_NEW_REG          BIT(2)
> +#define AST2600_I2CG_CTRL_NEW_CLK_DIV  BIT(1)
> +
> +#define AST2600_GLOBAL_INIT                                    \
> +                       (AST2600_I2CG_SLAVE_PKT_NAK |   \
> +                       AST2600_I2CG_CTRL_NEW_REG |             \
> +                       AST2600_I2CG_CTRL_NEW_CLK_DIV)
> +#define I2CCG_DIV_CTRL 0xC6411208

Please use lower-case hex consistently

Hmm these should really go in the header file too?

> +
> +struct ast2600_i2c_global_priv {
> +       void __iomem *regs;
> +       struct reset_ctl reset;
> +};
> +
> +/*
> + * APB clk : 100Mhz
> + * div  : scl       : baseclk [APB/((div/2) + 1)] : tBuf [1/bclk * 16]
> + * I2CG10[31:24] base clk4 for i2c auto recovery timeout counter (0xC6)
> + * I2CG10[23:16] base clk3 for Standard-mode (100Khz) min tBuf 4.7us
> + * 0x3c : 100.8Khz  : 3.225Mhz                    : 4.96us
> + * 0x3d : 99.2Khz   : 3.174Mhz                    : 5.04us
> + * 0x3e : 97.65Khz  : 3.125Mhz                    : 5.12us
> + * 0x40 : 97.75Khz  : 3.03Mhz                     : 5.28us
> + * 0x41 : 99.5Khz   : 2.98Mhz                     : 5.36us (default)
> + * I2CG10[15:8] base clk2 for Fast-mode (400Khz) min tBuf 1.3us
> + * 0x12 : 400Khz    : 10Mhz                       : 1.6us
> + * I2CG10[7:0] base clk1 for Fast-mode Plus (1Mhz) min tBuf 0.5us
> + * 0x08 : 1Mhz      : 20Mhz                       : 0.8us
> + */
> +
> +static int aspeed_i2c_global_probe(struct udevice *dev)
> +{
> +       struct ast2600_i2c_global_priv *i2c_global = dev_get_priv(dev);
> +       int ret = 0;
> +
> +       i2c_global->regs = dev_read_addr_ptr(dev);
> +       if (!(i2c_global->regs))

again too many (). Please fix globally

> +               return -EINVAL;
> +
> +       debug("%s(dev=%p)\n", __func__, dev);
> +
> +       ret = reset_get_by_index(dev, 0, &i2c_global->reset);
> +       if (ret) {
> +               printf("%s(): Failed to get reset signal\n", __func__);

log_err() if you want an error. Try to avoid using __func__ - use
log...() instead

> +               return ret;
> +       }
> +
> +       reset_deassert(&i2c_global->reset);

Can this fail?

> +
> +       writel(AST2600_GLOBAL_INIT, i2c_global->regs +
> +               AST2600_I2CG_CTRL);
> +       writel(I2CCG_DIV_CTRL, i2c_global->regs +
> +               AST2600_I2CG_CLK_DIV_CTRL);
> +
> +       return 0;
> +}
> +
> +static const struct udevice_id aspeed_i2c_global_ids[] = {
> +       {       .compatible = "aspeed,ast2600-i2c-global",      },
> +       { }
> +};
> +
> +U_BOOT_DRIVER(aspeed_i2c_global) = {
> +       .name           = "aspeed_i2c_global",
> +       .id                     = UCLASS_MISC,
> +       .of_match       = aspeed_i2c_global_ids,
> +       .probe          = aspeed_i2c_global_probe,
> +       .priv_auto  = sizeof(struct ast2600_i2c_global_priv),
> +};
> +
> --
> 2.34.1
>

Regards,
Simon


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