[PATCH u-boot v1 6/6] aspeed: I2C driver.

Simon Glass sjg at chromium.org
Thu Nov 24 07:26:41 AEDT 2016


Hi Maxim,

On 23 November 2016 at 12:50, Maxim Sloyko <maxims at google.com> wrote:
> The driver is very limited: only single master mode is supported
> and only byte-by-byte synchronous reads and writes are supported,
> no Pool Buffers or DMA.
>
> Signed-off-by: Maxim Sloyko <maxims at google.com>
> ---
>  drivers/i2c/Kconfig   |   9 ++
>  drivers/i2c/Makefile  |   1 +
>  drivers/i2c/ast_i2c.c | 334 ++++++++++++++++++++++++++++++++++++++++++++++++++
>  drivers/i2c/ast_i2c.h | 130 ++++++++++++++++++++
>  4 files changed, 474 insertions(+)
>  create mode 100644 drivers/i2c/ast_i2c.c
>  create mode 100644 drivers/i2c/ast_i2c.h

Please add a change log for each version.

>
> diff --git a/drivers/i2c/Kconfig b/drivers/i2c/Kconfig
> index 6e22bba..425766a 100644
> --- a/drivers/i2c/Kconfig
> +++ b/drivers/i2c/Kconfig
> @@ -90,6 +90,15 @@ config SYS_I2C_DW_ENABLE_STATUS_UNSUPPORTED
>           enable status register. This config option can be enabled in such
>           cases.
>
> +config SYS_I2C_AST
> +       bool "Aspeed I2C Controller"
> +       depends on DM_I2C
> +       help
> +         Say yes here to select Aspeed I2C Host Controller. The driver
> +         supports AST2500 and AST2400 controllers, but is very limited.
> +         Only single master mode is supported and only byte-by-byte
> +         synchronous reads and writes are supported, no Pool Buffers or DMA.
> +
>  config SYS_I2C_INTEL
>         bool "Intel I2C/SMBUS driver"
>         depends on DM_I2C
> diff --git a/drivers/i2c/Makefile b/drivers/i2c/Makefile
> index 167424d..89e046e 100644
> --- a/drivers/i2c/Makefile
> +++ b/drivers/i2c/Makefile
> @@ -16,6 +16,7 @@ obj-$(CONFIG_PCA9564_I2C) += pca9564_i2c.o
>  obj-$(CONFIG_TSI108_I2C) += tsi108_i2c.o
>  obj-$(CONFIG_SH_SH7734_I2C) += sh_sh7734_i2c.o
>  obj-$(CONFIG_SYS_I2C) += i2c_core.o
> +obj-$(CONFIG_SYS_I2C_AST) += ast_i2c.o
>  obj-$(CONFIG_SYS_I2C_CADENCE) += i2c-cdns.o
>  obj-$(CONFIG_SYS_I2C_DAVINCI) += davinci_i2c.o
>  obj-$(CONFIG_SYS_I2C_DW) += designware_i2c.o
> diff --git a/drivers/i2c/ast_i2c.c b/drivers/i2c/ast_i2c.c
> new file mode 100644
> index 0000000..e785f22
> --- /dev/null
> +++ b/drivers/i2c/ast_i2c.c
> @@ -0,0 +1,334 @@
> +/*
> + * Copyright (C) 2012-2020  ASPEED Technology Inc.
> + * Copyright 2016 IBM Corporation
> + * Copyright 2016 Google, Inc.
> + *
> + * SPDX-License-Identifier:    GPL-2.0+
> + */
> +
> +#include <common.h>
> +#include <dm.h>
> +#include <fdtdec.h>
> +#include <i2c.h>
> +
> +#include <asm/arch/ast_scu.h>
> +#include <asm/arch/regs-scu.h>
> +#include <asm/io.h>
> +#include <errno.h>
> +
> +#include "ast_i2c.h"
> +
> +#define I2C_TIMEOUT_US 100000
> +#define I2C_SLEEP_STEP_US 20
> +
> +DECLARE_GLOBAL_DATA_PTR;
> +
> +/*
> + * Device private data
> + */
> +struct ast_i2c {
> +       /* Device registers */
> +       struct ast_i2c_regs *regs;
> +       /* I2C speed in Hz */
> +       int speed;
> +};
> +
> +/*
> + * Given desired divider ratio, return the value that needs to be set
> + * in Clock and AC Timing Control register
> + */
> +static u32 get_clk_reg_val(ulong divider_ratio)
> +{
> +       ulong inc = 0, div;
> +       ulong scl_low, scl_high, data;
> +
> +       for (div = 0; divider_ratio >= 16; div++) {
> +               inc |= (divider_ratio & 1);
> +               divider_ratio >>= 1;
> +       }
> +       divider_ratio += inc;
> +       scl_low = (divider_ratio >> 1) - 1;
> +       scl_high = divider_ratio - scl_low - 2;
> +       data = I2CD_CACTC_BASE
> +                       | (scl_high << I2CD_TCKHIGH_SHIFT)
> +                       | (scl_low << I2CD_TCKLOW_SHIFT)
> +                       | (div << I2CD_BASE_DIV_SHIFT);
> +
> +       return data;
> +}
> +
> +static inline void ast_i2c_clear_interrupts(struct ast_i2c_regs *i2c_base)

Drop the inline

> +{
> +       writel(~0, &i2c_base->isr);
> +}
> +
> +static void ast_i2c_init_bus(struct ast_i2c *i2c_bus)
> +{
> +       /* Reset device */
> +       writel(0, &i2c_bus->regs->fcr);
> +       /* Enable Master Mode. Assuming single-master */
> +       debug("Enable Master for %p\n", i2c_bus->regs);
> +       writel(I2CD_MASTER_EN
> +              | I2CD_M_SDA_LOCK_EN
> +              | I2CD_MULTI_MASTER_DIS | I2CD_M_SCL_DRIVE_EN,
> +              &i2c_bus->regs->fcr);
> +       debug("FCR: %p\n", &i2c_bus->regs->fcr);
> +       /* Enable Interrupts */
> +       writel(I2CD_INTR_TX_ACK
> +              | I2CD_INTR_TX_NAK
> +              | I2CD_INTR_RX_DONE
> +              | I2CD_INTR_BUS_RECOVER_DONE
> +              | I2CD_INTR_NORMAL_STOP
> +              | I2CD_INTR_ABNORMAL, &i2c_bus->regs->icr);
> +}
> +
> +static int ast_i2c_ofdata_to_platdata(struct udevice *dev)
> +{
> +       struct ast_i2c *i2c_bus = dev_get_priv(dev);
> +       struct ast_i2c_regs *i2c_base = dev_get_addr_ptr(dev);

blank line here

> +       if (IS_ERR(i2c_base))

Actually this is supposed to return NULL if it fails (see the function
comment), but I see that the impl does not. It returns
FDT_ADDR_T_NONE. The correct fix would be to add a new patch to update
dev_get_addr_ptr() to return NULL in this case, I think.

> +               return PTR_ERR(i2c_base);
> +
> +       i2c_bus->regs = i2c_base;
> +
> +       return 0;
> +}
> +
> +static int ast_i2c_probe(struct udevice *dev)
> +{
> +       struct ast_i2c *i2c_bus = dev_get_priv(dev);
> +
> +       debug("Enabling I2C%u\n", dev->seq);
> +       ast_scu_enable_i2c(dev->seq);
> +
> +       ast_i2c_init_bus(i2c_bus);
> +
> +       return 0;
> +}
> +
> +static inline int ast_i2c_wait_isr(struct ast_i2c_regs *i2c_base, u32 flag)
> +{
> +       int timeout = I2C_TIMEOUT_US;
> +
> +       while (!(readl(&i2c_base->isr) & flag) && timeout > 0) {
> +               udelay(I2C_SLEEP_STEP_US);
> +               timeout -= I2C_SLEEP_STEP_US;
> +       }
> +
> +       ast_i2c_clear_interrupts(i2c_base);
> +       if (timeout <= 0)
> +               return -ETIMEDOUT;
> +
> +       return 0;
> +}
> +
> +static inline int ast_i2c_send_stop(struct ast_i2c_regs *i2c_base)
> +{
> +       writel(I2CD_M_STOP_CMD, &i2c_base->csr);
> +
> +       return ast_i2c_wait_isr(i2c_base, I2CD_INTR_NORMAL_STOP);
> +}
> +
> +static inline int ast_i2c_wait_tx(struct ast_i2c_regs *i2c_base)
> +{
> +       int timeout = I2C_TIMEOUT_US;
> +       u32 flag = I2CD_INTR_TX_ACK | I2CD_INTR_TX_NAK;
> +       u32 status = readl(&i2c_base->isr) & flag;
> +       int ret = 0;
> +
> +       while (!status && timeout > 0) {
> +               status = readl(&i2c_base->isr) & flag;
> +               udelay(I2C_SLEEP_STEP_US);
> +               timeout -= I2C_SLEEP_STEP_US;
> +       }
> +
> +       if (status == I2CD_INTR_TX_NAK)
> +               ret = -EREMOTEIO;
> +
> +       if (timeout <= 0)
> +               ret = -ETIMEDOUT;
> +
> +       ast_i2c_clear_interrupts(i2c_base);
> +
> +       return ret;
> +}
> +
> +static int ast_i2c_start_txn(struct ast_i2c_regs *i2c_base, uint devaddr)
> +{
> +       /* Start and Send Device Address */
> +       writel(devaddr, &i2c_base->trbbr);
> +       writel(I2CD_M_START_CMD | I2CD_M_TX_CMD, &i2c_base->csr);
> +
> +       return ast_i2c_wait_tx(i2c_base);
> +}
> +
> +static int ast_i2c_read_data(struct ast_i2c *i2c_bus, u8 chip_addr, u8 *buffer,
> +                            size_t len, bool send_stop)
> +{
> +       struct ast_i2c_regs *i2c_base = i2c_bus->regs;
> +       int i2c_error =
> +           ast_i2c_start_txn(i2c_base, (chip_addr << 1) | I2C_M_RD);
> +       u32 i2c_cmd = I2CD_M_RX_CMD;
> +
> +       if (i2c_error < 0)
> +               return i2c_error;
> +
> +       for (; len > 0; len--, buffer++) {
> +               if (len == 1)
> +                       i2c_cmd |= I2CD_M_S_RX_CMD_LAST;
> +               writel(i2c_cmd, &i2c_base->csr);
> +               i2c_error = ast_i2c_wait_isr(i2c_base, I2CD_INTR_RX_DONE);
> +               if (i2c_error < 0)
> +                       return i2c_error;
> +               *buffer = (readl(&i2c_base->trbbr) & I2CD_RX_DATA_MASK)
> +                               >> I2CD_RX_DATA_SHIFT;
> +       }
> +       ast_i2c_clear_interrupts(i2c_base);
> +
> +       if (send_stop)
> +               return ast_i2c_send_stop(i2c_base);
> +
> +       return 0;
> +}
> +
> +static int ast_i2c_write_data(struct ast_i2c *i2c_bus, u8 chip_addr, u8
> +                             *buffer, size_t len, bool send_stop)
> +{
> +       struct ast_i2c_regs *i2c_base = i2c_bus->regs;
> +       int i2c_error = ast_i2c_start_txn(i2c_base, (chip_addr << 1));
> +
> +       if (i2c_error < 0)
> +               return i2c_error;
> +
> +       for (; len > 0; len--, buffer++) {
> +               writel(*buffer, &i2c_base->trbbr);
> +               writel(I2CD_M_TX_CMD, &i2c_base->csr);
> +               i2c_error = ast_i2c_wait_tx(i2c_base);
> +               if (i2c_error < 0)
> +                       return i2c_error;
> +       }
> +
> +       if (send_stop)
> +               return ast_i2c_send_stop(i2c_base);
> +
> +       return 0;
> +}
> +
> +static int ast_i2c_deblock(struct udevice *dev)
> +{
> +       struct ast_i2c *i2c_bus = dev_get_priv(dev);
> +       struct ast_i2c_regs *i2c_base = i2c_bus->regs;

drop blank line

> +
> +       u32 csr = readl(&i2c_base->csr);
> +       bool sda_high = csr & I2CD_SDA_LINE_STS;
> +       bool scl_high = csr & I2CD_SCL_LINE_STS;
> +
> +       int ret = 0;
> +
> +       if (sda_high && scl_high) {
> +               /* Bus is idle, no deblocking needed. */
> +               return 0;
> +       } else if (sda_high) {
> +               /* Send stop command */
> +               debug("Unterminated TXN in (%x), sending stop\n", csr);
> +               ret = ast_i2c_send_stop(i2c_base);
> +       } else if (scl_high) {
> +               /* Possibly stuck slave */
> +               debug("Bus stuck (%x), attempting recovery\n", csr);
> +               writel(I2CD_BUS_RECOVER_CMD, &i2c_base->csr);
> +               ret = ast_i2c_wait_isr(
> +                       i2c_base, I2CD_INTR_BUS_RECOVER_DONE);

Parameters should go on the same line as the function name - if you
split over, align with the '('.

> +       } else {
> +               /* Just try to reinit the device. */
> +               ast_i2c_init_bus(i2c_bus);
> +       }
> +
> +       return ret;
> +}
> +
> +static int ast_i2c_xfer(struct udevice *dev, struct i2c_msg *msg, int nmsgs)
> +{
> +       struct ast_i2c *i2c_bus = dev_get_priv(dev);
> +       int ret;
> +
> +       (void)ast_i2c_deblock(dev);

Is this because you want to ignore the error? If so please add a
comment. If not, just return the error here.

> +       debug("i2c_xfer: %d messages\n", nmsgs);
> +       for (; nmsgs > 0; nmsgs--, msg++) {
> +               if (msg->flags & I2C_M_RD) {
> +                       debug("i2c_read: chip=0x%x, len=0x%x, flags=0x%x\n",
> +                             msg->addr, msg->len, msg->flags);
> +                       ret = ast_i2c_read_data(i2c_bus, msg->addr, msg->buf,
> +                                               msg->len, (nmsgs == 1));
> +               } else {
> +                       debug("i2c_write: chip=0x%x, len=0x%x, flags=0x%x\n",
> +                             msg->addr, msg->len, msg->flags);
> +                       ret = ast_i2c_write_data(i2c_bus, msg->addr, msg->buf,
> +                                                msg->len, (nmsgs == 1));
> +               }
> +               if (ret) {
> +                       debug("%s: error (%d)\n", __func__, ret);
> +                       return -EREMOTEIO;
> +               }
> +       }
> +
> +       return 0;
> +}
> +
> +static int ast_i2c_set_speed(struct udevice *dev, unsigned int speed)
> +{
> +       struct ast_i2c *i2c_bus = dev_get_priv(dev);
> +       struct ast_i2c_regs *i2c_base = i2c_bus->regs;
> +       ulong pclk, divider;
> +
> +       debug("Setting speed ofr I2C%d to <%u>\n", dev->seq, speed);
> +       if (!speed) {
> +               debug("No valid speed specified\n");
> +               return -EINVAL;
> +       }
> +
> +       pclk = ast_get_apbclk();
> +       divider = pclk / speed;
> +
> +       i2c_bus->speed = speed;
> +       if (speed > 400000) {
> +               debug("Enabling High Speed\n");
> +               setbits_le32(&i2c_base->fcr, I2CD_M_HIGH_SPEED_EN
> +                            | I2CD_M_SDA_DRIVE_1T_EN
> +                            | I2CD_SDA_DRIVE_1T_EN);
> +               writel(0x3, &i2c_base->cactcr2);
> +               writel(get_clk_reg_val(divider), &i2c_base->cactcr1);
> +       } else {
> +               debug("Enabling Normal Speed\n");
> +               writel(get_clk_reg_val(divider), &i2c_base->cactcr1);
> +               writel(I2CD_NO_TIMEOUT_CTRL, &i2c_base->cactcr2);
> +       }
> +
> +       ast_i2c_clear_interrupts(i2c_base);
> +
> +       return 0;
> +}
> +
> +static const struct dm_i2c_ops ast_i2c_ops = {
> +       .xfer = ast_i2c_xfer,
> +       .set_bus_speed = ast_i2c_set_speed,
> +       .deblock = ast_i2c_deblock,
> +};
> +
> +static const struct udevice_id ast_i2c_ids[] = {
> +       {.compatible = "aspeed,ast2400-i2c-controller",},
> +       {.compatible = "aspeed,ast2400-i2c-bus",},
> +       {},
> +};
> +
> +/* Tell GNU Indent to keep this as is: */
> +/* *INDENT-OFF* */
> +U_BOOT_DRIVER(i2c_aspeed) = {
> +       .name = "i2c_aspeed",
> +       .id = UCLASS_I2C,
> +       .of_match = ast_i2c_ids,
> +       .probe = ast_i2c_probe,
> +       .ofdata_to_platdata = ast_i2c_ofdata_to_platdata,
> +       .priv_auto_alloc_size = sizeof(struct ast_i2c),
> +       .ops = &ast_i2c_ops,
> +};
> +/* *INDENT-ON* */
> diff --git a/drivers/i2c/ast_i2c.h b/drivers/i2c/ast_i2c.h
> new file mode 100644
> index 0000000..ecdb4fe
> --- /dev/null
> +++ b/drivers/i2c/ast_i2c.h
> @@ -0,0 +1,130 @@
> +/*
> + * Copyright (C) 2012-2020  ASPEED Technology Inc.
> + * Copyright 2016 IBM Corporation
> + * Copyright 2016 Google, Inc.
> + *
> + * SPDX-License-Identifier:    GPL-2.0+
> + */
> +#ifndef __AST_I2C_H_
> +#define __AST_I2C_H_
> +
> +struct ast_i2c_regs {
> +       u32 fcr;
> +       u32 cactcr1;
> +       u32 cactcr2;
> +       u32 icr;
> +       u32 isr;
> +       u32 csr;
> +       u32 sdar;
> +       u32 pbcr;
> +       u32 trbbr;
> +#ifdef CONFIG_TARGET_AST_G5
> +       u32 dma_mbar;
> +       u32 dma_tlr;
> +#endif
> +};
> +
> +/* Device Register Definition */
> +/* 0x00 : I2CD Function Control Register  */
> +#define I2CD_BUFF_SEL_MASK                             (0x7 << 20)
> +#define I2CD_BUFF_SEL(x)                               (x << 20)
> +#define I2CD_M_SDA_LOCK_EN                     (0x1 << 16)
> +#define I2CD_MULTI_MASTER_DIS                  (0x1 << 15)
> +#define I2CD_M_SCL_DRIVE_EN            (0x1 << 14)
> +#define I2CD_MSB_STS                                   (0x1 << 9)
> +#define I2CD_SDA_DRIVE_1T_EN                   (0x1 << 8)
> +#define I2CD_M_SDA_DRIVE_1T_EN         (0x1 << 7)
> +#define I2CD_M_HIGH_SPEED_EN           (0x1 << 6)
> +#define I2CD_DEF_ADDR_EN                               (0x1 << 5)
> +#define I2CD_DEF_ALERT_EN                              (0x1 << 4)
> +#define I2CD_DEF_ARP_EN                                        (0x1 << 3)
> +#define I2CD_DEF_GCALL_EN                              (0x1 << 2)
> +#define I2CD_SLAVE_EN                                  (0x1 << 1)
> +#define I2CD_MASTER_EN                                 (0x1)
> +
> +/* 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 : I2CD Clock and AC Timing Control Register #2 */
> +#define I2CD_tTIMEOUT                                  1
> +#define I2CD_NO_TIMEOUT_CTRL                   0
> +
> +/* 0x0c : I2CD Interrupt Control Register &
> + * 0x10 : I2CD Interrupt Status Register
> + *
> + * These share bit definitions, so use the same values for the enable &
> + * status bits.
> + */
> +#define I2CD_INTR_SDA_DL_TIMEOUT                       (0x1 << 14)
> +#define I2CD_INTR_BUS_RECOVER_DONE                     (0x1 << 13)
> +#define I2CD_INTR_SMBUS_ALERT                  (0x1 << 12)
> +#define I2CD_INTR_SMBUS_ARP_ADDR                       (0x1 << 11)
> +#define I2CD_INTR_SMBUS_DEV_ALERT_ADDR         (0x1 << 10)
> +#define I2CD_INTR_SMBUS_DEF_ADDR                       (0x1 << 9)
> +#define I2CD_INTR_GCALL_ADDR                   (0x1 << 8)
> +#define I2CD_INTR_SLAVE_MATCH                  (0x1 << 7)
> +#define I2CD_INTR_SCL_TIMEOUT                  (0x1 << 6)
> +#define I2CD_INTR_ABNORMAL                             (0x1 << 5)
> +#define I2CD_INTR_NORMAL_STOP                  (0x1 << 4)
> +#define I2CD_INTR_ARBIT_LOSS                   (0x1 << 3)
> +#define I2CD_INTR_RX_DONE                              (0x1 << 2)
> +#define I2CD_INTR_TX_NAK                               (0x1 << 1)
> +#define I2CD_INTR_TX_ACK                               (0x1 << 0)
> +
> +/* 0x14 : I2CD Command/Status Register   */
> +#define I2CD_SDA_OE                                    (0x1 << 28)
> +#define I2CD_SDA_O                                     (0x1 << 27)
> +#define I2CD_SCL_OE                                    (0x1 << 26)
> +#define I2CD_SCL_O                                     (0x1 << 25)
> +#define I2CD_TX_TIMING                         (0x1 << 24)
> +#define I2CD_TX_STATUS                         (0x1 << 23)
> +
> +/* Tx State Machine */
> +#define I2CD_IDLE                                      0x0
> +#define I2CD_MACTIVE                           0x8
> +#define I2CD_MSTART                                    0x9
> +#define I2CD_MSTARTR                           0xa
> +#define I2CD_MSTOP                                     0xb
> +#define I2CD_MTXD                                      0xc
> +#define I2CD_MRXACK                                    0xd
> +#define I2CD_MRXD                                      0xe
> +#define I2CD_MTXACK                            0xf
> +#define I2CD_SWAIT                                     0x1
> +#define I2CD_SRXD                                      0x4
> +#define I2CD_STXACK                            0x5
> +#define I2CD_STXD                                      0x6
> +#define I2CD_SRXACK                            0x7
> +#define I2CD_RECOVER                           0x3
> +
> +#define I2CD_SCL_LINE_STS                              (0x1 << 18)
> +#define I2CD_SDA_LINE_STS                              (0x1 << 17)
> +#define I2CD_BUS_BUSY_STS                              (0x1 << 16)
> +#define I2CD_SDA_OE_OUT_DIR                            (0x1 << 15)
> +#define I2CD_SDA_O_OUT_DIR                             (0x1 << 14)
> +#define I2CD_SCL_OE_OUT_DIR                            (0x1 << 13)
> +#define I2CD_SCL_O_OUT_DIR                             (0x1 << 12)
> +#define I2CD_BUS_RECOVER_CMD                   (0x1 << 11)
> +#define I2CD_S_ALT_EN                          (0x1 << 10)
> +#define I2CD_RX_DMA_ENABLE                             (0x1 << 9)
> +#define I2CD_TX_DMA_ENABLE                             (0x1 << 8)
> +
> +/* Command Bit */
> +#define I2CD_RX_BUFF_ENABLE                            (0x1 << 7)
> +#define I2CD_TX_BUFF_ENABLE                            (0x1 << 6)
> +#define I2CD_M_STOP_CMD                                        (0x1 << 5)
> +#define I2CD_M_S_RX_CMD_LAST                   (0x1 << 4)
> +#define I2CD_M_RX_CMD                                  (0x1 << 3)
> +#define I2CD_S_TX_CMD                                  (0x1 << 2)
> +#define I2CD_M_TX_CMD                                  (0x1 << 1)
> +#define I2CD_M_START_CMD                               0x1
> +
> +#define I2CD_RX_DATA_SHIFT                     8
> +#define I2CD_RX_DATA_MASK                      (0xff << I2CD_RX_DATA_SHIFT)
> +
> +#endif                         /* __AST_I2C_H_ */
> --
> 2.8.0.rc3.226.g39d4020
>

Regards,
Simon


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