[PATCH v3] i2c: nuvoton: Add NPCM7xx i2c driver
Jim Liu
jim.t90615 at gmail.com
Thu Jun 23 04:50:40 CEST 2022
Hi Andre
Thanks for your reply and review
you are right.
i am followed upstream kernel document and copy sub describe to uboot.
https://github.com/torvalds/linux/blob/master/Documentation/devicetree/bindings/i2c/nuvoton%2Cnpcm7xx-i2c.yaml
i will remove this document next i2c version.
if Ardre or hs have any question or concern please let me know.
Cheers,
Jim
On Wed, Jun 15, 2022 at 5:48 PM Andre Przywara <andre.przywara at arm.com> wrote:
>
> On 14/06/2022 02:46, Jim Liu wrote:
>
> Hi,
>
> > Add Nuvoton BMC NPCM750 i2c driver
> >
> > Signed-off-by: Jim Liu <JJLIU0 at nuvoton.com>
> > ---
> > changes for v3:
> > - add i2c doc
>
> I don't think this is needed. For a start, it's an old-style text
> binding. But more importantly I see that the kernel's I2C maintainer
> seemed to have merged the proper binding into his -next tree already.
>
> https://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux.git/commit/?h=i2c/for-next&id=29d2bff1c34ad3e413bcdaa81b88e209b308031d
>
> So there is no need to duplicate this binding document in the U-Boot
> tree, so you can just drop it here (again).
>
> I haven't looked at the driver in detail, and I don't know the hardware
> nor can I test it, but at least I checked the devicetree aspect, and
> this is now in line with the accepted Linux kernel driver and DT
> changes, so it looks fine to me.
>
> Cheers,
> Andre
>
> > Changes for v2:
> > - use debug output in reset function
> > - use clr/setbits_8
> > ---
> > .../i2c/nuvoton,npcm7xx-i2c.txt | 28 +
> > drivers/i2c/Kconfig | 5 +
> > drivers/i2c/Makefile | 1 +
> > drivers/i2c/npcm-i2c.c | 631 ++++++++++++++++++
> > 4 files changed, 665 insertions(+)
> > create mode 100644 doc/device-tree-bindings/i2c/nuvoton,npcm7xx-i2c.txt
> > create mode 100644 drivers/i2c/npcm-i2c.c
> >
> > diff --git a/doc/device-tree-bindings/i2c/nuvoton,npcm7xx-i2c.txt b/doc/device-tree-bindings/i2c/nuvoton,npcm7xx-i2c.txt
> > new file mode 100644
> > index 0000000000..d120490b32
> > --- /dev/null
> > +++ b/doc/device-tree-bindings/i2c/nuvoton,npcm7xx-i2c.txt
> > @@ -0,0 +1,28 @@
> > +* The NPCM750x includes sixteen I2C bus controllers.
> > +
> > +Required properties :
> > +- compatible : Must be "nuvoton,npcm750-i2c"
> > +- reg : Offset and length of the register set for the device
> > +- clocks: Reference clock for the I2C bus
> > +- A pinctrl state named "default" must be defined to set pins in mode of
> > + operation for I2C transfer
> > +- #address-cells = <1>;
> > +- #size-cells = <0>;
> > +
> > +Optional properties :
> > +- clock-frequency : Desired I2C bus clock frequency in Hz. If not specified,
> > + the default 100 kHz frequency will be used.
> > + possible values are 100000, 400000 and 1000000.
> > +
> > +Example :
> > + #include <dt-bindings/clock/nuvoton,npcm7xx-clock.h>
> > + #include <dt-bindings/interrupt-controller/arm-gic.h>
> > + i2c0: i2c at 80000 {
> > + reg = <0x80000 0x1000>;
> > + compatible = "nuvoton,npcm750-i2c";
> > + #address-cells = <1>;
> > + #size-cells = <0>;
> > + clocks = <&clk NPCM7XX_CLK_APB2>;
> > + interrupts = <GIC_SPI 64 IRQ_TYPE_LEVEL_HIGH>;
> > + status = "disabled";
> > + };
> > diff --git a/drivers/i2c/Kconfig b/drivers/i2c/Kconfig
> > index d25c5736ef..7e113b289e 100644
> > --- a/drivers/i2c/Kconfig
> > +++ b/drivers/i2c/Kconfig
> > @@ -447,6 +447,11 @@ config SYS_I2C_NEXELL
> > have several I2C ports and all are provided, controlled by the
> > device tree.
> >
> > +config SYS_I2C_NPCM
> > + bool "Nuvoton NPCM I2C driver"
> > + help
> > + Support for Nuvoton I2C controller driver.
> > +
> > config SYS_I2C_OCORES
> > bool "ocores I2C driver"
> > depends on DM_I2C
> > diff --git a/drivers/i2c/Makefile b/drivers/i2c/Makefile
> > index 9d41f379bb..7e046f809a 100644
> > --- a/drivers/i2c/Makefile
> > +++ b/drivers/i2c/Makefile
> > @@ -33,6 +33,7 @@ obj-$(CONFIG_SYS_I2C_MV) += mv_i2c.o
> > obj-$(CONFIG_SYS_I2C_MVTWSI) += mvtwsi.o
> > obj-$(CONFIG_SYS_I2C_MXC) += mxc_i2c.o
> > obj-$(CONFIG_SYS_I2C_NEXELL) += nx_i2c.o
> > +obj-$(CONFIG_SYS_I2C_NPCM) += npcm_i2c.o
> > obj-$(CONFIG_SYS_I2C_OCORES) += ocores_i2c.o
> > obj-$(CONFIG_SYS_I2C_OCTEON) += octeon_i2c.o
> > obj-$(CONFIG_SYS_I2C_OMAP24XX) += omap24xx_i2c.o
> > diff --git a/drivers/i2c/npcm-i2c.c b/drivers/i2c/npcm-i2c.c
> > new file mode 100644
> > index 0000000000..dfac6483de
> > --- /dev/null
> > +++ b/drivers/i2c/npcm-i2c.c
> > @@ -0,0 +1,631 @@
> > +// SPDX-License-Identifier: GPL-2.0+
> > +/*
> > + * Copyright (c) 2021 Nuvoton Technology Corp.
> > + */
> > +
> > +#include <clk.h>
> > +#include <dm.h>
> > +#include <i2c.h>
> > +#include <asm/io.h>
> > +#include <linux/iopoll.h>
> > +#include <asm/arch/gcr.h>
> > +
> > +#define I2C_FREQ_100K 100000
> > +#define NPCM_I2C_TIMEOUT_MS 10
> > +#define NPCM7XX_I2CSEGCTL_INIT_VAL 0x0333F000
> > +#define NPCM8XX_I2CSEGCTL_INIT_VAL 0x9333F000
> > +
> > +/* SCLFRQ min/max field values */
> > +#define SCLFRQ_MIN 10
> > +#define SCLFRQ_MAX 511
> > +
> > +/* SMBCTL1 */
> > +#define SMBCTL1_START BIT(0)
> > +#define SMBCTL1_STOP BIT(1)
> > +#define SMBCTL1_INTEN BIT(2)
> > +#define SMBCTL1_ACK BIT(4)
> > +#define SMBCTL1_STASTRE BIT(7)
> > +
> > +/* SMBCTL2 */
> > +#define SMBCTL2_ENABLE BIT(0)
> > +
> > +/* SMBCTL3 */
> > +#define SMBCTL3_SCL_LVL BIT(7)
> > +#define SMBCTL3_SDA_LVL BIT(6)
> > +
> > +/* SMBCST */
> > +#define SMBCST_BB BIT(1)
> > +#define SMBCST_TGSCL BIT(5)
> > +
> > +/* SMBST */
> > +#define SMBST_XMIT BIT(0)
> > +#define SMBST_MASTER BIT(1)
> > +#define SMBST_STASTR BIT(3)
> > +#define SMBST_NEGACK BIT(4)
> > +#define SMBST_BER BIT(5)
> > +#define SMBST_SDAST BIT(6)
> > +
> > +/* SMBCST3 in bank0 */
> > +#define SMBCST3_EO_BUSY BIT(7)
> > +
> > +/* SMBFIF_CTS in bank1 */
> > +#define SMBFIF_CTS_CLR_FIFO BIT(6)
> > +
> > +#define SMBFIF_CTL_FIFO_EN BIT(4)
> > +#define SMBCTL3_BNK_SEL BIT(5)
> > +
> > +enum {
> > + I2C_ERR_NACK = 1,
> > + I2C_ERR_BER,
> > + I2C_ERR_TIMEOUT,
> > +};
> > +
> > +struct smb_bank0_regs {
> > + u8 addr3;
> > + u8 addr7;
> > + u8 addr4;
> > + u8 addr8;
> > + u16 addr5;
> > + u16 addr6;
> > + u8 cst2;
> > + u8 cst3;
> > + u8 ctl4;
> > + u8 ctl5;
> > + u8 scllt;
> > + u8 fif_ctl;
> > + u8 sclht;
> > +};
> > +
> > +struct smb_bank1_regs {
> > + u8 fif_cts;
> > + u8 fair_per;
> > + u16 txf_ctl;
> > + u32 t_out;
> > + u8 cst2;
> > + u8 cst3;
> > + u16 txf_sts;
> > + u16 rxf_sts;
> > + u8 rxf_ctl;
> > +};
> > +
> > +struct npcm_i2c_regs {
> > + u16 sda;
> > + u16 st;
> > + u16 cst;
> > + u16 ctl1;
> > + u16 addr;
> > + u16 ctl2;
> > + u16 addr2;
> > + u16 ctl3;
> > + union {
> > + struct smb_bank0_regs bank0;
> > + struct smb_bank1_regs bank1;
> > + };
> > +
> > +};
> > +
> > +struct npcm_i2c_bus {
> > + struct npcm_i2c_regs *reg;
> > + int num;
> > + u32 apb_clk;
> > + u32 freq;
> > + bool started;
> > +};
> > +
> > +static void npcm_dump_regs(struct npcm_i2c_bus *bus)
> > +{
> > + struct npcm_i2c_regs *reg = bus->reg;
> > +
> > + printf("\n");
> > + printf("SMBST=0x%x\n", readb(®->st));
> > + printf("SMBCST=0x%x\n", readb(®->cst));
> > + printf("SMBCTL1=0x%x\n", readb(®->ctl1));
> > + printf("\n");
> > +}
> > +
> > +static int npcm_i2c_check_sda(struct npcm_i2c_bus *bus)
> > +{
> > + struct npcm_i2c_regs *reg = bus->reg;
> > + ulong start_time;
> > + int err = I2C_ERR_TIMEOUT;
> > + u8 val;
> > +
> > + start_time = get_timer(0);
> > + /* wait SDAST to be 1 */
> > + while (get_timer(start_time) < NPCM_I2C_TIMEOUT_MS) {
> > + val = readb(®->st);
> > + if (val & SMBST_NEGACK) {
> > + err = I2C_ERR_NACK;
> > + break;
> > + }
> > + if (val & SMBST_BER) {
> > + err = I2C_ERR_BER;
> > + break;
> > + }
> > + if (val & SMBST_SDAST) {
> > + err = 0;
> > + break;
> > + }
> > + }
> > +
> > + if (err)
> > + printf("%s: err %d\n", __func__, err);
> > +
> > + return err;
> > +}
> > +
> > +static int npcm_i2c_send_start(struct npcm_i2c_bus *bus)
> > +{
> > + struct npcm_i2c_regs *reg = bus->reg;
> > + ulong start_time;
> > + int err = I2C_ERR_TIMEOUT;
> > +
> > + /* Generate START condition */
> > + setbits_8(®->ctl1, SMBCTL1_START);
> > +
> > + start_time = get_timer(0);
> > + while (get_timer(start_time) < NPCM_I2C_TIMEOUT_MS) {
> > + if (readb(®->st) & SMBST_BER)
> > + return I2C_ERR_BER;
> > + if (readb(®->st) & SMBST_MASTER) {
> > + err = 0;
> > + break;
> > + }
> > + }
> > + bus->started = true;
> > +
> > + return err;
> > +}
> > +
> > +static int npcm_i2c_send_stop(struct npcm_i2c_bus *bus, bool wait)
> > +{
> > + struct npcm_i2c_regs *reg = bus->reg;
> > + ulong start_time;
> > + int err = I2C_ERR_TIMEOUT;
> > +
> > + setbits_8(®->ctl1, SMBCTL1_STOP);
> > +
> > + /* Clear NEGACK, STASTR and BER bits */
> > + writeb(SMBST_STASTR | SMBST_NEGACK | SMBST_BER, ®->st);
> > +
> > + bus->started = false;
> > +
> > + if (!wait)
> > + return 0;
> > +
> > + start_time = get_timer(0);
> > + while (get_timer(start_time) < NPCM_I2C_TIMEOUT_MS) {
> > + if ((readb(®->ctl1) & SMBCTL1_STOP) == 0) {
> > + err = 0;
> > + break;
> > + }
> > + }
> > + if (err) {
> > + printf("%s: err %d\n", __func__, err);
> > + npcm_dump_regs(bus);
> > + }
> > +
> > + return err;
> > +}
> > +
> > +static void npcm_i2c_reset(struct npcm_i2c_bus *bus)
> > +{
> > + struct npcm_i2c_regs *reg = bus->reg;
> > +
> > + debug("%s: module %d\n", __func__, bus->num);
> > + /* disable & enable SMB moudle */
> > + clrbits_8(®->ctl2, SMBCTL2_ENABLE);
> > + setbits_8(®->ctl2, SMBCTL2_ENABLE);
> > +
> > + /* clear BB and status */
> > + writeb(SMBCST_BB, ®->cst);
> > + writeb(0xff, ®->st);
> > +
> > + /* select bank 1 */
> > + setbits_8(®->ctl3, SMBCTL3_BNK_SEL);
> > + /* Clear all fifo bits */
> > + writeb(SMBFIF_CTS_CLR_FIFO, ®->bank1.fif_cts);
> > +
> > + /* select bank 0 */
> > + clrbits_8(®->ctl3, SMBCTL3_BNK_SEL);
> > + /* clear EOB bit */
> > + writeb(SMBCST3_EO_BUSY, ®->bank0.cst3);
> > + /* single byte mode */
> > + clrbits_8(®->bank0.fif_ctl, SMBFIF_CTL_FIFO_EN);
> > +
> > + /* set POLL mode */
> > + writeb(0, ®->ctl1);
> > +}
> > +
> > +static void npcm_i2c_recovery(struct npcm_i2c_bus *bus, u32 addr)
> > +{
> > + u8 val;
> > + int iter = 27;
> > + struct npcm_i2c_regs *reg = bus->reg;
> > + int err;
> > +
> > + val = readb(®->ctl3);
> > + /* Skip recovery, bus not stucked */
> > + if ((val & SMBCTL3_SCL_LVL) && (val & SMBCTL3_SDA_LVL))
> > + return;
> > +
> > + printf("Performing I2C bus %d recovery...\n", bus->num);
> > + /* SCL/SDA are not releaed, perform recovery */
> > + while (1) {
> > + /* toggle SCL line */
> > + writeb(SMBCST_TGSCL, ®->cst);
> > +
> > + udelay(20);
> > + val = readb(®->ctl3);
> > + if (val & SMBCTL3_SDA_LVL)
> > + break;
> > + if (iter-- == 0)
> > + break;
> > + }
> > +
> > + if (val & SMBCTL3_SDA_LVL) {
> > + writeb((u8)((addr << 1) & 0xff), ®->sda);
> > + err = npcm_i2c_send_start(bus);
> > + if (!err) {
> > + udelay(20);
> > + npcm_i2c_send_stop(bus, false);
> > + udelay(200);
> > + printf("I2C bus %d recovery completed\n",
> > + bus->num);
> > + } else {
> > + printf("%s: send START err %d\n", __func__, err);
> > + }
> > + } else {
> > + printf("Fail to recover I2C bus %d\n", bus->num);
> > + }
> > + npcm_i2c_reset(bus);
> > +}
> > +
> > +static int npcm_i2c_send_address(struct npcm_i2c_bus *bus, u8 addr,
> > + bool stall)
> > +{
> > + struct npcm_i2c_regs *reg = bus->reg;
> > + ulong start_time;
> > + u8 val;
> > +
> > + /* Stall After Start Enable */
> > + if (stall)
> > + setbits_8(®->ctl1, SMBCTL1_STASTRE);
> > +
> > + writeb(addr, ®->sda);
> > + if (stall) {
> > + start_time = get_timer(0);
> > + while (get_timer(start_time) < NPCM_I2C_TIMEOUT_MS) {
> > + if (readb(®->st) & SMBST_STASTR)
> > + break;
> > +
> > + if (readb(®->st) & SMBST_BER) {
> > + clrbits_8(®->ctl1, SMBCTL1_STASTRE);
> > + return I2C_ERR_BER;
> > + }
> > + }
> > + }
> > +
> > + /* check ACK */
> > + val = readb(®->st);
> > + if (val & SMBST_NEGACK) {
> > + debug("NACK on addr 0x%x\n", addr >> 1);
> > + /* After a Stop condition, writing 1 to NEGACK clears it */
> > + return I2C_ERR_NACK;
> > + }
> > + if (val & SMBST_BER)
> > + return I2C_ERR_BER;
> > +
> > + return 0;
> > +}
> > +
> > +static int npcm_i2c_read_bytes(struct npcm_i2c_bus *bus, u8 *data, int len)
> > +{
> > + struct npcm_i2c_regs *reg = bus->reg;
> > + u8 val;
> > + int i;
> > + int err = 0;
> > +
> > + if (len == 1) {
> > + /* bus should be stalled before receiving last byte */
> > + setbits_8(®->ctl1, SMBCTL1_ACK);
> > +
> > + /* clear STASTRE if it is set */
> > + if (readb(®->ctl1) & SMBCTL1_STASTRE) {
> > + writeb(SMBST_STASTR, ®->st);
> > + clrbits_8(®->ctl1, SMBCTL1_STASTRE);
> > + }
> > + npcm_i2c_check_sda(bus);
> > + npcm_i2c_send_stop(bus, false);
> > + *data = readb(®->sda);
> > + /* this must be done to generate STOP condition */
> > + writeb(SMBST_NEGACK, ®->st);
> > + } else {
> > + for (i = 0; i < len; i++) {
> > + /*
> > + * When NEGACK bit is set to 1 after the transmission of a byte,
> > + * SDAST is not set to 1.
> > + */
> > + if (i != (len - 1)) {
> > + err = npcm_i2c_check_sda(bus);
> > + } else {
> > + err = readb_poll_timeout(®->ctl1, val,
> > + !(val & SMBCTL1_ACK), 100000);
> > + if (err) {
> > + printf("wait nack timeout\n");
> > + err = I2C_ERR_TIMEOUT;
> > + npcm_dump_regs(bus);
> > + }
> > + }
> > + if (err && err != I2C_ERR_TIMEOUT)
> > + break;
> > + if (i == (len - 2)) {
> > + /* set NACK before last byte */
> > + setbits_8(®->ctl1, SMBCTL1_ACK);
> > + }
> > + if (i == (len - 1)) {
> > + /* last byte, send STOP condition */
> > + npcm_i2c_send_stop(bus, false);
> > + *data = readb(®->sda);
> > + writeb(SMBST_NEGACK, ®->st);
> > + break;
> > + }
> > + *data = readb(®->sda);
> > + data++;
> > + }
> > + }
> > +
> > + return err;
> > +}
> > +
> > +static int npcm_i2c_send_bytes(struct npcm_i2c_bus *bus, u8 *data, int len)
> > +{
> > + struct npcm_i2c_regs *reg = bus->reg;
> > + u8 val;
> > + int i;
> > + int err = 0;
> > +
> > + val = readb(®->st);
> > + if (val & SMBST_NEGACK)
> > + return I2C_ERR_NACK;
> > + else if (val & SMBST_BER)
> > + return I2C_ERR_BER;
> > +
> > + /* clear STASTRE if it is set */
> > + if (readb(®->ctl1) & SMBCTL1_STASTRE)
> > + clrbits_8(®->ctl1, SMBCTL1_STASTRE);
> > +
> > + for (i = 0; i < len; i++) {
> > + err = npcm_i2c_check_sda(bus);
> > + if (err)
> > + break;
> > + writeb(*data, ®->sda);
> > + data++;
> > + }
> > + npcm_i2c_check_sda(bus);
> > +
> > + return err;
> > +}
> > +
> > +static int npcm_i2c_read(struct npcm_i2c_bus *bus, u32 addr, u8 *data,
> > + u32 len)
> > +{
> > + struct npcm_i2c_regs *reg = bus->reg;
> > + int err;
> > + bool stall;
> > +
> > + if (len <= 0)
> > + return -EINVAL;
> > +
> > + /* send START condition */
> > + err = npcm_i2c_send_start(bus);
> > + if (err) {
> > + debug("%s: send START err %d\n", __func__, err);
> > + return err;
> > + }
> > +
> > + stall = (len == 1) ? true : false;
> > + /* send address byte */
> > + err = npcm_i2c_send_address(bus, (u8)(addr << 1) | 0x1, stall);
> > +
> > + if (!err && len)
> > + npcm_i2c_read_bytes(bus, data, len);
> > +
> > + if (err == I2C_ERR_NACK) {
> > + /* clear NACK */
> > + writeb(SMBST_NEGACK, ®->st);
> > + }
> > +
> > + if (err)
> > + debug("%s: err %d\n", __func__, err);
> > +
> > + return err;
> > +}
> > +
> > +static int npcm_i2c_write(struct npcm_i2c_bus *bus, u32 addr, u8 *data,
> > + u32 len)
> > +{
> > + struct npcm_i2c_regs *reg = bus->reg;
> > + int err;
> > + bool stall;
> > +
> > + /* send START condition */
> > + err = npcm_i2c_send_start(bus);
> > + if (err) {
> > + debug("%s: send START err %d\n", __func__, err);
> > + return err;
> > + }
> > +
> > + stall = (len == 0) ? true : false;
> > + /* send address byte */
> > + err = npcm_i2c_send_address(bus, (u8)(addr << 1), stall);
> > +
> > + if (!err && len)
> > + err = npcm_i2c_send_bytes(bus, data, len);
> > +
> > + /* clear STASTRE if it is set */
> > + if (stall)
> > + clrbits_8(®->ctl1, SMBCTL1_STASTRE);
> > +
> > + if (err)
> > + debug("%s: err %d\n", __func__, err);
> > +
> > + return err;
> > +}
> > +
> > +static int npcm_i2c_xfer(struct udevice *dev,
> > + struct i2c_msg *msg, int nmsgs)
> > +{
> > + struct npcm_i2c_bus *bus = dev_get_priv(dev);
> > + struct npcm_i2c_regs *reg = bus->reg;
> > + int ret = 0, err = 0;
> > +
> > + if (nmsgs < 1 || nmsgs > 2) {
> > + printf("%s: commands not support\n", __func__);
> > + return -EREMOTEIO;
> > + }
> > + /* clear ST register */
> > + writeb(0xFF, ®->st);
> > +
> > + for ( ; nmsgs > 0; nmsgs--, msg++) {
> > + if (msg->flags & I2C_M_RD)
> > + err = npcm_i2c_read(bus, msg->addr, msg->buf,
> > + msg->len);
> > + else
> > + err = npcm_i2c_write(bus, msg->addr, msg->buf,
> > + msg->len);
> > + if (err) {
> > + debug("i2c_xfer: error %d\n", err);
> > + ret = -EREMOTEIO;
> > + break;
> > + }
> > + }
> > +
> > + if (bus->started)
> > + npcm_i2c_send_stop(bus, true);
> > +
> > + if (err)
> > + npcm_i2c_recovery(bus, msg->addr);
> > +
> > + return ret;
> > +}
> > +
> > +static int npcm_i2c_init_clk(struct npcm_i2c_bus *bus, u32 bus_freq)
> > +{
> > + struct npcm_i2c_regs *reg = bus->reg;
> > + u32 freq = bus->apb_clk;
> > + u32 sclfrq;
> > + u8 hldt, val;
> > +
> > + if (bus_freq > I2C_FREQ_100K) {
> > + printf("Support standard mode only\n");
> > + return -EINVAL;
> > + }
> > +
> > + /* SCLFRQ = T(SCL)/4/T(CLK) = FREQ(CLK)/4/FREQ(SCL) */
> > + sclfrq = freq / (bus_freq * 4);
> > + if (sclfrq < SCLFRQ_MIN || sclfrq > SCLFRQ_MAX)
> > + return -EINVAL;
> > +
> > + if (freq >= 40000000)
> > + hldt = 17;
> > + else if (freq >= 12500000)
> > + hldt = 15;
> > + else
> > + hldt = 7;
> > +
> > + val = readb(®->ctl2) & 0x1;
> > + val |= (sclfrq & 0x7F) << 1;
> > + writeb(val, ®->ctl2);
> > +
> > + /* clear 400K_MODE bit */
> > + val = readb(®->ctl3) & 0xc;
> > + val |= (sclfrq >> 7) & 0x3;
> > + writeb(val, ®->ctl3);
> > +
> > + writeb(hldt, ®->bank0.ctl4);
> > +
> > + return 0;
> > +}
> > +
> > +static int npcm_i2c_set_bus_speed(struct udevice *dev,
> > + unsigned int speed)
> > +{
> > + struct npcm_i2c_bus *bus = dev_get_priv(dev);
> > +
> > + return npcm_i2c_init_clk(bus, speed);
> > +}
> > +
> > +static int npcm_i2c_probe(struct udevice *dev)
> > +{
> > + struct npcm_i2c_bus *bus = dev_get_priv(dev);
> > + struct npcm_gcr *gcr = (struct npcm_gcr *)NPCM_GCR_BA;
> > + struct npcm_i2c_regs *reg;
> > + u32 i2csegctl_val = dev_get_driver_data(dev);
> > + struct clk clk;
> > + int ret;
> > +
> > + ret = clk_get_by_index(dev, 0, &clk);
> > + if (ret) {
> > + printf("%s: ret %d\n", __func__, ret);
> > + return ret;
> > + }
> > + bus->apb_clk = clk_get_rate(&clk);
> > + if (bus->apb_clk <= 0) {
> > + printf("%s: fail to get rate\n", __func__);
> > + return -EINVAL;
> > + }
> > + clk_free(&clk);
> > +
> > + bus->num = dev->seq_;
> > + bus->reg = dev_read_addr_ptr(dev);
> > + bus->freq = dev_read_u32_default(dev, "clock-frequency", 100000);
> > + bus->started = false;
> > + reg = bus->reg;
> > +
> > + if (npcm_i2c_init_clk(bus, bus->freq)) {
> > + printf("%s: init_clk failed\n", __func__);
> > + return -EINVAL;
> > + }
> > +
> > + /* set initial i2csegctl value */
> > + writel(i2csegctl_val, &gcr->i2csegctl);
> > +
> > + /* enable SMB module */
> > + setbits_8(®->ctl2, SMBCTL2_ENABLE);
> > +
> > + /* select register bank 0 */
> > + clrbits_8(®->ctl3, SMBCTL3_BNK_SEL);
> > +
> > + /* single byte mode */
> > + clrbits_8(®->bank0.fif_ctl, SMBFIF_CTL_FIFO_EN);
> > +
> > + /* set POLL mode */
> > + writeb(0, ®->ctl1);
> > +
> > + printf("I2C bus %d ready. speed=%d, base=0x%x, apb=%u\n",
> > + bus->num, bus->freq, (u32)(uintptr_t)bus->reg, bus->apb_clk);
> > +
> > + return 0;
> > +}
> > +
> > +static const struct dm_i2c_ops nuvoton_i2c_ops = {
> > + .xfer = npcm_i2c_xfer,
> > + .set_bus_speed = npcm_i2c_set_bus_speed,
> > +};
> > +
> > +static const struct udevice_id nuvoton_i2c_of_match[] = {
> > + { .compatible = "nuvoton,npcm845-i2c", .data = NPCM8XX_I2CSEGCTL_INIT_VAL},
> > + { .compatible = "nuvoton,npcm750-i2c", .data = NPCM7XX_I2CSEGCTL_INIT_VAL},
> > + {}
> > +};
> > +
> > +U_BOOT_DRIVER(npcm_i2c_bus) = {
> > + .name = "npcm-i2c",
> > + .id = UCLASS_I2C,
> > + .of_match = nuvoton_i2c_of_match,
> > + .probe = npcm_i2c_probe,
> > + .priv_auto = sizeof(struct npcm_i2c_bus),
> > + .ops = &nuvoton_i2c_ops,
> > +};
> > +
>
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