diff options
Diffstat (limited to 'drivers/i2c/npcm-i2c.c')
| -rw-r--r-- | drivers/i2c/npcm-i2c.c | 630 |
1 files changed, 630 insertions, 0 deletions
diff --git a/drivers/i2c/npcm-i2c.c b/drivers/i2c/npcm-i2c.c new file mode 100644 index 00000000000..ea4ef532565 --- /dev/null +++ b/drivers/i2c/npcm-i2c.c @@ -0,0 +1,630 @@ +// 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, +}; |