i2c: nuvoton: Add NPCM7xx i2c driver

Add Nuvoton BMC NPCM750 i2c driver

Signed-off-by: Jim Liu <JJLIU0@nuvoton.com>
Reviewed-by: Heiko Schocher <hs@denx.de>

diff --git a/drivers/i2c/Kconfig b/drivers/i2c/Kconfig
index 72d06e4..be4724b 100644 (file)
--- 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 9d41f37..7e046f8 100644 (file)
--- 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 (file)
index 0000000..ea4ef53
--- /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(&reg->st));
+       printf("SMBCST=0x%x\n", readb(&reg->cst));
+       printf("SMBCTL1=0x%x\n", readb(&reg->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(&reg->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(&reg->ctl1, SMBCTL1_START);
+
+       start_time = get_timer(0);
+       while (get_timer(start_time) < NPCM_I2C_TIMEOUT_MS) {
+               if (readb(&reg->st) & SMBST_BER)
+                       return I2C_ERR_BER;
+               if (readb(&reg->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(&reg->ctl1, SMBCTL1_STOP);
+
+       /* Clear NEGACK, STASTR and BER bits  */
+       writeb(SMBST_STASTR | SMBST_NEGACK | SMBST_BER, &reg->st);
+
+       bus->started = false;
+
+       if (!wait)
+               return 0;
+
+       start_time = get_timer(0);
+       while (get_timer(start_time) < NPCM_I2C_TIMEOUT_MS) {
+               if ((readb(&reg->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(&reg->ctl2, SMBCTL2_ENABLE);
+       setbits_8(&reg->ctl2, SMBCTL2_ENABLE);
+
+       /* clear BB and status */
+       writeb(SMBCST_BB, &reg->cst);
+       writeb(0xff, &reg->st);
+
+       /* select bank 1 */
+       setbits_8(&reg->ctl3, SMBCTL3_BNK_SEL);
+       /* Clear all fifo bits */
+       writeb(SMBFIF_CTS_CLR_FIFO, &reg->bank1.fif_cts);
+
+       /* select bank 0 */
+       clrbits_8(&reg->ctl3, SMBCTL3_BNK_SEL);
+       /* clear EOB bit */
+       writeb(SMBCST3_EO_BUSY, &reg->bank0.cst3);
+       /* single byte mode */
+       clrbits_8(&reg->bank0.fif_ctl, SMBFIF_CTL_FIFO_EN);
+
+       /* set POLL mode */
+       writeb(0, &reg->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(&reg->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, &reg->cst);
+
+               udelay(20);
+               val = readb(&reg->ctl3);
+               if (val & SMBCTL3_SDA_LVL)
+                       break;
+               if (iter-- == 0)
+                       break;
+       }
+
+       if (val & SMBCTL3_SDA_LVL) {
+               writeb((u8)((addr << 1) & 0xff), &reg->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(&reg->ctl1, SMBCTL1_STASTRE);
+
+       writeb(addr, &reg->sda);
+       if (stall) {
+               start_time = get_timer(0);
+               while (get_timer(start_time) < NPCM_I2C_TIMEOUT_MS) {
+                       if (readb(&reg->st) & SMBST_STASTR)
+                               break;
+
+                       if (readb(&reg->st) & SMBST_BER) {
+                               clrbits_8(&reg->ctl1, SMBCTL1_STASTRE);
+                               return I2C_ERR_BER;
+                       }
+               }
+       }
+
+       /* check ACK */
+       val = readb(&reg->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(&reg->ctl1, SMBCTL1_ACK);
+
+               /* clear STASTRE if it is set */
+               if (readb(&reg->ctl1) & SMBCTL1_STASTRE) {
+                       writeb(SMBST_STASTR, &reg->st);
+                       clrbits_8(&reg->ctl1, SMBCTL1_STASTRE);
+               }
+               npcm_i2c_check_sda(bus);
+               npcm_i2c_send_stop(bus, false);
+               *data = readb(&reg->sda);
+               /* this must be done to generate STOP condition */
+               writeb(SMBST_NEGACK, &reg->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(&reg->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(&reg->ctl1, SMBCTL1_ACK);
+                       }
+                       if (i == (len - 1)) {
+                               /* last byte, send STOP condition */
+                               npcm_i2c_send_stop(bus, false);
+                               *data = readb(&reg->sda);
+                               writeb(SMBST_NEGACK, &reg->st);
+                               break;
+                       }
+                       *data = readb(&reg->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(&reg->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(&reg->ctl1) & SMBCTL1_STASTRE)
+               clrbits_8(&reg->ctl1, SMBCTL1_STASTRE);
+
+       for (i = 0; i < len; i++) {
+               err = npcm_i2c_check_sda(bus);
+               if (err)
+                       break;
+               writeb(*data, &reg->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, &reg->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(&reg->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, &reg->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(&reg->ctl2) & 0x1;
+       val |= (sclfrq & 0x7F) << 1;
+       writeb(val, &reg->ctl2);
+
+       /* clear 400K_MODE bit */
+       val = readb(&reg->ctl3) & 0xc;
+       val |= (sclfrq >> 7) & 0x3;
+       writeb(val, &reg->ctl3);
+
+       writeb(hldt, &reg->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(&reg->ctl2, SMBCTL2_ENABLE);
+
+       /* select register bank 0 */
+       clrbits_8(&reg->ctl3, SMBCTL3_BNK_SEL);
+
+       /* single byte mode */
+       clrbits_8(&reg->bank0.fif_ctl, SMBFIF_CTL_FIFO_EN);
+
+       /* set POLL mode */
+       writeb(0, &reg->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,
+};