--- /dev/null
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ */
+
+#include <dm/device_compat.h>
+#include <linux/delay.h>
+#include <linux/errno.h>
+#include <linux/io.h>
+#include <linux/sizes.h>
+#include <linux/types.h>
+#include <dm.h>
+#include <fdtdec.h>
+#include <i2c.h>
+#include <clk.h>
+
+#define REG_BSR 0x0
+#define REG_BCR 0x4
+#define REG_CCR 0x8
+#define REG_ADR 0xc
+#define REG_DAR 0x10
+#define REG_CSR 0x14
+#define REG_FSR 0x18
+#define REG_BC2R 0x1c
+
+/* I2C register bit definitions */
+#define BSR_FBT BIT(0) // First Byte Transfer
+#define BSR_GCA BIT(1) // General Call Address
+#define BSR_AAS BIT(2) // Address as Slave
+#define BSR_TRX BIT(3) // Transfer/Receive
+#define BSR_LRB BIT(4) // Last Received Bit
+#define BSR_AL BIT(5) // Arbitration Lost
+#define BSR_RSC BIT(6) // Repeated Start Cond.
+#define BSR_BB BIT(7) // Bus Busy
+
+#define BCR_INT BIT(0) // Interrupt
+#define BCR_INTE BIT(1) // Interrupt Enable
+#define BCR_GCAA BIT(2) // Gen. Call Access Ack.
+#define BCR_ACK BIT(3) // Acknowledge
+#define BCR_MSS BIT(4) // Master Slave Select
+#define BCR_SCC BIT(5) // Start Condition Cont.
+#define BCR_BEIE BIT(6) // Bus Error Int Enable
+#define BCR_BER BIT(7) // Bus Error
+
+#define CCR_CS_MASK (0x1f) // CCR Clock Period Sel.
+#define CCR_EN BIT(5) // Enable
+#define CCR_FM BIT(6) // Speed Mode Select
+
+#define CSR_CS_MASK (0x3f) // CSR Clock Period Sel.
+
+#define BC2R_SCLL BIT(0) // SCL Low Drive
+#define BC2R_SDAL BIT(1) // SDA Low Drive
+#define BC2R_SCLS BIT(4) // SCL Status
+#define BC2R_SDAS BIT(5) // SDA Status
+
+/* PCLK frequency */
+#define BUS_CLK_FR(rate) (((rate) / 20000000) + 1)
+
+#define I2C_CLK_DEF 62500000
+
+/* STANDARD MODE frequency */
+#define CLK_MASTER_STD(rate) \
+ DIV_ROUND_UP(DIV_ROUND_UP((rate), I2C_SPEED_STANDARD_RATE) - 2, 2)
+/* FAST MODE frequency */
+#define CLK_MASTER_FAST(rate) \
+ DIV_ROUND_UP((DIV_ROUND_UP((rate), I2C_SPEED_FAST_RATE) - 2) * 2, 3)
+
+/* (clkrate <= 18000000) */
+/* calculate the value of CS bits in CCR register on standard mode */
+#define CCR_CS_STD_MAX_18M(rate) \
+ ((CLK_MASTER_STD(rate) - 65) \
+ & CCR_CS_MASK)
+
+/* calculate the value of CS bits in CSR register on standard mode */
+#define CSR_CS_STD_MAX_18M(rate) 0x00
+
+/* calculate the value of CS bits in CCR register on fast mode */
+#define CCR_CS_FAST_MAX_18M(rate) \
+ ((CLK_MASTER_FAST(rate) - 1) \
+ & CCR_CS_MASK)
+
+/* calculate the value of CS bits in CSR register on fast mode */
+#define CSR_CS_FAST_MAX_18M(rate) 0x00
+
+/* (clkrate > 18000000) */
+/* calculate the value of CS bits in CCR register on standard mode */
+#define CCR_CS_STD_MIN_18M(rate) \
+ ((CLK_MASTER_STD(rate) - 1) \
+ & CCR_CS_MASK)
+
+/* calculate the value of CS bits in CSR register on standard mode */
+#define CSR_CS_STD_MIN_18M(rate) \
+ (((CLK_MASTER_STD(rate) - 1) >> 5) \
+ & CSR_CS_MASK)
+
+/* calculate the value of CS bits in CCR register on fast mode */
+#define CCR_CS_FAST_MIN_18M(rate) \
+ ((CLK_MASTER_FAST(rate) - 1) \
+ & CCR_CS_MASK)
+
+/* calculate the value of CS bits in CSR register on fast mode */
+#define CSR_CS_FAST_MIN_18M(rate) \
+ (((CLK_MASTER_FAST(rate) - 1) >> 5) \
+ & CSR_CS_MASK)
+
+/* min I2C clock frequency 14M */
+#define MIN_CLK_RATE (14 * 1000000)
+/* max I2C clock frequency 200M */
+#define MAX_CLK_RATE (200 * 1000000)
+/* I2C clock frequency 18M */
+#define CLK_RATE_18M (18 * 1000000)
+
+#define SPEED_FM 400 // Fast Mode
+#define SPEED_SM 100 // Standard Mode
+
+DECLARE_GLOBAL_DATA_PTR;
+
+struct synquacer_i2c {
+ void __iomem *base;
+ unsigned long pclkrate;
+ unsigned long speed_khz;
+};
+
+static int wait_irq(struct udevice *dev)
+{
+ struct synquacer_i2c *i2c = dev_get_priv(dev);
+ int timeout = 500000;
+
+ do {
+ if (readb(i2c->base + REG_BCR) & BCR_INT)
+ return 0;
+ } while (timeout--);
+
+ pr_err("%s: timeout\n", __func__);
+ return -1;
+}
+
+static int synquacer_i2c_xfer_start(struct synquacer_i2c *i2c,
+ int addr, int read)
+{
+ u8 bsr, bcr;
+
+ writeb((addr << 1) | (read ? 1 : 0), i2c->base + REG_DAR);
+
+ bsr = readb(i2c->base + REG_BSR);
+ bcr = readb(i2c->base + REG_BCR);
+
+ if ((bsr & BSR_BB) && !(bcr & BCR_MSS))
+ return -EBUSY;
+
+ if (bsr & BSR_BB) {
+ writeb(bcr | BCR_SCC, i2c->base + REG_BCR);
+ } else {
+ if (bcr & BCR_MSS)
+ return -EAGAIN;
+ /* Start Condition + Enable Interrupts */
+ writeb(bcr | BCR_MSS | BCR_INTE | BCR_BEIE, i2c->base + REG_BCR);
+ }
+
+ udelay(100);
+ return 0;
+}
+
+static int synquacer_i2c_xfer(struct udevice *bus,
+ struct i2c_msg *msg, int nmsgs)
+{
+ struct synquacer_i2c *i2c = dev_get_priv(bus);
+ u8 bsr, bcr;
+ int idx;
+
+ for (; nmsgs > 0; nmsgs--, msg++) {
+ synquacer_i2c_xfer_start(i2c, msg->addr, msg->flags & I2C_M_RD);
+ if (wait_irq(bus))
+ return -EREMOTEIO;
+
+ bsr = readb(i2c->base + REG_BSR);
+ if (bsr & BSR_LRB) {
+ debug("%s: No ack received\n", __func__);
+ return -EREMOTEIO;
+ }
+
+ idx = 0;
+ do {
+ bsr = readb(i2c->base + REG_BSR);
+ bcr = readb(i2c->base + REG_BCR);
+ if (bcr & BCR_BER) {
+ debug("%s: Bus error detected\n", __func__);
+ return -EREMOTEIO;
+ }
+ if ((bsr & BSR_AL) || !(bcr & BCR_MSS)) {
+ debug("%s: Arbitration lost\n", __func__);
+ return -EREMOTEIO;
+ }
+
+ if (msg->flags & I2C_M_RD) {
+ bcr = BCR_MSS | BCR_INTE | BCR_BEIE;
+ if (idx < msg->len - 1)
+ bcr |= BCR_ACK;
+ writeb(bcr, i2c->base + REG_BCR);
+ if (wait_irq(bus))
+ return -EREMOTEIO;
+ bsr = readb(i2c->base + REG_BSR);
+ if (!(bsr & BSR_FBT))
+ msg->buf[idx++] = readb(i2c->base + REG_DAR);
+ } else {
+ writeb(msg->buf[idx++], i2c->base + REG_DAR);
+ bcr = BCR_MSS | BCR_INTE | BCR_BEIE;
+ writeb(bcr, i2c->base + REG_BCR);
+ if (wait_irq(bus))
+ return -EREMOTEIO;
+ bsr = readb(i2c->base + REG_BSR);
+ if (bsr & BSR_LRB) {
+ debug("%s: no ack\n", __func__);
+ return -EREMOTEIO;
+ }
+ }
+ } while (idx < msg->len);
+ }
+
+ /* Force bus state to idle, terminating any ongoing transfer */
+ writeb(0, i2c->base + REG_BCR);
+ udelay(100);
+
+ return 0;
+}
+
+static void synquacer_i2c_hw_reset(struct synquacer_i2c *i2c)
+{
+ /* Disable clock */
+ writeb(0, i2c->base + REG_CCR);
+ writeb(0, i2c->base + REG_CSR);
+
+ /* Set own Address */
+ writeb(0, i2c->base + REG_ADR);
+
+ /* Set PCLK frequency */
+ writeb(BUS_CLK_FR(i2c->pclkrate), i2c->base + REG_FSR);
+
+ /* clear IRQ (INT=0, BER=0), Interrupt Disable */
+ writeb(0, i2c->base + REG_BCR);
+ writeb(0, i2c->base + REG_BC2R);
+}
+
+static int synquacer_i2c_get_bus_speed(struct udevice *bus)
+{
+ struct synquacer_i2c *i2c = dev_get_priv(bus);
+
+ return i2c->speed_khz * 1000;
+}
+
+static int synquacer_i2c_set_bus_speed(struct udevice *bus, unsigned int speed)
+{
+ struct synquacer_i2c *i2c = dev_get_priv(bus);
+ u32 rt = i2c->pclkrate;
+ u8 ccr_cs, csr_cs;
+
+ /* Set PCLK frequency */
+ writeb(BUS_CLK_FR(i2c->pclkrate), i2c->base + REG_FSR);
+
+ if (speed >= SPEED_FM * 1000) {
+ i2c->speed_khz = SPEED_FM;
+ if (i2c->pclkrate <= CLK_RATE_18M) {
+ ccr_cs = CCR_CS_FAST_MAX_18M(rt);
+ csr_cs = CSR_CS_FAST_MAX_18M(rt);
+ } else {
+ ccr_cs = CCR_CS_FAST_MIN_18M(rt);
+ csr_cs = CSR_CS_FAST_MIN_18M(rt);
+ }
+
+ /* Set Clock and enable, Set fast mode */
+ writeb(ccr_cs | CCR_FM | CCR_EN, i2c->base + REG_CCR);
+ writeb(csr_cs, i2c->base + REG_CSR);
+ } else {
+ i2c->speed_khz = SPEED_SM;
+ if (i2c->pclkrate <= CLK_RATE_18M) {
+ ccr_cs = CCR_CS_STD_MAX_18M(rt);
+ csr_cs = CSR_CS_STD_MAX_18M(rt);
+ } else {
+ ccr_cs = CCR_CS_STD_MIN_18M(rt);
+ csr_cs = CSR_CS_STD_MIN_18M(rt);
+ }
+
+ /* Set Clock and enable, Set standard mode */
+ writeb(ccr_cs | CCR_EN, i2c->base + REG_CCR);
+ writeb(csr_cs, i2c->base + REG_CSR);
+ }
+
+ return 0;
+}
+
+static int synquacer_i2c_of_to_plat(struct udevice *bus)
+{
+ struct synquacer_i2c *priv = dev_get_priv(bus);
+ struct clk ck;
+ int ret;
+
+ ret = clk_get_by_index(bus, 0, &ck);
+ if (ret < 0) {
+ priv->pclkrate = I2C_CLK_DEF;
+ } else {
+ clk_enable(&ck);
+ priv->pclkrate = clk_get_rate(&ck);
+ }
+
+ return 0;
+}
+
+static int synquacer_i2c_probe(struct udevice *bus)
+{
+ struct synquacer_i2c *i2c = dev_get_priv(bus);
+
+ i2c->base = dev_read_addr_ptr(bus);
+ synquacer_i2c_hw_reset(i2c);
+ synquacer_i2c_set_bus_speed(bus, 400000); /* set default speed */
+ return 0;
+}
+
+static const struct dm_i2c_ops synquacer_i2c_ops = {
+ .xfer = synquacer_i2c_xfer,
+ .set_bus_speed = synquacer_i2c_set_bus_speed,
+ .get_bus_speed = synquacer_i2c_get_bus_speed,
+};
+
+static const struct udevice_id synquacer_i2c_ids[] = {
+ {
+ .compatible = "socionext,synquacer-i2c",
+ },
+ { }
+};
+
+U_BOOT_DRIVER(sni_synquacer_i2c) = {
+ .name = "sni_synquacer_i2c",
+ .id = UCLASS_I2C,
+ .of_match = synquacer_i2c_ids,
+ .of_to_plat = synquacer_i2c_of_to_plat,
+ .probe = synquacer_i2c_probe,
+ .priv_auto = sizeof(struct synquacer_i2c),
+ .ops = &synquacer_i2c_ops,
+};
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