--- /dev/null
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Microchip I2C controller driver
+ *
+ * Copyright (C) 2021 Microchip Technology Inc.
+ * Padmarao Begari <padmarao.begari@microchip.com>
+ */
+#include <common.h>
+#include <clk.h>
+#include <dm.h>
+#include <i2c.h>
+#include <asm/io.h>
+#include <dm/device_compat.h>
+#include <linux/bitops.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+
+#define MICROCHIP_I2C_TIMEOUT (1000 * 60)
+
+#define MPFS_I2C_CTRL (0x00)
+#define CTRL_CR0 (0x00)
+#define CTRL_CR1 (0x01)
+#define CTRL_AA BIT(2)
+#define CTRL_SI BIT(3)
+#define CTRL_STO BIT(4)
+#define CTRL_STA BIT(5)
+#define CTRL_ENS1 BIT(6)
+#define CTRL_CR2 (0x07)
+#define MPFS_I2C_STATUS (0x04)
+#define STATUS_BUS_ERROR (0x00)
+#define STATUS_M_START_SENT (0x08)
+#define STATUS_M_REPEATED_START_SENT (0x10)
+#define STATUS_M_SLAW_ACK (0x18)
+#define STATUS_M_SLAW_NACK (0x20)
+#define STATUS_M_TX_DATA_ACK (0x28)
+#define STATUS_M_TX_DATA_NACK (0x30)
+#define STATUS_M_ARB_LOST (0x38)
+#define STATUS_M_SLAR_ACK (0x40)
+#define STATUS_M_SLAR_NACK (0x48)
+#define STATUS_M_RX_DATA_ACKED (0x50)
+#define STATUS_M_RX_DATA_NACKED (0x58)
+#define STATUS_S_SLAW_ACKED (0x60)
+#define STATUS_S_ARB_LOST_SLAW_ACKED (0x68)
+#define STATUS_S_GENERAL_CALL_ACKED (0x70)
+#define STATUS_S_ARB_LOST_GENERAL_CALL_ACKED (0x78)
+#define STATUS_S_RX_DATA_ACKED (0x80)
+#define STATUS_S_RX_DATA_NACKED (0x88)
+#define STATUS_S_GENERAL_CALL_RX_DATA_ACKED (0x90)
+#define STATUS_S_GENERAL_CALL_RX_DATA_NACKED (0x98)
+#define STATUS_S_RX_STOP (0xA0)
+#define STATUS_S_SLAR_ACKED (0xA8)
+#define STATUS_S_ARB_LOST_SLAR_ACKED (0xB0)
+#define STATUS_S_TX_DATA_ACK (0xb8)
+#define STATUS_S_TX_DATA_NACK (0xC0)
+#define STATUS_LAST_DATA_ACK (0xC8)
+#define STATUS_M_SMB_MASTER_RESET (0xD0)
+#define STATUS_S_SCL_LOW_TIMEOUT (0xD8)
+#define STATUS_NO_STATE_INFO (0xF8)
+#define MPFS_I2C_DATA (0x08)
+#define MPFS_I2C_SLAVE0_ADDR (0x0c)
+#define MPFS_I2C_SMBUS (0x10)
+#define MPFS_I2C_FREQ (0x14)
+#define MPFS_I2C_GLITCHREG (0x18)
+#define MPFS_I2C_SLAVE1_ADDR (0x1c)
+
+#define PCLK_DIV_256 ((0 << CTRL_CR0) | (0 << CTRL_CR1) | (0 << CTRL_CR2))
+#define PCLK_DIV_224 ((1 << CTRL_CR0) | (0 << CTRL_CR1) | (0 << CTRL_CR2))
+#define PCLK_DIV_192 ((0 << CTRL_CR0) | (1 << CTRL_CR1) | (0 << CTRL_CR2))
+#define PCLK_DIV_160 ((1 << CTRL_CR0) | (1 << CTRL_CR1) | (0 << CTRL_CR2))
+#define PCLK_DIV_960 ((0 << CTRL_CR0) | (0 << CTRL_CR1) | (1 << CTRL_CR2))
+#define PCLK_DIV_120 ((1 << CTRL_CR0) | (0 << CTRL_CR1) | (1 << CTRL_CR2))
+#define PCLK_DIV_60 ((0 << CTRL_CR0) | (1 << CTRL_CR1) | (1 << CTRL_CR2))
+#define BCLK_DIV_8 ((1 << CTRL_CR0) | (1 << CTRL_CR1) | (1 << CTRL_CR2))
+#define CLK_MASK ((1 << CTRL_CR0) | (1 << CTRL_CR1) | (1 << CTRL_CR2))
+
+/*
+ * mpfs_i2c_bus - I2C bus context
+ * @base: pointer to register struct
+ * @msg_len: number of bytes transferred in msg
+ * @msg_err: error code for completed message
+ * @i2c_clk: clock reference for i2c input clock
+ * @clk_rate: current i2c bus clock rate
+ * @buf: ptr to msg buffer for easier use.
+ * @addr: i2c address.
+ * @isr_status: cached copy of local ISR status.
+ */
+struct mpfs_i2c_bus {
+ void __iomem *base;
+ size_t msg_len;
+ int msg_err;
+ struct clk i2c_clk;
+ u32 clk_rate;
+ u8 *buf;
+ u8 addr;
+ u32 isr_status;
+};
+
+static inline u8 i2c_8bit_addr_from_msg(const struct i2c_msg *msg)
+{
+ return (msg->addr << 1) | (msg->flags & I2C_M_RD ? 1 : 0);
+}
+
+static void mpfs_i2c_int_clear(struct mpfs_i2c_bus *bus)
+{
+ u8 ctrl = readl(bus->base + MPFS_I2C_CTRL);
+
+ ctrl &= ~CTRL_SI;
+ writel(ctrl, bus->base + MPFS_I2C_CTRL);
+}
+
+static void mpfs_i2c_core_disable(struct mpfs_i2c_bus *bus)
+{
+ u8 ctrl = readl(bus->base + MPFS_I2C_CTRL);
+
+ ctrl &= ~CTRL_ENS1;
+ writel(ctrl, bus->base + MPFS_I2C_CTRL);
+}
+
+static void mpfs_i2c_core_enable(struct mpfs_i2c_bus *bus)
+{
+ u8 ctrl = readl(bus->base + MPFS_I2C_CTRL);
+
+ ctrl |= CTRL_ENS1;
+ writel(ctrl, bus->base + MPFS_I2C_CTRL);
+}
+
+static void mpfs_i2c_reset(struct mpfs_i2c_bus *bus)
+{
+ mpfs_i2c_core_disable(bus);
+ mpfs_i2c_core_enable(bus);
+}
+
+static inline void mpfs_i2c_stop(struct mpfs_i2c_bus *bus)
+{
+ u8 ctrl = readl(bus->base + MPFS_I2C_CTRL);
+
+ ctrl |= CTRL_STO;
+ writel(ctrl, bus->base + MPFS_I2C_CTRL);
+}
+
+static inline int mpfs_generate_divisor(u32 rate, u8 *code)
+{
+ int ret = 0;
+
+ if (rate >= 960)
+ *code = PCLK_DIV_960;
+ else if (rate >= 256)
+ *code = PCLK_DIV_256;
+ else if (rate >= 224)
+ *code = PCLK_DIV_224;
+ else if (rate >= 192)
+ *code = PCLK_DIV_192;
+ else if (rate >= 160)
+ *code = PCLK_DIV_160;
+ else if (rate >= 120)
+ *code = PCLK_DIV_120;
+ else if (rate >= 60)
+ *code = PCLK_DIV_60;
+ else if (rate >= 8)
+ *code = BCLK_DIV_8;
+ else
+ ret = -EINVAL;
+
+ return ret;
+}
+
+static int mpfs_i2c_init(struct mpfs_i2c_bus *bus, struct udevice *dev)
+{
+ u32 clk_rate, divisor;
+ u8 clkval, ctrl;
+ int ret;
+
+ ret = clk_get_by_index(dev, 0, &bus->i2c_clk);
+ if (ret)
+ return -EINVAL;
+
+ ret = clk_enable(&bus->i2c_clk);
+ if (ret)
+ return ret;
+
+ clk_rate = clk_get_rate(&bus->i2c_clk);
+ if (!clk_rate)
+ return -EINVAL;
+
+ clk_free(&bus->i2c_clk);
+
+ divisor = clk_rate / bus->clk_rate;
+
+ ctrl = readl(bus->base + MPFS_I2C_CTRL);
+
+ ctrl &= ~CLK_MASK;
+
+ ret = mpfs_generate_divisor(divisor, &clkval);
+ if (ret)
+ return -EINVAL;
+
+ ctrl |= clkval;
+
+ writel(ctrl, bus->base + MPFS_I2C_CTRL);
+
+ ctrl = readl(bus->base + MPFS_I2C_CTRL);
+
+ /* Reset I2C core */
+ mpfs_i2c_reset(bus);
+
+ return 0;
+}
+
+static void mpfs_i2c_transfer(struct mpfs_i2c_bus *bus, u32 data)
+{
+ if (bus->msg_len > 0)
+ writel(data, bus->base + MPFS_I2C_DATA);
+}
+
+static void mpfs_i2c_empty_rx(struct mpfs_i2c_bus *bus)
+{
+ u8 ctrl;
+ u8 data_read;
+
+ if (bus->msg_len > 0) {
+ data_read = readl(bus->base + MPFS_I2C_DATA);
+ *bus->buf++ = data_read;
+ bus->msg_len--;
+ }
+
+ if (bus->msg_len == 0) {
+ ctrl = readl(bus->base + MPFS_I2C_CTRL);
+ ctrl &= ~CTRL_AA;
+ writel(ctrl, bus->base + MPFS_I2C_CTRL);
+ }
+}
+
+static int mpfs_i2c_fill_tx(struct mpfs_i2c_bus *bus)
+{
+ mpfs_i2c_transfer(bus, *bus->buf++);
+ bus->msg_len--;
+
+ return 0;
+}
+
+static int mpfs_i2c_service_handler(struct mpfs_i2c_bus *bus)
+{
+ bool finish = false;
+ u32 status;
+ u8 ctrl;
+
+ status = bus->isr_status;
+
+ switch (status) {
+ case STATUS_M_START_SENT:
+ case STATUS_M_REPEATED_START_SENT:
+ ctrl = readl(bus->base + MPFS_I2C_CTRL);
+ ctrl &= ~CTRL_STA;
+ writel(bus->addr, bus->base + MPFS_I2C_DATA);
+ writel(ctrl, bus->base + MPFS_I2C_CTRL);
+ break;
+ case STATUS_M_SLAW_ACK:
+ case STATUS_M_TX_DATA_ACK:
+ if (bus->msg_len > 0) {
+ mpfs_i2c_fill_tx(bus);
+ } else {
+ /* On the last byte to be transmitted, send STOP */
+ mpfs_i2c_stop(bus);
+ finish = true;
+ }
+ break;
+ case STATUS_M_SLAR_ACK:
+ ctrl = readl(bus->base + MPFS_I2C_CTRL);
+ ctrl |= CTRL_AA;
+ writel(ctrl, bus->base + MPFS_I2C_CTRL);
+ if (bus->msg_len == 0) {
+ /* On the last byte to be transmitted, send STOP */
+ mpfs_i2c_stop(bus);
+ finish = true;
+ }
+ break;
+ case STATUS_M_RX_DATA_ACKED:
+ mpfs_i2c_empty_rx(bus);
+ if (bus->msg_len == 0) {
+ /* On the last byte to be transmitted, send STOP */
+ mpfs_i2c_stop(bus);
+ finish = true;
+ }
+ break;
+ case STATUS_M_TX_DATA_NACK:
+ case STATUS_M_RX_DATA_NACKED:
+ case STATUS_M_SLAR_NACK:
+ case STATUS_M_SLAW_NACK:
+ bus->msg_err = -ENXIO;
+ mpfs_i2c_stop(bus);
+ finish = true;
+ break;
+
+ case STATUS_M_ARB_LOST:
+ /* Handle Lost Arbitration */
+ bus->msg_err = -EAGAIN;
+ finish = true;
+ break;
+ default:
+ break;
+ }
+
+ if (finish) {
+ ctrl = readl(bus->base + MPFS_I2C_CTRL);
+ ctrl &= ~CTRL_AA;
+ writel(ctrl, bus->base + MPFS_I2C_CTRL);
+ return 0;
+ }
+
+ return 1;
+}
+
+static int mpfs_i2c_service(struct mpfs_i2c_bus *bus)
+{
+ int ret = 0;
+ int si_bit;
+
+ si_bit = readl(bus->base + MPFS_I2C_CTRL);
+ if (si_bit & CTRL_SI) {
+ bus->isr_status = readl(bus->base + MPFS_I2C_STATUS);
+ ret = mpfs_i2c_service_handler(bus);
+ }
+ /* Clear the si flag */
+ mpfs_i2c_int_clear(bus);
+ si_bit = readl(bus->base + MPFS_I2C_CTRL);
+
+ return ret;
+}
+
+static int mpfs_i2c_check_service_change(struct mpfs_i2c_bus *bus)
+{
+ u8 ctrl;
+ u32 count = 0;
+
+ while (1) {
+ ctrl = readl(bus->base + MPFS_I2C_CTRL);
+ if (ctrl & CTRL_SI)
+ break;
+ udelay(1);
+ count += 1;
+ if (count == MICROCHIP_I2C_TIMEOUT)
+ return -ETIMEDOUT;
+ }
+ return 0;
+}
+
+static int mpfs_i2c_poll_device(struct mpfs_i2c_bus *bus)
+{
+ int ret;
+
+ while (1) {
+ ret = mpfs_i2c_check_service_change(bus);
+ if (ret)
+ return ret;
+
+ ret = mpfs_i2c_service(bus);
+ if (!ret)
+ /* all messages have been transferred */
+ return ret;
+ }
+}
+
+static int mpfs_i2c_xfer_msg(struct mpfs_i2c_bus *bus, struct i2c_msg *msg)
+{
+ u8 ctrl;
+ int ret;
+
+ if (!msg->len || !msg->buf)
+ return -EINVAL;
+
+ bus->addr = i2c_8bit_addr_from_msg(msg);
+ bus->msg_len = msg->len;
+ bus->buf = msg->buf;
+ bus->msg_err = 0;
+
+ mpfs_i2c_core_enable(bus);
+
+ ctrl = readl(bus->base + MPFS_I2C_CTRL);
+
+ ctrl |= CTRL_STA;
+
+ writel(ctrl, bus->base + MPFS_I2C_CTRL);
+
+ ret = mpfs_i2c_poll_device(bus);
+ if (ret)
+ return ret;
+
+ return bus->msg_err;
+}
+
+static int mpfs_i2c_xfer(struct udevice *dev, struct i2c_msg *msgs, int num_msgs)
+{
+ struct mpfs_i2c_bus *bus = dev_get_priv(dev);
+ int idx, ret;
+
+ if (!msgs || !num_msgs)
+ return -EINVAL;
+
+ for (idx = 0; idx < num_msgs; idx++) {
+ ret = mpfs_i2c_xfer_msg(bus, msgs++);
+ if (ret)
+ return ret;
+ }
+
+ return ret;
+}
+
+static int mpfs_i2c_probe_chip(struct udevice *dev, uint addr, uint flags)
+{
+ struct mpfs_i2c_bus *bus = dev_get_priv(dev);
+ int ret;
+ u8 ctrl, reg = 0;
+
+ /*
+ * Send the chip address and verify that the
+ * address was <ACK>ed.
+ */
+ bus->addr = addr << 1 | I2C_M_RD;
+ bus->buf = ®
+ bus->msg_len = 0;
+ bus->msg_err = 0;
+
+ mpfs_i2c_core_enable(bus);
+
+ ctrl = readl(bus->base + MPFS_I2C_CTRL);
+
+ ctrl |= CTRL_STA;
+
+ writel(ctrl, bus->base + MPFS_I2C_CTRL);
+
+ ret = mpfs_i2c_poll_device(bus);
+ if (ret)
+ return ret;
+
+ return bus->msg_err;
+}
+
+static int mpfs_i2c_probe(struct udevice *dev)
+{
+ int ret;
+ u32 val;
+ struct mpfs_i2c_bus *bus = dev_get_priv(dev);
+
+ bus->base = dev_read_addr_ptr(dev);
+ if (!bus->base)
+ return -EINVAL;
+
+ val = dev_read_u32(dev, "clock-frequency", &bus->clk_rate);
+ if (val) {
+ printf("Default to 100kHz\n");
+ /* default clock rate */
+ bus->clk_rate = 100000;
+ }
+
+ if (bus->clk_rate > 400000 || bus->clk_rate <= 0) {
+ printf("Invalid clock-frequency %d\n", bus->clk_rate);
+ return -EINVAL;
+ }
+
+ ret = mpfs_i2c_init(bus, dev);
+
+ return ret;
+}
+
+static const struct dm_i2c_ops mpfs_i2c_ops = {
+ .xfer = mpfs_i2c_xfer,
+ .probe_chip = mpfs_i2c_probe_chip,
+};
+
+static const struct udevice_id mpfs_i2c_ids[] = {
+ {.compatible = "microchip,mpfs-i2c"},
+ {}
+};
+
+U_BOOT_DRIVER(mpfs_i2c) = {
+ .name = "mpfs_i2c",
+ .id = UCLASS_I2C,
+ .of_match = mpfs_i2c_ids,
+ .ops = &mpfs_i2c_ops,
+ .probe = mpfs_i2c_probe,
+ .priv_auto = sizeof(struct mpfs_i2c_bus),
+};
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