--- /dev/null
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Xilinx AXI I2C driver
+ *
+ * Copyright (C) 2018 Marek Vasut <marex@denx.de>
+ *
+ * Based on Linux 4.14.y i2c-xiic.c
+ * Copyright (c) 2002-2007 Xilinx Inc.
+ * Copyright (c) 2009-2010 Intel Corporation
+ */
+
+#include <common.h>
+#include <clk.h>
+#include <dm.h>
+#include <i2c.h>
+#include <wait_bit.h>
+#include <asm/io.h>
+
+struct xilinx_xiic_priv {
+ void __iomem *base;
+ struct clk clk;
+};
+
+#define XIIC_MSB_OFFSET 0
+#define XIIC_REG_OFFSET (0x100+XIIC_MSB_OFFSET)
+
+/*
+ * Register offsets in bytes from RegisterBase. Three is added to the
+ * base offset to access LSB (IBM style) of the word
+ */
+#define XIIC_CR_REG_OFFSET (0x00+XIIC_REG_OFFSET) /* Control Register */
+#define XIIC_SR_REG_OFFSET (0x04+XIIC_REG_OFFSET) /* Status Register */
+#define XIIC_DTR_REG_OFFSET (0x08+XIIC_REG_OFFSET) /* Data Tx Register */
+#define XIIC_DRR_REG_OFFSET (0x0C+XIIC_REG_OFFSET) /* Data Rx Register */
+#define XIIC_ADR_REG_OFFSET (0x10+XIIC_REG_OFFSET) /* Address Register */
+#define XIIC_TFO_REG_OFFSET (0x14+XIIC_REG_OFFSET) /* Tx FIFO Occupancy */
+#define XIIC_RFO_REG_OFFSET (0x18+XIIC_REG_OFFSET) /* Rx FIFO Occupancy */
+#define XIIC_TBA_REG_OFFSET (0x1C+XIIC_REG_OFFSET) /* 10 Bit Address reg */
+#define XIIC_RFD_REG_OFFSET (0x20+XIIC_REG_OFFSET) /* Rx FIFO Depth reg */
+#define XIIC_GPO_REG_OFFSET (0x24+XIIC_REG_OFFSET) /* Output Register */
+
+/* Control Register masks */
+#define XIIC_CR_ENABLE_DEVICE_MASK 0x01 /* Device enable = 1 */
+#define XIIC_CR_TX_FIFO_RESET_MASK 0x02 /* Transmit FIFO reset=1 */
+#define XIIC_CR_MSMS_MASK 0x04 /* Master starts Txing=1 */
+#define XIIC_CR_DIR_IS_TX_MASK 0x08 /* Dir of tx. Txing=1 */
+#define XIIC_CR_NO_ACK_MASK 0x10 /* Tx Ack. NO ack = 1 */
+#define XIIC_CR_REPEATED_START_MASK 0x20 /* Repeated start = 1 */
+#define XIIC_CR_GENERAL_CALL_MASK 0x40 /* Gen Call enabled = 1 */
+
+/* Status Register masks */
+#define XIIC_SR_GEN_CALL_MASK 0x01 /* 1=a mstr issued a GC */
+#define XIIC_SR_ADDR_AS_SLAVE_MASK 0x02 /* 1=when addr as slave */
+#define XIIC_SR_BUS_BUSY_MASK 0x04 /* 1 = bus is busy */
+#define XIIC_SR_MSTR_RDING_SLAVE_MASK 0x08 /* 1=Dir: mstr <-- slave */
+#define XIIC_SR_TX_FIFO_FULL_MASK 0x10 /* 1 = Tx FIFO full */
+#define XIIC_SR_RX_FIFO_FULL_MASK 0x20 /* 1 = Rx FIFO full */
+#define XIIC_SR_RX_FIFO_EMPTY_MASK 0x40 /* 1 = Rx FIFO empty */
+#define XIIC_SR_TX_FIFO_EMPTY_MASK 0x80 /* 1 = Tx FIFO empty */
+
+/* Interrupt Status Register masks Interrupt occurs when... */
+#define XIIC_INTR_ARB_LOST_MASK 0x01 /* 1 = arbitration lost */
+#define XIIC_INTR_TX_ERROR_MASK 0x02 /* 1=Tx error/msg complete */
+#define XIIC_INTR_TX_EMPTY_MASK 0x04 /* 1 = Tx FIFO/reg empty */
+#define XIIC_INTR_RX_FULL_MASK 0x08 /* 1=Rx FIFO/reg=OCY level */
+#define XIIC_INTR_BNB_MASK 0x10 /* 1 = Bus not busy */
+#define XIIC_INTR_AAS_MASK 0x20 /* 1 = when addr as slave */
+#define XIIC_INTR_NAAS_MASK 0x40 /* 1 = not addr as slave */
+#define XIIC_INTR_TX_HALF_MASK 0x80 /* 1 = TX FIFO half empty */
+
+/* The following constants specify the depth of the FIFOs */
+#define IIC_RX_FIFO_DEPTH 16 /* Rx fifo capacity */
+#define IIC_TX_FIFO_DEPTH 16 /* Tx fifo capacity */
+
+/*
+ * Tx Fifo upper bit masks.
+ */
+#define XIIC_TX_DYN_START_MASK 0x0100 /* 1 = Set dynamic start */
+#define XIIC_TX_DYN_STOP_MASK 0x0200 /* 1 = Set dynamic stop */
+
+/*
+ * The following constants define the register offsets for the Interrupt
+ * registers. There are some holes in the memory map for reserved addresses
+ * to allow other registers to be added and still match the memory map of the
+ * interrupt controller registers
+ */
+#define XIIC_DGIER_OFFSET 0x1C /* Device Global Interrupt Enable Register */
+#define XIIC_IISR_OFFSET 0x20 /* Interrupt Status Register */
+#define XIIC_IIER_OFFSET 0x28 /* Interrupt Enable Register */
+#define XIIC_RESETR_OFFSET 0x40 /* Reset Register */
+
+#define XIIC_RESET_MASK 0xAUL
+
+static u8 i2c_8bit_addr_from_flags(uint addr, u16 flags)
+{
+ return (addr << 1) | (flags & I2C_M_RD ? 1 : 0);
+}
+
+static void xiic_irq_clr(struct xilinx_xiic_priv *priv, u32 mask)
+{
+ u32 isr = readl(priv->base + XIIC_IISR_OFFSET);
+
+ writel(isr & mask, priv->base + XIIC_IISR_OFFSET);
+}
+
+static int xiic_read_rx(struct xilinx_xiic_priv *priv,
+ struct i2c_msg *msg, int nmsgs)
+{
+ u8 bytes_in_fifo;
+ u32 pos = 0;
+ int i, ret;
+
+ while (pos < msg->len) {
+ ret = wait_for_bit_8(priv->base + XIIC_SR_REG_OFFSET,
+ XIIC_SR_RX_FIFO_EMPTY_MASK, false,
+ 1000, true);
+ if (ret)
+ return ret;
+
+ bytes_in_fifo = readb(priv->base + XIIC_RFO_REG_OFFSET) + 1;
+
+ if (bytes_in_fifo > msg->len)
+ bytes_in_fifo = msg->len;
+
+ for (i = 0; i < bytes_in_fifo; i++) {
+ msg->buf[pos++] = readb(priv->base +
+ XIIC_DRR_REG_OFFSET);
+ }
+ }
+
+ return 0;
+}
+
+static int xiic_tx_fifo_space(struct xilinx_xiic_priv *priv)
+{
+ /* return the actual space left in the FIFO */
+ return IIC_TX_FIFO_DEPTH - readb(priv->base + XIIC_TFO_REG_OFFSET) - 1;
+}
+
+static void xiic_fill_tx_fifo(struct xilinx_xiic_priv *priv,
+ struct i2c_msg *msg, int nmsgs)
+{
+ u8 fifo_space = xiic_tx_fifo_space(priv);
+ int len = msg->len;
+ u32 pos = 0;
+
+ len = (len > fifo_space) ? fifo_space : len;
+
+ while (len--) {
+ u16 data = msg->buf[pos++];
+
+ if (pos == len && nmsgs == 1) {
+ /* last message in transfer -> STOP */
+ data |= XIIC_TX_DYN_STOP_MASK;
+ }
+ writew(data, priv->base + XIIC_DTR_REG_OFFSET);
+ }
+}
+
+static void xilinx_xiic_set_addr(struct udevice *dev, u8 addr,
+ u16 flags, u32 len, u32 nmsgs)
+{
+ struct xilinx_xiic_priv *priv = dev_get_priv(dev);
+
+ xiic_irq_clr(priv, XIIC_INTR_TX_ERROR_MASK);
+
+ if (!(flags & I2C_M_NOSTART)) {
+ /* write the address */
+ u16 data = i2c_8bit_addr_from_flags(addr, flags) |
+ XIIC_TX_DYN_START_MASK;
+ if (nmsgs == 1 && len == 0)
+ /* no data and last message -> add STOP */
+ data |= XIIC_TX_DYN_STOP_MASK;
+
+ writew(data, priv->base + XIIC_DTR_REG_OFFSET);
+ }
+}
+
+static int xilinx_xiic_read_common(struct udevice *dev, struct i2c_msg *msg,
+ u32 nmsgs)
+{
+ struct xilinx_xiic_priv *priv = dev_get_priv(dev);
+ u8 rx_watermark;
+
+ /* Clear and enable Rx full interrupt. */
+ xiic_irq_clr(priv, XIIC_INTR_RX_FULL_MASK | XIIC_INTR_TX_ERROR_MASK);
+
+ /* we want to get all but last byte, because the TX_ERROR IRQ is used
+ * to inidicate error ACK on the address, and negative ack on the last
+ * received byte, so to not mix them receive all but last.
+ * In the case where there is only one byte to receive
+ * we can check if ERROR and RX full is set at the same time
+ */
+ rx_watermark = msg->len;
+ if (rx_watermark > IIC_RX_FIFO_DEPTH)
+ rx_watermark = IIC_RX_FIFO_DEPTH;
+
+ writeb(rx_watermark - 1, priv->base + XIIC_RFD_REG_OFFSET);
+
+ xilinx_xiic_set_addr(dev, msg->addr, msg->flags, msg->len, nmsgs);
+
+ xiic_irq_clr(priv, XIIC_INTR_BNB_MASK);
+
+ writew((msg->len & 0xff) | ((nmsgs == 1) ? XIIC_TX_DYN_STOP_MASK : 0),
+ priv->base + XIIC_DTR_REG_OFFSET);
+
+ if (nmsgs == 1)
+ /* very last, enable bus not busy as well */
+ xiic_irq_clr(priv, XIIC_INTR_BNB_MASK);
+
+ return xiic_read_rx(priv, msg, nmsgs);
+}
+
+static int xilinx_xiic_write_common(struct udevice *dev, struct i2c_msg *msg,
+ int nmsgs)
+{
+ struct xilinx_xiic_priv *priv = dev_get_priv(dev);
+ int ret;
+
+ xilinx_xiic_set_addr(dev, msg->addr, msg->flags, msg->len, nmsgs);
+ xiic_fill_tx_fifo(priv, msg, nmsgs);
+
+ ret = wait_for_bit_8(priv->base + XIIC_SR_REG_OFFSET,
+ XIIC_SR_TX_FIFO_EMPTY_MASK, false, 1000, true);
+ if (ret)
+ return ret;
+
+ /* Clear any pending Tx empty, Tx Error and then enable them. */
+ xiic_irq_clr(priv, XIIC_INTR_TX_EMPTY_MASK | XIIC_INTR_TX_ERROR_MASK |
+ XIIC_INTR_BNB_MASK);
+
+ return 0;
+}
+
+static void xiic_clear_rx_fifo(struct xilinx_xiic_priv *priv)
+{
+ u8 sr;
+
+ for (sr = readb(priv->base + XIIC_SR_REG_OFFSET);
+ !(sr & XIIC_SR_RX_FIFO_EMPTY_MASK);
+ sr = readb(priv->base + XIIC_SR_REG_OFFSET))
+ readb(priv->base + XIIC_DRR_REG_OFFSET);
+}
+
+static void xiic_reinit(struct xilinx_xiic_priv *priv)
+{
+ writel(XIIC_RESET_MASK, priv->base + XIIC_RESETR_OFFSET);
+
+ /* Set receive Fifo depth to maximum (zero based). */
+ writeb(IIC_RX_FIFO_DEPTH - 1, priv->base + XIIC_RFD_REG_OFFSET);
+
+ /* Reset Tx Fifo. */
+ writeb(XIIC_CR_TX_FIFO_RESET_MASK, priv->base + XIIC_CR_REG_OFFSET);
+
+ /* Enable IIC Device, remove Tx Fifo reset & disable general call. */
+ writeb(XIIC_CR_ENABLE_DEVICE_MASK, priv->base + XIIC_CR_REG_OFFSET);
+
+ /* make sure RX fifo is empty */
+ xiic_clear_rx_fifo(priv);
+
+ /* Disable interrupts */
+ writel(0, priv->base + XIIC_DGIER_OFFSET);
+
+ xiic_irq_clr(priv, XIIC_INTR_ARB_LOST_MASK);
+}
+
+static int xilinx_xiic_xfer(struct udevice *dev, struct i2c_msg *msg, int nmsgs)
+{
+ int ret = 0;
+
+ for (; nmsgs > 0; nmsgs--, msg++) {
+ if (msg->flags & I2C_M_RD)
+ ret = xilinx_xiic_read_common(dev, msg, nmsgs);
+ else
+ ret = xilinx_xiic_write_common(dev, msg, nmsgs);
+
+ if (ret)
+ return -EREMOTEIO;
+ }
+
+ return ret;
+}
+
+static int xilinx_xiic_probe_chip(struct udevice *dev, uint addr, uint flags)
+{
+ struct xilinx_xiic_priv *priv = dev_get_priv(dev);
+ u32 reg;
+ int ret;
+
+ xiic_reinit(priv);
+
+ xilinx_xiic_set_addr(dev, addr, 0, 0, 1);
+ ret = wait_for_bit_8(priv->base + XIIC_SR_REG_OFFSET,
+ XIIC_SR_BUS_BUSY_MASK, false, 1000, true);
+ if (ret)
+ return ret;
+
+ reg = readl(priv->base + XIIC_IISR_OFFSET);
+ if (reg & XIIC_INTR_TX_ERROR_MASK)
+ return -ENODEV;
+
+ return 0;
+}
+
+static int xilinx_xiic_set_speed(struct udevice *dev, uint speed)
+{
+ return 0;
+}
+
+static int xilinx_xiic_probe(struct udevice *dev)
+{
+ struct xilinx_xiic_priv *priv = dev_get_priv(dev);
+
+ priv->base = dev_read_addr_ptr(dev);
+
+ writel(XIIC_CR_TX_FIFO_RESET_MASK, priv->base + XIIC_CR_REG_OFFSET);
+ xiic_reinit(priv);
+
+ return 0;
+}
+
+static const struct dm_i2c_ops xilinx_xiic_ops = {
+ .xfer = xilinx_xiic_xfer,
+ .probe_chip = xilinx_xiic_probe_chip,
+ .set_bus_speed = xilinx_xiic_set_speed,
+};
+
+static const struct udevice_id xilinx_xiic_ids[] = {
+ { .compatible = "xlnx,xps-iic-2.00.a" },
+ { }
+};
+
+U_BOOT_DRIVER(xilinx_xiic) = {
+ .name = "xilinx_axi_i2c",
+ .id = UCLASS_I2C,
+ .of_match = xilinx_xiic_ids,
+ .probe = xilinx_xiic_probe,
+ .priv_auto_alloc_size = sizeof(struct xilinx_xiic_priv),
+ .ops = &xilinx_xiic_ops,
+};
projects / project / bcm63xx / u-boot.git / commitdiff