--- /dev/null
+/*
+ * Copyright (C) ST-Ericsson SA 2010
+ *
+ * Basic U-Boot I2C interface for STn8500/DB8500
+ * Author: Michael Brandt <Michael.Brandt@stericsson.com> for ST-Ericsson
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ */
+
+/*
+ * Only 7-bit I2C device addresses are supported.
+ */
+
+#include <common.h>
+#include <i2c.h>
+
+#include "u8500_i2c.h"
+#include <asm/io.h>
+#include <asm/arch/clock.h>
+
+#define U8500_I2C_ENDAD_COUNTER (CONFIG_SYS_HZ/100) /* I2C bus timeout */
+#define U8500_I2C_FIFO_FLUSH_COUNTER 500000 /* flush "timeout" */
+#define U8500_I2C_SCL_FREQ 100000 /* I2C bus clock freq */
+#define U8500_I2C_INPUT_FREQ 48000000 /* Input clock freq */
+#define TX_FIFO_THRESHOLD 0x4
+#define RX_FIFO_THRESHOLD 0x4
+#define SLAVE_SETUP_TIME 14 /* Slave data setup time, 250ns for 48MHz i2c_clk */
+
+#define WRITE_FIELD(var, mask, shift, value) \
+ (var = ((var & ~(mask)) | ((value) << (shift))))
+
+static unsigned int bus_initialized[CONFIG_SYS_U8500_I2C_BUS_MAX];
+static unsigned int i2c_bus_num;
+static unsigned int i2c_bus_speed[] = {
+ CONFIG_SYS_I2C_SPEED, CONFIG_SYS_I2C_SPEED,
+ CONFIG_SYS_I2C_SPEED, CONFIG_SYS_I2C_SPEED
+};
+static struct u8500_i2c_regs *i2c_dev[] = {
+ (struct u8500_i2c_regs *)CONFIG_SYS_U8500_I2C0_BASE,
+ (struct u8500_i2c_regs *)CONFIG_SYS_U8500_I2C1_BASE,
+ (struct u8500_i2c_regs *)CONFIG_SYS_U8500_I2C2_BASE,
+ (struct u8500_i2c_regs *)CONFIG_SYS_U8500_I2C3_BASE,
+};
+
+static struct {
+ int periph;
+ int pcken;
+ int kcken;
+} i2c_clock_bits[] = {
+ {3, 3, 3}, /* I2C0 */
+ {1, 2, 2}, /* I2C1 */
+ {1, 6, 6}, /* I2C2 */
+ {2, 0, 0}, /* I2C3 */
+};
+
+static void i2c_set_bit(void *reg, u32 mask)
+{
+ writel(readl(reg) | mask, reg);
+}
+
+static void i2c_clr_bit(void *reg, u32 mask)
+{
+ writel(readl(reg) & ~mask, reg);
+}
+
+static void i2c_write_field(void *reg, u32 mask, uint shift, u32 value)
+{
+ writel((readl(reg) & ~mask) | (value << shift), reg);
+}
+
+static int __i2c_set_bus_speed(unsigned int speed)
+{
+ u32 value;
+ struct u8500_i2c_regs *i2c_regs;
+
+ i2c_regs = i2c_dev[i2c_bus_num];
+
+ /* Select standard (100 kbps) speed mode */
+ i2c_write_field(&i2c_regs->cr, U8500_I2C_CR_SM,
+ U8500_I2C_CR_SHIFT_SM, 0x0);
+
+ /*
+ * Set the Baud Rate Counter 2 value
+ * Baud rate (standard) = fi2cclk / ( (BRCNT2 x 2) + Foncycle )
+ * Foncycle = 0 (no digital filtering)
+ */
+ value = (u32) (U8500_I2C_INPUT_FREQ / (speed * 2));
+ i2c_write_field(&i2c_regs->brcr, U8500_I2C_BRCR_BRCNT2,
+ U8500_I2C_BRCR_SHIFT_BRCNT2, value);
+
+ /* ensure that BRCNT value is zero */
+ i2c_write_field(&i2c_regs->brcr, U8500_I2C_BRCR_BRCNT1,
+ U8500_I2C_BRCR_SHIFT_BRCNT1, 0);
+
+ return U8500_I2C_INPUT_FREQ/(value * 2);
+}
+
+/*
+ * i2c_init - initialize the i2c bus
+ *
+ * speed: bus speed (in HZ)
+ * slaveaddr: address of device in slave mode
+ *
+ * Slave mode is not implemented.
+ */
+void i2c_init(int speed, int slaveaddr)
+{
+ struct u8500_i2c_regs *i2c_regs;
+
+ debug("i2c_init bus %d, speed %d\n", i2c_bus_num, speed);
+
+ u8500_clock_enable(i2c_clock_bits[i2c_bus_num].periph,
+ i2c_clock_bits[i2c_bus_num].pcken,
+ i2c_clock_bits[i2c_bus_num].kcken);
+
+ i2c_regs = i2c_dev[i2c_bus_num];
+
+ /* Disable the controller */
+ i2c_clr_bit(&i2c_regs->cr, U8500_I2C_CR_PE);
+
+ /* Clear registers */
+ writel(0, &i2c_regs->cr);
+ writel(0, &i2c_regs->scr);
+ writel(0, &i2c_regs->hsmcr);
+ writel(0, &i2c_regs->tftr);
+ writel(0, &i2c_regs->rftr);
+ writel(0, &i2c_regs->dmar);
+
+ i2c_bus_speed[i2c_bus_num] = __i2c_set_bus_speed(speed);
+
+ /*
+ * Set our own address.
+ * Set slave address mode to 7 bit addressing mode
+ */
+ i2c_clr_bit(&i2c_regs->cr, U8500_I2C_CR_SAM);
+ i2c_write_field(&i2c_regs->scr, U8500_I2C_SCR_ADDR,
+ U8500_I2C_SCR_SHIFT_ADDR, slaveaddr);
+ /* Slave Data Set up Time */
+ i2c_write_field(&i2c_regs->scr, U8500_I2C_SCR_DATA_SETUP_TIME,
+ U8500_I2C_SCR_SHIFT_DATA_SETUP_TIME, SLAVE_SETUP_TIME);
+
+ /* Disable the DMA sync logic */
+ i2c_write_field(&i2c_regs->cr, U8500_I2C_CR_DMA_SLE,
+ U8500_I2C_CR_SHIFT_DMA_SLE, 0);
+
+ /* Disable interrupts */
+ writel(0, &i2c_regs->imscr);
+
+ /* Configure bus master mode */
+ i2c_write_field(&i2c_regs->cr, U8500_I2C_CR_OM, U8500_I2C_CR_SHIFT_OM,
+ U8500_I2C_BUS_MASTER_MODE);
+ /* Set FIFO threshold values */
+ writel(TX_FIFO_THRESHOLD, &i2c_regs->tftr);
+ writel(RX_FIFO_THRESHOLD, &i2c_regs->rftr);
+
+ /* Enable the I2C Controller */
+ i2c_set_bit(&i2c_regs->cr, U8500_I2C_CR_PE);
+
+ bus_initialized[i2c_bus_num] = 1;
+}
+
+
+/*
+ * loop_till_bit_clear - polls on a bit till it clears
+ * ioreg: register where you want to check status
+ * mask: bit mask for the bit you wish to check
+ * timeout: timeout in ticks/s
+ */
+static int loop_till_bit_clear(void *io_reg, u32 mask, unsigned long timeout)
+{
+ unsigned long timebase = get_timer(0);
+
+ do {
+ if ((readl(io_reg) & mask) == 0x0UL)
+ return 0;
+ } while (get_timer(timebase) < timeout);
+
+ debug("loop_till_bit_clear timed out\n");
+ return -1;
+}
+
+/*
+ * loop_till_bit_set - polls on a bit till it is set.
+ * ioreg: register where you want to check status
+ * mask: bit mask for the bit you wish to check
+ * timeout: timeout in ticks/s
+ */
+static int loop_till_bit_set(void *io_reg, u32 mask, unsigned long timeout)
+{
+ unsigned long timebase = get_timer(0);
+
+ do {
+ if ((readl(io_reg) & mask) != 0x0UL)
+ return 0;
+ } while (get_timer(timebase) < timeout);
+
+ debug("loop_till_bit_set timed out\n");
+ return -1;
+}
+
+/*
+ * flush_fifo - flush the I2C TX and RX FIFOs
+ */
+static void flush_fifo(struct u8500_i2c_regs *i2c_regs)
+{
+ int counter = U8500_I2C_FIFO_FLUSH_COUNTER;
+
+ /* Flush Tx FIFO */
+ i2c_set_bit(&i2c_regs->cr, U8500_I2C_CR_FTX);
+ /* Flush Rx FIFO */
+ i2c_set_bit(&i2c_regs->cr, U8500_I2C_CR_FRX);
+ while (counter--) {
+ if (!(readl(&i2c_regs->cr) &
+ (U8500_I2C_CR_FTX | U8500_I2C_CR_FRX)))
+ break;
+ }
+ return;
+}
+
+#ifdef DEBUG
+static void print_abort_reason(struct u8500_i2c_regs *i2c_regs)
+{
+ int cause;
+
+ printf("abort: risr %08x, sr %08x\n", i2c_regs->risr, i2c_regs->sr);
+ cause = (readl(&i2c_regs->sr) & U8500_I2C_SR_CAUSE) >>
+ U8500_I2C_SR_SHIFT_CAUSE;
+ switch (cause) {
+ case U8500_I2C_NACK_ADDR:
+ printf("No Ack received after Slave Address xmission\n");
+ break;
+ case U8500_I2C_NACK_DATA:
+ printf("Valid for MASTER_WRITE: No Ack received "
+ "during data phase\n");
+ break;
+ case U8500_I2C_ACK_MCODE:
+ printf("Master recv ack after xmission of master code"
+ "in hs mode\n");
+ break;
+ case U8500_I2C_ARB_LOST:
+ printf("Master Lost arbitration\n");
+ break;
+ case U8500_I2C_BERR_START:
+ printf("Slave restarts\n");
+ break;
+ case U8500_I2C_BERR_STOP:
+ printf("Slave reset\n");
+ break;
+ case U8500_I2C_OVFL:
+ printf("Overflow\n");
+ break;
+ default:
+ printf("Unknown error type\n");
+ }
+}
+#endif
+
+/*
+ * i2c_abort - called when a I2C transaction failed
+ */
+static void i2c_abort(struct u8500_i2c_regs *i2c_regs)
+{
+#ifdef DEBUG
+ print_abort_reason(i2c_regs);
+#endif
+ /* flush RX and TX fifos */
+ flush_fifo(i2c_regs);
+
+ /* Acknowledge the Master Transaction Done */
+ i2c_set_bit(&i2c_regs->icr, U8500_I2C_INT_MTD);
+
+ /* Acknowledge the Master Transaction Done Without Stop */
+ i2c_set_bit(&i2c_regs->icr, U8500_I2C_INT_MTDWS);
+
+ i2c_init(i2c_bus_speed[i2c_bus_num], CONFIG_SYS_I2C_SLAVE);
+}
+
+/*
+ * write addr, alias index, to I2C bus.
+ */
+static int i2c_write_addr(struct u8500_i2c_regs *i2c_regs, uint addr, int alen)
+{
+ while (alen--) {
+ /* Wait until the Tx Fifo is not full */
+ if (loop_till_bit_clear((void *)&i2c_regs->risr,
+ U8500_I2C_INT_TXFF,
+ U8500_I2C_ENDAD_COUNTER)) {
+ i2c_abort(i2c_regs);
+ return -1;
+ }
+
+ /* MSB first */
+ writeb((addr >> (alen * 8)) & 0xff, &i2c_regs->tfr);
+ }
+
+ return 0;
+}
+
+/*
+ * Internal simplified read function:
+ * i2c_regs: Pointer to I2C registers for current bus
+ * chip: I2C chip address, range 0..127
+ * addr: Memory (register) address within the chip
+ * alen: Number of bytes to use for addr (typically 1, 2 for larger
+ * memories, 0 for register type devices with only one register)
+ * value: Where to put the data
+ *
+ * Returns: 0 on success, not 0 on failure
+ */
+static int i2c_read_byte(struct u8500_i2c_regs *i2c_regs, uchar chip,
+ uint addr, int alen, uchar *value)
+{
+ u32 mcr = 0;
+
+ /* Set the address mode to 7 bit */
+ WRITE_FIELD(mcr, U8500_I2C_MCR_AM, U8500_I2C_MCR_SHIFT_AM, 1);
+
+ /* Store the slave address in the master control register */
+ WRITE_FIELD(mcr, U8500_I2C_MCR_A7, U8500_I2C_MCR_SHIFT_A7, chip);
+
+ if (alen != 0) {
+ /* Master write operation */
+ mcr &= ~(U8500_I2C_MCR_OP);
+
+ /* Configure the Frame length to one byte */
+ WRITE_FIELD(mcr, U8500_I2C_MCR_LENGTH,
+ U8500_I2C_MCR_SHIFT_LENGTH, 1);
+
+ /* Repeated start, no stop */
+ mcr &= ~(U8500_I2C_MCR_STOP);
+
+ /* Write Master Control Register */
+ writel(mcr, &i2c_regs->mcr);
+
+ /* send addr/index */
+ if (i2c_write_addr(i2c_regs, addr, alen) != 0)
+ return -1;
+
+ /* Check for the Master Transaction Done Without Stop */
+ if (loop_till_bit_set((void *)&i2c_regs->risr,
+ U8500_I2C_INT_MTDWS,
+ U8500_I2C_ENDAD_COUNTER)) {
+ return -1;
+ }
+
+ /* Acknowledge the Master Transaction Done Without Stop */
+ i2c_set_bit(&i2c_regs->icr, U8500_I2C_INT_MTDWS);
+ }
+
+ /* Master control configuration for read operation */
+ mcr |= U8500_I2C_MCR_OP;
+
+ /* Configure the STOP condition, we read only one byte */
+ mcr |= U8500_I2C_MCR_STOP;
+
+ /* Set the frame length to one byte, we support only 1 byte reads */
+ WRITE_FIELD(mcr, U8500_I2C_MCR_LENGTH, U8500_I2C_MCR_SHIFT_LENGTH, 1);
+
+ i2c_write_field(&i2c_regs->mcr, U8500_I2C_MCR_LENGTH_STOP_OP,
+ U8500_I2C_MCR_SHIFT_LENGTH_STOP_OP, mcr);
+
+ /*
+ * receive_data_polling
+ */
+
+ /* Wait until the Rx FIFO is not empty */
+ if (loop_till_bit_clear((void *)&i2c_regs->risr,
+ U8500_I2C_INT_RXFE,
+ U8500_I2C_ENDAD_COUNTER))
+ return -1;
+
+ /* Read the data byte from Rx FIFO */
+ *value = readb(&i2c_regs->rfr);
+
+ /* Wait until the work is done */
+ if (loop_till_bit_set((void *)&i2c_regs->risr, U8500_I2C_INT_MTD,
+ U8500_I2C_ENDAD_COUNTER))
+ return -1;
+
+ /* Acknowledge the Master Transaction Done */
+ i2c_set_bit(&i2c_regs->icr, U8500_I2C_INT_MTD);
+
+ /* If MTD is set, Master Transaction Done Without Stop is set too */
+ i2c_set_bit(&i2c_regs->icr, U8500_I2C_INT_MTDWS);
+
+ return 0;
+}
+
+/*
+ * Internal simplified write function:
+ * i2c_regs: Pointer to I2C registers for current bus
+ * chip: I2C chip address, range 0..127
+ * addr: Memory (register) address within the chip
+ * alen: Number of bytes to use for addr (typically 1, 2 for larger
+ * memories, 0 for register type devices with only one register)
+ * data: Where to read the data
+ * len: How many bytes to write
+ *
+ * Returns: 0 on success, not 0 on failure
+ */
+static int __i2c_write(struct u8500_i2c_regs *i2c_regs, u8 chip, uint addr,
+ int alen, u8 *data, int len)
+{
+ int i;
+ u32 mcr = 0;
+
+ /* Set the address mode to 7 bit */
+ WRITE_FIELD(mcr, U8500_I2C_MCR_AM, U8500_I2C_MCR_SHIFT_AM, 1);
+
+ /* Store the slave address in the master control register */
+ WRITE_FIELD(mcr, U8500_I2C_MCR_A7, U8500_I2C_MCR_SHIFT_A7, chip);
+
+ /* Write operation */
+ mcr &= ~(U8500_I2C_MCR_OP);
+
+ /* Current transaction is terminated by STOP condition */
+ mcr |= U8500_I2C_MCR_STOP;
+
+ /* Frame length: addr byte + len */
+ WRITE_FIELD(mcr, U8500_I2C_MCR_LENGTH, U8500_I2C_MCR_SHIFT_LENGTH,
+ (alen + len));
+
+ /* Write MCR register */
+ writel(mcr, &i2c_regs->mcr);
+
+ if (i2c_write_addr(i2c_regs, addr, alen) != 0)
+ return -1;
+
+ for (i = 0; i < len; i++) {
+ /* Wait until the Tx FIFO is not full */
+ if (loop_till_bit_clear((void *)&i2c_regs->risr,
+ U8500_I2C_INT_TXFF,
+ U8500_I2C_ENDAD_COUNTER))
+ return -1;
+
+ /* it is a 32 bit register with upper 24 reserved R/O */
+ writeb(data[i], &i2c_regs->tfr);
+ }
+
+ /* Check for Master Transaction Done */
+ if (loop_till_bit_set((void *)&i2c_regs->risr,
+ U8500_I2C_INT_MTD,
+ U8500_I2C_ENDAD_COUNTER)) {
+ printf("i2c_write_byte error2: risr %08x\n",
+ i2c_regs->risr);
+ return -1;
+ }
+
+ /* Acknowledge Master Transaction Done */
+ i2c_set_bit(&i2c_regs->icr, U8500_I2C_INT_MTD);
+
+ /* Acknowledge Master Transaction Done Without Stop */
+ i2c_set_bit(&i2c_regs->icr, U8500_I2C_INT_MTDWS);
+
+ return 0;
+}
+
+/*
+ * Probe the given I2C chip address. Returns 0 if a chip responded,
+ * not 0 on failure.
+ */
+int i2c_probe(uchar chip)
+{
+ u32 mcr = 0;
+ struct u8500_i2c_regs *i2c_regs;
+
+ if (chip == CONFIG_SYS_I2C_SLAVE)
+ return 1;
+
+ i2c_regs = i2c_dev[i2c_bus_num];
+
+ /* Set the address mode to 7 bit */
+ WRITE_FIELD(mcr, U8500_I2C_MCR_AM, U8500_I2C_MCR_SHIFT_AM, 1);
+
+ /* Store the slave address in the master control register */
+ WRITE_FIELD(mcr, U8500_I2C_MCR_A10, U8500_I2C_MCR_SHIFT_A7, chip);
+
+ /* Read operation */
+ mcr |= U8500_I2C_MCR_OP;
+
+ /* Set the frame length to one byte */
+ WRITE_FIELD(mcr, U8500_I2C_MCR_LENGTH, U8500_I2C_MCR_SHIFT_LENGTH, 1);
+
+ /* Current transaction is terminated by STOP condition */
+ mcr |= U8500_I2C_MCR_STOP;
+
+ /* Write MCR register */
+ writel(mcr, &i2c_regs->mcr);
+
+ /* Wait until the Rx Fifo is not empty */
+ if (loop_till_bit_clear((void *)&i2c_regs->risr,
+ U8500_I2C_INT_RXFE,
+ U8500_I2C_ENDAD_COUNTER)) {
+ i2c_abort(i2c_regs);
+ return -1;
+ }
+
+ flush_fifo(i2c_regs);
+
+ /* Acknowledge the Master Transaction Done */
+ i2c_set_bit(&i2c_regs->icr, U8500_I2C_INT_MTD);
+
+ /* Acknowledge the Master Transaction Done Without Stop */
+ i2c_set_bit(&i2c_regs->icr, U8500_I2C_INT_MTDWS);
+
+ return 0;
+}
+
+/*
+ * Read/Write interface:
+ * chip: I2C chip address, range 0..127
+ * addr: Memory (register) address within the chip
+ * alen: Number of bytes to use for addr (typically 1, 2 for larger
+ * memories, 0 for register type devices with only one
+ * register)
+ * buffer: Where to read/write the data
+ * len: How many bytes to read/write
+ *
+ * Returns: 0 on success, not 0 on failure
+ */
+int i2c_read(uchar chip, uint addr, int alen, uchar *buffer, int len)
+{
+ int i;
+ int rc;
+ struct u8500_i2c_regs *i2c_regs;
+
+ if (alen > 2) {
+ debug("I2C read: addr len %d not supported\n", alen);
+ return 1;
+ }
+
+ i2c_regs = i2c_dev[i2c_bus_num];
+
+ for (i = 0; i < len; i++) {
+ rc = i2c_read_byte(i2c_regs, chip, addr + i, alen, &buffer[i]);
+ if (rc != 0) {
+ debug("I2C read: I/O error: %d\n", rc);
+ i2c_abort(i2c_regs);
+ return rc;
+ }
+ }
+
+ return 0;
+}
+
+int i2c_write(uchar chip, uint addr, int alen, uchar *buffer, int len)
+{
+ int rc;
+ struct u8500_i2c_regs *i2c_regs;
+ i2c_regs = i2c_dev[i2c_bus_num];
+
+ rc = __i2c_write(i2c_regs, chip, addr, alen, buffer,
+ len);
+ if (rc != 0) {
+ debug("I2C write: I/O error\n");
+ i2c_abort(i2c_regs);
+ return rc;
+ }
+ return 0;
+}
+
+int i2c_set_bus_num(unsigned int bus)
+{
+ if (bus > ARRAY_SIZE(i2c_dev) - 1) {
+ debug("i2c_set_bus_num: only up to bus %d supported\n",
+ ARRAY_SIZE(i2c_dev)-1);
+ return -1;
+ }
+
+ i2c_bus_num = bus;
+
+ if (!bus_initialized[i2c_bus_num])
+ i2c_init(CONFIG_SYS_I2C_SPEED, CONFIG_SYS_I2C_SLAVE);
+
+ return 0;
+}
+
+int i2c_set_bus_speed(unsigned int speed)
+{
+
+ if (speed > U8500_I2C_MAX_STANDARD_SCL) {
+ debug("i2c_set_bus_speed: only up to %d supported\n",
+ U8500_I2C_MAX_STANDARD_SCL);
+ return -1;
+ }
+
+ /* sets as side effect i2c_bus_speed[i2c_bus_num] */
+ i2c_init(speed, CONFIG_SYS_I2C_SLAVE);
+
+ return 0;
+}
+
+unsigned int i2c_get_bus_num(void)
+{
+ return i2c_bus_num;
+}
+
+unsigned int i2c_get_bus_speed(void)
+{
+ return i2c_bus_speed[i2c_bus_num];
+}
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