--- /dev/null
+/*
+ * LPC32xx I2C interface driver
+ *
+ * (C) Copyright 2014 DENX Software Engineering GmbH
+ * Written-by: Albert ARIBAUD - 3ADEV <albert.aribaud@3adev.fr>
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ */
+
+#include <common.h>
+#include <asm/io.h>
+#include <i2c.h>
+#include <asm/errno.h>
+#include <asm/arch/clk.h>
+
+/*
+ * Provide default speed and slave if target did not
+ */
+
+#if !defined(CONFIG_SYS_I2C_LPC32XX_SPEED)
+#define CONFIG_SYS_I2C_LPC32XX_SPEED 350000
+#endif
+
+#if !defined(CONFIG_SYS_I2C_LPC32XX_SLAVE)
+#define CONFIG_SYS_I2C_LPC32XX_SLAVE 0
+#endif
+
+/* i2c register set */
+struct lpc32xx_i2c_registers {
+ union {
+ u32 rx;
+ u32 tx;
+ };
+ u32 stat;
+ u32 ctrl;
+ u32 clk_hi;
+ u32 clk_lo;
+ u32 adr;
+ u32 rxfl;
+ u32 txfl;
+ u32 rxb;
+ u32 txb;
+ u32 stx;
+ u32 stxfl;
+};
+
+/* TX register fields */
+#define LPC32XX_I2C_TX_START 0x00000100
+#define LPC32XX_I2C_TX_STOP 0x00000200
+
+/* Control register values */
+#define LPC32XX_I2C_SOFT_RESET 0x00000100
+
+/* Status register values */
+#define LPC32XX_I2C_STAT_TFF 0x00000400
+#define LPC32XX_I2C_STAT_RFE 0x00000200
+#define LPC32XX_I2C_STAT_DRMI 0x00000008
+#define LPC32XX_I2C_STAT_NAI 0x00000004
+#define LPC32XX_I2C_STAT_TDI 0x00000001
+
+static struct lpc32xx_i2c_registers *lpc32xx_i2c[] = {
+ (struct lpc32xx_i2c_registers *)I2C1_BASE,
+ (struct lpc32xx_i2c_registers *)I2C2_BASE
+};
+
+/* Set I2C bus speed */
+static unsigned int lpc32xx_i2c_set_bus_speed(struct i2c_adapter *adap,
+ unsigned int speed)
+{
+ int half_period;
+
+ if (speed == 0)
+ return -EINVAL;
+
+ half_period = (105000000 / speed) / 2;
+
+ if ((half_period > 255) || (half_period < 0))
+ return -EINVAL;
+
+ writel(half_period, &lpc32xx_i2c[adap->hwadapnr]->clk_hi);
+ writel(half_period, &lpc32xx_i2c[adap->hwadapnr]->clk_lo);
+ return 0;
+}
+
+/* I2C init called by cmd_i2c when doing 'i2c reset'. */
+static void _i2c_init(struct i2c_adapter *adap,
+ int requested_speed, int slaveadd)
+{
+ struct lpc32xx_i2c_registers *i2c = lpc32xx_i2c[adap->hwadapnr];
+
+ /* soft reset (auto-clears) */
+ writel(LPC32XX_I2C_SOFT_RESET, &i2c->ctrl);
+ /* set HI and LO periods for about 350 kHz */
+ lpc32xx_i2c_set_bus_speed(adap, requested_speed);
+}
+
+/* I2C probe called by cmd_i2c when doing 'i2c probe'. */
+static int lpc32xx_i2c_probe(struct i2c_adapter *adap, u8 dev)
+{
+ struct lpc32xx_i2c_registers *i2c = lpc32xx_i2c[adap->hwadapnr];
+ int stat;
+
+ /* Soft-reset the controller */
+ writel(LPC32XX_I2C_SOFT_RESET, &i2c->ctrl);
+ while (readl(&i2c->ctrl) & LPC32XX_I2C_SOFT_RESET)
+ ;
+ /* Addre slave for write with start before and stop after */
+ writel((dev<<1) | LPC32XX_I2C_TX_START | LPC32XX_I2C_TX_STOP,
+ &i2c->tx);
+ /* wait for end of transation */
+ while (!((stat = readl(&i2c->stat)) & LPC32XX_I2C_STAT_TDI))
+ ;
+ /* was there no acknowledge? */
+ return (stat & LPC32XX_I2C_STAT_NAI) ? -1 : 0;
+}
+
+/*
+ * I2C read called by cmd_i2c when doing 'i2c read' and by cmd_eeprom.c
+ * Begin write, send address byte(s), begin read, receive data bytes, end.
+ */
+static int lpc32xx_i2c_read(struct i2c_adapter *adap, u8 dev, uint addr,
+ int alen, u8 *data, int length)
+{
+ struct lpc32xx_i2c_registers *i2c = lpc32xx_i2c[adap->hwadapnr];
+ int stat, wlen;
+
+ /* Soft-reset the controller */
+ writel(LPC32XX_I2C_SOFT_RESET, &i2c->ctrl);
+ while (readl(&i2c->ctrl) & LPC32XX_I2C_SOFT_RESET)
+ ;
+ /* do we need to write an address at all? */
+ if (alen) {
+ /* Address slave in write mode */
+ writel((dev<<1) | LPC32XX_I2C_TX_START, &i2c->tx);
+ /* write address bytes */
+ while (alen--) {
+ /* compute address byte + stop for the last one */
+ int a = (addr >> (8 * alen)) & 0xff;
+ if (!alen)
+ a |= LPC32XX_I2C_TX_STOP;
+ /* Send address byte */
+ writel(a, &i2c->tx);
+ }
+ /* wait for end of transation */
+ while (!((stat = readl(&i2c->stat)) & LPC32XX_I2C_STAT_TDI))
+ ;
+ /* clear end-of-transaction flag */
+ writel(1, &i2c->stat);
+ }
+ /* do we have to read data at all? */
+ if (length) {
+ /* Address slave in read mode */
+ writel(1 | (dev<<1) | LPC32XX_I2C_TX_START, &i2c->tx);
+ wlen = length;
+ /* get data */
+ while (length | wlen) {
+ /* read status for TFF and RFE */
+ stat = readl(&i2c->stat);
+ /* must we, can we write a trigger byte? */
+ if ((wlen > 0)
+ & (!(stat & LPC32XX_I2C_STAT_TFF))) {
+ wlen--;
+ /* write trigger byte + stop if last */
+ writel(wlen ? 0 :
+ LPC32XX_I2C_TX_STOP, &i2c->tx);
+ }
+ /* must we, can we read a data byte? */
+ if ((length > 0)
+ & (!(stat & LPC32XX_I2C_STAT_RFE))) {
+ length--;
+ /* read byte */
+ *(data++) = readl(&i2c->rx);
+ }
+ }
+ }
+ /* wait for end of transation */
+ while (!((stat = readl(&i2c->stat)) & LPC32XX_I2C_STAT_TDI))
+ ;
+ /* clear end-of-transaction flag */
+ writel(1, &i2c->stat);
+ /* success */
+ return 0;
+}
+
+/*
+ * I2C write called by cmd_i2c when doing 'i2c write' and by cmd_eeprom.c
+ * Begin write, send address byte(s), send data bytes, end.
+ */
+static int lpc32xx_i2c_write(struct i2c_adapter *adap, u8 dev, uint addr,
+ int alen, u8 *data, int length)
+{
+ struct lpc32xx_i2c_registers *i2c = lpc32xx_i2c[adap->hwadapnr];
+ int stat;
+
+ /* Soft-reset the controller */
+ writel(LPC32XX_I2C_SOFT_RESET, &i2c->ctrl);
+ while (readl(&i2c->ctrl) & LPC32XX_I2C_SOFT_RESET)
+ ;
+ /* do we need to write anything at all? */
+ if (alen | length)
+ /* Address slave in write mode */
+ writel((dev<<1) | LPC32XX_I2C_TX_START, &i2c->tx);
+ /* write address bytes */
+ while (alen) {
+ /* wait for transmit fifo not full */
+ stat = readl(&i2c->stat);
+ if (!(stat & LPC32XX_I2C_STAT_TFF)) {
+ alen--;
+ int a = (addr >> (8 * alen)) & 0xff;
+ if (!(alen | length))
+ a |= LPC32XX_I2C_TX_STOP;
+ /* Send address byte */
+ writel(a, &i2c->tx);
+ }
+ }
+ while (length) {
+ /* wait for transmit fifo not full */
+ stat = readl(&i2c->stat);
+ if (!(stat & LPC32XX_I2C_STAT_TFF)) {
+ /* compute data byte, add stop if length==0 */
+ length--;
+ int d = *(data++);
+ if (!length)
+ d |= LPC32XX_I2C_TX_STOP;
+ /* Send data byte */
+ writel(d, &i2c->tx);
+ }
+ }
+ /* wait for end of transation */
+ while (!((stat = readl(&i2c->stat)) & LPC32XX_I2C_STAT_TDI))
+ ;
+ /* clear end-of-transaction flag */
+ writel(1, &i2c->stat);
+ return 0;
+}
+
+U_BOOT_I2C_ADAP_COMPLETE(lpc32xx_0, _i2c_init, lpc32xx_i2c_probe,
+ lpc32xx_i2c_read, lpc32xx_i2c_write,
+ lpc32xx_i2c_set_bus_speed,
+ CONFIG_SYS_I2C_LPC32XX_SPEED,
+ CONFIG_SYS_I2C_LPC32XX_SLAVE,
+ 0)
+
+U_BOOT_I2C_ADAP_COMPLETE(lpc32xx_1, _i2c_init, lpc32xx_i2c_probe,
+ lpc32xx_i2c_read, lpc32xx_i2c_write,
+ lpc32xx_i2c_set_bus_speed,
+ CONFIG_SYS_I2C_LPC32XX_SPEED,
+ CONFIG_SYS_I2C_LPC32XX_SLAVE,
+ 1)
projects / oweals / u-boot.git / commitdiff