diff options
Diffstat (limited to 'drivers/i2c/lpc32xx_i2c.c')
| -rw-r--r-- | drivers/i2c/lpc32xx_i2c.c | 249 |
1 files changed, 249 insertions, 0 deletions
diff --git a/drivers/i2c/lpc32xx_i2c.c b/drivers/i2c/lpc32xx_i2c.c new file mode 100644 index 0000000000..78d26e48c3 --- /dev/null +++ b/drivers/i2c/lpc32xx_i2c.c @@ -0,0 +1,249 @@ +/* + * 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) |