drivers/i2c/lpc32xx_i2c.c - github/trini/u-boot - Gitiles

 /*
  * 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 = (get_hclk_clk_rate() / 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);
 	else
 		return 0;
 	/* 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)
	/*
	* 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 = (get_hclk_clk_rate() / 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);
	else
	return 0;
	/* 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)