replace device/i2c.h with simpler version

The existing header was imported along with the Exynos code and left
mostly unchanged. This is the first patch in a series intended to
replace the imported u-boot I2C API with a much simpler and cleaner
interface:

- We only need to expose i2c_read() and i2c_write() in our public API.
  Everything else is board/chip-dependent and should remain hidden
  away.

- i2c_read and i2c_write functions will take bus number as an arg
  and we'll eliminate i2c_get_bus and i2c_set_bus. Those are prone to
  error and end up cluttering the code since the user needs to save
  the old bus number, set the new one, do the read/write, and restore
  the old value (3 added steps to do a simple transaction).

- Stop setting default values for board-specific things like SPD
  and RTC bus numbers (as if we always have an SPD or RTC on I2C).

- Death to all the trivial inline wrappers. And in case there was any
  doubt, we really don't care about the MPC8xx. Though if we did then
  we would not pollute the public API with its idiosyncrasies.

Change-Id: I4410a3c82ed5a6b2e80e3d8c0163464a9ca7c3b0
Signed-off-by: David Hendricks <dhendrix@chromium.org>
Reviewed-on: http://review.coreboot.org/3043
Tested-by: build bot (Jenkins)
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>

6 files changed, 299 insertions, 270 deletions

diff --git a/src/cpu/samsung/exynos5-common/exynos-fb.c b/src/cpu/samsung/exynos5-common/exynos-fb.c
index 30d0767923..d3710a3a6d 100644
--- a/src/cpu/samsung/exynos5-common/exynos-fb.c
+++ b/src/cpu/samsung/exynos5-common/exynos-fb.c
@@ -33,7 +33,7 @@
 #include <cpu/samsung/exynos5250/sysreg.h>
 #include <drivers/maxim/max77686/max77686.h>
 
-#include "device/i2c.h"
+#include "device/i2c-old.h"
 #include "cpu/samsung/exynos5-common/i2c.h"
 #include "cpu/samsung/exynos5250/dsim.h"
 #include "cpu/samsung/exynos5250/fimd.h"
diff --git a/src/cpu/samsung/exynos5-common/i2c.c b/src/cpu/samsung/exynos5-common/i2c.c
index 7384b506df..c5315304b8 100644
--- a/src/cpu/samsung/exynos5-common/i2c.c
+++ b/src/cpu/samsung/exynos5-common/i2c.c
@@ -36,7 +36,7 @@
 #include "cpu/samsung/exynos5250/pinmux.h"
 
 //#include <fdtdec.h>
-#include "device/i2c.h"
+#include "device/i2c-old.h"
 #include "i2c.h"
 
 #define I2C_WRITE	0
diff --git a/src/drivers/maxim/max77686/max77686.c b/src/drivers/maxim/max77686/max77686.c
index 16fa7f50bb..2cac4dfc12 100644
--- a/src/drivers/maxim/max77686/max77686.c
+++ b/src/drivers/maxim/max77686/max77686.c
@@ -24,7 +24,7 @@
 #include <arch/io.h>
 #include <common.h>
 //#include <smbus.h>
-#include <device/i2c.h>
+#include <device/i2c-old.h>
 
 #include "max77686.h"
 
diff --git a/src/include/device/i2c-old.h b/src/include/device/i2c-old.h
new file mode 100644
index 0000000000..bd6dd0c231
--- /dev/null
+++ b/src/include/device/i2c-old.h
@@ -0,0 +1,281 @@
+/*
+ * (C) Copyright 2001
+ * Gerald Van Baren, Custom IDEAS, vanbaren@cideas.com.
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ *
+ * The original I2C interface was
+ *   (C) 2000 by Paolo Scaffardi (arsenio@tin.it)
+ *   AIRVENT SAM s.p.a - RIMINI(ITALY)
+ * but has been changed substantially.
+ */
+
+#ifndef _I2C_H_
+#define _I2C_H_
+
+/*
+ * WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING
+ *
+ * The implementation MUST NOT use static or global variables if the
+ * I2C routines are used to read SDRAM configuration information
+ * because this is done before the memories are initialized. Limited
+ * use of stack-based variables are OK (the initial stack size is
+ * limited).
+ *
+ * WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING
+ */
+
+/*
+ * Configuration items.
+ */
+#define I2C_RXTX_LEN	128	/* maximum tx/rx buffer length */
+
+#ifdef	CONFIG_I2C_MULTI_BUS
+#define	MAX_I2C_BUS			2
+#define	I2C_MULTI_BUS			1
+#else
+#define	MAX_I2C_BUS			1
+#define	I2C_MULTI_BUS			0
+#endif
+
+#if !defined(CONFIG_SYS_MAX_I2C_BUS)
+#define CONFIG_SYS_MAX_I2C_BUS		MAX_I2C_BUS
+#endif
+
+/* define the I2C bus number for RTC and DTT if not already done */
+#if !defined(CONFIG_SYS_RTC_BUS_NUM)
+#define CONFIG_SYS_RTC_BUS_NUM		0
+#endif
+#if !defined(CONFIG_SYS_DTT_BUS_NUM)
+#define CONFIG_SYS_DTT_BUS_NUM		0
+#endif
+#if !defined(CONFIG_SYS_SPD_BUS_NUM)
+#define CONFIG_SYS_SPD_BUS_NUM		0
+#endif
+
+#ifndef I2C_SOFT_DECLARATIONS
+# if defined(CONFIG_MPC8260)
+#  define I2C_SOFT_DECLARATIONS volatile ioport_t *iop = ioport_addr((immap_t *)CONFIG_SYS_IMMR, I2C_PORT);
+# elif defined(CONFIG_8xx)
+#  define I2C_SOFT_DECLARATIONS	volatile immap_t *immr = (immap_t *)CONFIG_SYS_IMMR;
+
+# elif (defined(CONFIG_AT91RM9200) || \
+	defined(CONFIG_AT91SAM9260) ||  defined(CONFIG_AT91SAM9261) || \
+	defined(CONFIG_AT91SAM9263)) && !defined(CONFIG_AT91_LEGACY)
+#  define I2C_SOFT_DECLARATIONS	at91_pio_t *pio	= (at91_pio_t *) ATMEL_BASE_PIOA;
+# else
+#  define I2C_SOFT_DECLARATIONS
+# endif
+#endif
+
+#ifdef CONFIG_8xx
+/* Set default value for the I2C bus speed on 8xx. In the
+ * future, we'll define these in all 8xx board config files.
+ */
+#ifndef	CONFIG_SYS_I2C_SPEED
+#define	CONFIG_SYS_I2C_SPEED	50000
+#endif
+#endif
+
+/*
+ * Many boards/controllers/drivers don't support an I2C slave interface so
+ * provide a default slave address for them for use in common code.  A real
+ * value for CONFIG_SYS_I2C_SLAVE should be defined for any board which does
+ * support a slave interface.
+ */
+#ifndef	CONFIG_SYS_I2C_SLAVE
+#define	CONFIG_SYS_I2C_SLAVE	0xfe
+#endif
+
+/*
+ * Initialization, must be called once on start up, may be called
+ * repeatedly to change the speed and slave addresses.
+ */
+void i2c_init(int speed, int slaveaddr);
+void i2c_init_board(void);
+#ifdef CONFIG_SYS_I2C_BOARD_LATE_INIT
+void i2c_board_late_init(void);
+#endif
+
+#if defined(CONFIG_I2C_MUX)
+
+typedef struct _mux {
+	unsigned char chip;
+	unsigned char channel;
+	char	*name;
+	struct _mux	*next;
+} I2C_MUX;
+
+typedef struct _mux_device {
+	int	busid;
+	I2C_MUX	*mux;	/* List of muxes, to reach the device */
+	struct _mux_device	*next;
+} I2C_MUX_DEVICE;
+
+I2C_MUX_DEVICE	*i2c_mux_search_device(int id);
+I2C_MUX_DEVICE *i2c_mux_ident_muxstring (unsigned char *buf);
+int i2x_mux_select_mux(int bus);
+int i2c_mux_ident_muxstring_f (unsigned char *buf);
+#endif
+
+/*
+ * Probe the given I2C chip address.  Returns 0 if a chip responded,
+ * not 0 on failure.
+ */
+int i2c_probe(unsigned char chip);
+
+/*
+ * 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(unsigned char chip, unsigned int addr, int alen,
+		unsigned char *buffer, int len);
+int i2c_write(unsigned char chip, unsigned int addr, int alen,
+		unsigned char *buffer, int len);
+
+/*
+ * Utility routines to read/write registers.
+ */
+static inline u8 i2c_reg_read(u8 addr, u8 reg)
+{
+	u8 buf;
+
+#ifdef CONFIG_8xx
+	/* MPC8xx needs this.  Maybe one day we can get rid of it. */
+	i2c_init(CONFIG_SYS_I2C_SPEED, CONFIG_SYS_I2C_SLAVE);
+#endif
+
+#ifdef DEBUG
+	printf("%s: addr=0x%02x, reg=0x%02x\n", __func__, addr, reg);
+#endif
+
+	i2c_read(addr, reg, 1, &buf, 1);
+
+	return buf;
+}
+
+static inline void i2c_reg_write(u8 addr, u8 reg, u8 val)
+{
+#ifdef CONFIG_8xx
+	/* MPC8xx needs this.  Maybe one day we can get rid of it. */
+	i2c_init(CONFIG_SYS_I2C_SPEED, CONFIG_SYS_I2C_SLAVE);
+#endif
+
+#ifdef DEBUG
+	printf("%s: addr=0x%02x, reg=0x%02x, val=0x%02x\n",
+	       __func__, addr, reg, val);
+#endif
+
+	i2c_write(addr, reg, 1, &val, 1);
+}
+
+/*
+ * Functions for setting the current I2C bus and its speed
+ */
+
+/*
+ * i2c_set_bus_num:
+ *
+ *  Change the active I2C bus.  Subsequent read/write calls will
+ *  go to this one.
+ *
+ *	bus - bus index, zero based
+ *
+ *	Returns: 0 on success, not 0 on failure
+ *
+ */
+int i2c_set_bus_num(unsigned int bus);
+
+/*
+ * i2c_get_bus_num:
+ *
+ *  Returns index of currently active I2C bus.  Zero-based.
+ */
+
+unsigned int i2c_get_bus_num(void);
+
+/*
+ * i2c_set_bus_speed:
+ *
+ *  Change the speed of the active I2C bus
+ *
+ *	speed - bus speed in Hz
+ *
+ *	Returns: 0 on success, not 0 on failure
+ *
+ */
+int i2c_set_bus_speed(unsigned int);
+
+/*
+ * i2c_get_bus_speed:
+ *
+ *  Returns speed of currently active I2C bus in Hz
+ */
+
+unsigned int i2c_get_bus_speed(void);
+
+/* NOTE: These two functions MUST be always_inline to avoid code growth! */
+static inline unsigned int I2C_GET_BUS(void) __attribute__((always_inline));
+static inline unsigned int I2C_GET_BUS(void)
+{
+	return I2C_MULTI_BUS ? i2c_get_bus_num() : 0;
+}
+
+static inline void I2C_SET_BUS(unsigned int bus) __attribute__((always_inline));
+static inline void I2C_SET_BUS(unsigned int bus)
+{
+	if (I2C_MULTI_BUS)
+		i2c_set_bus_num(bus);
+}
+
+/*
+ * Set an early register base for a given i2c peripheral.
+ * This is used to access a single i2c bus early on in the boot sequence.
+ *
+ * @param base:	The base address of the i2c peripheral's register map
+ */
+void i2c_set_early_reg(unsigned int base);
+
+/**
+ * Find the I2C bus number by given a FDT I2C node.
+ *
+ * @param blob	Device tree blbo
+ * @param node	FDT I2C node to find
+ * @return the number of I2C bus (zero based), or -1 on error
+ */
+int i2c_get_bus_num_fdt(const void *blob, int node);
+
+/**
+ * Reset the I2C bus represented by the given a FDT I2C node.
+ *
+ * @param blob	Device tree blbo
+ * @param node	FDT I2C node to find
+ * @return 0 if port was reset, -1 if not found
+ */
+int i2c_reset_port_fdt(const void *blob, int node);
+
+#endif	/* _I2C_H_ */
diff --git a/src/include/device/i2c.h b/src/include/device/i2c.h
index bd6dd0c231..d880a7bbae 100644
--- a/src/include/device/i2c.h
+++ b/src/include/device/i2c.h
@@ -1,14 +1,11 @@
 /*
- * (C) Copyright 2001
- * Gerald Van Baren, Custom IDEAS, vanbaren@cideas.com.
+ * This file is part of the coreboot project.
  *
- * See file CREDITS for list of people who contributed to this
- * project.
+ * Copyright (C) 2013 Google, Inc.
  *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License as
- * published by the Free Software Foundation; either version 2 of
- * the License, or (at your option) any later version.
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
  *
  * This program is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ -17,265 +14,16 @@
  *
  * You should have received a copy of the GNU General Public License
  * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
- * MA 02111-1307 USA
- *
- * The original I2C interface was
- *   (C) 2000 by Paolo Scaffardi (arsenio@tin.it)
- *   AIRVENT SAM s.p.a - RIMINI(ITALY)
- * but has been changed substantially.
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA, 02110-1301 USA
  */
 
-#ifndef _I2C_H_
-#define _I2C_H_
-
-/*
- * WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING
- *
- * The implementation MUST NOT use static or global variables if the
- * I2C routines are used to read SDRAM configuration information
- * because this is done before the memories are initialized. Limited
- * use of stack-based variables are OK (the initial stack size is
- * limited).
- *
- * WARNING WARNING WARNING WARNING WARNING WARNING WARNING WARNING
- */
-
-/*
- * Configuration items.
- */
-#define I2C_RXTX_LEN	128	/* maximum tx/rx buffer length */
-
-#ifdef	CONFIG_I2C_MULTI_BUS
-#define	MAX_I2C_BUS			2
-#define	I2C_MULTI_BUS			1
-#else
-#define	MAX_I2C_BUS			1
-#define	I2C_MULTI_BUS			0
-#endif
-
-#if !defined(CONFIG_SYS_MAX_I2C_BUS)
-#define CONFIG_SYS_MAX_I2C_BUS		MAX_I2C_BUS
-#endif
-
-/* define the I2C bus number for RTC and DTT if not already done */
-#if !defined(CONFIG_SYS_RTC_BUS_NUM)
-#define CONFIG_SYS_RTC_BUS_NUM		0
-#endif
-#if !defined(CONFIG_SYS_DTT_BUS_NUM)
-#define CONFIG_SYS_DTT_BUS_NUM		0
-#endif
-#if !defined(CONFIG_SYS_SPD_BUS_NUM)
-#define CONFIG_SYS_SPD_BUS_NUM		0
-#endif
-
-#ifndef I2C_SOFT_DECLARATIONS
-# if defined(CONFIG_MPC8260)
-#  define I2C_SOFT_DECLARATIONS volatile ioport_t *iop = ioport_addr((immap_t *)CONFIG_SYS_IMMR, I2C_PORT);
-# elif defined(CONFIG_8xx)
-#  define I2C_SOFT_DECLARATIONS	volatile immap_t *immr = (immap_t *)CONFIG_SYS_IMMR;
-
-# elif (defined(CONFIG_AT91RM9200) || \
-	defined(CONFIG_AT91SAM9260) ||  defined(CONFIG_AT91SAM9261) || \
-	defined(CONFIG_AT91SAM9263)) && !defined(CONFIG_AT91_LEGACY)
-#  define I2C_SOFT_DECLARATIONS	at91_pio_t *pio	= (at91_pio_t *) ATMEL_BASE_PIOA;
-# else
-#  define I2C_SOFT_DECLARATIONS
-# endif
-#endif
-
-#ifdef CONFIG_8xx
-/* Set default value for the I2C bus speed on 8xx. In the
- * future, we'll define these in all 8xx board config files.
- */
-#ifndef	CONFIG_SYS_I2C_SPEED
-#define	CONFIG_SYS_I2C_SPEED	50000
-#endif
-#endif
-
-/*
- * Many boards/controllers/drivers don't support an I2C slave interface so
- * provide a default slave address for them for use in common code.  A real
- * value for CONFIG_SYS_I2C_SLAVE should be defined for any board which does
- * support a slave interface.
- */
-#ifndef	CONFIG_SYS_I2C_SLAVE
-#define	CONFIG_SYS_I2C_SLAVE	0xfe
-#endif
-
-/*
- * Initialization, must be called once on start up, may be called
- * repeatedly to change the speed and slave addresses.
- */
-void i2c_init(int speed, int slaveaddr);
-void i2c_init_board(void);
-#ifdef CONFIG_SYS_I2C_BOARD_LATE_INIT
-void i2c_board_late_init(void);
-#endif
-
-#if defined(CONFIG_I2C_MUX)
-
-typedef struct _mux {
-	unsigned char chip;
-	unsigned char channel;
-	char	*name;
-	struct _mux	*next;
-} I2C_MUX;
-
-typedef struct _mux_device {
-	int	busid;
-	I2C_MUX	*mux;	/* List of muxes, to reach the device */
-	struct _mux_device	*next;
-} I2C_MUX_DEVICE;
-
-I2C_MUX_DEVICE	*i2c_mux_search_device(int id);
-I2C_MUX_DEVICE *i2c_mux_ident_muxstring (unsigned char *buf);
-int i2x_mux_select_mux(int bus);
-int i2c_mux_ident_muxstring_f (unsigned char *buf);
-#endif
-
-/*
- * Probe the given I2C chip address.  Returns 0 if a chip responded,
- * not 0 on failure.
- */
-int i2c_probe(unsigned char chip);
-
-/*
- * 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(unsigned char chip, unsigned int addr, int alen,
-		unsigned char *buffer, int len);
-int i2c_write(unsigned char chip, unsigned int addr, int alen,
-		unsigned char *buffer, int len);
-
-/*
- * Utility routines to read/write registers.
- */
-static inline u8 i2c_reg_read(u8 addr, u8 reg)
-{
-	u8 buf;
-
-#ifdef CONFIG_8xx
-	/* MPC8xx needs this.  Maybe one day we can get rid of it. */
-	i2c_init(CONFIG_SYS_I2C_SPEED, CONFIG_SYS_I2C_SLAVE);
-#endif
-
-#ifdef DEBUG
-	printf("%s: addr=0x%02x, reg=0x%02x\n", __func__, addr, reg);
-#endif
-
-	i2c_read(addr, reg, 1, &buf, 1);
-
-	return buf;
-}
-
-static inline void i2c_reg_write(u8 addr, u8 reg, u8 val)
-{
-#ifdef CONFIG_8xx
-	/* MPC8xx needs this.  Maybe one day we can get rid of it. */
-	i2c_init(CONFIG_SYS_I2C_SPEED, CONFIG_SYS_I2C_SLAVE);
-#endif
+#ifndef _DEVICE_I2C_H_
+#define _DEVICE_I2C_H_
 
-#ifdef DEBUG
-	printf("%s: addr=0x%02x, reg=0x%02x, val=0x%02x\n",
-	       __func__, addr, reg, val);
-#endif
-
-	i2c_write(addr, reg, 1, &val, 1);
-}
-
-/*
- * Functions for setting the current I2C bus and its speed
- */
-
-/*
- * i2c_set_bus_num:
- *
- *  Change the active I2C bus.  Subsequent read/write calls will
- *  go to this one.
- *
- *	bus - bus index, zero based
- *
- *	Returns: 0 on success, not 0 on failure
- *
- */
-int i2c_set_bus_num(unsigned int bus);
-
-/*
- * i2c_get_bus_num:
- *
- *  Returns index of currently active I2C bus.  Zero-based.
- */
-
-unsigned int i2c_get_bus_num(void);
-
-/*
- * i2c_set_bus_speed:
- *
- *  Change the speed of the active I2C bus
- *
- *	speed - bus speed in Hz
- *
- *	Returns: 0 on success, not 0 on failure
- *
- */
-int i2c_set_bus_speed(unsigned int);
-
-/*
- * i2c_get_bus_speed:
- *
- *  Returns speed of currently active I2C bus in Hz
- */
-
-unsigned int i2c_get_bus_speed(void);
-
-/* NOTE: These two functions MUST be always_inline to avoid code growth! */
-static inline unsigned int I2C_GET_BUS(void) __attribute__((always_inline));
-static inline unsigned int I2C_GET_BUS(void)
-{
-	return I2C_MULTI_BUS ? i2c_get_bus_num() : 0;
-}
-
-static inline void I2C_SET_BUS(unsigned int bus) __attribute__((always_inline));
-static inline void I2C_SET_BUS(unsigned int bus)
-{
-	if (I2C_MULTI_BUS)
-		i2c_set_bus_num(bus);
-}
-
-/*
- * Set an early register base for a given i2c peripheral.
- * This is used to access a single i2c bus early on in the boot sequence.
- *
- * @param base:	The base address of the i2c peripheral's register map
- */
-void i2c_set_early_reg(unsigned int base);
-
-/**
- * Find the I2C bus number by given a FDT I2C node.
- *
- * @param blob	Device tree blbo
- * @param node	FDT I2C node to find
- * @return the number of I2C bus (zero based), or -1 on error
- */
-int i2c_get_bus_num_fdt(const void *blob, int node);
-
-/**
- * Reset the I2C bus represented by the given a FDT I2C node.
- *
- * @param blob	Device tree blbo
- * @param node	FDT I2C node to find
- * @return 0 if port was reset, -1 if not found
- */
-int i2c_reset_port_fdt(const void *blob, int node);
+/* note: chip is the 7-bit I2C address */
+int i2c_read(unsigned bus, unsigned chip, unsigned addr,
+		unsigned alen, unsigned char *buf, unsigned len);
+int i2c_write(unsigned bus, unsigned chip, unsigned addr,
+		unsigned alen, unsigned char *buf, unsigned len);
 
-#endif	/* _I2C_H_ */
+#endif	/* _DEVICE_I2C_H_ */
diff --git a/src/mainboard/google/snow/romstage.c b/src/mainboard/google/snow/romstage.c
index ca7ba9c23b..94ca222b71 100644
--- a/src/mainboard/google/snow/romstage.c
+++ b/src/mainboard/google/snow/romstage.c
@@ -36,7 +36,7 @@
 #include <arch/stages.h>
 
 #include <drivers/maxim/max77686/max77686.h>
-#include <device/i2c.h>
+#include <device/i2c-old.h>
 
 #include "mainboard.h"