cmd_i2c.c

/*
 * (C) Copyright 2009
 * Sergey Kubushyn, himself, ksi@koi8.net
 *
 * Changes for unified multibus/multiadapter I2C support.
 *
 * (C) Copyright 2001
 * Gerald Van Baren, Custom IDEAS, vanbaren@cideas.com.
 *
 * SPDX-License-Identifier:	GPL-2.0+
 */

/*
 * I2C Functions similar to the standard memory functions.
 *
 * There are several parameters in many of the commands that bear further
 * explanations:
 *
 * {i2c_chip} is the I2C chip address (the first byte sent on the bus).
 *   Each I2C chip on the bus has a unique address.  On the I2C data bus,
 *   the address is the upper seven bits and the LSB is the "read/write"
 *   bit.  Note that the {i2c_chip} address specified on the command
 *   line is not shifted up: e.g. a typical EEPROM memory chip may have
 *   an I2C address of 0x50, but the data put on the bus will be 0xA0
 *   for write and 0xA1 for read.  This "non shifted" address notation
 *   matches at least half of the data sheets :-/.
 *
 * {addr} is the address (or offset) within the chip.  Small memory
 *   chips have 8 bit addresses.  Large memory chips have 16 bit
 *   addresses.  Other memory chips have 9, 10, or 11 bit addresses.
 *   Many non-memory chips have multiple registers and {addr} is used
 *   as the register index.  Some non-memory chips have only one register
 *   and therefore don't need any {addr} parameter.
 *
 *   The default {addr} parameter is one byte (.1) which works well for
 *   memories and registers with 8 bits of address space.
 *
 *   You can specify the length of the {addr} field with the optional .0,
 *   .1, or .2 modifier (similar to the .b, .w, .l modifier).  If you are
 *   manipulating a single register device which doesn't use an address
 *   field, use "0.0" for the address and the ".0" length field will
 *   suppress the address in the I2C data stream.  This also works for
 *   successive reads using the I2C auto-incrementing memory pointer.
 *
 *   If you are manipulating a large memory with 2-byte addresses, use
 *   the .2 address modifier, e.g. 210.2 addresses location 528 (decimal).
 *
 *   Then there are the unfortunate memory chips that spill the most
 *   significant 1, 2, or 3 bits of address into the chip address byte.
 *   This effectively makes one chip (logically) look like 2, 4, or
 *   8 chips.  This is handled (awkwardly) by #defining
 *   CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW and using the .1 modifier on the
 *   {addr} field (since .1 is the default, it doesn't actually have to
 *   be specified).  Examples: given a memory chip at I2C chip address
 *   0x50, the following would happen...
 *     i2c md 50 0 10   display 16 bytes starting at 0x000
 *                      On the bus: <S> A0 00 <E> <S> A1 <rd> ... <rd>
 *     i2c md 50 100 10 display 16 bytes starting at 0x100
 *                      On the bus: <S> A2 00 <E> <S> A3 <rd> ... <rd>
 *     i2c md 50 210 10 display 16 bytes starting at 0x210
 *                      On the bus: <S> A4 10 <E> <S> A5 <rd> ... <rd>
 *   This is awfully ugly.  It would be nice if someone would think up
 *   a better way of handling this.
 *
 * Adapted from cmd_mem.c which is copyright Wolfgang Denk (wd@denx.de).
 */

#include <common.h>
#include <bootretry.h>
#include <cli.h>
#include <command.h>
#include <console.h>
#include <dm.h>
#include <edid.h>
#include <environment.h>
#include <errno.h>
#include <i2c.h>
#include <malloc.h>
#include <asm/byteorder.h>
#include <linux/compiler.h>

DECLARE_GLOBAL_DATA_PTR;

/* Display values from last command.
 * Memory modify remembered values are different from display memory.
 */
static uint	i2c_dp_last_chip;
static uint	i2c_dp_last_addr;
static uint	i2c_dp_last_alen;
static uint	i2c_dp_last_length = 0x10;

static uint	i2c_mm_last_chip;
static uint	i2c_mm_last_addr;
static uint	i2c_mm_last_alen;

/* If only one I2C bus is present, the list of devices to ignore when
 * the probe command is issued is represented by a 1D array of addresses.
 * When multiple buses are present, the list is an array of bus-address
 * pairs.  The following macros take care of this */

#if defined(CONFIG_SYS_I2C_NOPROBES)
#if defined(CONFIG_SYS_I2C) || defined(CONFIG_I2C_MULTI_BUS)
static struct
{
	uchar	bus;
	uchar	addr;
} i2c_no_probes[] = CONFIG_SYS_I2C_NOPROBES;
#define GET_BUS_NUM	i2c_get_bus_num()
#define COMPARE_BUS(b,i)	(i2c_no_probes[(i)].bus == (b))
#define COMPARE_ADDR(a,i)	(i2c_no_probes[(i)].addr == (a))
#define NO_PROBE_ADDR(i)	i2c_no_probes[(i)].addr
#else		/* single bus */
static uchar i2c_no_probes[] = CONFIG_SYS_I2C_NOPROBES;
#define GET_BUS_NUM	0
#define COMPARE_BUS(b,i)	((b) == 0)	/* Make compiler happy */
#define COMPARE_ADDR(a,i)	(i2c_no_probes[(i)] == (a))
#define NO_PROBE_ADDR(i)	i2c_no_probes[(i)]
#endif	/* defined(CONFIG_SYS_I2C) */
#endif

#define DISP_LINE_LEN	16

/*
 * Default for driver model is to use the chip's existing address length.
 * For legacy code, this is not stored, so we need to use a suitable
 * default.
 */
#ifdef CONFIG_DM_I2C
#define DEFAULT_ADDR_LEN	(-1)
#else
#define DEFAULT_ADDR_LEN	1
#endif

#ifdef CONFIG_DM_I2C
static struct udevice *i2c_cur_bus;

static int cmd_i2c_set_bus_num(unsigned int busnum)
{
	struct udevice *bus;
	int ret;

	ret = uclass_get_device_by_seq(UCLASS_I2C, busnum, &bus);
	if (ret) {
		debug("%s: No bus %d\n", __func__, busnum);
		return ret;
	}
	i2c_cur_bus = bus;

	return 0;
}

static int i2c_get_cur_bus(struct udevice **busp)
{
	if (!i2c_cur_bus) {
		puts("No I2C bus selected\n");
		return -ENODEV;
	}
	*busp = i2c_cur_bus;

	return 0;
}

static int i2c_get_cur_bus_chip(uint chip_addr, struct udevice **devp)
{
	struct udevice *bus;
	int ret;

	ret = i2c_get_cur_bus(&bus);
	if (ret)
		return ret;

	return i2c_get_chip(bus, chip_addr, 1, devp);
}

#endif

/**
 * i2c_init_board() - Board-specific I2C bus init
 *
 * This function is the default no-op implementation of I2C bus
 * initialization. This function can be overriden by board-specific
 * implementation if needed.
 */
__weak
void i2c_init_board(void)
{
}

/* TODO: Implement architecture-specific get/set functions */

/**
 * i2c_get_bus_speed() - Return I2C bus speed
 *
 * This function is the default implementation of function for retrieveing
 * the current I2C bus speed in Hz.
 *
 * A driver implementing runtime switching of I2C bus speed must override
 * this function to report the speed correctly. Simple or legacy drivers
 * can use this fallback.
 *