C++ smbus_read_byte函数代码示例

static inline void dump_smbus_registers(void)
{
	u32 device;

	print_debug("\n");
	for (device = 1; device < 0x80; device++) {
		int j;
		if (smbus_read_byte(device, 0) < 0)
			continue;
		printk(BIOS_DEBUG, "smbus: %02x", device);
		for (j = 0; j < 256; j++) {
			int status;
			unsigned char byte;
			status = smbus_read_byte(device, j);
			if (status < 0) {
				break;
			}
			if ((j & 0xf) == 0) {
				printk(BIOS_DEBUG, "\n%02x: ", j);
			}
			byte = status & 0xff;
			printk(BIOS_DEBUG, "%02x ", byte);
		}
		print_debug("\n");
	}
}

void dump_spd_registers(void)
{
	unsigned device;
	device = SMBUS_MEM_DEVICE_START;
	printk(BIOS_DEBUG, "\n");
	while(device <= SMBUS_MEM_DEVICE_END) {
		int status = 0;
		int i;
		printk(BIOS_DEBUG, "dimm %02x", device);
		for(i = 0; (i < 256) && (status == 0); i++) {
			unsigned char byte;
			if ((i % 20) == 0) {
				printk(BIOS_DEBUG, "\n%3d: ", i);
			}
			status = smbus_read_byte(device, i, &byte);
			if (status != 0) {
				printk(BIOS_DEBUG, "bad device\n");
				continue;
			}
			printk(BIOS_DEBUG, "%02x ", byte);
		}
		device += SMBUS_MEM_DEVICE_INC;
		printk(BIOS_DEBUG, "\n");
	}
}

static void at24rf08c_read_string(u8 bank, u8 start, u8 len, char *result)
{
	int i;
	device_t dev;

	dev = dev_find_slot_on_smbus(1, 0x54 | bank);
	if (dev == 0) {
		printk(BIOS_WARNING, "EEPROM not found\n");
		memcpy(result, "*INVALID*", sizeof ("*INVALID*"));
		return;
	}

	for (i = 0; i < len; i++) {
		int t;
		int j;
		/* After a register write AT24RF08C (which we issued in init function) sometimes stops responding.
		   Retry several times in case of failure.
		*/
		for (j = 0; j < 100; j++) {
			t = smbus_read_byte(dev, start + i);
			if (t >= 0)
				break;
		}
		if (t < 0x20 || t > 0x7f) {
			memcpy(result, "*INVALID*", sizeof ("*INVALID*"));
			return;
		}
		result[i] = t;
	}
}

static inline int spd_read_byte(unsigned int device, unsigned int address)
{
	if (device != DIMM0)
		return 0xFF;	/* No DIMM1, don't even try. */

	return smbus_read_byte(device, address);
}

void dump_spd_registers(void)
{
	int i;
	printk(BIOS_DEBUG, "\n");
	for (i = 0; i < DIMM_SOCKETS; i++) {
		unsigned device;
		device = DIMM0 + i;
		if (device) {
			int j;
			printk(BIOS_DEBUG, "DIMM %d: %02x", i, device);
			for (j = 0; j < 256; j++) {
				int status;
				unsigned char byte;
				if ((j & 0xf) == 0) {
					printk(BIOS_DEBUG, "\n%02x: ", j);
				}
				status = smbus_read_byte(device, j);
				if (status < 0) {
					printk(BIOS_DEBUG, "bad device\n");
					break;
				}
				byte = status & 0xff;
				printk(BIOS_DEBUG, "%02x ", byte);
			}
			printk(BIOS_DEBUG, "\n");
		}
	}
}

int spd_read_byte(unsigned int device, unsigned int address)
{
	/* Only DIMM0 is available. */
	if (device != DIMM0)
		return 0xFF;

	return smbus_read_byte(device, address);
}

static void adm1027_enable_monitoring(device_t dev)
{
	int result;

	result = smbus_read_byte(dev, ADM1027_REG_CONFIG1);

	if (!(result & CFG1_RDY)) {
		printk(BIOS_DEBUG, "ADM1027: monitoring not ready\n");
		return;
	}
	result = (result | CFG1_STRT);
	result = smbus_write_byte(dev, ADM1027_REG_CONFIG1, result);

	result = smbus_read_byte(dev, ADM1027_REG_CONFIG1);
	if (!(result & CFG1_STRT)) {
		printk(BIOS_DEBUG, "ADM1027: monitoring would not enable\n");
	}
	printk(BIOS_DEBUG, "ADM1027: monitoring enabled\n");
}

static void lm63_init(struct device *dev)
{
	int result;
	if (dev->enabled && dev->path.type == DEVICE_PATH_I2C) {
		if (ops_smbus_bus(get_pbus_smbus(dev))) {
			if (dev->bus->dev->path.type == DEVICE_PATH_I2C)
				smbus_set_link(dev);	// it is under mux
			result = smbus_read_byte(dev, 0x03);
//                      result &= ~0x04;
			result |= 0x04;
			smbus_write_byte(dev, 0x03, result & 0xff);	// config lm63
		}
	}
}

void smbios_mainboard_set_uuid(u8 *uuid)
{
	static char result[16];
	unsigned i;
	static int already_read;
	device_t dev;
	const int remap[16] = {
		/* UUID byteswap.  */
		3, 2, 1, 0, 5, 4, 7, 6, 8, 9, 10, 11, 12, 13, 14, 15
	};


	if (already_read) {
		memcpy (uuid, result, 16);
		return;
	}

	memset (result, 0, sizeof (result));

	dev = dev_find_slot_on_smbus(1, 0x56);
	if (dev == 0) {
		printk(BIOS_WARNING, "eeprom not found\n");
		already_read = 1;
		memset (uuid, 0, 16);
		return;
	}

	for (i = 0; i < 16; i++) {
		int t;
		int j;
		/* After a register write AT24RF08C (which we issued in init function) sometimes stops responding.
		   Retry several times in case of failure.
		*/
		for (j = 0; j < 100; j++) {
			t = smbus_read_byte(dev, 0x12 + i);
			if (t >= 0)
				break;
		}
		if (t < 0) {
			memset (result, 0, sizeof (result));
			break;
		}
		result[remap[i]] = t;
	}

	already_read = 1;

	memcpy (uuid, result, 16);
}

static void spd_enable_refresh(void)
{
    /*
     * Effects:	Uses serial presence detect to set the
     *              refresh rate in the DRAMC register.
     *		see spd_set_dramc for the other values.
     * FIXME:	Check for illegal/unsupported ram configurations and abort
     */
#if HAVE_STATIC_ARRAY_SUPPORT
    static const unsigned char refresh_rates[] = {
        0x01, /* Normal        15.625 us -> 15.6 us */
        0x05, /* Reduced(.25X) 3.9 us    -> 7.8 us */
        0x05, /* Reduced(.5X)  7.8 us    -> 7.8 us */
        0x02, /* Extended(2x)  31.3 us   -> 31.2 us */
        0x03, /* Extended(4x)  62.5 us   -> 62.4 us */
        0x04, /* Extended(8x)  125 us    -> 124.8 us */
    };
#endif
    /* Find the first dimm and assume the rest are the same */
    int status;
    int byte;
    unsigned device;
    unsigned refresh_rate;
    byte = -1;
    status = -1;
    device = SMBUS_MEM_DEVICE_START;
    while ((byte < 0) && (device <= SMBUS_MEM_DEVICE_END)) {
        byte = smbus_read_byte(device, 12);
        device += SMBUS_MEM_DEVICE_INC;
    }
    if (byte < 0) {
        /* We couldn't find anything we must have no memory */
        sdram_no_memory();
    }
    byte &= 0x7f;
    /* Default refresh rate be conservative */
    refresh_rate = 5;
    /* see if the ram refresh is a supported one */
    if (byte < 6) {
#if HAVE_STATIC_ARRAY_SUPPORT
        refresh_rate = refresh_rates[byte];
#endif
    }
    byte = pcibios_read_config_byte(I440GX_BUS, I440GX_DEVFN, 0x57);
    byte &= 0xf8;
    byte |= refresh_rate;
    pcibios_write_config_byte(I440GX_BUS, I440GX_DEVFN, 0x57, byte);
}

/**
 * The onboard 64MB PC133 memory does not have a SPD EEPROM so the
 * values have to be set manually, the SO-DIMM socket is located in
 * socket0 (0x50/DIMM0), and the onboard memory is located in socket1
 * (0x51/DIMM1).
 */
static inline int spd_read_byte(unsigned device, unsigned address)
{
	int i;

	if (device == DIMM0) {
		return smbus_read_byte(device, address);
	} else if (device == DIMM1) {
		for (i = 0; i < ARRAY_SIZE(spd_table); i++) {
			if (spd_table[i].address == address)
				return spd_table[i].data;
		}
		return 0xFF; /* Return 0xFF when address is not found. */
	} else {
		return 0xFF; /* Return 0xFF on any failures. */
	}
}

static void init(struct device *dev)
{
	unsigned int i;
	u32 chksum = 0;
	char block[20];
	msr_t reset;
	device_t eeprom_dev = dev_find_slot_on_smbus(1, 0x52);

	if (eeprom_dev == 0) {
		printk(BIOS_WARNING, "eeprom not found\n");
		return;
	}

	/* turn off all leds except led_ini */
	outb(0x02, 0x5a); /* bit0 - led_run */
			  /* bit1 - led_ini */
			  /* bit2 - led_err */
			  /* bit3-bit7 - write has no effect */
	outb(0x00, 0x49); /* bit0-bit6 - led_7-led_1 */
			  /* bit7 - write has no effect */

	/* read the whole block and check if checksum is okay */
	for (i = 0; i < 20; i++) {
		block[i] = smbus_read_byte(eeprom_dev, i);
		chksum += block[i];
	}

	if (chksum != 0) {
		printk(BIOS_WARNING, "wrong checksum: 0x%0x\n", chksum);
	}

	hw_rev = block[5];

	printk(BIOS_DEBUG, "hw revision: %u\n", hw_rev);

	/* Reset MFGPT7 (standby power domain) - this is done via
	 * an undocumented register */
	reset = rdmsr(0x5140002b);
	reset.lo |= 1 << 7;
	wrmsr(0x5140002b, reset);
}

uint8_t pcal9538a_get_output_type(PCAL9538A *pcal, uint8_t *result){
  return smbus_read_byte(pcal->config.i2c, pcal->config.address, PCAL9538A_RA_OUT_TYPE, result);
}

uint8_t pcal9538a_read_outputs(PCAL9538A *pcal, uint8_t *result){
  return smbus_read_byte(pcal->config.i2c, pcal->config.address, PCAL9538A_RA_OUTPUT, result);
}

uint8_t pcal9538a_get_input_inversion(PCAL9538A *pcal, uint8_t *result){
  return smbus_read_byte(pcal->config.i2c, pcal->config.address, PCAL9538A_RA_INVERSION, result);
}