Add i2c_scan_dimm_bus to declare that a particular i2c_adapter contains DIMMs. This will probe (and autoload modules!) for useful SMBUS devices that live on DIMMs.
As more SMBUS-addressable DIMM components become supported, this code can be extended to probe for them. Signed-off-by: Andy Lutomirski <[email protected]> --- drivers/i2c/busses/Kconfig | 4 +++ drivers/i2c/busses/Makefile | 4 +++ drivers/i2c/busses/dimm-bus.c | 84 +++++++++++++++++++++++++++++++++++++++++++ include/linux/i2c/dimm-bus.h | 24 +++++++++++++ 4 files changed, 116 insertions(+) create mode 100644 drivers/i2c/busses/dimm-bus.c create mode 100644 include/linux/i2c/dimm-bus.h diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig index adfee98..e837f0e 100644 --- a/drivers/i2c/busses/Kconfig +++ b/drivers/i2c/busses/Kconfig @@ -133,6 +133,10 @@ config I2C_ISMT This driver can also be built as a module. If so, the module will be called i2c-ismt. +config I2C_DIMM_BUS + tristate + default n + config I2C_PIIX4 tristate "Intel PIIX4 and compatible (ATI/AMD/Serverworks/Broadcom/SMSC)" depends on PCI diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile index 8f4fc23..226bb2e 100644 --- a/drivers/i2c/busses/Makefile +++ b/drivers/i2c/busses/Makefile @@ -24,6 +24,10 @@ obj-$(CONFIG_I2C_SIS96X) += i2c-sis96x.o obj-$(CONFIG_I2C_VIA) += i2c-via.o obj-$(CONFIG_I2C_VIAPRO) += i2c-viapro.o +# DIMM busses +obj-$(CONFIG_I2C_DIMM_BUS) += dimm-bus.o +obj-$(CONFIG_I2C_IMC) += i2c-imc.o + # Mac SMBus host controller drivers obj-$(CONFIG_I2C_HYDRA) += i2c-hydra.o obj-$(CONFIG_I2C_POWERMAC) += i2c-powermac.o diff --git a/drivers/i2c/busses/dimm-bus.c b/drivers/i2c/busses/dimm-bus.c new file mode 100644 index 0000000..9012638 --- /dev/null +++ b/drivers/i2c/busses/dimm-bus.c @@ -0,0 +1,84 @@ +/* + * Copyright (c) 2013 Andrew Lutomirski <[email protected]> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 + * as published by the Free Software Foundation. + * + * 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., 675 Mass Ave, Cambridge, MA 02139, USA. + */ + +#include <linux/i2c.h> +#include <linux/bug.h> +#include <linux/module.h> +#include <linux/i2c/dimm-bus.h> + +static bool probe_addr(struct i2c_adapter *adapter, int addr) +{ + /* + * So far, all known devices that live on DIMMs can be safely + * and reliably detected by trying to read a byte at address + * zero. + */ + union i2c_smbus_data dummy; + return i2c_smbus_xfer(adapter, addr, 0, I2C_SMBUS_READ, 0, + I2C_SMBUS_BYTE_DATA, &dummy) >= 0; +} + +/** + * i2c_scan_dimm_bus() - Scans an SMBUS segment known to contain DIMMs + * @adapter: The SMBUS adapter to scan + * + * This function tells the DIMM-bus code that the adapter is known to + * contain DIMMs. i2c_scan_dimm_bus will probe for devices known to + * live on DIMMs. + * + * Do NOT call this function on general-purpose system SMBUS segments + * unless you know that the only things on the bus are DIMMs. + * Otherwise is it very likely to mis-identify other things on the + * bus. + * + * Callers are advised not to set adapter->class = I2C_CLASS_SPD. + */ +void i2c_scan_dimm_bus(struct i2c_adapter *adapter) +{ + struct i2c_board_info info = {}; + int slot; + + /* + * We probe with "read byte data". If any DIMM SMBUS driver can't + * support that access type, this function should be updated. + */ + if (WARN_ON(!i2c_check_functionality(adapter, + I2C_FUNC_SMBUS_READ_BYTE_DATA))) + return; + + for (slot = 0; slot < 8; slot++) { + /* If there's no SPD, then assume there's no DIMM here. */ + if (!probe_addr(adapter, 0x50 | slot)) + continue; + + strcpy(info.type, "eeprom"); + info.addr = 0x50 | slot; + i2c_new_device(adapter, &info); + + if (probe_addr(adapter, 0x18 | slot)) { + /* This is a temperature sensor. */ + strcpy(info.type, "tsod"); + info.addr = 0x18 | slot; + i2c_new_device(adapter, &info); + } + } +} +EXPORT_SYMBOL(i2c_scan_dimm_bus); + +MODULE_AUTHOR("Andrew Lutomirski <[email protected]>"); +MODULE_DESCRIPTION("i2c DIMM bus support"); +MODULE_LICENSE("GPL"); diff --git a/include/linux/i2c/dimm-bus.h b/include/linux/i2c/dimm-bus.h new file mode 100644 index 0000000..3d44df4 --- /dev/null +++ b/include/linux/i2c/dimm-bus.h @@ -0,0 +1,24 @@ +/* + * Copyright (c) 2013 Andrew Lutomirski <[email protected]> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 + * as published by the Free Software Foundation. + * + * 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., 675 Mass Ave, Cambridge, MA 02139, USA. + */ + +#ifndef _I2C_DIMM_BUS +#define _I2C_DIMM_BUS + +struct i2c_adapter; +void i2c_scan_dimm_bus(struct i2c_adapter *adapter); + +#endif /* _I2C_DIMM_BUS */ -- 1.8.1.4 -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
