eeprom: Add IDT 89HPESx EEPROM/CSR driver
This driver provides an access to EEPROM of IDT PCIe-switches. IDT PCIe- switches expose a simple SMBus interface to perform IO-operations from/to EEPROM, which is located at private (so called Master) SMBus. The driver creates a simple binary sysfs-file to have an access to the EEPROM using the SMBus-slave interface in the i2c-device susfs-directory: /sys/bus/i2c/devices/<bus>-<devaddr>/eeprom In case if read-only flag is specified at dts-node of the device, User-space applications won't be able to write to the EEPROM sysfs-node. Additionally IDT 89HPESx SMBus interface has an ability to read/write values of device CSRs. This driver exposes debugfs-file to perform simple IO-operations using that ability for just basic debug purpose. Particularly the next file is created in the specific debugfs-directory: /sys/kernel/debug/idt_csr/ Format of the debugfs-file value is: $ cat /sys/kernel/debug/idt_csr/<bus>-<devaddr>/<devname>; <CSR address>:<CSR value> So reading the content of the file gives current CSR address and it value. If User-space application wishes to change current CSR address, it can just write a proper value to the sysfs-file: $ echo "<CSR address>" > /sys/kernel/debug/idt_csr/<bus>-<devaddr>/<devname> If it wants to change the CSR value as well, the format of the write operation is: $ echo "<CSR address>:<CSR value>" > \ /sys/kernel/debug/idt_csr/<bus>-<devaddr>/<devname>; CSR address and value can be any of hexadecimal, decimal or octal format. Signed-off-by:Serge Semin <fancer.lancer@gmail.com> Signed-off-by:
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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