18c2ecf20Sopenharmony_ci======================= 28c2ecf20Sopenharmony_ciw1_ds2406 kernel driver 38c2ecf20Sopenharmony_ci======================= 48c2ecf20Sopenharmony_ci 58c2ecf20Sopenharmony_ciSupported chips: 68c2ecf20Sopenharmony_ci 78c2ecf20Sopenharmony_ci * Maxim DS2406 (and other family 0x12) addressable switches 88c2ecf20Sopenharmony_ci 98c2ecf20Sopenharmony_ciAuthor: Scott Alfter <scott@alfter.us> 108c2ecf20Sopenharmony_ci 118c2ecf20Sopenharmony_ciDescription 128c2ecf20Sopenharmony_ci----------- 138c2ecf20Sopenharmony_ci 148c2ecf20Sopenharmony_ciThe w1_ds2406 driver allows connected devices to be switched on and off. 158c2ecf20Sopenharmony_ciThese chips also provide 128 bytes of OTP EPROM, but reading/writing it is 168c2ecf20Sopenharmony_cinot supported. In TSOC-6 form, the DS2406 provides two switch outputs and 178c2ecf20Sopenharmony_cican be provided with power on a dedicated input. In TO-92 form, it provides 188c2ecf20Sopenharmony_cione output and uses parasitic power only. 198c2ecf20Sopenharmony_ci 208c2ecf20Sopenharmony_ciThe driver provides two sysfs files. state is readable; it gives the 218c2ecf20Sopenharmony_cicurrent state of each switch, with PIO A in bit 0 and PIO B in bit 1. The 228c2ecf20Sopenharmony_cidriver ORs this state with 0x30, so shell scripts get an ASCII 0/1/2/3 to 238c2ecf20Sopenharmony_ciwork with. output is writable; bits 0 and 1 control PIO A and B, 248c2ecf20Sopenharmony_cirespectively. Bits 2-7 are ignored, so it's safe to write ASCII data. 258c2ecf20Sopenharmony_ci 268c2ecf20Sopenharmony_ciCRCs are checked on read and write. Failed checks cause an I/O error to be 278c2ecf20Sopenharmony_cireturned. On a failed write, the switch status is not changed. 28