18c2ecf20Sopenharmony_ciKernel driver pwm-fan 28c2ecf20Sopenharmony_ci===================== 38c2ecf20Sopenharmony_ci 48c2ecf20Sopenharmony_ciThis driver enables the use of a PWM module to drive a fan. It uses the 58c2ecf20Sopenharmony_cigeneric PWM interface thus it is hardware independent. It can be used on 68c2ecf20Sopenharmony_cimany SoCs, as long as the SoC supplies a PWM line driver that exposes 78c2ecf20Sopenharmony_cithe generic PWM API. 88c2ecf20Sopenharmony_ci 98c2ecf20Sopenharmony_ciAuthor: Kamil Debski <k.debski@samsung.com> 108c2ecf20Sopenharmony_ci 118c2ecf20Sopenharmony_ciDescription 128c2ecf20Sopenharmony_ci----------- 138c2ecf20Sopenharmony_ci 148c2ecf20Sopenharmony_ciThe driver implements a simple interface for driving a fan connected to 158c2ecf20Sopenharmony_cia PWM output. It uses the generic PWM interface, thus it can be used with 168c2ecf20Sopenharmony_cia range of SoCs. The driver exposes the fan to the user space through 178c2ecf20Sopenharmony_cithe hwmon's sysfs interface. 188c2ecf20Sopenharmony_ci 198c2ecf20Sopenharmony_ciThe fan rotation speed returned via the optional 'fan1_input' is extrapolated 208c2ecf20Sopenharmony_cifrom the sampled interrupts from the tachometer signal within 1 second. 21