On Sun, Jan 29, 2017 at 3:13 AM, Drew Fustini <pdp7p...@gmail.com> wrote: > eqep was working for me in 4.4.x but I get a segmentation fault when I > read the sysfs position file: > # cat /sys/devices/platform/ocp/48304000.epwmss/48304180.eqep/position > [ 1858.108446] Unhandled fault: external abort on non-linefetch > (0x1028) at 0xfa304184 > > I'm now reading about pm_runtime_get_sync() in > Documentation/power/runtime_pm.txt. I'll update if I make any > progress.
I'm still investigating but I did notice that the original tieqep driver had this code to enable the clock to the eQEP unit: https://github.com/Teknoman117/beaglebot/blob/master/encoders/patches/0001-tieqep-driver.patch#L721 // Enable the clock to the eQEP unit status = pwmss_submodule_state_change(pdev->dev.parent, PWMSS_EQEPCLK_EN); // If we failed to enable the clocks, fail out if (!(status & PWMSS_EQEPCLK_EN_ACK)) { dev_err(&pdev->dev, "PWMSS config space clock enable failed\n"); ret = -EINVAL; goto pwmss_clk_failure; } The function pwmss_submodule_state_change() appears to have been removed by this commit: commit cc37655e6bbf83ded1e4d1d7ffd977786a845a67 Author: Cooper Jr., Franklin <fcoo...@ti.com> Date: Mon Mar 7 13:33:56 2016 -0600 pwm: pwm-ti*: Remove support for local clock gating The PWMSS local clock gating registers have no real purpose on OMAP ARM devices. These registers were left over registers from DSP IP where the PRCM doesn't exist. There is a silicon bug where gating and ungating clocks don't function properly. TRMs will be update to indicate that these registers shouldn't be touched. Therefore, all code that accesses the PWMSS_CLKCONFIG or PWMSS_CLKSTATUS will be removed by this patch with zero loss of functionality by the ECAP and EPWM drivers. -Drew -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to beagleboard+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/CAPgEAj4EVcmo8coL7aMfxvX_E4p%2BVwgcNhYAvWque9m%2BgajRmg%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
