1. 03 Feb, 2015 2 commits
    • Brad Griffis's avatar
      Input: ti_am335x_tsc - remove udelay in interrupt handler · 344d635b
      Brad Griffis authored
      TSC interrupt handler had udelay to avoid reporting of false pen-up
      interrupt to user space. This patch implements workaround suggesting in
      Advisory 1.0.31 of silicon errata for am335x, thus eliminating udelay and
      touchscreen lag. This also improves performance of touchscreen and
      eliminates sudden jump of cursor at touch release.
      
      IDLECONFIG and CHARGECONFIG registers are to be configured with same values
      in order to eliminate false pen-up events. This workaround may result in
      false pen-down to be detected, hence considerable charge step delay needs
      to be added. The charge delay is set to 0xB000 (in terms of ADC clock
      cycles) by default.
      
      TSC steps are disabled at the end of every sampling cycle and EOS bit is
      set. Once the EOS bit is set, the TSC steps need to be re-enabled to begin
      next sampling cycle.
      Signed-off-by: default avatarBrad Griffis <bgriffis@ti.com>
      [vigneshr@ti.com: Ported the patch from v3.12 to v3.19rc1]
      Signed-off-by: default avatarVignesh R <vigneshr@ti.com>
      Signed-off-by: default avatarDmitry Torokhov <dmitry.torokhov@gmail.com>
      344d635b
    • Brad Griffis's avatar
      Input: ti_am335x_tsc - interchange touchscreen and ADC steps · 3a59684c
      Brad Griffis authored
      This patch makes the initial changes required to workaround TSC-false
      pen-up interrupts. It is required to implement these changes in order to
      remove udelay in the TSC interrupt handler and false pen-up events.  The
      charge step is to be executed immediately after sampling X+. Hence TSC is
      made to use higher numbered steps (steps 5 to 16 for 5 co-ordinate
      readouts, 4 wire TSC configuration) and ADC to use lower ones. Further X
      co-ordinate readouts must be the last to be sampled, thus co-ordinates are
      sampled in the order Y-Z-X.
      Signed-off-by: default avatarBrad Griffis <bgriffis@ti.com>
      [vigneshr@ti.com: Ported the patch from v3.12 to v3.19rc1]
      Signed-off-by: default avatarVignesh R <vigneshr@ti.com>
      Acked-by: default avatarJonathan Cameron <jic23@kernel.org>
      Signed-off-by: default avatarDmitry Torokhov <dmitry.torokhov@gmail.com>
      3a59684c
  2. 01 Feb, 2015 4 commits
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  4. 23 Jan, 2015 1 commit
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  8. 11 Jan, 2015 10 commits