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  1. Aug 14, 2015
  2. Aug 12, 2015
  3. Aug 08, 2015
  4. Aug 06, 2015
    • Simon Glass's avatar
      dm: video: Add support for the Parade PS8622/625 bridge · bcd5dfff
      Simon Glass authored
      
      This chip provides an eDP to LVDS bridge which is useful for SoCs that don't
      support LVDS displays (or it would waste scarce pins). The setup is included
      in the device tree.
      
      Signed-off-by: default avatarSimon Glass <sjg@chromium.org>
      bcd5dfff
    • Simon Glass's avatar
      i2c: Add a mux for GPIO-based I2C bus arbitration · b725dc45
      Simon Glass authored
      
      While I2C supports multi-master buses this is difficult to get right.
      The implementation on the master side in software is quite complex.
      Clock-stretching and the arbitrary time that an I2C transaction can take
      make it difficult to share the bus fairly in the face of high traffic.
      When one or more masters can be reset independently part-way through a
      transaction it is hard to know the state of the bus.
      
      This driver provides a scheme based on two 'claim' GPIOs, one driven by the
      AP (Application Processor, meaning the main CPU) and one driven by the EC
      (Embedded Controller, a small CPU aimed at handling system tasks). With
      these they can communicate and reliably share the bus. This scheme has
      minimal overhead and involves very little code. It is used on snow to
      permit the EC and the AP to share access to the main system PMIC and
      battery. The scheme can survive reboots by either side without difficulty.
      This scheme has been tested in the field with millions of devices.
      
      Since U-Boot runs on the AP, the terminology used is 'our' claim GPIO,
      meaning the AP's, and 'their' claim GPIO, meaning the EC's. This terminology
      is used by the device tree bindings in Linux also.
      
      Signed-off-by: default avatarSimon Glass <sjg@chromium.org>
      b725dc45
    • Simon Glass's avatar
      dm: i2c: Add support for multiplexed I2C buses · 3d1957f0
      Simon Glass authored
      
      Add a new I2C_MUX uclass. Devices in this class can multiplex between
      several I2C buses, selecting them one at a time for use by the system.
      The multiplexing mechanism is left to the driver to decide - it may be
      controlled by GPIOs, for example.
      
      The uclass supports only two methods: select() and deselect().
      
      The current mux state is expected to be stored in the mux itself since
      it is the only thing that knows how to make things work. The mux can
      record the current state and then avoid switching unless it is necessary.
      So select() can be skipped if the mux is already in the correct state.
      Also deselect() can be made a nop if required.
      
      Signed-off-by: default avatarSimon Glass <sjg@chromium.org>
      3d1957f0
  5. Aug 05, 2015
  6. Jul 28, 2015
  7. Jul 23, 2015
  8. Jul 22, 2015
  9. Jul 21, 2015
  10. Jul 15, 2015
  11. Jul 08, 2015
  12. Jul 03, 2015
  13. Jul 01, 2015
  14. Jun 11, 2015
  15. Jun 08, 2015
  16. Jun 05, 2015
    • Paul Kocialkowski's avatar
      fdt: Pass the device serial number through devicetree · 10be5b5d
      Paul Kocialkowski authored
      
      Before device-tree, the device serial number used to be passed to the kernel
      using ATAGs (on ARM). This is now deprecated and all the handover to the kernel
      should now be done using device-tree. Thus, this passes the serial-number
      property to the kernel using the serial-number property of the root node, as
      expected by the kernel.
      
      The serial number is a string that somewhat represents the device's serial
      number. It might come from some form of storage (e.g. an eeprom) and be
      programmed at factory-time by the manufacturer or come from identification
      bits available in e.g. the SoC.
      
      Signed-off-by: default avatarPaul Kocialkowski <contact@paulk.fr>
      Reviewed-by: default avatarSimon Glass <sgj@chromium.org>
      10be5b5d
  17. Jun 04, 2015
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