1. Apr 12, 2015
  2. Apr 11, 2015
    • Martin Sperl's avatar
      spi: bcm2835: enabling polling mode for transfers shorter than 30us · 704f32d4
      Martin Sperl authored
      
      
      In cases of short transfer times the CPU is spending lots of time
      in the interrupt handler and scheduler to reschedule the worker thread.
      
      Measurements show that we have times where it takes 29.32us to between
      the last clock change and the time that the worker-thread is running again
      returning from wait_for_completion_timeout().
      
      During this time the interrupt-handler is running calling complete()
      and then also the scheduler is rescheduling the worker thread.
      
      This time can vary depending on how much of the code is still in
      CPU-caches, when there is a burst of spi transfers the subsequent delays
      are in the order of 25us, so the value of 30us seems reasonable.
      
      With polling the whole transfer of 4 bytes at 10MHz finishes after 6.16us
      (CS down to up) with the real transfer (clock running) taking 3.56us.
      So the efficiency has much improved and is also freeing CPU cycles,
      reducing interrupts and context switches.
      
      Because of the above 30us seems to be a reasonable limit for polling.
      
      Signed-off-by: default avatarMartin Sperl <kernel@martin.sperl.org>
      Signed-off-by: default avatarMark Brown <broonie@kernel.org>
      704f32d4
    • Martin Sperl's avatar
      spi: bcm2835: transform native-cs to gpio-cs on first spi_setup · a30a555d
      Martin Sperl authored
      Transforms the bcm-2835 native SPI-chip select to their gpio-cs equivalent.
      
      This allows for some support of some optimizations that are not
      possible due to HW-gliches on the CS line - especially filling
      the FIFO before enabling SPI interrupts (by writing to CS register)
      while the transfer is already in progress (See commit: e3a2be30
      
      )
      
      This patch also works arround some issues in bcm2835-pinctrl which does not
      set the value when setting the GPIO as output - it just sets up output and
      (typically) leaves the GPIO as low.  When a fix for this is merged then this
      gpio_set_value can get removed from bcm2835_spi_setup.
      
      Signed-off-by: default avatarMartin Sperl <kernel@martin.sperl.org>
      Signed-off-by: default avatarMark Brown <broonie@kernel.org>
      a30a555d
  3. Apr 09, 2015
  4. Apr 08, 2015
  5. Apr 07, 2015
  6. Apr 06, 2015
  7. Apr 05, 2015
    • Linus Torvalds's avatar
      Merge tag 'usb-4.0-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb · f8b3d8a5
      Linus Torvalds authored
      Pull USB fixes from Greg KH:
       "Here are some small USB fixes and new device ids for 4.0-rc6.  Nothing
        major, some xhci fixes for reported problems, and some usb-serial
        device ids.
      
        All have been in linux-next for a while"
      
      * tag 'usb-4.0-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb:
        USB: ftdi_sio: Use jtag quirk for SNAP Connect E10
        usb: isp1760: fix spin unlock in the error path of isp1760_udc_start
        usb: xhci: apply XHCI_AVOID_BEI quirk to all Intel xHCI controllers
        usb: xhci: handle Config Error Change (CEC) in xhci driver
        USB: keyspan_pda: add new device id
        USB: ftdi_sio: Added custom PID for Synapse Wireless product
      f8b3d8a5
    • Linus Torvalds's avatar
      Merge tag 'staging-4.0-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging · 8eb6dcf9
      Linus Torvalds authored
      Pull staging driver fixes from Greg KH:
       "Here are some staging driver fixes, well, really all just IIO driver
        fixes, for 4.0-rc6.  They fix issues that have been reported with
        these drivers.
      
        All of these patches have been in linux-next for a while"
      
      * tag 'staging-4.0-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging:
        iio: imu: Use iio_trigger_get for indio_dev->trig assignment
        iio: adc: vf610: use ADC clock within specification
        iio/adc/cc10001_adc.c: Fix !HAS_IOMEM build
        iio: core: Fix double free.
        iio:inv-mpu6050: Fix inconsistency for the scale channel
        staging: iio: dummy: Fix undefined symbol build error
        iio: inv_mpu6050: Clear timestamps fifo while resetting hardware fifo
        staging: iio: hmc5843: Set iio name property in sysfs
        iio: bmc150: change sampling frequency
        iio: fix drivers that check buffer->scan_mask
      8eb6dcf9
    • Linus Torvalds's avatar
      Merge tag 'tty-4.0-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty · eca8258b
      Linus Torvalds authored
      Pull tty/serial fixes from Greg KH:
       "Here are 3 serial driver fixes for 4.0-rc6.  They fix some reported
        issues with the samsung and fsl_lpuart drivers.
      
        All have been in linux-next for a while"
      
      * tag 'tty-4.0-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty:
        tty: serial: fsl_lpuart: clear receive flag on FIFO flush
        tty: serial: fsl_lpuart: specify transmit FIFO size
        serial: samsung: Clear operation mode on UART shutdown
      eca8258b