• Petr Cvek's avatar
    ARM: pxa: magician: Add support for ADS7846 touchscreen · 7ade445c
    Petr Cvek authored
    This patch adds a support for ADS7846 touchscreen driver.
    
    The basic functionality was tested, x_plate_ohms and y_plate_ohms were
    physically measured. The value pressure_max was empirically set to match
    the measured range, which is affected by x_plate_ohms and ADS samples.
    
    The value of keep_vref_on should be set. A tested model (T-Mobile MDA
    Compact PM10A) doesn't seem to use Vref pin as the input from an external
    source. On this model the unset keep_vref_on cause high jitter of measured
    values.
    
    SPI framing pin (gpio_cs) must be used in GPIO mode due to an incompatible
    autoframing of PXA27x controller and ADS7846 device.
    Signed-off-by: default avatarPetr Cvek <petr.cvek@tul.cz>
    Signed-off-by: default avatarRobert Jarzmik <robert.jarzmik@free.fr>
    7ade445c
magician.h 4.24 KB