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authorMilo Kim <milo.kim@ti.com>2013-12-06 11:18:42 +0900
committerLee Jones <lee.jones@linaro.org>2014-01-21 08:27:57 +0000
commit0cc59b9d98d554168915b3765a14e8b4ad75918c (patch)
tree7939471290934e3482ecc8bc5a679e455159c205 /drivers/mfd
parent25a7a6f4a200e2eb04d87fb1c06130b1a85aa688 (diff)
gpio: add LP3943 I2C GPIO expander driver
This is one of LP3943 MFD driver. LP3943 is configurable as a GPIO expander, up to 16 GPIOs. * Application note: how to configure LP3943 as a GPIO expander http://www.ti.com/lit/an/snva287a/snva287a.pdf * Supported GPIO controller operations request, free, direction_input, direction_output, get and set * GPIO direction register not supported LP3943 doesn't have the GPIO direction register. It only provides input and output status registers. So, private data for the direction should be handled manually. This variable is updated whenever the direction is changed and used in 'get' operation. * Pin assignment A driver data, 'pin_used' is checked when a GPIO is requested. If the GPIO is already assigned, then returns as failure. If the GPIO is available, 'pin_used' is set. When the GPIO is not used anymore, then it is cleared. It is defined as unsigned long type for atomic bit operation APIs, but only LSB 16bits are used because LP3943 has 16 outputs. Signed-off-by: Milo Kim <milo.kim@ti.com> Reviewed-by: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Lee Jones <lee.jones@linaro.org>
Diffstat (limited to 'drivers/mfd')
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