The patch is based on mainline v5.1 and extends DT-bindings for Opencore based I2C device in FU540 SoC, available on HiFive unleashed board (Rev A00), and also provides a workaround for broken IRQ which affect I2C polling mode interface on FU540 chipsets.
The polling mode workaround patch fixes the CPU stall issue, when-ever i2c transfer are initiated. This workaround checks if it's a FU540 chipset based on device tree information, and check's for open core's IF(interrupt flag) and TIP flags to break from the polling loop upon completion of transfer. To test the patch, a PMOD-AD2 sensor is connected to HiFive Unleashed board over J1 connector, and appropriate device node is added into board specific device tree as per the information provided in dt-bindings in Documentation/devicetree/bindings/i2c/i2c-sifive.txt. Without this workaround, the CPU stall's infinitely. Busybox i2c utilities used to verify workaround : i2cdetect, i2cdump, i2cset, i2cget Patch History: V0<->V1: -Incorporate review comments from Andrew -Extend dt bindings into i2c-ocores.txt instead of adding new file -Rename SIFIVE_FLAG_POLL to OCORES_FLAG_BROKEN_IRQ V0: -Update dt bindings for sifive i2c devices -Fix broken IRQ affecting i2c polling mode interface. Sagar Shrikant Kadam (3): dt-bindings: i2c: extend existing opencore bindings. i2c-ocore: sifive: add support for i2c device on FU540-c000 SoC. i2c-ocores: sifive: add polling mode workaround for FU540-C000 SoC. .../devicetree/bindings/i2c/i2c-ocores.txt | 20 +++++++++++++ drivers/i2c/busses/i2c-ocores.c | 33 +++++++++++++++++++--- 2 files changed, 49 insertions(+), 4 deletions(-) -- 1.9.1 -- The information transmitted is intended only for the person or entity to which it is addressed and may contain confidential and/or privileged material. If you are not the intended recipient of this message please do not read, copy, use or disclose this communication and notify the sender immediately. It should be noted that any review, retransmission, dissemination or other use of, or taking action or reliance upon, this information by persons or entities other than the intended recipient is prohibited.
