Since there are no registers controlling the hardware parameters
IC_CAP_LOADING and IC_CLK_FREQ_OPTIMIZATION, their values can only be
declared in the device tree.
snps,bus-capacitance-pf indicates the bus capacitance in picofarads (pF).
It affects the high and low pulse width of SCL line in high speed mode.
The legal values for this property are 100 and 400 only, and default
value is 100. This property corresponds to IC_CAP_LOADING.
snps,clk-freq-optimized indicates whether the hardware reduce its
internal clock frequency by reducing the internal latency required to
generate the high period and low period of SCL line. This property
corresponds to IC_CLK_FREQ_OPTIMIZATION.
The driver can calculate the high period count and low period count of
SCL line for high speed mode based on these two properties.
Signed-off-by: Michael Wu <michael.wu@kneron.us>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Andi Shyti <andi.shyti@kernel.org>
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
The "#address-cells" and "#size-cells" are required only when the I2C
controller has subnodes. However, some I2C controllers defined in
"arch/arm64/boot/dts/amd/" and "arch/arm64/boot/dts/hisilicon/"
directories do not have child nodes. So they don't need these two
properties and don't write them explicitly.
Therefore, setting properties "#address-cells" and "#size-cells" as
"required" in this yaml file causes the following warnings:
/root/linux-next/arch/arm64/boot/dts/hisilicon/hi6220-hikey.dt.yaml: \
i2c@f7100000: '#address-cells' is a required property
/root/linux-next/arch/arm64/boot/dts/hisilicon/hi6220-hikey.dt.yaml: \
i2c@f7100000: '#size-cells' is a required property
Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Link: https://lore.kernel.org/r/20201214124347.2120-2-thunder.leizhen@huawei.com
Signed-off-by: Rob Herring <robh@kernel.org>
Add the "baikal,bt1-sys-i2c" compatible string to the DW I2C binding. Even
though the corresponding node is supposed to be a child of the Baikal-T1
System Controller, its reg property is left required for compatibility.
Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Wolfram Sang <wsa@kernel.org>
dtc currently doesn't support I2C_OWN_SLAVE_ADDRESS flag set in the
i2c "reg" property. If dtc finds an i2c-slave sub-node having an address
higher than ten-bits wide it'll print an ugly warning:
Warning (i2c_bus_reg): /example-2/i2c@1120000/eeprom@64: I2C bus unit address format error, expected "40000064"
Warning (i2c_bus_reg): /example-2/i2c@1120000/eeprom@64:reg: I2C address must be less than 10-bits, got "0x40000064"
In order to silence dtc up let's replace the corresponding DT binding
example with a normal DW I2C master mode-based one. It's done by clearing
the I2C_OWN_SLAVE_ADDRESS bit in the reg property and converting the
sub-node to be compatible with normal EEPROM like "atmel,24c02".
Just revert this commit when dtc is fixed.
Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Wolfram Sang <wsa@kernel.org>
Modern device tree bindings are supposed to be created as YAML-files
in accordance with dt-schema. This commit replaces Synopsys DW I2C
legacy bare text bindings with YAML file. As before the bindings file
states that the corresponding dts node is supposed to be compatible
either with generic DW I2C controller or with Microsemi Ocelot SoC I2C
one, to have registers, interrupts and clocks properties. In addition
the node may have clock-frequency, i2c-sda-hold-time-ns,
i2c-scl-falling-time-ns and i2c-sda-falling-time-ns optional properties.
Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Wolfram Sang <wsa@kernel.org>
