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Currently syscon has a fixed configuration of 32 bits for register and values widths. In some cases, it would be desirable to be able to customize the value width. For example, certain boards (like the ones manufactured by Technologic Systems) have a FPGA that is memory-mapped, but its registers are only 16-bit wide. This patch adds an optional "reg-io-width" DT binding for syscon that allows to change the width for the data bus (i.e. val_bits). If this property is provided, it will also set the register stride to reg-io-width's value. If not provided, the default configuration is used. Signed-off-by: Damien Riegel <damien.riegel@savoirfairelinux.com> Acked-by: Rob Herring <robh@kernel.org> Acked-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Lee Jones <lee.jones@linaro.org>
25 lines
894 B
Plaintext
25 lines
894 B
Plaintext
* System Controller Registers R/W driver
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System controller node represents a register region containing a set
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of miscellaneous registers. The registers are not cohesive enough to
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represent as any specific type of device. The typical use-case is for
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some other node's driver, or platform-specific code, to acquire a
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reference to the syscon node (e.g. by phandle, node path, or search
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using a specific compatible value), interrogate the node (or associated
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OS driver) to determine the location of the registers, and access the
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registers directly.
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Required properties:
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- compatible: Should contain "syscon".
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- reg: the register region can be accessed from syscon
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Optional property:
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- reg-io-width: the size (in bytes) of the IO accesses that should be
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performed on the device.
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Examples:
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gpr: iomuxc-gpr@020e0000 {
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compatible = "fsl,imx6q-iomuxc-gpr", "syscon";
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reg = <0x020e0000 0x38>;
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};
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