spi: Extend the core to ease integration of SPI memory controllers
Some controllers are exposing high-level interfaces to access various kind of SPI memories. Unfortunately they do not fit in the current spi_controller model and usually have drivers placed in drivers/mtd/spi-nor which are only supporting SPI NORs and not SPI memories in general. This is an attempt at defining a SPI memory interface which works for all kinds of SPI memories (NORs, NANDs, SRAMs). Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com> Reviewed-by: Frieder Schrempf <frieder.schrempf@exceet.de> Tested-by: Frieder Schrempf <frieder.schrempf@exceet.de> Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Boris Brezillon
committed by
Mark Brown
Mark Brown
parent
055ed0dabc
commit
c36ff266dc
249
include/linux/spi/spi-mem.h
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249
include/linux/spi/spi-mem.h
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@@ -0,0 +1,249 @@
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/* SPDX-License-Identifier: GPL-2.0+ */
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/*
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* Copyright (C) 2018 Exceet Electronics GmbH
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* Copyright (C) 2018 Bootlin
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*
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* Author: Boris Brezillon <boris.brezillon@bootlin.com>
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*/
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#ifndef __LINUX_SPI_MEM_H
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#define __LINUX_SPI_MEM_H
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#include <linux/spi/spi.h>
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#define SPI_MEM_OP_CMD(__opcode, __buswidth) \
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{ \
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.buswidth = __buswidth, \
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.opcode = __opcode, \
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}
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#define SPI_MEM_OP_ADDR(__nbytes, __val, __buswidth) \
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{ \
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.nbytes = __nbytes, \
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.val = __val, \
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.buswidth = __buswidth, \
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}
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#define SPI_MEM_OP_NO_ADDR { }
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#define SPI_MEM_OP_DUMMY(__nbytes, __buswidth) \
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{ \
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.nbytes = __nbytes, \
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.buswidth = __buswidth, \
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}
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#define SPI_MEM_OP_NO_DUMMY { }
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#define SPI_MEM_OP_DATA_IN(__nbytes, __buf, __buswidth) \
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{ \
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.dir = SPI_MEM_DATA_IN, \
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.nbytes = __nbytes, \
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.buf.in = __buf, \
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.buswidth = __buswidth, \
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}
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#define SPI_MEM_OP_DATA_OUT(__nbytes, __buf, __buswidth) \
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{ \
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.dir = SPI_MEM_DATA_OUT, \
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.nbytes = __nbytes, \
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.buf.out = __buf, \
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.buswidth = __buswidth, \
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}
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#define SPI_MEM_OP_NO_DATA { }
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/**
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* enum spi_mem_data_dir - describes the direction of a SPI memory data
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* transfer from the controller perspective
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* @SPI_MEM_DATA_IN: data coming from the SPI memory
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* @SPI_MEM_DATA_OUT: data sent the SPI memory
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*/
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enum spi_mem_data_dir {
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SPI_MEM_DATA_IN,
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SPI_MEM_DATA_OUT,
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};
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/**
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* struct spi_mem_op - describes a SPI memory operation
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* @cmd.buswidth: number of IO lines used to transmit the command
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* @cmd.opcode: operation opcode
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* @addr.nbytes: number of address bytes to send. Can be zero if the operation
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* does not need to send an address
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* @addr.buswidth: number of IO lines used to transmit the address cycles
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* @addr.val: address value. This value is always sent MSB first on the bus.
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* Note that only @addr.nbytes are taken into account in this
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* address value, so users should make sure the value fits in the
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* assigned number of bytes.
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* @dummy.nbytes: number of dummy bytes to send after an opcode or address. Can
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* be zero if the operation does not require dummy bytes
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* @dummy.buswidth: number of IO lanes used to transmit the dummy bytes
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* @data.buswidth: number of IO lanes used to send/receive the data
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* @data.dir: direction of the transfer
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* @data.buf.in: input buffer
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* @data.buf.out: output buffer
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*/
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struct spi_mem_op {
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struct {
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u8 buswidth;
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u8 opcode;
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} cmd;
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struct {
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u8 nbytes;
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u8 buswidth;
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u64 val;
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} addr;
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struct {
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u8 nbytes;
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u8 buswidth;
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} dummy;
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struct {
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u8 buswidth;
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enum spi_mem_data_dir dir;
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unsigned int nbytes;
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/* buf.{in,out} must be DMA-able. */
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union {
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void *in;
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const void *out;
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} buf;
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} data;
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};
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#define SPI_MEM_OP(__cmd, __addr, __dummy, __data) \
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{ \
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.cmd = __cmd, \
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.addr = __addr, \
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.dummy = __dummy, \
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.data = __data, \
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}
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/**
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* struct spi_mem - describes a SPI memory device
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* @spi: the underlying SPI device
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* @drvpriv: spi_mem_drviver private data
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*
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* Extra information that describe the SPI memory device and may be needed by
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* the controller to properly handle this device should be placed here.
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*
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* One example would be the device size since some controller expose their SPI
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* mem devices through a io-mapped region.
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*/
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struct spi_mem {
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struct spi_device *spi;
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void *drvpriv;
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};
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/**
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* struct spi_mem_set_drvdata() - attach driver private data to a SPI mem
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* device
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* @mem: memory device
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* @data: data to attach to the memory device
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*/
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static inline void spi_mem_set_drvdata(struct spi_mem *mem, void *data)
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{
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mem->drvpriv = data;
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}
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/**
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* struct spi_mem_get_drvdata() - get driver private data attached to a SPI mem
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* device
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* @mem: memory device
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*
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* Return: the data attached to the mem device.
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*/
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static inline void *spi_mem_get_drvdata(struct spi_mem *mem)
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{
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return mem->drvpriv;
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}
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/**
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* struct spi_controller_mem_ops - SPI memory operations
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* @adjust_op_size: shrink the data xfer of an operation to match controller's
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* limitations (can be alignment of max RX/TX size
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* limitations)
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* @supports_op: check if an operation is supported by the controller
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* @exec_op: execute a SPI memory operation
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*
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* This interface should be implemented by SPI controllers providing an
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* high-level interface to execute SPI memory operation, which is usually the
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* case for QSPI controllers.
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*/
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struct spi_controller_mem_ops {
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int (*adjust_op_size)(struct spi_mem *mem, struct spi_mem_op *op);
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bool (*supports_op)(struct spi_mem *mem,
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const struct spi_mem_op *op);
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int (*exec_op)(struct spi_mem *mem,
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const struct spi_mem_op *op);
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};
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/**
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* struct spi_mem_driver - SPI memory driver
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* @spidrv: inherit from a SPI driver
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* @probe: probe a SPI memory. Usually where detection/initialization takes
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* place
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* @remove: remove a SPI memory
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* @shutdown: take appropriate action when the system is shutdown
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*
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* This is just a thin wrapper around a spi_driver. The core takes care of
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* allocating the spi_mem object and forwarding the probe/remove/shutdown
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* request to the spi_mem_driver. The reason we use this wrapper is because
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* we might have to stuff more information into the spi_mem struct to let
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* SPI controllers know more about the SPI memory they interact with, and
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* having this intermediate layer allows us to do that without adding more
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* useless fields to the spi_device object.
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*/
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struct spi_mem_driver {
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struct spi_driver spidrv;
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int (*probe)(struct spi_mem *mem);
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int (*remove)(struct spi_mem *mem);
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void (*shutdown)(struct spi_mem *mem);
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};
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#if IS_ENABLED(CONFIG_SPI_MEM)
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int spi_controller_dma_map_mem_op_data(struct spi_controller *ctlr,
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const struct spi_mem_op *op,
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struct sg_table *sg);
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void spi_controller_dma_unmap_mem_op_data(struct spi_controller *ctlr,
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const struct spi_mem_op *op,
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struct sg_table *sg);
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#else
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static inline int
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spi_controller_dma_map_mem_op_data(struct spi_controller *ctlr,
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const struct spi_mem_op *op,
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struct sg_table *sg)
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{
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return -ENOTSUPP;
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}
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static inline void
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spi_controller_dma_unmap_mem_op_data(struct spi_controller *ctlr,
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const struct spi_mem_op *op,
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struct sg_table *sg)
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{
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}
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#endif /* CONFIG_SPI_MEM */
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int spi_mem_adjust_op_size(struct spi_mem *mem, struct spi_mem_op *op);
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bool spi_mem_supports_op(struct spi_mem *mem,
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const struct spi_mem_op *op);
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int spi_mem_exec_op(struct spi_mem *mem,
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const struct spi_mem_op *op);
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int spi_mem_driver_register_with_owner(struct spi_mem_driver *drv,
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struct module *owner);
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void spi_mem_driver_unregister(struct spi_mem_driver *drv);
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#define spi_mem_driver_register(__drv) \
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spi_mem_driver_register_with_owner(__drv, THIS_MODULE)
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#define module_spi_mem_driver(__drv) \
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module_driver(__drv, spi_mem_driver_register, \
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spi_mem_driver_unregister)
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#endif /* __LINUX_SPI_MEM_H */
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@@ -27,6 +27,7 @@ struct property_entry;
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struct spi_controller;
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struct spi_transfer;
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struct spi_flash_read_message;
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struct spi_controller_mem_ops;
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/*
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* INTERFACES between SPI master-side drivers and SPI slave protocol handlers,
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@@ -376,6 +377,9 @@ static inline void spi_unregister_driver(struct spi_driver *sdrv)
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* transfer_one callback.
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* @handle_err: the subsystem calls the driver to handle an error that occurs
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* in the generic implementation of transfer_one_message().
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* @mem_ops: optimized/dedicated operations for interactions with SPI memory.
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* This field is optional and should only be implemented if the
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* controller has native support for memory like operations.
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* @unprepare_message: undo any work done by prepare_message().
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* @slave_abort: abort the ongoing transfer request on an SPI slave controller
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* @spi_flash_read: to support spi-controller hardwares that provide
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@@ -564,6 +568,9 @@ struct spi_controller {
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void (*handle_err)(struct spi_controller *ctlr,
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struct spi_message *message);
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/* Optimized handlers for SPI memory-like operations. */
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const struct spi_controller_mem_ops *mem_ops;
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/* gpio chip select */
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int *cs_gpios;
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