linux/drivers/nvmem/rave-sp-eeprom.c

// SPDX-License-Identifier: GPL-2.0+

/*
 * EEPROM driver for RAVE SP
 *
 * Copyright (C) 2018 Zodiac Inflight Innovations
 *
 */
#include <linux/kernel.h>
#include <linux/mfd/rave-sp.h>
#include <linux/module.h>
#include <linux/nvmem-provider.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/sizes.h>

/**
 * enum rave_sp_eeprom_access_type - Supported types of EEPROM access
 *
 * @RAVE_SP_EEPROM_WRITE:	EEPROM write
 * @RAVE_SP_EEPROM_READ:	EEPROM read
 */
enum rave_sp_eeprom_access_type { … };

/**
 * enum rave_sp_eeprom_header_size - EEPROM command header sizes
 *
 * @RAVE_SP_EEPROM_HEADER_SMALL: EEPROM header size for "small" devices (< 8K)
 * @RAVE_SP_EEPROM_HEADER_BIG:	 EEPROM header size for "big" devices (> 8K)
 */
enum rave_sp_eeprom_header_size { … };
#define RAVE_SP_EEPROM_HEADER_MAX …

#define RAVE_SP_EEPROM_PAGE_SIZE …

/**
 * struct rave_sp_eeprom_page - RAVE SP EEPROM page
 *
 * @type:	Access type (see enum rave_sp_eeprom_access_type)
 * @success:	Success flag (Success = 1, Failure = 0)
 * @data:	Read data
 *
 * Note this structure corresponds to RSP_*_EEPROM payload from RAVE
 * SP ICD
 */
struct rave_sp_eeprom_page { … } __packed;

/**
 * struct rave_sp_eeprom - RAVE SP EEPROM device
 *
 * @sp:			Pointer to parent RAVE SP device
 * @mutex:		Lock protecting access to EEPROM
 * @address:		EEPROM device address
 * @header_size:	Size of EEPROM command header for this device
 * @dev:		Pointer to corresponding struct device used for logging
 */
struct rave_sp_eeprom { … };

/**
 * rave_sp_eeprom_io - Low-level part of EEPROM page access
 *
 * @eeprom:	EEPROM device to write to
 * @type:	EEPROM access type (read or write)
 * @idx:	number of the EEPROM page
 * @page:	Data to write or buffer to store result (via page->data)
 *
 * This function does all of the low-level work required to perform a
 * EEPROM access. This includes formatting correct command payload,
 * sending it and checking received results.
 *
 * Returns zero in case of success or negative error code in
 * case of failure.
 */
static int rave_sp_eeprom_io(struct rave_sp_eeprom *eeprom,
			     enum rave_sp_eeprom_access_type type,
			     u16 idx,
			     struct rave_sp_eeprom_page *page)
{ … }

/**
 * rave_sp_eeprom_page_access - Access single EEPROM page
 *
 * @eeprom:	EEPROM device to access
 * @type:	Access type to perform (read or write)
 * @offset:	Offset within EEPROM to access
 * @data:	Data buffer
 * @data_len:	Size of the data buffer
 *
 * This function performs a generic access to a single page or a
 * portion thereof. Requested access MUST NOT cross the EEPROM page
 * boundary.
 *
 * Returns zero in case of success or negative error code in
 * case of failure.
 */
static int
rave_sp_eeprom_page_access(struct rave_sp_eeprom *eeprom,
			   enum rave_sp_eeprom_access_type type,
			   unsigned int offset, u8 *data,
			   size_t data_len)
{ … }

/**
 * rave_sp_eeprom_access - Access EEPROM data
 *
 * @eeprom:	EEPROM device to access
 * @type:	Access type to perform (read or write)
 * @offset:	Offset within EEPROM to access
 * @data:	Data buffer
 * @data_len:	Size of the data buffer
 *
 * This function performs a generic access (either read or write) at
 * arbitrary offset (not necessary page aligned) of arbitrary length
 * (is not constrained by EEPROM page size).
 *
 * Returns zero in case of success or negative error code in case of
 * failure.
 */
static int rave_sp_eeprom_access(struct rave_sp_eeprom *eeprom,
				 enum rave_sp_eeprom_access_type type,
				 unsigned int offset, u8 *data,
				 unsigned int data_len)
{ … }

static int rave_sp_eeprom_reg_read(void *eeprom, unsigned int offset,
				   void *val, size_t bytes)
{ … }

static int rave_sp_eeprom_reg_write(void *eeprom, unsigned int offset,
				    void *val, size_t bytes)
{ … }

static int rave_sp_eeprom_probe(struct platform_device *pdev)
{ … }

static const struct of_device_id rave_sp_eeprom_of_match[] = …;
MODULE_DEVICE_TABLE(of, rave_sp_eeprom_of_match);

static struct platform_driver rave_sp_eeprom_driver = …;
module_platform_driver(…) …;

MODULE_LICENSE(…) …;
MODULE_AUTHOR(…) …;
MODULE_AUTHOR(…) …;
MODULE_AUTHOR(…) …;
MODULE_DESCRIPTION(…) …;