diff options
Diffstat (limited to 'drivers/nvmem/max77759-nvmem.c')
| -rw-r--r-- | drivers/nvmem/max77759-nvmem.c | 145 |
1 files changed, 145 insertions, 0 deletions
diff --git a/drivers/nvmem/max77759-nvmem.c b/drivers/nvmem/max77759-nvmem.c new file mode 100644 index 000000000000..c9961ad0e232 --- /dev/null +++ b/drivers/nvmem/max77759-nvmem.c @@ -0,0 +1,145 @@ +// SPDX-License-Identifier: GPL-2.0-only +// +// Copyright 2020 Google Inc +// Copyright 2025 Linaro Ltd. +// +// NVMEM driver for Maxim MAX77759 + +#include <linux/dev_printk.h> +#include <linux/device.h> +#include <linux/device/driver.h> +#include <linux/err.h> +#include <linux/mfd/max77759.h> +#include <linux/mod_devicetable.h> +#include <linux/module.h> +#include <linux/nvmem-provider.h> +#include <linux/overflow.h> +#include <linux/platform_device.h> +#include <linux/string.h> + +#define MAX77759_NVMEM_OPCODE_HEADER_LEN 3 +/* + * NVMEM commands have a three byte header (which becomes part of the command), + * so we need to subtract that. + */ +#define MAX77759_NVMEM_SIZE (MAX77759_MAXQ_OPCODE_MAXLENGTH \ + - MAX77759_NVMEM_OPCODE_HEADER_LEN) + +struct max77759_nvmem { + struct device *dev; + struct max77759 *max77759; +}; + +static int max77759_nvmem_reg_read(void *priv, unsigned int offset, + void *val, size_t bytes) +{ + struct max77759_nvmem *nvmem = priv; + DEFINE_FLEX(struct max77759_maxq_command, cmd, cmd, length, + MAX77759_NVMEM_OPCODE_HEADER_LEN); + DEFINE_FLEX(struct max77759_maxq_response, rsp, rsp, length, + MAX77759_MAXQ_OPCODE_MAXLENGTH); + int ret; + + cmd->cmd[0] = MAX77759_MAXQ_OPCODE_USER_SPACE_READ; + cmd->cmd[1] = offset; + cmd->cmd[2] = bytes; + rsp->length = bytes + MAX77759_NVMEM_OPCODE_HEADER_LEN; + + ret = max77759_maxq_command(nvmem->max77759, cmd, rsp); + if (ret < 0) + return ret; + + if (memcmp(cmd->cmd, rsp->rsp, MAX77759_NVMEM_OPCODE_HEADER_LEN)) { + dev_warn(nvmem->dev, "protocol error (read)\n"); + return -EIO; + } + + memcpy(val, &rsp->rsp[MAX77759_NVMEM_OPCODE_HEADER_LEN], bytes); + + return 0; +} + +static int max77759_nvmem_reg_write(void *priv, unsigned int offset, + void *val, size_t bytes) +{ + struct max77759_nvmem *nvmem = priv; + DEFINE_FLEX(struct max77759_maxq_command, cmd, cmd, length, + MAX77759_MAXQ_OPCODE_MAXLENGTH); + DEFINE_FLEX(struct max77759_maxq_response, rsp, rsp, length, + MAX77759_MAXQ_OPCODE_MAXLENGTH); + int ret; + + cmd->cmd[0] = MAX77759_MAXQ_OPCODE_USER_SPACE_WRITE; + cmd->cmd[1] = offset; + cmd->cmd[2] = bytes; + memcpy(&cmd->cmd[MAX77759_NVMEM_OPCODE_HEADER_LEN], val, bytes); + cmd->length = bytes + MAX77759_NVMEM_OPCODE_HEADER_LEN; + rsp->length = cmd->length; + + ret = max77759_maxq_command(nvmem->max77759, cmd, rsp); + if (ret < 0) + return ret; + + if (memcmp(cmd->cmd, rsp->rsp, cmd->length)) { + dev_warn(nvmem->dev, "protocol error (write)\n"); + return -EIO; + } + + return 0; +} + +static int max77759_nvmem_probe(struct platform_device *pdev) +{ + struct nvmem_config config = { + .dev = &pdev->dev, + .name = dev_name(&pdev->dev), + .id = NVMEM_DEVID_NONE, + .type = NVMEM_TYPE_EEPROM, + .ignore_wp = true, + .size = MAX77759_NVMEM_SIZE, + .word_size = sizeof(u8), + .stride = sizeof(u8), + .reg_read = max77759_nvmem_reg_read, + .reg_write = max77759_nvmem_reg_write, + }; + struct max77759_nvmem *nvmem; + + nvmem = devm_kzalloc(&pdev->dev, sizeof(*nvmem), GFP_KERNEL); + if (!nvmem) + return -ENOMEM; + + nvmem->dev = &pdev->dev; + nvmem->max77759 = dev_get_drvdata(pdev->dev.parent); + + config.priv = nvmem; + + return PTR_ERR_OR_ZERO(devm_nvmem_register(config.dev, &config)); +} + +static const struct of_device_id max77759_nvmem_of_id[] = { + { .compatible = "maxim,max77759-nvmem", }, + { } +}; +MODULE_DEVICE_TABLE(of, max77759_nvmem_of_id); + +static const struct platform_device_id max77759_nvmem_platform_id[] = { + { "max77759-nvmem", }, + { } +}; +MODULE_DEVICE_TABLE(platform, max77759_nvmem_platform_id); + +static struct platform_driver max77759_nvmem_driver = { + .driver = { + .name = "max77759-nvmem", + .probe_type = PROBE_PREFER_ASYNCHRONOUS, + .of_match_table = max77759_nvmem_of_id, + }, + .probe = max77759_nvmem_probe, + .id_table = max77759_nvmem_platform_id, +}; + +module_platform_driver(max77759_nvmem_driver); + +MODULE_AUTHOR("André Draszik <andre.draszik@linaro.org>"); +MODULE_DESCRIPTION("NVMEM driver for Maxim MAX77759"); +MODULE_LICENSE("GPL"); |