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8824dc7f94
The Maxim MAX77759 is a companion PMIC for USB Type-C applications and includes Battery Charger, Fuel Gauge, temperature sensors, USB Type-C Port Controller (TCPC), NVMEM, and a GPIO expander. This driver exposes the non volatile memory using the platform device registered by the core MFD driver. Signed-off-by: André Draszik <andre.draszik@linaro.org> Acked-by: Srinivas Kandagatla <srini@kernel.org> Acked-by: Peter Griffin <peter.griffin@linaro.org> Link: https://lore.kernel.org/r/20250509-max77759-mfd-v10-3-962ac15ee3ef@linaro.org Signed-off-by: Lee Jones <lee@kernel.org>
145 lines
3.8 KiB
C
145 lines
3.8 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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//
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// Copyright 2020 Google Inc
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// Copyright 2025 Linaro Ltd.
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//
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// NVMEM driver for Maxim MAX77759
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#include <linux/dev_printk.h>
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#include <linux/device.h>
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#include <linux/device/driver.h>
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#include <linux/err.h>
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#include <linux/mfd/max77759.h>
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#include <linux/mod_devicetable.h>
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#include <linux/module.h>
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#include <linux/nvmem-provider.h>
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#include <linux/overflow.h>
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#include <linux/platform_device.h>
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#include <linux/string.h>
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#define MAX77759_NVMEM_OPCODE_HEADER_LEN 3
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/*
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* NVMEM commands have a three byte header (which becomes part of the command),
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* so we need to subtract that.
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*/
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#define MAX77759_NVMEM_SIZE (MAX77759_MAXQ_OPCODE_MAXLENGTH \
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- MAX77759_NVMEM_OPCODE_HEADER_LEN)
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struct max77759_nvmem {
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struct device *dev;
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struct max77759 *max77759;
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};
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static int max77759_nvmem_reg_read(void *priv, unsigned int offset,
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void *val, size_t bytes)
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{
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struct max77759_nvmem *nvmem = priv;
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DEFINE_FLEX(struct max77759_maxq_command, cmd, cmd, length,
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MAX77759_NVMEM_OPCODE_HEADER_LEN);
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DEFINE_FLEX(struct max77759_maxq_response, rsp, rsp, length,
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MAX77759_MAXQ_OPCODE_MAXLENGTH);
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int ret;
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cmd->cmd[0] = MAX77759_MAXQ_OPCODE_USER_SPACE_READ;
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cmd->cmd[1] = offset;
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cmd->cmd[2] = bytes;
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rsp->length = bytes + MAX77759_NVMEM_OPCODE_HEADER_LEN;
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ret = max77759_maxq_command(nvmem->max77759, cmd, rsp);
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if (ret < 0)
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return ret;
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if (memcmp(cmd->cmd, rsp->rsp, MAX77759_NVMEM_OPCODE_HEADER_LEN)) {
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dev_warn(nvmem->dev, "protocol error (read)\n");
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return -EIO;
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}
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memcpy(val, &rsp->rsp[MAX77759_NVMEM_OPCODE_HEADER_LEN], bytes);
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return 0;
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}
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static int max77759_nvmem_reg_write(void *priv, unsigned int offset,
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void *val, size_t bytes)
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{
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struct max77759_nvmem *nvmem = priv;
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DEFINE_FLEX(struct max77759_maxq_command, cmd, cmd, length,
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MAX77759_MAXQ_OPCODE_MAXLENGTH);
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DEFINE_FLEX(struct max77759_maxq_response, rsp, rsp, length,
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MAX77759_MAXQ_OPCODE_MAXLENGTH);
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int ret;
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cmd->cmd[0] = MAX77759_MAXQ_OPCODE_USER_SPACE_WRITE;
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cmd->cmd[1] = offset;
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cmd->cmd[2] = bytes;
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memcpy(&cmd->cmd[MAX77759_NVMEM_OPCODE_HEADER_LEN], val, bytes);
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cmd->length = bytes + MAX77759_NVMEM_OPCODE_HEADER_LEN;
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rsp->length = cmd->length;
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ret = max77759_maxq_command(nvmem->max77759, cmd, rsp);
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if (ret < 0)
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return ret;
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if (memcmp(cmd->cmd, rsp->rsp, cmd->length)) {
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dev_warn(nvmem->dev, "protocol error (write)\n");
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return -EIO;
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}
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return 0;
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}
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static int max77759_nvmem_probe(struct platform_device *pdev)
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{
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struct nvmem_config config = {
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.dev = &pdev->dev,
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.name = dev_name(&pdev->dev),
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.id = NVMEM_DEVID_NONE,
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.type = NVMEM_TYPE_EEPROM,
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.ignore_wp = true,
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.size = MAX77759_NVMEM_SIZE,
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.word_size = sizeof(u8),
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.stride = sizeof(u8),
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.reg_read = max77759_nvmem_reg_read,
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.reg_write = max77759_nvmem_reg_write,
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};
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struct max77759_nvmem *nvmem;
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nvmem = devm_kzalloc(&pdev->dev, sizeof(*nvmem), GFP_KERNEL);
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if (!nvmem)
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return -ENOMEM;
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nvmem->dev = &pdev->dev;
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nvmem->max77759 = dev_get_drvdata(pdev->dev.parent);
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config.priv = nvmem;
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return PTR_ERR_OR_ZERO(devm_nvmem_register(config.dev, &config));
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}
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static const struct of_device_id max77759_nvmem_of_id[] = {
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{ .compatible = "maxim,max77759-nvmem", },
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{ }
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};
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MODULE_DEVICE_TABLE(of, max77759_nvmem_of_id);
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static const struct platform_device_id max77759_nvmem_platform_id[] = {
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{ "max77759-nvmem", },
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{ }
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};
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MODULE_DEVICE_TABLE(platform, max77759_nvmem_platform_id);
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static struct platform_driver max77759_nvmem_driver = {
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.driver = {
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.name = "max77759-nvmem",
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.probe_type = PROBE_PREFER_ASYNCHRONOUS,
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.of_match_table = max77759_nvmem_of_id,
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},
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.probe = max77759_nvmem_probe,
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.id_table = max77759_nvmem_platform_id,
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};
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module_platform_driver(max77759_nvmem_driver);
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MODULE_AUTHOR("André Draszik <andre.draszik@linaro.org>");
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MODULE_DESCRIPTION("NVMEM driver for Maxim MAX77759");
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MODULE_LICENSE("GPL");
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