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// SPDX-License-Identifier: GPL-2.0
/*
* Apple SoC SPMI device driver
*
* Copyright The Asahi Linux Contributors
*
* Inspired by:
* OpenBSD support Copyright (c) 2021 Mark Kettenis <kettenis@openbsd.org>
* Correllium support Copyright (C) 2021 Corellium LLC
* hisi-spmi-controller.c
* spmi-pmic-arb.c Copyright (c) 2021, The Linux Foundation.
*/
#include <linux/io.h>
#include <linux/iopoll.h>
#include <linux/module.h>
#include <linux/mod_devicetable.h>
#include <linux/platform_device.h>
#include <linux/spmi.h>
/* SPMI Controller Registers */
#define SPMI_STATUS_REG 0
#define SPMI_CMD_REG 0x4
#define SPMI_RSP_REG 0x8
#define SPMI_RX_FIFO_EMPTY BIT(24)
#define REG_POLL_INTERVAL_US 10000
#define REG_POLL_TIMEOUT_US (REG_POLL_INTERVAL_US * 5)
struct apple_spmi {
void __iomem *regs;
};
#define poll_reg(spmi, reg, val, cond) \
readl_poll_timeout((spmi)->regs + (reg), (val), (cond), \
REG_POLL_INTERVAL_US, REG_POLL_TIMEOUT_US)
static inline u32 apple_spmi_pack_cmd(u8 opc, u8 sid, u16 saddr, size_t len)
{
return opc | sid << 8 | saddr << 16 | (len - 1) | (1 << 15);
}
/* Wait for Rx FIFO to have something */
static int apple_spmi_wait_rx_not_empty(struct spmi_controller *ctrl)
{
struct apple_spmi *spmi = spmi_controller_get_drvdata(ctrl);
int ret;
u32 status;
ret = poll_reg(spmi, SPMI_STATUS_REG, status, !(status & SPMI_RX_FIFO_EMPTY));
if (ret) {
dev_err(&ctrl->dev,
"failed to wait for RX FIFO not empty\n");
return ret;
}
return 0;
}
static int spmi_read_cmd(struct spmi_controller *ctrl, u8 opc, u8 sid,
u16 saddr, u8 *buf, size_t len)
{
struct apple_spmi *spmi = spmi_controller_get_drvdata(ctrl);
u32 spmi_cmd = apple_spmi_pack_cmd(opc, sid, saddr, len);
u32 rsp;
size_t len_read = 0;
u8 i;
int ret;
writel(spmi_cmd, spmi->regs + SPMI_CMD_REG);
ret = apple_spmi_wait_rx_not_empty(ctrl);
if (ret)
return ret;
/* Discard SPMI reply status */
readl(spmi->regs + SPMI_RSP_REG);
/* Read SPMI data reply */
while (len_read < len) {
rsp = readl(spmi->regs + SPMI_RSP_REG);
i = 0;
while ((len_read < len) && (i < 4)) {
buf[len_read++] = ((0xff << (8 * i)) & rsp) >> (8 * i);
i += 1;
}
}
return 0;
}
static int spmi_write_cmd(struct spmi_controller *ctrl, u8 opc, u8 sid,
u16 saddr, const u8 *buf, size_t len)
{
struct apple_spmi *spmi = spmi_controller_get_drvdata(ctrl);
u32 spmi_cmd = apple_spmi_pack_cmd(opc, sid, saddr, len);
size_t i = 0, j;
int ret;
writel(spmi_cmd, spmi->regs + SPMI_CMD_REG);
while (i < len) {
j = 0;
spmi_cmd = 0;
while ((j < 4) & (i < len))
spmi_cmd |= buf[i++] << (j++ * 8);
writel(spmi_cmd, spmi->regs + SPMI_CMD_REG);
}
ret = apple_spmi_wait_rx_not_empty(ctrl);
if (ret)
return ret;
/* Discard */
readl(spmi->regs + SPMI_RSP_REG);
return 0;
}
static int apple_spmi_probe(struct platform_device *pdev)
{
struct apple_spmi *spmi;
struct spmi_controller *ctrl;
int ret;
ctrl = devm_spmi_controller_alloc(&pdev->dev, sizeof(*spmi));
if (IS_ERR(ctrl))
return -ENOMEM;
spmi = spmi_controller_get_drvdata(ctrl);
spmi->regs = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(spmi->regs))
return PTR_ERR(spmi->regs);
ctrl->dev.of_node = pdev->dev.of_node;
ctrl->read_cmd = spmi_read_cmd;
ctrl->write_cmd = spmi_write_cmd;
ret = devm_spmi_controller_add(&pdev->dev, ctrl);
if (ret)
return dev_err_probe(&pdev->dev, ret,
"spmi_controller_add failed\n");
return 0;
}
static const struct of_device_id apple_spmi_match_table[] = {
{ .compatible = "apple,spmi", },
{}
};
MODULE_DEVICE_TABLE(of, apple_spmi_match_table);
static struct platform_driver apple_spmi_driver = {
.probe = apple_spmi_probe,
.driver = {
.name = "apple-spmi",
.of_match_table = apple_spmi_match_table,
},
};
module_platform_driver(apple_spmi_driver);
MODULE_AUTHOR("Jean-Francois Bortolotti <jeff@borto.fr>");
MODULE_DESCRIPTION("Apple SoC SPMI driver");
MODULE_LICENSE("GPL");
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