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linux-zen-server/drivers/i2c/busses/i2c-microchip-corei2c.c

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2023-08-30 17:53:23 +02:00
// SPDX-License-Identifier: GPL-2.0
/*
* Microchip CoreI2C I2C controller driver
*
* Copyright (c) 2018-2022 Microchip Corporation. All rights reserved.
*
* Author: Daire McNamara <daire.mcnamara@microchip.com>
* Author: Conor Dooley <conor.dooley@microchip.com>
*/
#include <linux/clk.h>
#include <linux/clkdev.h>
#include <linux/err.h>
#include <linux/i2c.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#define CORE_I2C_CTRL (0x00)
#define CTRL_CR0 BIT(0)
#define CTRL_CR1 BIT(1)
#define CTRL_AA BIT(2)
#define CTRL_SI BIT(3)
#define CTRL_STO BIT(4)
#define CTRL_STA BIT(5)
#define CTRL_ENS1 BIT(6)
#define CTRL_CR2 BIT(7)
#define STATUS_BUS_ERROR (0x00)
#define STATUS_M_START_SENT (0x08)
#define STATUS_M_REPEATED_START_SENT (0x10)
#define STATUS_M_SLAW_ACK (0x18)
#define STATUS_M_SLAW_NACK (0x20)
#define STATUS_M_TX_DATA_ACK (0x28)
#define STATUS_M_TX_DATA_NACK (0x30)
#define STATUS_M_ARB_LOST (0x38)
#define STATUS_M_SLAR_ACK (0x40)
#define STATUS_M_SLAR_NACK (0x48)
#define STATUS_M_RX_DATA_ACKED (0x50)
#define STATUS_M_RX_DATA_NACKED (0x58)
#define STATUS_S_SLAW_ACKED (0x60)
#define STATUS_S_ARB_LOST_SLAW_ACKED (0x68)
#define STATUS_S_GENERAL_CALL_ACKED (0x70)
#define STATUS_S_ARB_LOST_GENERAL_CALL_ACKED (0x78)
#define STATUS_S_RX_DATA_ACKED (0x80)
#define STATUS_S_RX_DATA_NACKED (0x88)
#define STATUS_S_GENERAL_CALL_RX_DATA_ACKED (0x90)
#define STATUS_S_GENERAL_CALL_RX_DATA_NACKED (0x98)
#define STATUS_S_RX_STOP (0xA0)
#define STATUS_S_SLAR_ACKED (0xA8)
#define STATUS_S_ARB_LOST_SLAR_ACKED (0xB0)
#define STATUS_S_TX_DATA_ACK (0xB8)
#define STATUS_S_TX_DATA_NACK (0xC0)
#define STATUS_LAST_DATA_ACK (0xC8)
#define STATUS_M_SMB_MASTER_RESET (0xD0)
#define STATUS_S_SCL_LOW_TIMEOUT (0xD8) /* 25 ms */
#define STATUS_NO_STATE_INFO (0xF8)
#define CORE_I2C_STATUS (0x04)
#define CORE_I2C_DATA (0x08)
#define WRITE_BIT (0x0)
#define READ_BIT (0x1)
#define SLAVE_ADDR_SHIFT (1)
#define CORE_I2C_SLAVE0_ADDR (0x0c)
#define GENERAL_CALL_BIT (0x0)
#define CORE_I2C_SMBUS (0x10)
#define SMBALERT_INT_ENB (0x0)
#define SMBSUS_INT_ENB (0x1)
#define SMBUS_ENB (0x2)
#define SMBALERT_NI_STATUS (0x3)
#define SMBALERT_NO_CTRL (0x4)
#define SMBSUS_NI_STATUS (0x5)
#define SMBSUS_NO_CTRL (0x6)
#define SMBUS_RESET (0x7)
#define CORE_I2C_FREQ (0x14)
#define CORE_I2C_GLITCHREG (0x18)
#define CORE_I2C_SLAVE1_ADDR (0x1c)
#define PCLK_DIV_960 (CTRL_CR2)
#define PCLK_DIV_256 (0)
#define PCLK_DIV_224 (CTRL_CR0)
#define PCLK_DIV_192 (CTRL_CR1)
#define PCLK_DIV_160 (CTRL_CR0 | CTRL_CR1)
#define PCLK_DIV_120 (CTRL_CR0 | CTRL_CR2)
#define PCLK_DIV_60 (CTRL_CR1 | CTRL_CR2)
#define BCLK_DIV_8 (CTRL_CR0 | CTRL_CR1 | CTRL_CR2)
#define CLK_MASK (CTRL_CR0 | CTRL_CR1 | CTRL_CR2)
/**
* struct mchp_corei2c_dev - Microchip CoreI2C device private data
*
* @base: pointer to register struct
* @dev: device reference
* @i2c_clk: clock reference for i2c input clock
* @buf: pointer to msg buffer for easier use
* @msg_complete: xfer completion object
* @adapter: core i2c abstraction
* @msg_err: error code for completed message
* @bus_clk_rate: current i2c bus clock rate
* @isr_status: cached copy of local ISR status
* @msg_len: number of bytes transferred in msg
* @addr: address of the current slave
*/
struct mchp_corei2c_dev {
void __iomem *base;
struct device *dev;
struct clk *i2c_clk;
u8 *buf;
struct completion msg_complete;
struct i2c_adapter adapter;
int msg_err;
u32 bus_clk_rate;
u32 isr_status;
u16 msg_len;
u8 addr;
};
static void mchp_corei2c_core_disable(struct mchp_corei2c_dev *idev)
{
u8 ctrl = readb(idev->base + CORE_I2C_CTRL);
ctrl &= ~CTRL_ENS1;
writeb(ctrl, idev->base + CORE_I2C_CTRL);
}
static void mchp_corei2c_core_enable(struct mchp_corei2c_dev *idev)
{
u8 ctrl = readb(idev->base + CORE_I2C_CTRL);
ctrl |= CTRL_ENS1;
writeb(ctrl, idev->base + CORE_I2C_CTRL);
}
static void mchp_corei2c_reset(struct mchp_corei2c_dev *idev)
{
mchp_corei2c_core_disable(idev);
mchp_corei2c_core_enable(idev);
}
static inline void mchp_corei2c_stop(struct mchp_corei2c_dev *idev)
{
u8 ctrl = readb(idev->base + CORE_I2C_CTRL);
ctrl |= CTRL_STO;
writeb(ctrl, idev->base + CORE_I2C_CTRL);
}
static inline int mchp_corei2c_set_divisor(u32 rate,
struct mchp_corei2c_dev *idev)
{
u8 clkval, ctrl;
if (rate >= 960)
clkval = PCLK_DIV_960;
else if (rate >= 256)
clkval = PCLK_DIV_256;
else if (rate >= 224)
clkval = PCLK_DIV_224;
else if (rate >= 192)
clkval = PCLK_DIV_192;
else if (rate >= 160)
clkval = PCLK_DIV_160;
else if (rate >= 120)
clkval = PCLK_DIV_120;
else if (rate >= 60)
clkval = PCLK_DIV_60;
else if (rate >= 8)
clkval = BCLK_DIV_8;
else
return -EINVAL;
ctrl = readb(idev->base + CORE_I2C_CTRL);
ctrl &= ~CLK_MASK;
ctrl |= clkval;
writeb(ctrl, idev->base + CORE_I2C_CTRL);
ctrl = readb(idev->base + CORE_I2C_CTRL);
if ((ctrl & CLK_MASK) != clkval)
return -EIO;
return 0;
}
static int mchp_corei2c_init(struct mchp_corei2c_dev *idev)
{
u32 clk_rate = clk_get_rate(idev->i2c_clk);
u32 divisor = clk_rate / idev->bus_clk_rate;
int ret;
ret = mchp_corei2c_set_divisor(divisor, idev);
if (ret)
return ret;
mchp_corei2c_reset(idev);
return 0;
}
static void mchp_corei2c_empty_rx(struct mchp_corei2c_dev *idev)
{
u8 ctrl;
if (idev->msg_len > 0) {
*idev->buf++ = readb(idev->base + CORE_I2C_DATA);
idev->msg_len--;
}
if (idev->msg_len <= 1) {
ctrl = readb(idev->base + CORE_I2C_CTRL);
ctrl &= ~CTRL_AA;
writeb(ctrl, idev->base + CORE_I2C_CTRL);
}
}
static int mchp_corei2c_fill_tx(struct mchp_corei2c_dev *idev)
{
if (idev->msg_len > 0)
writeb(*idev->buf++, idev->base + CORE_I2C_DATA);
idev->msg_len--;
return 0;
}
static irqreturn_t mchp_corei2c_handle_isr(struct mchp_corei2c_dev *idev)
{
u32 status = idev->isr_status;
u8 ctrl;
bool last_byte = false, finished = false;
if (!idev->buf)
return IRQ_NONE;
switch (status) {
case STATUS_M_START_SENT:
case STATUS_M_REPEATED_START_SENT:
ctrl = readb(idev->base + CORE_I2C_CTRL);
ctrl &= ~CTRL_STA;
writeb(idev->addr, idev->base + CORE_I2C_DATA);
writeb(ctrl, idev->base + CORE_I2C_CTRL);
if (idev->msg_len == 0)
finished = true;
break;
case STATUS_M_ARB_LOST:
idev->msg_err = -EAGAIN;
finished = true;
break;
case STATUS_M_SLAW_ACK:
case STATUS_M_TX_DATA_ACK:
if (idev->msg_len > 0)
mchp_corei2c_fill_tx(idev);
else
last_byte = true;
break;
case STATUS_M_TX_DATA_NACK:
case STATUS_M_SLAR_NACK:
case STATUS_M_SLAW_NACK:
idev->msg_err = -ENXIO;
last_byte = true;
break;
case STATUS_M_SLAR_ACK:
ctrl = readb(idev->base + CORE_I2C_CTRL);
if (idev->msg_len == 1u) {
ctrl &= ~CTRL_AA;
writeb(ctrl, idev->base + CORE_I2C_CTRL);
} else {
ctrl |= CTRL_AA;
writeb(ctrl, idev->base + CORE_I2C_CTRL);
}
if (idev->msg_len < 1u)
last_byte = true;
break;
case STATUS_M_RX_DATA_ACKED:
mchp_corei2c_empty_rx(idev);
break;
case STATUS_M_RX_DATA_NACKED:
mchp_corei2c_empty_rx(idev);
if (idev->msg_len == 0)
last_byte = true;
break;
default:
break;
}
/* On the last byte to be transmitted, send STOP */
if (last_byte)
mchp_corei2c_stop(idev);
if (last_byte || finished)
complete(&idev->msg_complete);
return IRQ_HANDLED;
}
static irqreturn_t mchp_corei2c_isr(int irq, void *_dev)
{
struct mchp_corei2c_dev *idev = _dev;
irqreturn_t ret = IRQ_NONE;
u8 ctrl;
ctrl = readb(idev->base + CORE_I2C_CTRL);
if (ctrl & CTRL_SI) {
idev->isr_status = readb(idev->base + CORE_I2C_STATUS);
ret = mchp_corei2c_handle_isr(idev);
}
ctrl = readb(idev->base + CORE_I2C_CTRL);
ctrl &= ~CTRL_SI;
writeb(ctrl, idev->base + CORE_I2C_CTRL);
return ret;
}
static int mchp_corei2c_xfer_msg(struct mchp_corei2c_dev *idev,
struct i2c_msg *msg)
{
u8 ctrl;
unsigned long time_left;
idev->addr = i2c_8bit_addr_from_msg(msg);
idev->msg_len = msg->len;
idev->buf = msg->buf;
idev->msg_err = 0;
reinit_completion(&idev->msg_complete);
mchp_corei2c_core_enable(idev);
ctrl = readb(idev->base + CORE_I2C_CTRL);
ctrl |= CTRL_STA;
writeb(ctrl, idev->base + CORE_I2C_CTRL);
time_left = wait_for_completion_timeout(&idev->msg_complete,
idev->adapter.timeout);
if (!time_left)
return -ETIMEDOUT;
return idev->msg_err;
}
static int mchp_corei2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
int num)
{
struct mchp_corei2c_dev *idev = i2c_get_adapdata(adap);
int i, ret;
for (i = 0; i < num; i++) {
ret = mchp_corei2c_xfer_msg(idev, msgs++);
if (ret)
return ret;
}
return num;
}
static u32 mchp_corei2c_func(struct i2c_adapter *adap)
{
return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
}
static const struct i2c_algorithm mchp_corei2c_algo = {
.master_xfer = mchp_corei2c_xfer,
.functionality = mchp_corei2c_func,
};
static int mchp_corei2c_probe(struct platform_device *pdev)
{
struct mchp_corei2c_dev *idev;
struct resource *res;
int irq, ret;
idev = devm_kzalloc(&pdev->dev, sizeof(*idev), GFP_KERNEL);
if (!idev)
return -ENOMEM;
idev->base = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
if (IS_ERR(idev->base))
return PTR_ERR(idev->base);
irq = platform_get_irq(pdev, 0);
if (irq <= 0)
return dev_err_probe(&pdev->dev, -ENXIO,
"invalid IRQ %d for I2C controller\n", irq);
idev->i2c_clk = devm_clk_get(&pdev->dev, NULL);
if (IS_ERR(idev->i2c_clk))
return dev_err_probe(&pdev->dev, PTR_ERR(idev->i2c_clk),
"missing clock\n");
idev->dev = &pdev->dev;
init_completion(&idev->msg_complete);
ret = device_property_read_u32(idev->dev, "clock-frequency",
&idev->bus_clk_rate);
if (ret || !idev->bus_clk_rate) {
dev_info(&pdev->dev, "default to 100kHz\n");
idev->bus_clk_rate = 100000;
}
if (idev->bus_clk_rate > 400000)
return dev_err_probe(&pdev->dev, -EINVAL,
"clock-frequency too high: %d\n",
idev->bus_clk_rate);
/*
* This driver supports both the hard peripherals & soft FPGA cores.
* The hard peripherals do not have shared IRQs, but we don't have
* control over what way the interrupts are wired for the soft cores.
*/
ret = devm_request_irq(&pdev->dev, irq, mchp_corei2c_isr, IRQF_SHARED,
pdev->name, idev);
if (ret)
return dev_err_probe(&pdev->dev, ret,
"failed to claim irq %d\n", irq);
ret = clk_prepare_enable(idev->i2c_clk);
if (ret)
return dev_err_probe(&pdev->dev, ret,
"failed to enable clock\n");
ret = mchp_corei2c_init(idev);
if (ret) {
clk_disable_unprepare(idev->i2c_clk);
return dev_err_probe(&pdev->dev, ret, "failed to program clock divider\n");
}
i2c_set_adapdata(&idev->adapter, idev);
snprintf(idev->adapter.name, sizeof(idev->adapter.name),
"Microchip I2C hw bus at %08lx", (unsigned long)res->start);
idev->adapter.owner = THIS_MODULE;
idev->adapter.algo = &mchp_corei2c_algo;
idev->adapter.dev.parent = &pdev->dev;
idev->adapter.dev.of_node = pdev->dev.of_node;
idev->adapter.timeout = HZ;
platform_set_drvdata(pdev, idev);
ret = i2c_add_adapter(&idev->adapter);
if (ret) {
clk_disable_unprepare(idev->i2c_clk);
return ret;
}
dev_info(&pdev->dev, "registered CoreI2C bus driver\n");
return 0;
}
static int mchp_corei2c_remove(struct platform_device *pdev)
{
struct mchp_corei2c_dev *idev = platform_get_drvdata(pdev);
clk_disable_unprepare(idev->i2c_clk);
i2c_del_adapter(&idev->adapter);
return 0;
}
static const struct of_device_id mchp_corei2c_of_match[] = {
{ .compatible = "microchip,mpfs-i2c" },
{ .compatible = "microchip,corei2c-rtl-v7" },
{},
};
MODULE_DEVICE_TABLE(of, mchp_corei2c_of_match);
static struct platform_driver mchp_corei2c_driver = {
.probe = mchp_corei2c_probe,
.remove = mchp_corei2c_remove,
.driver = {
.name = "microchip-corei2c",
.of_match_table = mchp_corei2c_of_match,
},
};
module_platform_driver(mchp_corei2c_driver);
MODULE_DESCRIPTION("Microchip CoreI2C bus driver");
MODULE_AUTHOR("Daire McNamara <daire.mcnamara@microchip.com>");
MODULE_AUTHOR("Conor Dooley <conor.dooley@microchip.com>");
MODULE_LICENSE("GPL");