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/*
* I2C bus driver for the Cadence I2C controller.
*
* Copyright (C) 2009 - 2014 Xilinx, Inc.
*
* This program is free software; you can redistribute it
* and/or modify it under the terms of the GNU General Public
* License as published by the Free Software Foundation;
* either version 2 of the License, or (at your option) any
* later version.
*/
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/i2c.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/of.h>
#include <linux/pm_runtime.h>
/* Register offsets for the I2C device. */
#define CDNS_I2C_CR_OFFSET 0x00 /* Control Register, RW */
#define CDNS_I2C_SR_OFFSET 0x04 /* Status Register, RO */
#define CDNS_I2C_ADDR_OFFSET 0x08 /* I2C Address Register, RW */
#define CDNS_I2C_DATA_OFFSET 0x0C /* I2C Data Register, RW */
#define CDNS_I2C_ISR_OFFSET 0x10 /* IRQ Status Register, RW */
#define CDNS_I2C_XFER_SIZE_OFFSET 0x14 /* Transfer Size Register, RW */
#define CDNS_I2C_TIME_OUT_OFFSET 0x1C /* Time Out Register, RW */
#define CDNS_I2C_IER_OFFSET 0x24 /* IRQ Enable Register, WO */
#define CDNS_I2C_IDR_OFFSET 0x28 /* IRQ Disable Register, WO */
/* Control Register Bit mask definitions */
#define CDNS_I2C_CR_HOLD BIT(4) /* Hold Bus bit */
#define CDNS_I2C_CR_ACK_EN BIT(3)
#define CDNS_I2C_CR_NEA BIT(2)
#define CDNS_I2C_CR_MS BIT(1)
/* Read or Write Master transfer 0 = Transmitter, 1 = Receiver */
#define CDNS_I2C_CR_RW BIT(0)
/* 1 = Auto init FIFO to zeroes */
#define CDNS_I2C_CR_CLR_FIFO BIT(6)
#define CDNS_I2C_CR_DIVA_SHIFT 14
#define CDNS_I2C_CR_DIVA_MASK (3 << CDNS_I2C_CR_DIVA_SHIFT)
#define CDNS_I2C_CR_DIVB_SHIFT 8
#define CDNS_I2C_CR_DIVB_MASK (0x3f << CDNS_I2C_CR_DIVB_SHIFT)
/* Status Register Bit mask definitions */
#define CDNS_I2C_SR_BA BIT(8)
#define CDNS_I2C_SR_RXDV BIT(5)
/*
* I2C Address Register Bit mask definitions
* Normal addressing mode uses [6:0] bits. Extended addressing mode uses [9:0]
* bits. A write access to this register always initiates a transfer if the I2C
* is in master mode.
*/
#define CDNS_I2C_ADDR_MASK 0x000003FF /* I2C Address Mask */
/*
* I2C Interrupt Registers Bit mask definitions
* All the four interrupt registers (Status/Mask/Enable/Disable) have the same
* bit definitions.
*/
#define CDNS_I2C_IXR_ARB_LOST BIT(9)
#define CDNS_I2C_IXR_RX_UNF BIT(7)
#define CDNS_I2C_IXR_TX_OVF BIT(6)
#define CDNS_I2C_IXR_RX_OVF BIT(5)
#define CDNS_I2C_IXR_SLV_RDY BIT(4)
#define CDNS_I2C_IXR_TO BIT(3)
#define CDNS_I2C_IXR_NACK BIT(2)
#define CDNS_I2C_IXR_DATA BIT(1)
#define CDNS_I2C_IXR_COMP BIT(0)
#define CDNS_I2C_IXR_ALL_INTR_MASK (CDNS_I2C_IXR_ARB_LOST | \
CDNS_I2C_IXR_RX_UNF | \
CDNS_I2C_IXR_TX_OVF | \
CDNS_I2C_IXR_RX_OVF | \
CDNS_I2C_IXR_SLV_RDY | \
CDNS_I2C_IXR_TO | \
CDNS_I2C_IXR_NACK | \
CDNS_I2C_IXR_DATA | \
CDNS_I2C_IXR_COMP)
#define CDNS_I2C_IXR_ERR_INTR_MASK (CDNS_I2C_IXR_ARB_LOST | \
CDNS_I2C_IXR_RX_UNF | \
CDNS_I2C_IXR_TX_OVF | \
CDNS_I2C_IXR_RX_OVF | \
CDNS_I2C_IXR_NACK)
#define CDNS_I2C_ENABLED_INTR_MASK (CDNS_I2C_IXR_ARB_LOST | \
CDNS_I2C_IXR_RX_UNF | \
CDNS_I2C_IXR_TX_OVF | \
CDNS_I2C_IXR_RX_OVF | \
CDNS_I2C_IXR_NACK | \
CDNS_I2C_IXR_DATA | \
CDNS_I2C_IXR_COMP)
#define CDNS_I2C_TIMEOUT msecs_to_jiffies(1000)
/* timeout for pm runtime autosuspend */
#define CNDS_I2C_PM_TIMEOUT 1000 /* ms */
#define CDNS_I2C_FIFO_DEPTH 16
/* FIFO depth at which the DATA interrupt occurs */
#define CDNS_I2C_DATA_INTR_DEPTH (CDNS_I2C_FIFO_DEPTH - 2)
#define CDNS_I2C_MAX_TRANSFER_SIZE 255
/* Transfer size in multiples of data interrupt depth */
#define CDNS_I2C_TRANSFER_SIZE (CDNS_I2C_MAX_TRANSFER_SIZE - 3)
#define DRIVER_NAME "cdns-i2c"
#define CDNS_I2C_SPEED_MAX 400000
#define CDNS_I2C_SPEED_DEFAULT 100000
#define CDNS_I2C_DIVA_MAX 4
#define CDNS_I2C_DIVB_MAX 64
#define CDNS_I2C_TIMEOUT_MAX 0xFF
#define CDNS_I2C_BROKEN_HOLD_BIT BIT(0)
#define cdns_i2c_readreg(offset) readl_relaxed(id->membase + offset)
#define cdns_i2c_writereg(val, offset) writel_relaxed(val, id->membase + offset)
/**
* struct cdns_i2c - I2C device private data structure
*
* @dev: Pointer to device structure
* @membase: Base address of the I2C device
* @adap: I2C adapter instance
* @p_msg: Message pointer
* @err_status: Error status in Interrupt Status Register
* @xfer_done: Transfer complete status
* @p_send_buf: Pointer to transmit buffer
* @p_recv_buf: Pointer to receive buffer
* @send_count: Number of bytes still expected to send
* @recv_count: Number of bytes still expected to receive
* @curr_recv_count: Number of bytes to be received in current transfer
* @irq: IRQ number
* @input_clk: Input clock to I2C controller
* @i2c_clk: Maximum I2C clock speed
* @bus_hold_flag: Flag used in repeated start for clearing HOLD bit
* @clk: Pointer to struct clk
* @clk_rate_change_nb: Notifier block for clock rate changes
* @quirks: flag for broken hold bit usage in r1p10
*/
struct cdns_i2c {
struct device *dev;
void __iomem *membase;
struct i2c_adapter adap;
struct i2c_msg *p_msg;
int err_status;
struct completion xfer_done;
unsigned char *p_send_buf;
unsigned char *p_recv_buf;
unsigned int send_count;
unsigned int recv_count;
unsigned int curr_recv_count;
int irq;
unsigned long input_clk;
unsigned int i2c_clk;
unsigned int bus_hold_flag;
struct clk *clk;
struct notifier_block clk_rate_change_nb;
u32 quirks;
};
struct cdns_platform_data {
u32 quirks;
};
#define to_cdns_i2c(_nb) container_of(_nb, struct cdns_i2c, \
clk_rate_change_nb)
/**
* cdns_i2c_clear_bus_hold - Clear bus hold bit
* @id: Pointer to driver data struct
*
* Helper to clear the controller's bus hold bit.
*/
static void cdns_i2c_clear_bus_hold(struct cdns_i2c *id)
{
u32 reg = cdns_i2c_readreg(CDNS_I2C_CR_OFFSET);
if (reg & CDNS_I2C_CR_HOLD)
cdns_i2c_writereg(reg & ~CDNS_I2C_CR_HOLD, CDNS_I2C_CR_OFFSET);
}
static inline bool cdns_is_holdquirk(struct cdns_i2c *id, bool hold_wrkaround)
{
return (hold_wrkaround &&
(id->curr_recv_count == CDNS_I2C_FIFO_DEPTH + 1));
}
/**
* cdns_i2c_isr - Interrupt handler for the I2C device
* @irq: irq number for the I2C device
* @ptr: void pointer to cdns_i2c structure
*
* This function handles the data interrupt, transfer complete interrupt and
* the error interrupts of the I2C device.
*
* Return: IRQ_HANDLED always
*/
static irqreturn_t cdns_i2c_isr(int irq, void *ptr)
{
unsigned int isr_status, avail_bytes, updatetx;
unsigned int bytes_to_send;
bool hold_quirk;
struct cdns_i2c *id = ptr;
/* Signal completion only after everything is updated */
int done_flag = 0;
irqreturn_t status = IRQ_NONE;
isr_status = cdns_i2c_readreg(CDNS_I2C_ISR_OFFSET);
cdns_i2c_writereg(isr_status, CDNS_I2C_ISR_OFFSET);
/* Handling nack and arbitration lost interrupt */
if (isr_status & (CDNS_I2C_IXR_NACK | CDNS_I2C_IXR_ARB_LOST)) {
done_flag = 1;
status = IRQ_HANDLED;
}
/*
* Check if transfer size register needs to be updated again for a
* large data receive operation.
*/
updatetx = 0;
if (id->recv_count > id->curr_recv_count)
updatetx = 1;
hold_quirk = (id->quirks & CDNS_I2C_BROKEN_HOLD_BIT) && updatetx;
/* When receiving, handle data interrupt and completion interrupt */
if (id->p_recv_buf &&
((isr_status & CDNS_I2C_IXR_COMP) ||
(isr_status <
|