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/* SPDX-License-Identifier: GPL-2.0 */
/*
* i2c Support for Atmel's AT91 Two-Wire Interface (TWI)
*
* Copyright (C) 2011 Weinmann Medical GmbH
* Author: Nikolaus Voss <n.voss@weinmann.de>
*
* Evolved from original work by:
* Copyright (C) 2004 Rick Bronson
* Converted to 2.6 by Andrew Victor <andrew@sanpeople.com>
*
* Borrowed heavily from original work by:
* Copyright (C) 2000 Philip Edelbrock <phil@stimpy.netroedge.com>
*/
#include <linux/clk.h>
#include <linux/completion.h>
#include <linux/dma-mapping.h>
#include <linux/dmaengine.h>
#include <linux/i2c.h>
#include <linux/platform_data/dma-atmel.h>
#include <linux/platform_device.h>
#define DEFAULT_TWI_CLK_HZ 100000 /* max 400 Kbits/s */
#define AT91_I2C_TIMEOUT msecs_to_jiffies(100) /* transfer timeout */
#define AT91_I2C_DMA_THRESHOLD 8 /* enable DMA if transfer size is bigger than this threshold */
#define AUTOSUSPEND_TIMEOUT 2000
#define AT91_I2C_MAX_ALT_CMD_DATA_SIZE 256
/* AT91 TWI register definitions */
#define AT91_TWI_CR 0x0000 /* Control Register */
#define AT91_TWI_START BIT(0) /* Send a Start Condition */
#define AT91_TWI_STOP BIT(1) /* Send a Stop Condition */
#define AT91_TWI_MSEN BIT(2) /* Master Transfer Enable */
#define AT91_TWI_MSDIS BIT(3) /* Master Transfer Disable */
#define AT91_TWI_SVEN BIT(4) /* Slave Transfer Enable */
#define AT91_TWI_SVDIS BIT(5) /* Slave Transfer Disable */
#define AT91_TWI_QUICK BIT(6) /* SMBus quick command */
#define AT91_TWI_SWRST BIT(7) /* Software Reset */
#define AT91_TWI_ACMEN BIT(16) /* Alternative Command Mode Enable */
#define AT91_TWI_ACMDIS BIT(17) /* Alternative Command Mode Disable */
#define AT91_TWI_THRCLR BIT(24) /* Transmit Holding Register Clear */
#define AT91_TWI_RHRCLR BIT(25) /* Receive Holding Register Clear */
#define AT91_TWI_LOCKCLR BIT(26) /* Lock Clear */
#define AT91_TWI_FIFOEN BIT(28) /* FIFO Enable */
#define AT91_TWI_FIFODIS BIT(29) /* FIFO Disable */
#define AT91_TWI_MMR 0x0004 /* Master Mode Register */
#define AT91_TWI_IADRSZ_1 0x0100 /* Internal Device Address Size */
#define AT91_TWI_MREAD BIT(12) /* Master Read Direction */
#define AT91_TWI_SMR 0x0008 /* Slave Mode Register */
#define AT91_TWI_SMR_SADR_MAX 0x007f
#define AT91_TWI_SMR_SADR(x) (((x) & AT91_TWI_SMR_SADR_MAX) << 16)
#define AT91_TWI_IADR 0x000c /* Internal Address Register */
#define AT91_TWI_CWGR 0x0010 /* Clock Waveform Generator Reg */
#define AT91_TWI_CWGR_HOLD_MAX 0x1f
#define AT91_TWI_CWGR_HOLD(x) (((x) & AT91_TWI_CWGR_HOLD_MAX) << 24)
#define AT91_TWI_SR 0x0020 /* Status Register */
#define AT91_TWI_TXCOMP BIT(0) /* Transmission Complete */
#define AT91_TWI_RXRDY BIT(1) /* Receive Holding Register Ready */
#define AT91_TWI_TXRDY BIT(2) /* Transmit Holding Register Ready */
#define AT91_TWI_SVREAD BIT(3) /* Slave Read */
#define AT91_TWI_SVACC BIT(4) /* Slave Access */
#define AT91_TWI_OVRE BIT(6) /* Overrun Error */
#define AT91_TWI_UNRE BIT(7) /* Underrun Error */
#define AT91_TWI_NACK BIT(8) /* Not Acknowledged */
#define AT91_TWI_EOSACC BIT(11) /* End Of Slave Access */
#define AT91_TWI_LOCK BIT(23) /* TWI Lock due to Frame Errors */
#define AT91_TWI_INT_MASK \
(AT91_TWI_TXCOMP | AT91_TWI_RXRDY | AT91_TWI_TXRDY | AT91_TWI_NACK \
| AT91_TWI_SVACC | AT91_TWI_EOSACC)
#define AT91_TWI_IER 0x0024 /* Interrupt Enable Register */
#define AT91_TWI_IDR 0x0028 /* Interrupt Disable Register */
#define AT91_TWI_IMR 0x002c /* Interrupt Mask Register */
#define AT91_TWI_RHR 0x0030 /* Receive Holding Register */
#define AT91_TWI_THR 0x0034 /* Transmit Holding Register */
#define AT91_TWI_ACR 0x0040 /* Alternative Command Register */
#define AT91_TWI_ACR_DATAL(len) ((len) & 0xff)
#define AT91_TWI_ACR_DIR BIT(8)
#define AT91_TWI_FMR 0x0050 /* FIFO Mode Register */
#define AT91_TWI_FMR_TXRDYM(mode) (((mode) & 0x3) << 0)
#define AT91_TWI_FMR_TXRDYM_MASK (0x3 << 0)
#define AT91_TWI_FMR_RXRDYM(mode) (((mode) & 0x3) << 4)
#define AT91_TWI_FMR_RXRDYM_MASK (0x3 << 4)
#define AT91_TWI_ONE_DATA 0x0
#define AT91_TWI_TWO_DATA 0x1
#define AT91_TWI_FOUR_DATA 0x2
#define AT91_TWI_FLR 0x0054 /* FIFO Level Register */
#define AT91_TWI_FSR 0x0060 /* FIFO Status Register */
#define AT91_TWI_FIER 0x0064 /* FIFO Interrupt Enable Register */
#define AT91_TWI_FIDR 0x0068 /* FIFO Interrupt Disable Register */
#define AT91_TWI_FIMR 0x006c /* FIFO Interrupt Mask Register */
#define AT91_TWI_VER 0x00fc /* Version Register */
struct at91_twi_pdata {
unsigned clk_max_div;
unsigned clk_offset;
bool has_unre_flag;
bool has_alt_cmd;
bool has_hold_field;
struct at_dma_slave dma_slave;
};
struct at91_twi_dma {
struct dma_chan *chan_rx;
struct dma_chan *chan_tx;
struct scatterlist sg[2];
struct dma_async_tx_descriptor *data_desc;
enum dma_data_direction direction;
bool buf_mapped;
bool xfer_in_progress;
};
struct at91_twi_dev {
struct device *dev;
void __iomem *base;
struct completion cmd_complete;
struct clk *clk;
u8 *buf;
size_t buf_len;
struct i2c_msg *msg;
int irq;
unsigned imr;
unsigned transfer_status;
struct i2c_adapter adapter;
unsigned twi_cwgr_reg;
struct at91_twi_pdata *pdata;
bool use_dma;
bool use_alt_cmd;
bool recv_len_abort;
u32 fifo_size;
struct at91_twi_dma dma;
bool slave_detected;
#ifdef CONFIG_I2C_AT91_SLAVE_EXPERIMENTAL
unsigned smr;
struct i2c_client *slave;
#endif
};
unsigned at91_twi_read(struct at91_twi_dev *dev, unsigned reg);
void at91_twi_write(struct at91_twi_dev *dev, unsigned reg, unsigned val);
void at91_disable_twi_interrupts(struct at91_twi_dev *dev);
void at91_twi_irq_save(struct at91_twi_dev *dev);
void at91_twi_irq_restore(struct at91_twi_dev *dev);
void at91_init_twi_bus(struct at91_twi_dev *dev);
void at91_init_twi_bus_master(struct at91_twi_dev *dev);
int at91_twi_probe_master(struct platform_device *pdev, u32 phy_addr,
struct at91_twi_dev *dev);
#ifdef CONFIG_I2C_AT91_SLAVE_EXPERIMENTAL
void at91_init_twi_bus_slave(struct at91_twi_dev *dev);
int at91_twi_probe_slave(struct platform_device *pdev, u32 phy_addr,
struct at91_twi_dev *dev);
#else
static inline void at91_init_twi_bus_slave(struct at91_twi_dev *dev) {}
static inline int at91_twi_probe_slave(struct platform_device *pdev,
u32 phy_addr, struct at91_twi_dev *dev)
{
return -EINVAL;
}
#endif
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