/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* i2c Support for Atmel's AT91 Two-Wire Interface (TWI)
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*
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* Copyright (C) 2011 Weinmann Medical GmbH
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* Author: Nikolaus Voss <n.voss@weinmann.de>
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*
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* Evolved from original work by:
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* Copyright (C) 2004 Rick Bronson
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* Converted to 2.6 by Andrew Victor <andrew@sanpeople.com>
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*
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* Borrowed heavily from original work by:
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* Copyright (C) 2000 Philip Edelbrock <phil@stimpy.netroedge.com>
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*/
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#include <linux/clk.h>
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#include <linux/completion.h>
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#include <linux/dma-mapping.h>
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#include <linux/dmaengine.h>
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#include <linux/i2c.h>
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#include <linux/platform_data/dma-atmel.h>
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#include <linux/platform_device.h>
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#define AT91_I2C_TIMEOUT msecs_to_jiffies(100) /* transfer timeout */
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#define AT91_I2C_DMA_THRESHOLD 8 /* enable DMA if transfer size is bigger than this threshold */
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#define AUTOSUSPEND_TIMEOUT 2000
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#define AT91_I2C_MAX_ALT_CMD_DATA_SIZE 256
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/* AT91 TWI register definitions */
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#define AT91_TWI_CR 0x0000 /* Control Register */
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#define AT91_TWI_START BIT(0) /* Send a Start Condition */
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#define AT91_TWI_STOP BIT(1) /* Send a Stop Condition */
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#define AT91_TWI_MSEN BIT(2) /* Master Transfer Enable */
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#define AT91_TWI_MSDIS BIT(3) /* Master Transfer Disable */
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#define AT91_TWI_SVEN BIT(4) /* Slave Transfer Enable */
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#define AT91_TWI_SVDIS BIT(5) /* Slave Transfer Disable */
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#define AT91_TWI_QUICK BIT(6) /* SMBus quick command */
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#define AT91_TWI_SWRST BIT(7) /* Software Reset */
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#define AT91_TWI_CLEAR BIT(15) /* Bus clear command */
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#define AT91_TWI_ACMEN BIT(16) /* Alternative Command Mode Enable */
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#define AT91_TWI_ACMDIS BIT(17) /* Alternative Command Mode Disable */
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#define AT91_TWI_THRCLR BIT(24) /* Transmit Holding Register Clear */
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#define AT91_TWI_RHRCLR BIT(25) /* Receive Holding Register Clear */
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#define AT91_TWI_LOCKCLR BIT(26) /* Lock Clear */
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#define AT91_TWI_FIFOEN BIT(28) /* FIFO Enable */
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#define AT91_TWI_FIFODIS BIT(29) /* FIFO Disable */
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#define AT91_TWI_MMR 0x0004 /* Master Mode Register */
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#define AT91_TWI_IADRSZ_1 0x0100 /* Internal Device Address Size */
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#define AT91_TWI_MREAD BIT(12) /* Master Read Direction */
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#define AT91_TWI_SMR 0x0008 /* Slave Mode Register */
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#define AT91_TWI_SMR_SADR_MAX 0x007f
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#define AT91_TWI_SMR_SADR(x) (((x) & AT91_TWI_SMR_SADR_MAX) << 16)
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#define AT91_TWI_IADR 0x000c /* Internal Address Register */
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#define AT91_TWI_CWGR 0x0010 /* Clock Waveform Generator Reg */
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#define AT91_TWI_CWGR_HOLD_MAX 0x1f
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#define AT91_TWI_CWGR_HOLD(x) (((x) & AT91_TWI_CWGR_HOLD_MAX) << 24)
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#define AT91_TWI_SR 0x0020 /* Status Register */
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#define AT91_TWI_TXCOMP BIT(0) /* Transmission Complete */
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#define AT91_TWI_RXRDY BIT(1) /* Receive Holding Register Ready */
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#define AT91_TWI_TXRDY BIT(2) /* Transmit Holding Register Ready */
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#define AT91_TWI_SVREAD BIT(3) /* Slave Read */
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#define AT91_TWI_SVACC BIT(4) /* Slave Access */
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#define AT91_TWI_OVRE BIT(6) /* Overrun Error */
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#define AT91_TWI_UNRE BIT(7) /* Underrun Error */
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#define AT91_TWI_NACK BIT(8) /* Not Acknowledged */
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#define AT91_TWI_EOSACC BIT(11) /* End Of Slave Access */
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#define AT91_TWI_LOCK BIT(23) /* TWI Lock due to Frame Errors */
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#define AT91_TWI_SCL BIT(24) /* TWI SCL status */
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#define AT91_TWI_SDA BIT(25) /* TWI SDA status */
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#define AT91_TWI_INT_MASK \
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(AT91_TWI_TXCOMP | AT91_TWI_RXRDY | AT91_TWI_TXRDY | AT91_TWI_NACK \
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| AT91_TWI_SVACC | AT91_TWI_EOSACC)
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#define AT91_TWI_IER 0x0024 /* Interrupt Enable Register */
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#define AT91_TWI_IDR 0x0028 /* Interrupt Disable Register */
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#define AT91_TWI_IMR 0x002c /* Interrupt Mask Register */
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#define AT91_TWI_RHR 0x0030 /* Receive Holding Register */
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#define AT91_TWI_THR 0x0034 /* Transmit Holding Register */
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#define AT91_TWI_ACR 0x0040 /* Alternative Command Register */
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#define AT91_TWI_ACR_DATAL_MASK GENMASK(15, 0)
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#define AT91_TWI_ACR_DATAL(len) ((len) & AT91_TWI_ACR_DATAL_MASK)
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#define AT91_TWI_ACR_DIR BIT(8)
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#define AT91_TWI_FILTR 0x0044
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#define AT91_TWI_FILTR_FILT BIT(0)
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#define AT91_TWI_FILTR_PADFEN BIT(1)
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#define AT91_TWI_FILTR_THRES(v) ((v) << 8)
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#define AT91_TWI_FILTR_THRES_MAX 7
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#define AT91_TWI_FILTR_THRES_MASK GENMASK(10, 8)
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#define AT91_TWI_FMR 0x0050 /* FIFO Mode Register */
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#define AT91_TWI_FMR_TXRDYM(mode) (((mode) & 0x3) << 0)
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#define AT91_TWI_FMR_TXRDYM_MASK (0x3 << 0)
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#define AT91_TWI_FMR_RXRDYM(mode) (((mode) & 0x3) << 4)
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#define AT91_TWI_FMR_RXRDYM_MASK (0x3 << 4)
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#define AT91_TWI_ONE_DATA 0x0
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#define AT91_TWI_TWO_DATA 0x1
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#define AT91_TWI_FOUR_DATA 0x2
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#define AT91_TWI_FLR 0x0054 /* FIFO Level Register */
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#define AT91_TWI_FSR 0x0060 /* FIFO Status Register */
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#define AT91_TWI_FIER 0x0064 /* FIFO Interrupt Enable Register */
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#define AT91_TWI_FIDR 0x0068 /* FIFO Interrupt Disable Register */
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#define AT91_TWI_FIMR 0x006c /* FIFO Interrupt Mask Register */
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#define AT91_TWI_VER 0x00fc /* Version Register */
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struct at91_twi_pdata {
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unsigned clk_max_div;
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unsigned clk_offset;
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bool has_unre_flag;
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bool has_alt_cmd;
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bool has_hold_field;
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bool has_dig_filtr;
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bool has_adv_dig_filtr;
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bool has_ana_filtr;
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bool has_clear_cmd;
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struct at_dma_slave dma_slave;
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};
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struct at91_twi_dma {
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struct dma_chan *chan_rx;
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struct dma_chan *chan_tx;
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struct scatterlist sg[2];
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struct dma_async_tx_descriptor *data_desc;
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enum dma_data_direction direction;
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bool buf_mapped;
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bool xfer_in_progress;
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};
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struct at91_twi_dev {
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struct device *dev;
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void __iomem *base;
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struct completion cmd_complete;
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struct clk *clk;
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u8 *buf;
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size_t buf_len;
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struct i2c_msg *msg;
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int irq;
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unsigned imr;
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unsigned transfer_status;
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struct i2c_adapter adapter;
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unsigned twi_cwgr_reg;
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struct at91_twi_pdata *pdata;
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bool use_dma;
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bool use_alt_cmd;
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bool recv_len_abort;
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u32 fifo_size;
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struct at91_twi_dma dma;
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bool slave_detected;
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struct i2c_bus_recovery_info rinfo;
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#ifdef CONFIG_I2C_AT91_SLAVE_EXPERIMENTAL
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unsigned smr;
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struct i2c_client *slave;
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#endif
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bool enable_dig_filt;
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bool enable_ana_filt;
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u32 filter_width;
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};
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unsigned at91_twi_read(struct at91_twi_dev *dev, unsigned reg);
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void at91_twi_write(struct at91_twi_dev *dev, unsigned reg, unsigned val);
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void at91_disable_twi_interrupts(struct at91_twi_dev *dev);
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void at91_twi_irq_save(struct at91_twi_dev *dev);
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void at91_twi_irq_restore(struct at91_twi_dev *dev);
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void at91_init_twi_bus(struct at91_twi_dev *dev);
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void at91_init_twi_bus_master(struct at91_twi_dev *dev);
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int at91_twi_probe_master(struct platform_device *pdev, u32 phy_addr,
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struct at91_twi_dev *dev);
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#ifdef CONFIG_I2C_AT91_SLAVE_EXPERIMENTAL
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void at91_init_twi_bus_slave(struct at91_twi_dev *dev);
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int at91_twi_probe_slave(struct platform_device *pdev, u32 phy_addr,
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struct at91_twi_dev *dev);
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#else
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static inline void at91_init_twi_bus_slave(struct at91_twi_dev *dev) {}
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static inline int at91_twi_probe_slave(struct platform_device *pdev,
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u32 phy_addr, struct at91_twi_dev *dev)
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{
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return -EINVAL;
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}
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#endif
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