1 /* SPDX-License-Identifier: GPL-2.0 */ 2 /* 3 * i2c Support for Atmel's AT91 Two-Wire Interface (TWI) 4 * 5 * Copyright (C) 2011 Weinmann Medical GmbH 6 * Author: Nikolaus Voss <n.voss@weinmann.de> 7 * 8 * Evolved from original work by: 9 * Copyright (C) 2004 Rick Bronson 10 * Converted to 2.6 by Andrew Victor <andrew@sanpeople.com> 11 * 12 * Borrowed heavily from original work by: 13 * Copyright (C) 2000 Philip Edelbrock <phil@stimpy.netroedge.com> 14 */ 15 16 #include <linux/clk.h> 17 #include <linux/completion.h> 18 #include <linux/dma-mapping.h> 19 #include <linux/dmaengine.h> 20 #include <linux/i2c.h> 21 #include <linux/platform_data/dma-atmel.h> 22 #include <linux/platform_device.h> 23 24 #define AT91_I2C_TIMEOUT msecs_to_jiffies(100) /* transfer timeout */ 25 #define AT91_I2C_DMA_THRESHOLD 8 /* enable DMA if transfer size is bigger than this threshold */ 26 #define AUTOSUSPEND_TIMEOUT 2000 27 #define AT91_I2C_MAX_ALT_CMD_DATA_SIZE 256 28 29 /* AT91 TWI register definitions */ 30 #define AT91_TWI_CR 0x0000 /* Control Register */ 31 #define AT91_TWI_START BIT(0) /* Send a Start Condition */ 32 #define AT91_TWI_STOP BIT(1) /* Send a Stop Condition */ 33 #define AT91_TWI_MSEN BIT(2) /* Master Transfer Enable */ 34 #define AT91_TWI_MSDIS BIT(3) /* Master Transfer Disable */ 35 #define AT91_TWI_SVEN BIT(4) /* Slave Transfer Enable */ 36 #define AT91_TWI_SVDIS BIT(5) /* Slave Transfer Disable */ 37 #define AT91_TWI_QUICK BIT(6) /* SMBus quick command */ 38 #define AT91_TWI_SWRST BIT(7) /* Software Reset */ 39 #define AT91_TWI_ACMEN BIT(16) /* Alternative Command Mode Enable */ 40 #define AT91_TWI_ACMDIS BIT(17) /* Alternative Command Mode Disable */ 41 #define AT91_TWI_THRCLR BIT(24) /* Transmit Holding Register Clear */ 42 #define AT91_TWI_RHRCLR BIT(25) /* Receive Holding Register Clear */ 43 #define AT91_TWI_LOCKCLR BIT(26) /* Lock Clear */ 44 #define AT91_TWI_FIFOEN BIT(28) /* FIFO Enable */ 45 #define AT91_TWI_FIFODIS BIT(29) /* FIFO Disable */ 46 47 #define AT91_TWI_MMR 0x0004 /* Master Mode Register */ 48 #define AT91_TWI_IADRSZ_1 0x0100 /* Internal Device Address Size */ 49 #define AT91_TWI_MREAD BIT(12) /* Master Read Direction */ 50 51 #define AT91_TWI_SMR 0x0008 /* Slave Mode Register */ 52 #define AT91_TWI_SMR_SADR_MAX 0x007f 53 #define AT91_TWI_SMR_SADR(x) (((x) & AT91_TWI_SMR_SADR_MAX) << 16) 54 55 #define AT91_TWI_IADR 0x000c /* Internal Address Register */ 56 57 #define AT91_TWI_CWGR 0x0010 /* Clock Waveform Generator Reg */ 58 #define AT91_TWI_CWGR_HOLD_MAX 0x1f 59 #define AT91_TWI_CWGR_HOLD(x) (((x) & AT91_TWI_CWGR_HOLD_MAX) << 24) 60 61 #define AT91_TWI_SR 0x0020 /* Status Register */ 62 #define AT91_TWI_TXCOMP BIT(0) /* Transmission Complete */ 63 #define AT91_TWI_RXRDY BIT(1) /* Receive Holding Register Ready */ 64 #define AT91_TWI_TXRDY BIT(2) /* Transmit Holding Register Ready */ 65 #define AT91_TWI_SVREAD BIT(3) /* Slave Read */ 66 #define AT91_TWI_SVACC BIT(4) /* Slave Access */ 67 #define AT91_TWI_OVRE BIT(6) /* Overrun Error */ 68 #define AT91_TWI_UNRE BIT(7) /* Underrun Error */ 69 #define AT91_TWI_NACK BIT(8) /* Not Acknowledged */ 70 #define AT91_TWI_EOSACC BIT(11) /* End Of Slave Access */ 71 #define AT91_TWI_LOCK BIT(23) /* TWI Lock due to Frame Errors */ 72 73 #define AT91_TWI_INT_MASK \ 74 (AT91_TWI_TXCOMP | AT91_TWI_RXRDY | AT91_TWI_TXRDY | AT91_TWI_NACK \ 75 | AT91_TWI_SVACC | AT91_TWI_EOSACC) 76 77 #define AT91_TWI_IER 0x0024 /* Interrupt Enable Register */ 78 #define AT91_TWI_IDR 0x0028 /* Interrupt Disable Register */ 79 #define AT91_TWI_IMR 0x002c /* Interrupt Mask Register */ 80 #define AT91_TWI_RHR 0x0030 /* Receive Holding Register */ 81 #define AT91_TWI_THR 0x0034 /* Transmit Holding Register */ 82 83 #define AT91_TWI_ACR 0x0040 /* Alternative Command Register */ 84 #define AT91_TWI_ACR_DATAL(len) ((len) & 0xff) 85 #define AT91_TWI_ACR_DIR BIT(8) 86 87 #define AT91_TWI_FMR 0x0050 /* FIFO Mode Register */ 88 #define AT91_TWI_FMR_TXRDYM(mode) (((mode) & 0x3) << 0) 89 #define AT91_TWI_FMR_TXRDYM_MASK (0x3 << 0) 90 #define AT91_TWI_FMR_RXRDYM(mode) (((mode) & 0x3) << 4) 91 #define AT91_TWI_FMR_RXRDYM_MASK (0x3 << 4) 92 #define AT91_TWI_ONE_DATA 0x0 93 #define AT91_TWI_TWO_DATA 0x1 94 #define AT91_TWI_FOUR_DATA 0x2 95 96 #define AT91_TWI_FLR 0x0054 /* FIFO Level Register */ 97 98 #define AT91_TWI_FSR 0x0060 /* FIFO Status Register */ 99 #define AT91_TWI_FIER 0x0064 /* FIFO Interrupt Enable Register */ 100 #define AT91_TWI_FIDR 0x0068 /* FIFO Interrupt Disable Register */ 101 #define AT91_TWI_FIMR 0x006c /* FIFO Interrupt Mask Register */ 102 103 #define AT91_TWI_VER 0x00fc /* Version Register */ 104 105 struct at91_twi_pdata { 106 unsigned clk_max_div; 107 unsigned clk_offset; 108 bool has_unre_flag; 109 bool has_alt_cmd; 110 bool has_hold_field; 111 struct at_dma_slave dma_slave; 112 }; 113 114 struct at91_twi_dma { 115 struct dma_chan *chan_rx; 116 struct dma_chan *chan_tx; 117 struct scatterlist sg[2]; 118 struct dma_async_tx_descriptor *data_desc; 119 enum dma_data_direction direction; 120 bool buf_mapped; 121 bool xfer_in_progress; 122 }; 123 124 struct at91_twi_dev { 125 struct device *dev; 126 void __iomem *base; 127 struct completion cmd_complete; 128 struct clk *clk; 129 u8 *buf; 130 size_t buf_len; 131 struct i2c_msg *msg; 132 int irq; 133 unsigned imr; 134 unsigned transfer_status; 135 struct i2c_adapter adapter; 136 unsigned twi_cwgr_reg; 137 struct at91_twi_pdata *pdata; 138 bool use_dma; 139 bool use_alt_cmd; 140 bool recv_len_abort; 141 u32 fifo_size; 142 struct at91_twi_dma dma; 143 bool slave_detected; 144 #ifdef CONFIG_I2C_AT91_SLAVE_EXPERIMENTAL 145 unsigned smr; 146 struct i2c_client *slave; 147 #endif 148 }; 149 150 unsigned at91_twi_read(struct at91_twi_dev *dev, unsigned reg); 151 void at91_twi_write(struct at91_twi_dev *dev, unsigned reg, unsigned val); 152 void at91_disable_twi_interrupts(struct at91_twi_dev *dev); 153 void at91_twi_irq_save(struct at91_twi_dev *dev); 154 void at91_twi_irq_restore(struct at91_twi_dev *dev); 155 void at91_init_twi_bus(struct at91_twi_dev *dev); 156 157 void at91_init_twi_bus_master(struct at91_twi_dev *dev); 158 int at91_twi_probe_master(struct platform_device *pdev, u32 phy_addr, 159 struct at91_twi_dev *dev); 160 161 #ifdef CONFIG_I2C_AT91_SLAVE_EXPERIMENTAL 162 void at91_init_twi_bus_slave(struct at91_twi_dev *dev); 163 int at91_twi_probe_slave(struct platform_device *pdev, u32 phy_addr, 164 struct at91_twi_dev *dev); 165 166 #else 167 static inline void at91_init_twi_bus_slave(struct at91_twi_dev *dev) {} 168 static inline int at91_twi_probe_slave(struct platform_device *pdev, 169 u32 phy_addr, struct at91_twi_dev *dev) 170 { 171 return -EINVAL; 172 } 173 174 #endif 175