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_device.h>
22
23#define AT91_I2C_TIMEOUT msecs_to_jiffies(100) /* transfer timeout */
24#define AT91_I2C_DMA_THRESHOLD 8 /* enable DMA if transfer size is bigger than this threshold */
25#define AUTOSUSPEND_TIMEOUT 2000
26#define AT91_I2C_MAX_ALT_CMD_DATA_SIZE 256
27
28/* AT91 TWI register definitions */
29#define AT91_TWI_CR 0x0000 /* Control Register */
30#define AT91_TWI_START BIT(0) /* Send a Start Condition */
31#define AT91_TWI_STOP BIT(1) /* Send a Stop Condition */
32#define AT91_TWI_MSEN BIT(2) /* Master Transfer Enable */
33#define AT91_TWI_MSDIS BIT(3) /* Master Transfer Disable */
34#define AT91_TWI_SVEN BIT(4) /* Slave Transfer Enable */
35#define AT91_TWI_SVDIS BIT(5) /* Slave Transfer Disable */
36#define AT91_TWI_QUICK BIT(6) /* SMBus quick command */
37#define AT91_TWI_SWRST BIT(7) /* Software Reset */
38#define AT91_TWI_CLEAR BIT(15) /* Bus clear command */
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#define AT91_TWI_SCL BIT(24) /* TWI SCL status */
73#define AT91_TWI_SDA BIT(25) /* TWI SDA status */
74
75#define AT91_TWI_INT_MASK \
76 (AT91_TWI_TXCOMP | AT91_TWI_RXRDY | AT91_TWI_TXRDY | AT91_TWI_NACK \
77 | AT91_TWI_SVACC | AT91_TWI_EOSACC)
78
79#define AT91_TWI_IER 0x0024 /* Interrupt Enable Register */
80#define AT91_TWI_IDR 0x0028 /* Interrupt Disable Register */
81#define AT91_TWI_IMR 0x002c /* Interrupt Mask Register */
82#define AT91_TWI_RHR 0x0030 /* Receive Holding Register */
83#define AT91_TWI_THR 0x0034 /* Transmit Holding Register */
84
85#define AT91_TWI_ACR 0x0040 /* Alternative Command Register */
86#define AT91_TWI_ACR_DATAL_MASK GENMASK(15, 0)
87#define AT91_TWI_ACR_DATAL(len) ((len) & AT91_TWI_ACR_DATAL_MASK)
88#define AT91_TWI_ACR_DIR BIT(8)
89
90#define AT91_TWI_FILTR 0x0044
91#define AT91_TWI_FILTR_FILT BIT(0)
92#define AT91_TWI_FILTR_PADFEN BIT(1)
93#define AT91_TWI_FILTR_THRES(v) ((v) << 8)
94#define AT91_TWI_FILTR_THRES_MAX 7
95#define AT91_TWI_FILTR_THRES_MASK GENMASK(10, 8)
96
97#define AT91_TWI_FMR 0x0050 /* FIFO Mode Register */
98#define AT91_TWI_FMR_TXRDYM(mode) (((mode) & 0x3) << 0)
99#define AT91_TWI_FMR_TXRDYM_MASK (0x3 << 0)
100#define AT91_TWI_FMR_RXRDYM(mode) (((mode) & 0x3) << 4)
101#define AT91_TWI_FMR_RXRDYM_MASK (0x3 << 4)
102#define AT91_TWI_ONE_DATA 0x0
103#define AT91_TWI_TWO_DATA 0x1
104#define AT91_TWI_FOUR_DATA 0x2
105
106#define AT91_TWI_FLR 0x0054 /* FIFO Level Register */
107
108#define AT91_TWI_FSR 0x0060 /* FIFO Status Register */
109#define AT91_TWI_FIER 0x0064 /* FIFO Interrupt Enable Register */
110#define AT91_TWI_FIDR 0x0068 /* FIFO Interrupt Disable Register */
111#define AT91_TWI_FIMR 0x006c /* FIFO Interrupt Mask Register */
112
113#define AT91_TWI_VER 0x00fc /* Version Register */
114
115struct at91_twi_pdata {
116 unsigned clk_max_div;
117 unsigned clk_offset;
118 bool has_unre_flag;
119 bool has_alt_cmd;
120 bool has_hold_field;
121 bool has_dig_filtr;
122 bool has_adv_dig_filtr;
123 bool has_ana_filtr;
124 bool has_clear_cmd;
125};
126
127struct at91_twi_dma {
128 struct dma_chan *chan_rx;
129 struct dma_chan *chan_tx;
130 struct scatterlist sg[2];
131 struct dma_async_tx_descriptor *data_desc;
132 enum dma_data_direction direction;
133 bool buf_mapped;
134 bool xfer_in_progress;
135};
136
137struct at91_twi_dev {
138 struct device *dev;
139 void __iomem *base;
140 struct completion cmd_complete;
141 struct clk *clk;
142 u8 *buf;
143 size_t buf_len;
144 struct i2c_msg *msg;
145 int irq;
146 unsigned imr;
147 unsigned transfer_status;
148 struct i2c_adapter adapter;
149 unsigned twi_cwgr_reg;
150 struct at91_twi_pdata *pdata;
151 bool use_dma;
152 bool use_alt_cmd;
153 bool recv_len_abort;
154 u32 fifo_size;
155 struct at91_twi_dma dma;
156 bool slave_detected;
157 struct i2c_bus_recovery_info rinfo;
158#ifdef CONFIG_I2C_AT91_SLAVE_EXPERIMENTAL
159 unsigned smr;
160 struct i2c_client *slave;
161#endif
162 bool enable_dig_filt;
163 bool enable_ana_filt;
164 u32 filter_width;
165};
166
167unsigned at91_twi_read(struct at91_twi_dev *dev, unsigned reg);
168void at91_twi_write(struct at91_twi_dev *dev, unsigned reg, unsigned val);
169void at91_disable_twi_interrupts(struct at91_twi_dev *dev);
170void at91_twi_irq_save(struct at91_twi_dev *dev);
171void at91_twi_irq_restore(struct at91_twi_dev *dev);
172void at91_init_twi_bus(struct at91_twi_dev *dev);
173
174void at91_init_twi_bus_master(struct at91_twi_dev *dev);
175int at91_twi_probe_master(struct platform_device *pdev, u32 phy_addr,
176 struct at91_twi_dev *dev);
177
178#ifdef CONFIG_I2C_AT91_SLAVE_EXPERIMENTAL
179void at91_init_twi_bus_slave(struct at91_twi_dev *dev);
180int at91_twi_probe_slave(struct platform_device *pdev, u32 phy_addr,
181 struct at91_twi_dev *dev);
182
183#else
184static inline void at91_init_twi_bus_slave(struct at91_twi_dev *dev) {}
185static inline int at91_twi_probe_slave(struct platform_device *pdev,
186 u32 phy_addr, struct at91_twi_dev *dev)
187{
188 return -EINVAL;
189}
190
191#endif
192

source code of linux/drivers/i2c/busses/i2c-at91.h