1 /* SPDX-License-Identifier: GPL-2.0 */
2 #include <linux/atomic.h>
3 #include <linux/clk.h>
4 #include <linux/delay.h>
5 #include <linux/device.h>
6 #include <linux/i2c.h>
7 #include <linux/i2c-smbus.h>
8 #include <linux/io.h>
9 #include <linux/kernel.h>
10 
11 /* Controller command patterns */
12 #define SW_TWSI_V		BIT_ULL(63)	/* Valid bit */
13 #define SW_TWSI_EIA		BIT_ULL(61)	/* Extended internal address */
14 #define SW_TWSI_R		BIT_ULL(56)	/* Result or read bit */
15 #define SW_TWSI_SOVR		BIT_ULL(55)	/* Size override */
16 #define SW_TWSI_SIZE_SHIFT	52
17 #define SW_TWSI_ADDR_SHIFT	40
18 #define SW_TWSI_IA_SHIFT	32		/* Internal address */
19 
20 /* Controller opcode word (bits 60:57) */
21 #define SW_TWSI_OP_SHIFT	57
22 #define SW_TWSI_OP_7		(0ULL << SW_TWSI_OP_SHIFT)
23 #define SW_TWSI_OP_7_IA		(1ULL << SW_TWSI_OP_SHIFT)
24 #define SW_TWSI_OP_10		(2ULL << SW_TWSI_OP_SHIFT)
25 #define SW_TWSI_OP_10_IA	(3ULL << SW_TWSI_OP_SHIFT)
26 #define SW_TWSI_OP_TWSI_CLK	(4ULL << SW_TWSI_OP_SHIFT)
27 #define SW_TWSI_OP_EOP		(6ULL << SW_TWSI_OP_SHIFT) /* Extended opcode */
28 
29 /* Controller extended opcode word (bits 34:32) */
30 #define SW_TWSI_EOP_SHIFT	32
31 #define SW_TWSI_EOP_TWSI_DATA	(SW_TWSI_OP_EOP | 1ULL << SW_TWSI_EOP_SHIFT)
32 #define SW_TWSI_EOP_TWSI_CTL	(SW_TWSI_OP_EOP | 2ULL << SW_TWSI_EOP_SHIFT)
33 #define SW_TWSI_EOP_TWSI_CLKCTL	(SW_TWSI_OP_EOP | 3ULL << SW_TWSI_EOP_SHIFT)
34 #define SW_TWSI_EOP_TWSI_STAT	(SW_TWSI_OP_EOP | 3ULL << SW_TWSI_EOP_SHIFT)
35 #define SW_TWSI_EOP_TWSI_RST	(SW_TWSI_OP_EOP | 7ULL << SW_TWSI_EOP_SHIFT)
36 
37 /* Controller command and status bits */
38 #define TWSI_CTL_CE		0x80	/* High level controller enable */
39 #define TWSI_CTL_ENAB		0x40	/* Bus enable */
40 #define TWSI_CTL_STA		0x20	/* Master-mode start, HW clears when done */
41 #define TWSI_CTL_STP		0x10	/* Master-mode stop, HW clears when done */
42 #define TWSI_CTL_IFLG		0x08	/* HW event, SW writes 0 to ACK */
43 #define TWSI_CTL_AAK		0x04	/* Assert ACK */
44 
45 /* Status values */
46 #define STAT_BUS_ERROR		0x00
47 #define STAT_START		0x08
48 #define STAT_REP_START		0x10
49 #define STAT_TXADDR_ACK		0x18
50 #define STAT_TXADDR_NAK		0x20
51 #define STAT_TXDATA_ACK		0x28
52 #define STAT_TXDATA_NAK		0x30
53 #define STAT_LOST_ARB_38	0x38
54 #define STAT_RXADDR_ACK		0x40
55 #define STAT_RXADDR_NAK		0x48
56 #define STAT_RXDATA_ACK		0x50
57 #define STAT_RXDATA_NAK		0x58
58 #define STAT_SLAVE_60		0x60
59 #define STAT_LOST_ARB_68	0x68
60 #define STAT_SLAVE_70		0x70
61 #define STAT_LOST_ARB_78	0x78
62 #define STAT_SLAVE_80		0x80
63 #define STAT_SLAVE_88		0x88
64 #define STAT_GENDATA_ACK	0x90
65 #define STAT_GENDATA_NAK	0x98
66 #define STAT_SLAVE_A0		0xA0
67 #define STAT_SLAVE_A8		0xA8
68 #define STAT_LOST_ARB_B0	0xB0
69 #define STAT_SLAVE_LOST		0xB8
70 #define STAT_SLAVE_NAK		0xC0
71 #define STAT_SLAVE_ACK		0xC8
72 #define STAT_AD2W_ACK		0xD0
73 #define STAT_AD2W_NAK		0xD8
74 #define STAT_IDLE		0xF8
75 
76 /* TWSI_INT values */
77 #define TWSI_INT_ST_INT		BIT_ULL(0)
78 #define TWSI_INT_TS_INT		BIT_ULL(1)
79 #define TWSI_INT_CORE_INT	BIT_ULL(2)
80 #define TWSI_INT_ST_EN		BIT_ULL(4)
81 #define TWSI_INT_TS_EN		BIT_ULL(5)
82 #define TWSI_INT_CORE_EN	BIT_ULL(6)
83 #define TWSI_INT_SDA_OVR	BIT_ULL(8)
84 #define TWSI_INT_SCL_OVR	BIT_ULL(9)
85 #define TWSI_INT_SDA		BIT_ULL(10)
86 #define TWSI_INT_SCL		BIT_ULL(11)
87 
88 #define I2C_OCTEON_EVENT_WAIT 80 /* microseconds */
89 
90 /* Register offsets */
91 struct octeon_i2c_reg_offset {
92 	unsigned int sw_twsi;
93 	unsigned int twsi_int;
94 	unsigned int sw_twsi_ext;
95 };
96 
97 #define SW_TWSI(x)	(x->roff.sw_twsi)
98 #define TWSI_INT(x)	(x->roff.twsi_int)
99 #define SW_TWSI_EXT(x)	(x->roff.sw_twsi_ext)
100 
101 struct octeon_i2c {
102 	wait_queue_head_t queue;
103 	struct i2c_adapter adap;
104 	struct octeon_i2c_reg_offset roff;
105 	struct clk *clk;
106 	int irq;
107 	int hlc_irq;		/* For cn7890 only */
108 	u32 twsi_freq;
109 	int sys_freq;
110 	void __iomem *twsi_base;
111 	struct device *dev;
112 	bool hlc_enabled;
113 	bool broken_irq_mode;
114 	bool broken_irq_check;
115 	void (*int_enable)(struct octeon_i2c *);
116 	void (*int_disable)(struct octeon_i2c *);
117 	void (*hlc_int_enable)(struct octeon_i2c *);
118 	void (*hlc_int_disable)(struct octeon_i2c *);
119 	atomic_t int_enable_cnt;
120 	atomic_t hlc_int_enable_cnt;
121 	struct i2c_smbus_alert_setup alert_data;
122 	struct i2c_client *ara;
123 };
124 
125 static inline void octeon_i2c_writeq_flush(u64 val, void __iomem *addr)
126 {
127 	__raw_writeq(val, addr);
128 	__raw_readq(addr);	/* wait for write to land */
129 }
130 
131 /**
132  * octeon_i2c_reg_write - write an I2C core register
133  * @i2c: The struct octeon_i2c
134  * @eop_reg: Register selector
135  * @data: Value to be written
136  *
137  * The I2C core registers are accessed indirectly via the SW_TWSI CSR.
138  */
139 static inline void octeon_i2c_reg_write(struct octeon_i2c *i2c, u64 eop_reg, u8 data)
140 {
141 	int tries = 1000;
142 	u64 tmp;
143 
144 	__raw_writeq(SW_TWSI_V | eop_reg | data, i2c->twsi_base + SW_TWSI(i2c));
145 	do {
146 		tmp = __raw_readq(i2c->twsi_base + SW_TWSI(i2c));
147 		if (--tries < 0)
148 			return;
149 	} while ((tmp & SW_TWSI_V) != 0);
150 }
151 
152 #define octeon_i2c_ctl_write(i2c, val)					\
153 	octeon_i2c_reg_write(i2c, SW_TWSI_EOP_TWSI_CTL, val)
154 #define octeon_i2c_data_write(i2c, val)					\
155 	octeon_i2c_reg_write(i2c, SW_TWSI_EOP_TWSI_DATA, val)
156 
157 /**
158  * octeon_i2c_reg_read - read lower bits of an I2C core register
159  * @i2c: The struct octeon_i2c
160  * @eop_reg: Register selector
161  *
162  * Returns the data.
163  *
164  * The I2C core registers are accessed indirectly via the SW_TWSI CSR.
165  */
166 static inline int octeon_i2c_reg_read(struct octeon_i2c *i2c, u64 eop_reg,
167 				      int *error)
168 {
169 	int tries = 1000;
170 	u64 tmp;
171 
172 	__raw_writeq(SW_TWSI_V | eop_reg | SW_TWSI_R, i2c->twsi_base + SW_TWSI(i2c));
173 	do {
174 		tmp = __raw_readq(i2c->twsi_base + SW_TWSI(i2c));
175 		if (--tries < 0) {
176 			/* signal that the returned data is invalid */
177 			if (error)
178 				*error = -EIO;
179 			return 0;
180 		}
181 	} while ((tmp & SW_TWSI_V) != 0);
182 
183 	return tmp & 0xFF;
184 }
185 
186 #define octeon_i2c_ctl_read(i2c)					\
187 	octeon_i2c_reg_read(i2c, SW_TWSI_EOP_TWSI_CTL, NULL)
188 #define octeon_i2c_data_read(i2c, error)				\
189 	octeon_i2c_reg_read(i2c, SW_TWSI_EOP_TWSI_DATA, error)
190 #define octeon_i2c_stat_read(i2c)					\
191 	octeon_i2c_reg_read(i2c, SW_TWSI_EOP_TWSI_STAT, NULL)
192 
193 /**
194  * octeon_i2c_read_int - read the TWSI_INT register
195  * @i2c: The struct octeon_i2c
196  *
197  * Returns the value of the register.
198  */
199 static inline u64 octeon_i2c_read_int(struct octeon_i2c *i2c)
200 {
201 	return __raw_readq(i2c->twsi_base + TWSI_INT(i2c));
202 }
203 
204 /**
205  * octeon_i2c_write_int - write the TWSI_INT register
206  * @i2c: The struct octeon_i2c
207  * @data: Value to be written
208  */
209 static inline void octeon_i2c_write_int(struct octeon_i2c *i2c, u64 data)
210 {
211 	octeon_i2c_writeq_flush(data, i2c->twsi_base + TWSI_INT(i2c));
212 }
213 
214 /* Prototypes */
215 irqreturn_t octeon_i2c_isr(int irq, void *dev_id);
216 int octeon_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num);
217 int octeon_i2c_init_lowlevel(struct octeon_i2c *i2c);
218 void octeon_i2c_set_clock(struct octeon_i2c *i2c);
219 extern struct i2c_bus_recovery_info octeon_i2c_recovery_info;
220