2 * Copyright 2012 Red Hat Inc.
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5 * copy of this software and associated documentation files (the "Software"),
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9 * Software is furnished to do so, subject to the following conditions:
11 * The above copyright notice and this permission notice shall be included in
12 * all copies or substantial portions of the Software.
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15 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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20 * OTHER DEALINGS IN THE SOFTWARE.
26 #ifdef CONFIG_NOUVEAU_I2C_INTERNAL
27 #define T_TIMEOUT 2200000
28 #define T_RISEFALL 1000
32 i2c_drive_scl(struct nvkm_i2c_port *port, int state)
34 port->func->drive_scl(port, state);
38 i2c_drive_sda(struct nvkm_i2c_port *port, int state)
40 port->func->drive_sda(port, state);
44 i2c_sense_scl(struct nvkm_i2c_port *port)
46 return port->func->sense_scl(port);
50 i2c_sense_sda(struct nvkm_i2c_port *port)
52 return port->func->sense_sda(port);
56 i2c_delay(struct nvkm_i2c_port *port, u32 nsec)
58 udelay((nsec + 500) / 1000);
62 i2c_raise_scl(struct nvkm_i2c_port *port)
64 u32 timeout = T_TIMEOUT / T_RISEFALL;
66 i2c_drive_scl(port, 1);
68 i2c_delay(port, T_RISEFALL);
69 } while (!i2c_sense_scl(port) && --timeout);
75 i2c_start(struct nvkm_i2c_port *port)
79 if (!i2c_sense_scl(port) ||
80 !i2c_sense_sda(port)) {
81 i2c_drive_scl(port, 0);
82 i2c_drive_sda(port, 1);
83 if (!i2c_raise_scl(port))
87 i2c_drive_sda(port, 0);
88 i2c_delay(port, T_HOLD);
89 i2c_drive_scl(port, 0);
90 i2c_delay(port, T_HOLD);
95 i2c_stop(struct nvkm_i2c_port *port)
97 i2c_drive_scl(port, 0);
98 i2c_drive_sda(port, 0);
99 i2c_delay(port, T_RISEFALL);
101 i2c_drive_scl(port, 1);
102 i2c_delay(port, T_HOLD);
103 i2c_drive_sda(port, 1);
104 i2c_delay(port, T_HOLD);
108 i2c_bitw(struct nvkm_i2c_port *port, int sda)
110 i2c_drive_sda(port, sda);
111 i2c_delay(port, T_RISEFALL);
113 if (!i2c_raise_scl(port))
115 i2c_delay(port, T_HOLD);
117 i2c_drive_scl(port, 0);
118 i2c_delay(port, T_HOLD);
123 i2c_bitr(struct nvkm_i2c_port *port)
127 i2c_drive_sda(port, 1);
128 i2c_delay(port, T_RISEFALL);
130 if (!i2c_raise_scl(port))
132 i2c_delay(port, T_HOLD);
134 sda = i2c_sense_sda(port);
136 i2c_drive_scl(port, 0);
137 i2c_delay(port, T_HOLD);
142 i2c_get_byte(struct nvkm_i2c_port *port, u8 *byte, bool last)
147 for (i = 7; i >= 0; i--) {
148 bit = i2c_bitr(port);
154 return i2c_bitw(port, last ? 1 : 0);
158 i2c_put_byte(struct nvkm_i2c_port *port, u8 byte)
161 for (i = 7; i >= 0; i--) {
162 ret = i2c_bitw(port, !!(byte & (1 << i)));
167 ret = i2c_bitr(port);
168 if (ret == 1) /* nack */
174 i2c_addr(struct nvkm_i2c_port *port, struct i2c_msg *msg)
176 u32 addr = msg->addr << 1;
177 if (msg->flags & I2C_M_RD)
179 return i2c_put_byte(port, addr);
183 i2c_bit_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
185 struct nvkm_i2c_port *port = adap->algo_data;
186 struct i2c_msg *msg = msgs;
187 int ret = 0, mcnt = num;
189 ret = nvkm_i2c(port)->acquire(port, nsecs_to_jiffies(T_TIMEOUT));
193 while (!ret && mcnt--) {
194 u8 remaining = msg->len;
197 ret = i2c_start(port);
199 ret = i2c_addr(port, msg);
201 if (msg->flags & I2C_M_RD) {
202 while (!ret && remaining--)
203 ret = i2c_get_byte(port, ptr++, !remaining);
205 while (!ret && remaining--)
206 ret = i2c_put_byte(port, *ptr++);
213 nvkm_i2c(port)->release(port);
214 return (ret < 0) ? ret : num;
218 i2c_bit_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
225 i2c_bit_func(struct i2c_adapter *adap)
227 return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
230 const struct i2c_algorithm nvkm_i2c_bit_algo = {
231 .master_xfer = i2c_bit_xfer,
232 .functionality = i2c_bit_func