Annotation of src/sys/dev/ic/pcf8584.c, Revision 1.1.16.3
1.1.16.3! yamt 1: /* $NetBSD: pcf8584.c,v 1.1.16.2 2007/09/03 14:35:04 yamt Exp $ */
1.1.16.2 yamt 2:
3: /*-
4: * Copyright (c) 2007 The NetBSD Foundation, Inc.
5: * All rights reserved.
6: *
7: * This code is derived from software contributed to The NetBSD Foundation
8: * by Tobias Nygren.
9: *
10: * Redistribution and use in source and binary forms, with or without
11: * modification, are permitted provided that the following conditions
12: * are met:
13: * 1. Redistributions of source code must retain the above copyright
14: * notice, this list of conditions and the following disclaimer.
15: * 2. Redistributions in binary form must reproduce the above copyright
16: * notice, this list of conditions and the following disclaimer in the
17: * documentation and/or other materials provided with the distribution.
18: * 3. All advertising materials mentioning features or use of this software
19: * must display the following acknowledgement:
20: * This product includes software developed by the NetBSD
21: * Foundation, Inc. and its contributors.
22: * 4. Neither the name of The NetBSD Foundation nor the names of its
23: * contributors may be used to endorse or promote products derived
24: * from this software without specific prior written permission.
25: *
26: * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
27: * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
28: * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
29: * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
30: * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
31: * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
32: * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
33: * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
34: * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
35: * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
36: * POSSIBILITY OF SUCH DAMAGE.
37: */
38:
39: /*
40: * Philips PCF8584 I2C Bus Controller
41: *
42: * This driver does not yet support multi-master arbitration, concurrent access
43: * or interrupts, but it should be usable for single-master applications.
44: * It is currently used by the envctrl(4) driver on sparc64.
45: */
46:
47: #include <sys/cdefs.h>
1.1.16.3! yamt 48: __KERNEL_RCSID(0, "$NetBSD: pcf8584.c,v 1.1.16.2 2007/09/03 14:35:04 yamt Exp $");
1.1.16.2 yamt 49:
50: #include <sys/param.h>
51: #include <sys/device.h>
52: #include <sys/kernel.h>
53: #include <sys/systm.h>
54: #include <sys/condvar.h>
55: #include <sys/mutex.h>
1.1.16.3! yamt 56: #include <sys/bus.h>
1.1.16.2 yamt 57: #include <machine/param.h>
58: #include <dev/i2c/i2cvar.h>
59: #include <dev/ic/pcf8584reg.h>
60: #include <dev/ic/pcf8584var.h>
61:
62: static void pcf8584_bus_reset(struct pcf8584_handle *, int);
63: static int pcf8584_exec(void *, i2c_op_t, i2c_addr_t, const void *, size_t,
64: void *, size_t, int);
65: static int pcf8584_acquire_bus(void *, int);
66: static void pcf8584_release_bus(void *, int);
67: static void pcf8584_wait(struct pcf8584_handle *, int);
68:
69: /* Must delay for 500 ns between bus accesses according to manual. */
70: #define DATA_W(x) (DELAY(1), bus_space_write_1(ha->ha_iot, ha->ha_ioh, 0, x))
71: #define DATA_R() (DELAY(1), bus_space_read_1(ha->ha_iot, ha->ha_ioh, 0))
72: #define CSR_W(x) (DELAY(1), bus_space_write_1(ha->ha_iot, ha->ha_ioh, 1, x))
73: #define STATUS_R() (DELAY(1), bus_space_read_1(ha->ha_iot, ha->ha_ioh, 1))
74: #define BUSY() ((STATUS_R() & PCF8584_STATUS_BBN) == 0)
75: #define PENDING() ((STATUS_R() & PCF8584_STATUS_PIN) == 0)
76: #define NAK() ((STATUS_R() & PCF8584_STATUS_LRB) != 0)
77:
78: /*
79: * Wait for an interrupt.
80: */
81: static void
82: pcf8584_wait(struct pcf8584_handle *ha, int flags)
83: {
84: int timeo;
85:
86: if (flags & I2C_F_POLL) {
87: timeo = 20;
88: while (timeo && !PENDING()) {
89: DELAY(1000);
90: timeo--;
91: }
92: } else {
93: mutex_enter(&ha->ha_intrmtx);
94: cv_timedwait(&ha->ha_intrcond, &ha->ha_intrmtx, mstohz(20));
95: mutex_exit(&ha->ha_intrmtx);
96: }
97: }
98:
99: #ifdef notyet
100: static void
101: pcf8584_intr(struct pcf8584_handle *ha) {
102:
103: cv_wakeup(&ha->ha_intrcond);
104: }
105: #endif
106:
107: int
108: pcf8584_init(struct pcf8584_handle *ha)
109: {
110:
111: ha->ha_i2c.ic_cookie = ha;
112: ha->ha_i2c.ic_acquire_bus = pcf8584_acquire_bus;
113: ha->ha_i2c.ic_release_bus = pcf8584_release_bus;
114: ha->ha_i2c.ic_exec = pcf8584_exec;
115:
116: mutex_init(&ha->ha_intrmtx, MUTEX_DEFAULT, IPL_NONE);
117: cv_init(&ha->ha_intrcond, "pcf8584");
118:
119: pcf8584_bus_reset(ha, I2C_F_POLL);
120:
121: return 0;
122: }
123:
124: /*
125: * Reset i2c bus.
126: */
127: static void
128: pcf8584_bus_reset(struct pcf8584_handle *ha, int flags)
129: {
130:
131: /* initialize PCF8584 */
132: CSR_W(PCF8584_CTRL_PIN);
133: DATA_W(0x55);
134: CSR_W(PCF8584_CTRL_PIN | PCF8584_REG_S2);
135: DATA_W(PCF8584_CLK_12 | PCF8584_SCL_90);
136: CSR_W(PCF8584_CTRL_PIN | PCF8584_CTRL_ESO | PCF8584_CTRL_ACK);
137:
138: /* XXX needs multi-master synchronization delay here */
139:
140: /*
141: * Blindly attempt a write at a nonexistent i2c address (0x7F).
142: * This allows hung i2c devices to pick up the stop condition.
143: */
144: DATA_W(0x7F << 1);
145: CSR_W(PCF8584_CMD_START);
146: pcf8584_wait(ha, flags);
147: CSR_W(PCF8584_CMD_STOP);
148: pcf8584_wait(ha, flags);
149: }
150:
151: static int
152: pcf8584_exec(void *cookie, i2c_op_t op, i2c_addr_t addr,
153: const void *cmdbuf, size_t cmdlen, void *buf,
154: size_t len, int flags)
155: {
156: int i;
157: struct pcf8584_handle *ha = cookie;
158: uint8_t *p = buf;
159:
160: KASSERT(cmdlen == 0);
161: KASSERT(op == I2C_OP_READ_WITH_STOP || op == I2C_OP_WRITE_WITH_STOP);
162:
163: if (BUSY()) {
164: /* We're the only master on the bus, something is wrong. */
165: printf("*%s: i2c bus busy!\n", ha->ha_parent->dv_xname);
166: pcf8584_bus_reset(ha, flags);
167: }
168: if (op == I2C_OP_READ_WITH_STOP)
169: DATA_W((addr << 1) | 1);
170: else
171: DATA_W(addr << 1);
172:
173: CSR_W(PCF8584_CMD_START);
174: pcf8584_wait(ha, flags);
175: if (!PENDING()) {
176: printf("%s: no intr after i2c sla\n", ha->ha_parent->dv_xname);
177: }
178: if (NAK())
179: goto fail;
180:
181: if (op == I2C_OP_READ_WITH_STOP) {
182: (void) DATA_R();/* dummy read */
183: for (i = 0; i < len; i++) {
184: /* wait for a byte to arrive */
185: pcf8584_wait(ha, flags);
186: if (!PENDING()) {
187: printf("%s: lost intr during i2c read\n",
188: ha->ha_parent->dv_xname);
189: goto fail;
190: }
191: if (NAK())
192: goto fail;
193: if (i == len - 1) {
194: /*
195: * we're about to read the final byte, so we
196: * set the controller to NAK the following
197: * byte, if any.
198: */
199: CSR_W(PCF8584_CMD_NAK);
200: }
201: *p++ = DATA_R();
202: }
203: pcf8584_wait(ha, flags);
204: if (!PENDING()) {
205: printf("%s: no intr on final i2c nak\n",
206: ha->ha_parent->dv_xname);
207: goto fail;
208: }
209: CSR_W(PCF8584_CMD_STOP);
210: (void) DATA_R();/* dummy read */
211: } else {
212: for (i = 0; i < len; i++) {
213: DATA_W(*p++);
214: pcf8584_wait(ha, flags);
215: if (!PENDING()) {
216: printf("%s: no intr during i2c write\n",
217: ha->ha_parent->dv_xname);
218: goto fail;
219: }
220: if (NAK())
221: goto fail;
222: }
223: CSR_W(PCF8584_CMD_STOP);
224: }
225: pcf8584_wait(ha, flags);
226: return 0;
227: fail:
228: CSR_W(PCF8584_CMD_STOP);
229: pcf8584_wait(ha, flags);
230:
231: return 1;
232: }
233:
234: static int
235: pcf8584_acquire_bus(void *cookie, int flags)
236: {
237:
238: /* XXX concurrent access not yet implemented */
239: return 0;
240: }
241:
242: static void
243: pcf8584_release_bus(void *cookie, int flags)
244: {
245:
246: }
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