ddc.c revision 1.1.2.2
1 1.1.2.2 elad /* $NetBSD: ddc.c,v 1.1.2.2 2006/05/11 23:28:30 elad Exp $ */ 2 1.1.2.2 elad 3 1.1.2.2 elad /*- 4 1.1.2.2 elad * Copyright (c) 2006 Itronix Inc. 5 1.1.2.2 elad * All rights reserved. 6 1.1.2.2 elad * 7 1.1.2.2 elad * Written by Garrett D'Amore for Itronix Inc. 8 1.1.2.2 elad * 9 1.1.2.2 elad * Redistribution and use in source and binary forms, with or without 10 1.1.2.2 elad * modification, are permitted provided that the following conditions 11 1.1.2.2 elad * are met: 12 1.1.2.2 elad * 1. Redistributions of source code must retain the above copyright 13 1.1.2.2 elad * notice, this list of conditions and the following disclaimer. 14 1.1.2.2 elad * 2. Redistributions in binary form must reproduce the above copyright 15 1.1.2.2 elad * notice, this list of conditions and the following disclaimer in the 16 1.1.2.2 elad * documentation and/or other materials provided with the distribution. 17 1.1.2.2 elad * 3. The name of Itronix Inc. may not be used to endorse 18 1.1.2.2 elad * or promote products derived from this software without specific 19 1.1.2.2 elad * prior written permission. 20 1.1.2.2 elad * 21 1.1.2.2 elad * THIS SOFTWARE IS PROVIDED BY ITRONIX INC. ``AS IS'' AND ANY EXPRESS 22 1.1.2.2 elad * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 23 1.1.2.2 elad * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 1.1.2.2 elad * ARE DISCLAIMED. IN NO EVENT SHALL ITRONIX INC. BE LIABLE FOR ANY 25 1.1.2.2 elad * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 1.1.2.2 elad * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE 27 1.1.2.2 elad * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 28 1.1.2.2 elad * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 29 1.1.2.2 elad * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING 30 1.1.2.2 elad * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS 31 1.1.2.2 elad * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 32 1.1.2.2 elad */ 33 1.1.2.2 elad 34 1.1.2.2 elad #include <sys/cdefs.h> 35 1.1.2.2 elad __KERNEL_RCSID(0, "$NetBSD: ddc.c,v 1.1.2.2 2006/05/11 23:28:30 elad Exp $"); 36 1.1.2.2 elad 37 1.1.2.2 elad #include <sys/param.h> 38 1.1.2.2 elad #include <sys/systm.h> 39 1.1.2.2 elad #include <sys/device.h> 40 1.1.2.2 elad #include <sys/kernel.h> 41 1.1.2.2 elad 42 1.1.2.2 elad #include <machine/bus.h> 43 1.1.2.2 elad #include <dev/i2c/i2cvar.h> 44 1.1.2.2 elad #include <dev/i2c/ddcreg.h> 45 1.1.2.2 elad #include <dev/i2c/ddcvar.h> 46 1.1.2.2 elad 47 1.1.2.2 elad /* 48 1.1.2.2 elad * VESA Display Data Channel I2C client, used to access EDID 49 1.1.2.2 elad * information. 50 1.1.2.2 elad * 51 1.1.2.2 elad * Note that this only supports DDC version 2, which uses normal I2C. 52 1.1.2.2 elad * The older DDCv1 standard used sync signaling to provide the I2C 53 1.1.2.2 elad * clock, and is typically not used on reasonably recent monitors. 54 1.1.2.2 elad */ 55 1.1.2.2 elad 56 1.1.2.2 elad struct ddc_softc { 57 1.1.2.2 elad struct device sc_dev; 58 1.1.2.2 elad i2c_tag_t sc_tag; 59 1.1.2.2 elad int sc_address; 60 1.1.2.2 elad }; 61 1.1.2.2 elad 62 1.1.2.2 elad static int ddc_match(struct device *, struct cfdata *, void *); 63 1.1.2.2 elad static void ddc_attach(struct device *, struct device *, void *); 64 1.1.2.2 elad 65 1.1.2.2 elad CFATTACH_DECL(ddc, sizeof (struct ddc_softc), 66 1.1.2.2 elad ddc_match, ddc_attach, NULL, NULL); 67 1.1.2.2 elad 68 1.1.2.2 elad static int 69 1.1.2.2 elad ddc_match(struct device *parent, struct cfdata *cf, void *aux) 70 1.1.2.2 elad { 71 1.1.2.2 elad struct i2c_attach_args *ia = aux; 72 1.1.2.2 elad 73 1.1.2.2 elad if (ia->ia_addr == DDC_ADDR) 74 1.1.2.2 elad return 1; 75 1.1.2.2 elad return 0; 76 1.1.2.2 elad } 77 1.1.2.2 elad 78 1.1.2.2 elad static void 79 1.1.2.2 elad ddc_attach(struct device *parent, struct device *self, void *aux) 80 1.1.2.2 elad { 81 1.1.2.2 elad struct ddc_softc *sc = device_private(self); 82 1.1.2.2 elad struct i2c_attach_args *ia = aux; 83 1.1.2.2 elad 84 1.1.2.2 elad sc->sc_address = ia->ia_addr; 85 1.1.2.2 elad 86 1.1.2.2 elad aprint_naive(": DDC\n"); 87 1.1.2.2 elad aprint_normal(": DDC\n"); 88 1.1.2.2 elad } 89 1.1.2.2 elad 90 1.1.2.2 elad /* XXX: add cdev ops? */ 91 1.1.2.2 elad 92 1.1.2.2 elad int 93 1.1.2.2 elad ddc_read_edid(i2c_tag_t tag, uint8_t *dest, size_t len) 94 1.1.2.2 elad { 95 1.1.2.2 elad uint8_t wbuf[2]; 96 1.1.2.2 elad 97 1.1.2.2 elad if (iic_acquire_bus(tag, I2C_F_POLL) != 0) 98 1.1.2.2 elad return -1; 99 1.1.2.2 elad 100 1.1.2.2 elad wbuf[0] = DDC_EDID_START; /* start address */ 101 1.1.2.2 elad 102 1.1.2.2 elad if (iic_exec(tag, I2C_OP_READ_WITH_STOP, DDC_ADDR, wbuf, 1, dest, 103 1.1.2.2 elad len, I2C_F_POLL)) { 104 1.1.2.2 elad iic_release_bus(tag, I2C_F_POLL); 105 1.1.2.2 elad return -1; 106 1.1.2.2 elad } 107 1.1.2.2 elad iic_release_bus(tag, I2C_F_POLL); 108 1.1.2.2 elad return 0; 109 1.1.2.2 elad } 110
Indexes created Thu Oct 02 01:09:59 GMT 2025