1 /*- 2 * Copyright (C) 2008 MARVELL INTERNATIONAL LTD. 3 * All rights reserved. 4 * 5 * Developed by Semihalf. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. Neither the name of MARVELL nor the names of contributors 16 * may be used to endorse or promote products derived from this software 17 * without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED BY AUTHOR AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL AUTHOR OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 */ 31 32 /* 33 * Driver for the TWSI (aka I2C, aka IIC) bus controller found on Marvell 34 * and Allwinner SoCs. Supports master operation only, and works in polling mode. 35 * 36 * Calls to DELAY() are needed per Application Note AN-179 "TWSI Software 37 * Guidelines for Discovery(TM), Horizon (TM) and Feroceon(TM) Devices". 38 */ 39 40 #include <sys/cdefs.h> 41 #include <sys/param.h> 42 #include <sys/systm.h> 43 #include <sys/bus.h> 44 #include <sys/kernel.h> 45 #include <sys/module.h> 46 #include <sys/resource.h> 47 48 #include <machine/_inttypes.h> 49 #include <machine/bus.h> 50 #include <machine/resource.h> 51 52 #include <sys/rman.h> 53 54 #include <sys/lock.h> 55 #include <sys/mutex.h> 56 57 #include <dev/iicbus/iiconf.h> 58 #include <dev/iicbus/iicbus.h> 59 #include <dev/ofw/ofw_bus.h> 60 #include <dev/ofw/ofw_bus_subr.h> 61 62 #include <dev/extres/clk/clk.h> 63 64 #include <arm/mv/mvreg.h> 65 #include <arm/mv/mvvar.h> 66 #include <dev/iicbus/controller/twsi/twsi.h> 67 68 #include "iicbus_if.h" 69 70 #define MV_TWSI_NAME "twsi" 71 #define IICBUS_DEVNAME "iicbus" 72 73 #define TWSI_ADDR 0x00 74 #define TWSI_DATA 0x04 75 #define TWSI_CNTR 0x08 76 #define TWSI_XADDR 0x10 77 #define TWSI_STAT 0x0c 78 #define TWSI_BAUD_RATE 0x0c 79 #define TWSI_SRST 0x1c 80 81 #define TWSI_BAUD_RATE_RAW(C,M,N) ((C)/((10*(M+1))<<(N+1))) 82 #define TWSI_BAUD_RATE_SLOW 50000 /* 50kHz */ 83 #define TWSI_BAUD_RATE_FAST 100000 /* 100kHz */ 84 85 #define TWSI_DEBUG 86 #undef TWSI_DEBUG 87 88 #ifdef TWSI_DEBUG 89 #define debugf(fmt, args...) do { printf("%s(): ", __func__); printf(fmt,##args); } while (0) 90 #else 91 #define debugf(fmt, args...) 92 #endif 93 94 static phandle_t mv_twsi_get_node(device_t, device_t); 95 static int mv_twsi_probe(device_t); 96 static int mv_twsi_attach(device_t); 97 98 static struct ofw_compat_data compat_data[] = { 99 { "mrvl,twsi", true }, 100 { "marvell,mv64xxx-i2c", true }, 101 { "marvell,mv78230-i2c", true }, 102 { NULL, false } 103 }; 104 105 static device_method_t mv_twsi_methods[] = { 106 /* device interface */ 107 DEVMETHOD(device_probe, mv_twsi_probe), 108 DEVMETHOD(device_attach, mv_twsi_attach), 109 110 /* ofw_bus interface */ 111 DEVMETHOD(ofw_bus_get_node, mv_twsi_get_node), 112 113 DEVMETHOD_END 114 }; 115 116 DEFINE_CLASS_1(twsi, mv_twsi_driver, mv_twsi_methods, 117 sizeof(struct twsi_softc), twsi_driver); 118 119 DRIVER_MODULE(twsi, simplebus, mv_twsi_driver, 0, 0); 120 DRIVER_MODULE(iicbus, twsi, iicbus_driver, 0, 0); 121 MODULE_DEPEND(twsi, iicbus, 1, 1, 1); 122 SIMPLEBUS_PNP_INFO(compat_data); 123 124 static phandle_t 125 mv_twsi_get_node(device_t bus, device_t dev) 126 { 127 128 /* Used by ofw_iicbus. */ 129 return (ofw_bus_get_node(bus)); 130 } 131 132 static int 133 mv_twsi_probe(device_t dev) 134 { 135 136 if (!ofw_bus_status_okay(dev)) 137 return (ENXIO); 138 139 if (!ofw_bus_search_compatible(dev, compat_data)->ocd_data) 140 return (ENXIO); 141 142 device_set_desc(dev, "Marvell Integrated I2C Bus Controller"); 143 return (BUS_PROBE_DEFAULT); 144 } 145 146 #define ABSSUB(a,b) (((a) > (b)) ? (a) - (b) : (b) - (a)) 147 static void 148 mv_twsi_cal_baud_rate(struct twsi_softc *sc, const uint32_t target, 149 struct twsi_baud_rate *rate) 150 { 151 uint64_t clk; 152 uint32_t cur, diff, diff0; 153 int m, n, m0, n0; 154 155 /* Calculate baud rate. */ 156 m0 = n0 = 4; /* Default values on reset */ 157 diff0 = 0xffffffff; 158 clk_get_freq(sc->clk_core, &clk); 159 160 for (n = 0; n < 8; n++) { 161 for (m = 0; m < 16; m++) { 162 cur = TWSI_BAUD_RATE_RAW(clk,m,n); 163 diff = ABSSUB(target, cur); 164 if (diff < diff0) { 165 m0 = m; 166 n0 = n; 167 diff0 = diff; 168 } 169 } 170 } 171 rate->raw = TWSI_BAUD_RATE_RAW(clk, m0, n0); 172 rate->param = TWSI_BAUD_RATE_PARAM(m0, n0); 173 rate->m = m0; 174 rate->n = n0; 175 } 176 177 static int 178 mv_twsi_attach(device_t dev) 179 { 180 struct twsi_softc *sc; 181 int error; 182 183 sc = device_get_softc(dev); 184 sc->dev = dev; 185 186 /* Activate clock */ 187 error = clk_get_by_ofw_index(dev, 0, 0, &sc->clk_core); 188 if (error != 0) { 189 device_printf(dev, "could not find core clock\n"); 190 return (error); 191 } 192 error = clk_enable(sc->clk_core); 193 if (error != 0) { 194 device_printf(dev, "could not enable core clock\n"); 195 return (error); 196 } 197 198 if (clk_get_by_ofw_index(dev, 0, 1, &sc->clk_reg) == 0) { 199 error = clk_enable(sc->clk_reg); 200 if (error != 0) { 201 device_printf(dev, "could not enable core clock\n"); 202 return (error); 203 } 204 } 205 206 mv_twsi_cal_baud_rate(sc, TWSI_BAUD_RATE_SLOW, &sc->baud_rate[IIC_SLOW]); 207 mv_twsi_cal_baud_rate(sc, TWSI_BAUD_RATE_FAST, &sc->baud_rate[IIC_FAST]); 208 if (bootverbose) 209 device_printf(dev, "calculated baud rates are:\n" 210 " %" PRIu32 " kHz (M=%d, N=%d) for slow,\n" 211 " %" PRIu32 " kHz (M=%d, N=%d) for fast.\n", 212 sc->baud_rate[IIC_SLOW].raw / 1000, 213 sc->baud_rate[IIC_SLOW].m, 214 sc->baud_rate[IIC_SLOW].n, 215 sc->baud_rate[IIC_FAST].raw / 1000, 216 sc->baud_rate[IIC_FAST].m, 217 sc->baud_rate[IIC_FAST].n); 218 219 sc->reg_data = TWSI_DATA; 220 sc->reg_slave_addr = TWSI_ADDR; 221 sc->reg_slave_ext_addr = TWSI_XADDR; 222 sc->reg_control = TWSI_CNTR; 223 sc->reg_status = TWSI_STAT; 224 sc->reg_baud_rate = TWSI_BAUD_RATE; 225 sc->reg_soft_reset = TWSI_SRST; 226 227 return (twsi_attach(dev)); 228 } 229