1 /* $NetBSD: sunxi_twi.c,v 1.20 2025/09/25 13:44:31 thorpej Exp $ */ 2 3 /*- 4 * Copyright (c) 2017 Jared McNeill <jmcneill (at) invisible.ca> 5 * All rights reserved. 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 * 16 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 17 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 18 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 19 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 20 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 21 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 22 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 23 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 24 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 25 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 26 * POSSIBILITY OF SUCH DAMAGE. 27 */ 28 29 #include <sys/cdefs.h> 30 31 __KERNEL_RCSID(0, "$NetBSD: sunxi_twi.c,v 1.20 2025/09/25 13:44:31 thorpej Exp $"); 32 33 #include <sys/param.h> 34 #include <sys/bus.h> 35 #include <sys/device.h> 36 #include <sys/intr.h> 37 #include <sys/systm.h> 38 #include <sys/time.h> 39 40 #include <dev/i2c/i2cvar.h> 41 #include <dev/i2c/gttwsivar.h> 42 #include <dev/i2c/gttwsireg.h> 43 44 #include <dev/fdt/fdtvar.h> 45 46 #define TWI_CCR_REG 0x14 47 #define TWI_CCR_CLK_M __BITS(6,3) 48 #define TWI_CCR_CLK_N __BITS(2,0) 49 50 static const bus_size_t sunxi_twi_regmap[] = { 51 [TWSI_SLAVEADDR] = TWSI_ALLWINNER_SLAVEADDR, 52 [TWSI_EXTEND_SLAVEADDR] = TWSI_ALLWINNER_EXTEND_SLAVEADDR, 53 [TWSI_DATA] = TWSI_ALLWINNER_DATA, 54 [TWSI_CONTROL] = TWSI_ALLWINNER_CONTROL, 55 [TWSI_STATUS] = TWSI_ALLWINNER_STATUS, 56 [TWSI_BAUDRATE] = TWSI_ALLWINNER_BAUDRATE, 57 [TWSI_SOFTRESET] = TWSI_ALLWINNER_SOFTRESET, 58 }; 59 60 static int sunxi_twi_match(device_t, cfdata_t, void *); 61 static void sunxi_twi_attach(device_t, device_t, void *); 62 63 struct sunxi_twi_config { 64 bool iflg_rwc; 65 }; 66 67 static const struct sunxi_twi_config sun4i_a10_i2c_config = { 68 .iflg_rwc = false, 69 }; 70 71 static const struct sunxi_twi_config sun6i_a31_i2c_config = { 72 .iflg_rwc = true, 73 }; 74 75 static const struct device_compatible_entry compat_data[] = { 76 { .compat = "allwinner,sun4i-a10-i2c", .data = &sun4i_a10_i2c_config }, 77 { .compat = "allwinner,sun6i-a31-i2c", .data = &sun6i_a31_i2c_config }, 78 DEVICE_COMPAT_EOL 79 }; 80 81 CFATTACH_DECL_NEW(sunxi_twi, sizeof(struct gttwsi_softc), 82 sunxi_twi_match, sunxi_twi_attach, NULL, NULL); 83 84 static u_int 85 sunxi_twi_calc_rate(u_int parent_rate, u_int n, u_int m) 86 { 87 return parent_rate / (10 * (m + 1) * (1 << n)); 88 } 89 90 static void 91 sunxi_twi_set_clock(struct gttwsi_softc *sc, u_int parent_rate, u_int rate) 92 { 93 uint32_t baud; 94 u_int n, m, best_rate; 95 96 baud = gttwsi_read_4(sc, TWSI_BAUDRATE); 97 98 for (best_rate = 0, n = 0; n < 8; n++) { 99 for (m = 0; m < 16; m++) { 100 const u_int tmp_rate = 101 sunxi_twi_calc_rate(parent_rate, n, m); 102 if (tmp_rate <= rate && tmp_rate > best_rate) { 103 best_rate = tmp_rate; 104 baud = __SHIFTIN(n, TWI_CCR_CLK_N) | 105 __SHIFTIN(m, TWI_CCR_CLK_M); 106 } 107 } 108 } 109 110 gttwsi_write_4(sc, TWSI_BAUDRATE, baud); 111 delay(10000); 112 } 113 114 static int 115 sunxi_twi_match(device_t parent, cfdata_t cf, void *aux) 116 { 117 struct fdt_attach_args * const faa = aux; 118 119 return of_compatible_match(faa->faa_phandle, compat_data); 120 } 121 122 static void 123 sunxi_twi_attach(device_t parent, device_t self, void *aux) 124 { 125 struct gttwsi_softc * const sc = device_private(self); 126 struct fdt_attach_args * const faa = aux; 127 const struct sunxi_twi_config *conf; 128 const int phandle = faa->faa_phandle; 129 bus_space_tag_t bst = faa->faa_bst; 130 bus_space_handle_t bsh; 131 struct fdtbus_reset *rst; 132 struct clk *clk; 133 char intrstr[128]; 134 bus_addr_t addr; 135 bus_size_t size; 136 void *ih; 137 138 if (fdtbus_get_reg(phandle, 0, &addr, &size) != 0) { 139 aprint_error(": couldn't get registers\n"); 140 return; 141 } 142 143 if (bus_space_map(bst, addr, size, 0, &bsh) != 0) { 144 aprint_error(": couldn't map registers\n"); 145 return; 146 } 147 148 if (!fdtbus_intr_str(phandle, 0, intrstr, sizeof(intrstr))) { 149 aprint_error(": failed to decode interrupt\n"); 150 return; 151 } 152 153 if ((clk = fdtbus_clock_get_index(phandle, 0)) != NULL) 154 if (clk_enable(clk) != 0) { 155 aprint_error(": couldn't enable clock\n"); 156 return; 157 } 158 if ((rst = fdtbus_reset_get_index(phandle, 0)) != NULL) 159 if (fdtbus_reset_deassert(rst) != 0) { 160 aprint_error(": couldn't de-assert reset\n"); 161 return; 162 } 163 164 conf = of_compatible_lookup(phandle, compat_data)->data; 165 sc->sc_iflg_rwc = conf->iflg_rwc; 166 167 /* Attach gttwsi core */ 168 gttwsi_attach_subr(self, bst, bsh, sunxi_twi_regmap); 169 170 /* 171 * Set clock rate to 100kHz. 172 */ 173 if (clk != NULL) 174 sunxi_twi_set_clock(sc, clk_get_rate(clk), 100000); 175 176 ih = fdtbus_intr_establish_xname(phandle, 0, IPL_VM, 0, gttwsi_intr, 177 sc, device_xname(self)); 178 if (ih == NULL) { 179 aprint_error_dev(self, "couldn't establish interrupt on %s\n", 180 intrstr); 181 return; 182 } 183 aprint_normal_dev(self, "interrupting on %s\n", intrstr); 184 185 iicbus_attach(self, &sc->sc_i2c); 186 } 187
Indexes created Sun Oct 25 00:26:45 UTC 2026