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1// SPDX-License-Identifier: GPL-2.02/*3 * I2C driver for stand-alone PCF8584 style adapters on Zorro cards4 *5 * Original ICY documentation can be found on Aminet:6 * https://aminet.net/package/docs/hard/icy7 *8 * There has been a modern community re-print of this design in 2019:9 * https://www.a1k.org/forum/index.php?threads/70106/10 *11 * The card is basically a Philips PCF8584 connected straight to the12 * beginning of the AutoConfig'd address space (register S1 on base+2),13 * with /INT on /INT2 on the Zorro bus.14 *15 * Copyright (c) 2019 Max Staudt <max@enpas.org>16 *17 * This started as a fork of i2c-elektor.c and has evolved since.18 * Thanks go to its authors for providing a base to grow on.19 *20 *21 * IRQ support is currently not implemented.22 *23 * As it turns out, i2c-algo-pcf is really written with i2c-elektor's24 * edge-triggered ISA interrupts in mind, while the Amiga's Zorro bus has25 * level-triggered interrupts. This means that once an interrupt occurs, we26 * have to tell the PCF8584 to shut up immediately, or it will keep the27 * interrupt line busy and cause an IRQ storm.28 29 * However, because of the PCF8584's host-side protocol, there is no good30 * way to just quieten it without side effects. Rather, we have to perform31 * the next read/write operation straight away, which will reset the /INT32 * pin. This entails re-designing the core of i2c-algo-pcf in the future.33 * For now, we never request an IRQ from the PCF8584, and poll it instead.34 */35 36#include <linux/delay.h>37#include <linux/init.h>38#include <linux/io.h>39#include <linux/ioport.h>40#include <linux/kernel.h>41#include <linux/module.h>42 43#include <linux/i2c.h>44#include <linux/i2c-algo-pcf.h>45 46#include <asm/amigahw.h>47#include <asm/amigaints.h>48#include <linux/zorro.h>49 50#include "../algos/i2c-algo-pcf.h"51 52struct icy_i2c {53 struct i2c_adapter adapter;54 55 void __iomem *reg_s0;56 void __iomem *reg_s1;57 struct i2c_client *ltc2990_client;58};59 60/*61 * Functions called by i2c-algo-pcf62 */63static void icy_pcf_setpcf(void *data, int ctl, int val)64{65 struct icy_i2c *i2c = (struct icy_i2c *)data;66 67 u8 __iomem *address = ctl ? i2c->reg_s1 : i2c->reg_s0;68 69 z_writeb(val, address);70}71 72static int icy_pcf_getpcf(void *data, int ctl)73{74 struct icy_i2c *i2c = (struct icy_i2c *)data;75 76 u8 __iomem *address = ctl ? i2c->reg_s1 : i2c->reg_s0;77 78 return z_readb(address);79}80 81static int icy_pcf_getown(void *data)82{83 return 0x55;84}85 86static int icy_pcf_getclock(void *data)87{88 return 0x1c;89}90 91static void icy_pcf_waitforpin(void *data)92{93 usleep_range(50, 150);94}95 96/*97 * Main i2c-icy part98 */99static unsigned short const icy_ltc2990_addresses[] = {100 0x4c, 0x4d, 0x4e, 0x4f, I2C_CLIENT_END101};102 103/*104 * Additional sensors exposed once this property is applied:105 *106 * in1 will be the voltage of the 5V rail, divided by 2.107 * in2 will be the voltage of the 12V rail, divided by 4.108 * temp3 will be measured using a PCB loop next the chip.109 */110static const u32 icy_ltc2990_meas_mode[] = {0, 3};111 112static const struct property_entry icy_ltc2990_props[] = {113 PROPERTY_ENTRY_U32_ARRAY("lltc,meas-mode", icy_ltc2990_meas_mode),114 { }115};116 117static const struct software_node icy_ltc2990_node = {118 .properties = icy_ltc2990_props,119};120 121static int icy_probe(struct zorro_dev *z,122 const struct zorro_device_id *ent)123{124 struct icy_i2c *i2c;125 struct i2c_algo_pcf_data *algo_data;126 struct i2c_board_info ltc2990_info = {127 .type = "ltc2990",128 .swnode = &icy_ltc2990_node,129 };130 131 i2c = devm_kzalloc(&z->dev, sizeof(*i2c), GFP_KERNEL);132 if (!i2c)133 return -ENOMEM;134 135 algo_data = devm_kzalloc(&z->dev, sizeof(*algo_data), GFP_KERNEL);136 if (!algo_data)137 return -ENOMEM;138 139 dev_set_drvdata(&z->dev, i2c);140 i2c->adapter.dev.parent = &z->dev;141 i2c->adapter.owner = THIS_MODULE;142 /* i2c->adapter.algo assigned by i2c_pcf_add_bus() */143 i2c->adapter.algo_data = algo_data;144 strscpy(i2c->adapter.name, "ICY I2C Zorro adapter",145 sizeof(i2c->adapter.name));146 147 if (!devm_request_mem_region(&z->dev,148 z->resource.start,149 4, i2c->adapter.name))150 return -ENXIO;151 152 /* Driver private data */153 i2c->reg_s0 = ZTWO_VADDR(z->resource.start);154 i2c->reg_s1 = ZTWO_VADDR(z->resource.start + 2);155 156 algo_data->data = i2c;157 algo_data->setpcf = icy_pcf_setpcf;158 algo_data->getpcf = icy_pcf_getpcf;159 algo_data->getown = icy_pcf_getown;160 algo_data->getclock = icy_pcf_getclock;161 algo_data->waitforpin = icy_pcf_waitforpin;162 163 if (i2c_pcf_add_bus(&i2c->adapter)) {164 dev_err(&z->dev, "i2c_pcf_add_bus() failed\n");165 return -ENXIO;166 }167 168 dev_info(&z->dev, "ICY I2C controller at %pa, IRQ not implemented\n",169 &z->resource.start);170 171 /*172 * The 2019 a1k.org PCBs have an LTC2990 at 0x4c, so start173 * it automatically once ltc2990 is modprobed.174 *175 * in0 is the voltage of the internal 5V power supply.176 * temp1 is the temperature inside the chip.177 *178 * See property_entry above for in1, in2, temp3.179 */180 i2c->ltc2990_client = i2c_new_scanned_device(&i2c->adapter,181 <c2990_info,182 icy_ltc2990_addresses,183 NULL);184 return 0;185}186 187static void icy_remove(struct zorro_dev *z)188{189 struct icy_i2c *i2c = dev_get_drvdata(&z->dev);190 191 i2c_unregister_device(i2c->ltc2990_client);192 i2c_del_adapter(&i2c->adapter);193}194 195static const struct zorro_device_id icy_zorro_tbl[] = {196 { ZORRO_ID(VMC, 15, 0), },197 { 0 }198};199 200MODULE_DEVICE_TABLE(zorro, icy_zorro_tbl);201 202static struct zorro_driver icy_driver = {203 .name = "i2c-icy",204 .id_table = icy_zorro_tbl,205 .probe = icy_probe,206 .remove = icy_remove,207};208 209module_driver(icy_driver,210 zorro_register_driver,211 zorro_unregister_driver);212 213MODULE_AUTHOR("Max Staudt <max@enpas.org>");214MODULE_DESCRIPTION("I2C bus via PCF8584 on ICY Zorro card");215MODULE_LICENSE("GPL v2");216