1// SPDX-License-Identifier: GPL-2.0 2/* 3 * PCF8575 I2C GPIO EXPANDER DRIVER 4 * 5 * Copyright (C) 2016 Texas Instruments Incorporated - https://www.ti.com/ 6 * 7 * Vignesh R <vigneshr@ti.com> 8 * 9 * 10 * Driver for TI PCF-8575 16-bit I2C gpio expander. Based on 11 * gpio-pcf857x Linux Kernel(v4.7) driver. 12 * 13 * Copyright (C) 2007 David Brownell 14 * 15 * Add support for 8 bit expanders - like pca8574 16 * Copyright (C) 2021 Lukasz Majewski - DENX Software Engineering 17 * 18 */ 19 20#include <common.h> 21#include <dm.h> 22#include <i2c.h> 23#include <log.h> 24#include <asm-generic/gpio.h> 25#include <asm/global_data.h> 26#include <linux/bitops.h> 27 28DECLARE_GLOBAL_DATA_PTR; 29 30struct pcf8575_chip { 31 /* NOTE: these chips have strange "quasi-bidirectional" I/O pins. 32 * We can't actually know whether a pin is configured (a) as output 33 * and driving the signal low, or (b) as input and reporting a low 34 * value ... without knowing the last value written since the chip 35 * came out of reset (if any). We can't read the latched output. 36 * In short, the only reliable solution for setting up pin direction 37 * is to do it explicitly. 38 * 39 * Using "out" avoids that trouble. When left initialized to zero, 40 * our software copy of the "latch" then matches the chip's all-ones 41 * reset state. Otherwise it flags pins to be driven low. 42 */ 43 unsigned int out; /* software latch */ 44}; 45 46/* Read/Write to I/O expander */ 47 48static int pcf8575_i2c_write(struct udevice *dev, unsigned int word) 49{ 50 struct dm_i2c_chip *chip = dev_get_parent_plat(dev); 51 u8 buf[2] = { word & 0xff, word >> 8, }; 52 int ret; 53 54 ret = dm_i2c_write(dev, 0, buf, dev_get_driver_data(dev)); 55 if (ret) 56 printf("%s i2c write failed to addr %x\n", __func__, 57 chip->chip_addr); 58 59 return ret; 60} 61 62static int pcf8575_i2c_read(struct udevice *dev) 63{ 64 struct dm_i2c_chip *chip = dev_get_parent_plat(dev); 65 u8 buf[2] = {0x00, 0x00}; 66 int ret; 67 68 ret = dm_i2c_read(dev, 0, buf, dev_get_driver_data(dev)); 69 if (ret) { 70 printf("%s i2c read failed from addr %x\n", __func__, 71 chip->chip_addr); 72 return ret; 73 } 74 75 return (buf[1] << 8) | buf[0]; 76} 77 78static int pcf8575_direction_input(struct udevice *dev, unsigned offset) 79{ 80 struct pcf8575_chip *plat = dev_get_plat(dev); 81 int status; 82 83 plat->out |= BIT(offset); 84 status = pcf8575_i2c_write(dev, plat->out); 85 86 return status; 87} 88 89static int pcf8575_direction_output(struct udevice *dev, 90 unsigned int offset, int value) 91{ 92 struct pcf8575_chip *plat = dev_get_plat(dev); 93 int ret; 94 95 if (value) 96 plat->out |= BIT(offset); 97 else 98 plat->out &= ~BIT(offset); 99 100 ret = pcf8575_i2c_write(dev, plat->out); 101 102 return ret; 103} 104 105static int pcf8575_get_value(struct udevice *dev, unsigned int offset) 106{ 107 int value; 108 109 value = pcf8575_i2c_read(dev); 110 111 return (value < 0) ? value : ((value & BIT(offset)) >> offset); 112} 113 114static int pcf8575_set_value(struct udevice *dev, unsigned int offset, 115 int value) 116{ 117 return pcf8575_direction_output(dev, offset, value); 118} 119 120static int pcf8575_ofdata_plat(struct udevice *dev) 121{ 122 struct pcf8575_chip *plat = dev_get_plat(dev); 123 struct gpio_dev_priv *uc_priv = dev_get_uclass_priv(dev); 124 125 int n_latch; 126 127 /* 128 * Number of pins depends on the expander device and is specified 129 * in the struct udevice_id (as in the Linue kernel). 130 */ 131 uc_priv->gpio_count = dev_get_driver_data(dev) * 8; 132 uc_priv->bank_name = fdt_getprop(gd->fdt_blob, dev_of_offset(dev), 133 "gpio-bank-name", NULL); 134 if (!uc_priv->bank_name) 135 uc_priv->bank_name = fdt_get_name(gd->fdt_blob, 136 dev_of_offset(dev), NULL); 137 138 n_latch = fdtdec_get_uint(gd->fdt_blob, dev_of_offset(dev), 139 "lines-initial-states", 0); 140 plat->out = ~n_latch; 141 142 return 0; 143} 144 145static int pcf8575_gpio_probe(struct udevice *dev) 146{ 147 struct gpio_dev_priv *uc_priv = dev_get_uclass_priv(dev); 148 149 debug("%s GPIO controller with %d gpios probed\n", 150 uc_priv->bank_name, uc_priv->gpio_count); 151 152 return 0; 153} 154 155static const struct dm_gpio_ops pcf8575_gpio_ops = { 156 .direction_input = pcf8575_direction_input, 157 .direction_output = pcf8575_direction_output, 158 .get_value = pcf8575_get_value, 159 .set_value = pcf8575_set_value, 160}; 161 162static const struct udevice_id pcf8575_gpio_ids[] = { 163 { .compatible = "nxp,pcf8575", .data = 2 }, 164 { .compatible = "ti,pcf8575", .data = 2 }, 165 { .compatible = "nxp,pca8574", .data = 1 }, 166 { } 167}; 168 169U_BOOT_DRIVER(gpio_pcf8575) = { 170 .name = "gpio_pcf8575", 171 .id = UCLASS_GPIO, 172 .ops = &pcf8575_gpio_ops, 173 .of_match = pcf8575_gpio_ids, 174 .of_to_plat = pcf8575_ofdata_plat, 175 .probe = pcf8575_gpio_probe, 176 .plat_auto = sizeof(struct pcf8575_chip), 177}; 178