1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Support to GPOs on ROHM BD71815 4 * Copyright 2021 ROHM Semiconductors. 5 * Author: Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com> 6 * 7 * Copyright 2014 Embest Technology Co. Ltd. Inc. 8 * Author: yanglsh@embest-tech.com 9 */ 10 11 #include <linux/gpio/driver.h> 12 #include <linux/init.h> 13 #include <linux/irq.h> 14 #include <linux/module.h> 15 #include <linux/of.h> 16 #include <linux/platform_device.h> 17 /* For the BD71815 register definitions */ 18 #include <linux/mfd/rohm-bd71815.h> 19 20 struct bd71815_gpio { 21 /* chip.parent points the MFD which provides DT node and regmap */ 22 struct gpio_chip chip; 23 /* dev points to the platform device for devm and prints */ 24 struct device *dev; 25 struct regmap *regmap; 26 }; 27 28 static int bd71815gpo_get(struct gpio_chip *chip, unsigned int offset) 29 { 30 struct bd71815_gpio *bd71815 = gpiochip_get_data(chip); 31 int ret, val; 32 33 ret = regmap_read(bd71815->regmap, BD71815_REG_GPO, &val); 34 if (ret) 35 return ret; 36 37 return (val >> offset) & 1; 38 } 39 40 static void bd71815gpo_set(struct gpio_chip *chip, unsigned int offset, 41 int value) 42 { 43 struct bd71815_gpio *bd71815 = gpiochip_get_data(chip); 44 int ret, bit; 45 46 bit = BIT(offset); 47 48 if (value) 49 ret = regmap_set_bits(bd71815->regmap, BD71815_REG_GPO, bit); 50 else 51 ret = regmap_clear_bits(bd71815->regmap, BD71815_REG_GPO, bit); 52 53 if (ret) 54 dev_warn(bd71815->dev, "failed to toggle GPO\n"); 55 } 56 57 static int bd71815_gpio_set_config(struct gpio_chip *chip, unsigned int offset, 58 unsigned long config) 59 { 60 struct bd71815_gpio *bdgpio = gpiochip_get_data(chip); 61 62 switch (pinconf_to_config_param(config)) { 63 case PIN_CONFIG_DRIVE_OPEN_DRAIN: 64 return regmap_update_bits(bdgpio->regmap, 65 BD71815_REG_GPO, 66 BD71815_GPIO_DRIVE_MASK << offset, 67 BD71815_GPIO_OPEN_DRAIN << offset); 68 case PIN_CONFIG_DRIVE_PUSH_PULL: 69 return regmap_update_bits(bdgpio->regmap, 70 BD71815_REG_GPO, 71 BD71815_GPIO_DRIVE_MASK << offset, 72 BD71815_GPIO_CMOS << offset); 73 default: 74 break; 75 } 76 return -ENOTSUPP; 77 } 78 79 /* BD71815 GPIO is actually GPO */ 80 static int bd71815gpo_direction_get(struct gpio_chip *gc, unsigned int offset) 81 { 82 return GPIO_LINE_DIRECTION_OUT; 83 } 84 85 /* Template for GPIO chip */ 86 static const struct gpio_chip bd71815gpo_chip = { 87 .label = "bd71815", 88 .owner = THIS_MODULE, 89 .get = bd71815gpo_get, 90 .get_direction = bd71815gpo_direction_get, 91 .set = bd71815gpo_set, 92 .set_config = bd71815_gpio_set_config, 93 .can_sleep = true, 94 }; 95 96 #define BD71815_TWO_GPIOS GENMASK(1, 0) 97 #define BD71815_ONE_GPIO BIT(0) 98 99 /* 100 * Sigh. The BD71815 and BD71817 were originally designed to support two GPO 101 * pins. At some point it was noticed the second GPO pin which is the E5 pin 102 * located at the center of IC is hard to use on PCB (due to the location). It 103 * was decided to not promote this second GPO and the pin is marked as GND in 104 * the datasheet. The functionality is still there though! I guess driving a GPO 105 * connected to the ground is a bad idea. Thus we do not support it by default. 106 * OTOH - the original driver written by colleagues at Embest did support 107 * controlling this second GPO. It is thus possible this is used in some of the 108 * products. 109 * 110 * This driver does not by default support configuring this second GPO 111 * but allows using it by providing the DT property 112 * "rohm,enable-hidden-gpo". 113 */ 114 static int bd71815_init_valid_mask(struct gpio_chip *gc, 115 unsigned long *valid_mask, 116 unsigned int ngpios) 117 { 118 if (ngpios != 2) 119 return 0; 120 121 if (gc->parent && device_property_present(gc->parent, 122 "rohm,enable-hidden-gpo")) 123 *valid_mask = BD71815_TWO_GPIOS; 124 else 125 *valid_mask = BD71815_ONE_GPIO; 126 127 return 0; 128 } 129 130 static int gpo_bd71815_probe(struct platform_device *pdev) 131 { 132 struct bd71815_gpio *g; 133 struct device *parent, *dev; 134 135 /* 136 * Bind devm lifetime to this platform device => use dev for devm. 137 * also the prints should originate from this device. 138 */ 139 dev = &pdev->dev; 140 /* The device-tree and regmap come from MFD => use parent for that */ 141 parent = dev->parent; 142 143 g = devm_kzalloc(dev, sizeof(*g), GFP_KERNEL); 144 if (!g) 145 return -ENOMEM; 146 147 g->chip = bd71815gpo_chip; 148 149 /* 150 * FIXME: As writing of this the sysfs interface for GPIO control does 151 * not respect the valid_mask. Do not trust it but rather set the ngpios 152 * to 1 if "rohm,enable-hidden-gpo" is not given. 153 * 154 * This check can be removed later if the sysfs export is fixed and 155 * if the fix is backported. 156 * 157 * For now it is safest to just set the ngpios though. 158 */ 159 if (device_property_present(parent, "rohm,enable-hidden-gpo")) 160 g->chip.ngpio = 2; 161 else 162 g->chip.ngpio = 1; 163 164 g->chip.init_valid_mask = bd71815_init_valid_mask; 165 g->chip.base = -1; 166 g->chip.parent = parent; 167 g->regmap = dev_get_regmap(parent, NULL); 168 g->dev = dev; 169 170 return devm_gpiochip_add_data(dev, &g->chip, g); 171 } 172 173 static struct platform_driver gpo_bd71815_driver = { 174 .driver = { 175 .name = "bd71815-gpo", 176 }, 177 .probe = gpo_bd71815_probe, 178 }; 179 module_platform_driver(gpo_bd71815_driver); 180 181 MODULE_ALIAS("platform:bd71815-gpo"); 182 MODULE_AUTHOR("Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>"); 183 MODULE_AUTHOR("Peter Yang <yanglsh@embest-tech.com>"); 184 MODULE_DESCRIPTION("GPO interface for BD71815"); 185 MODULE_LICENSE("GPL"); 186