1 // SPDX-License-Identifier: GPL-2.0+ 2 // 3 // Synopsys CREG (Control REGisters) GPIO driver 4 // 5 // Copyright (C) 2018 Synopsys 6 // Author: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com> 7 8 #include <linux/gpio/driver.h> 9 #include <linux/io.h> 10 #include <linux/of.h> 11 #include <linux/platform_device.h> 12 13 #define MAX_GPIO 32 14 15 struct creg_layout { 16 u8 ngpio; 17 u8 shift[MAX_GPIO]; 18 u8 on[MAX_GPIO]; 19 u8 off[MAX_GPIO]; 20 u8 bit_per_gpio[MAX_GPIO]; 21 }; 22 23 struct creg_gpio { 24 struct gpio_chip gc; 25 void __iomem *regs; 26 spinlock_t lock; 27 const struct creg_layout *layout; 28 }; 29 30 static void creg_gpio_set(struct gpio_chip *gc, unsigned int offset, int val) 31 { 32 struct creg_gpio *hcg = gpiochip_get_data(gc); 33 const struct creg_layout *layout = hcg->layout; 34 u32 reg, reg_shift, value; 35 unsigned long flags; 36 int i; 37 38 value = val ? hcg->layout->on[offset] : hcg->layout->off[offset]; 39 40 reg_shift = layout->shift[offset]; 41 for (i = 0; i < offset; i++) 42 reg_shift += layout->bit_per_gpio[i] + layout->shift[i]; 43 44 spin_lock_irqsave(&hcg->lock, flags); 45 reg = readl(hcg->regs); 46 reg &= ~(GENMASK(layout->bit_per_gpio[i] - 1, 0) << reg_shift); 47 reg |= (value << reg_shift); 48 writel(reg, hcg->regs); 49 spin_unlock_irqrestore(&hcg->lock, flags); 50 } 51 52 static int creg_gpio_dir_out(struct gpio_chip *gc, unsigned int offset, int val) 53 { 54 creg_gpio_set(gc, offset, val); 55 56 return 0; 57 } 58 59 static int creg_gpio_validate_pg(struct device *dev, struct creg_gpio *hcg, 60 int i) 61 { 62 const struct creg_layout *layout = hcg->layout; 63 64 if (layout->bit_per_gpio[i] < 1 || layout->bit_per_gpio[i] > 8) 65 return -EINVAL; 66 67 /* Check that on value fits its placeholder */ 68 if (GENMASK(31, layout->bit_per_gpio[i]) & layout->on[i]) 69 return -EINVAL; 70 71 /* Check that off value fits its placeholder */ 72 if (GENMASK(31, layout->bit_per_gpio[i]) & layout->off[i]) 73 return -EINVAL; 74 75 if (layout->on[i] == layout->off[i]) 76 return -EINVAL; 77 78 return 0; 79 } 80 81 static int creg_gpio_validate(struct device *dev, struct creg_gpio *hcg, 82 u32 ngpios) 83 { 84 u32 reg_len = 0; 85 int i; 86 87 if (hcg->layout->ngpio < 1 || hcg->layout->ngpio > MAX_GPIO) 88 return -EINVAL; 89 90 if (ngpios < 1 || ngpios > hcg->layout->ngpio) { 91 dev_err(dev, "ngpios must be in [1:%u]\n", hcg->layout->ngpio); 92 return -EINVAL; 93 } 94 95 for (i = 0; i < hcg->layout->ngpio; i++) { 96 if (creg_gpio_validate_pg(dev, hcg, i)) 97 return -EINVAL; 98 99 reg_len += hcg->layout->shift[i] + hcg->layout->bit_per_gpio[i]; 100 } 101 102 /* Check that we fit in 32 bit register */ 103 if (reg_len > 32) 104 return -EINVAL; 105 106 return 0; 107 } 108 109 static const struct creg_layout hsdk_cs_ctl = { 110 .ngpio = 10, 111 .shift = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 }, 112 .off = { 2, 2, 2, 2, 2, 2, 2, 2, 2, 2 }, 113 .on = { 3, 3, 3, 3, 3, 3, 3, 3, 3, 3 }, 114 .bit_per_gpio = { 2, 2, 2, 2, 2, 2, 2, 2, 2, 2 } 115 }; 116 117 static const struct creg_layout axs10x_flsh_cs_ctl = { 118 .ngpio = 1, 119 .shift = { 0 }, 120 .off = { 1 }, 121 .on = { 3 }, 122 .bit_per_gpio = { 2 } 123 }; 124 125 static const struct of_device_id creg_gpio_ids[] = { 126 { 127 .compatible = "snps,creg-gpio-axs10x", 128 .data = &axs10x_flsh_cs_ctl 129 }, { 130 .compatible = "snps,creg-gpio-hsdk", 131 .data = &hsdk_cs_ctl 132 }, { /* sentinel */ } 133 }; 134 135 static int creg_gpio_probe(struct platform_device *pdev) 136 { 137 const struct of_device_id *match; 138 struct device *dev = &pdev->dev; 139 struct creg_gpio *hcg; 140 u32 ngpios; 141 int ret; 142 143 hcg = devm_kzalloc(dev, sizeof(struct creg_gpio), GFP_KERNEL); 144 if (!hcg) 145 return -ENOMEM; 146 147 hcg->regs = devm_platform_ioremap_resource(pdev, 0); 148 if (IS_ERR(hcg->regs)) 149 return PTR_ERR(hcg->regs); 150 151 match = of_match_node(creg_gpio_ids, pdev->dev.of_node); 152 hcg->layout = match->data; 153 if (!hcg->layout) 154 return -EINVAL; 155 156 ret = of_property_read_u32(dev->of_node, "ngpios", &ngpios); 157 if (ret) 158 return ret; 159 160 ret = creg_gpio_validate(dev, hcg, ngpios); 161 if (ret) 162 return ret; 163 164 spin_lock_init(&hcg->lock); 165 166 hcg->gc.parent = dev; 167 hcg->gc.label = dev_name(dev); 168 hcg->gc.base = -1; 169 hcg->gc.ngpio = ngpios; 170 hcg->gc.set = creg_gpio_set; 171 hcg->gc.direction_output = creg_gpio_dir_out; 172 173 ret = devm_gpiochip_add_data(dev, &hcg->gc, hcg); 174 if (ret) 175 return ret; 176 177 dev_info(dev, "GPIO controller with %d gpios probed\n", ngpios); 178 179 return 0; 180 } 181 182 static struct platform_driver creg_gpio_snps_driver = { 183 .driver = { 184 .name = "snps-creg-gpio", 185 .of_match_table = creg_gpio_ids, 186 }, 187 .probe = creg_gpio_probe, 188 }; 189 builtin_platform_driver(creg_gpio_snps_driver); 190