root/drivers/soc/aspeed/aspeed-uart-routing.c
// SPDX-License-Identifier: GPL-2.0+
/*
 * Copyright (c) 2018 Google LLC
 * Copyright (c) 2021 Aspeed Technology Inc.
 */
#include <linux/device.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/mfd/syscon.h>
#include <linux/regmap.h>
#include <linux/platform_device.h>

/* register offsets */
#define HICR9   0x98
#define HICRA   0x9c

/* attributes options */
#define UART_ROUTING_IO1        "io1"
#define UART_ROUTING_IO2        "io2"
#define UART_ROUTING_IO3        "io3"
#define UART_ROUTING_IO4        "io4"
#define UART_ROUTING_IO5        "io5"
#define UART_ROUTING_IO6        "io6"
#define UART_ROUTING_IO10       "io10"
#define UART_ROUTING_UART1      "uart1"
#define UART_ROUTING_UART2      "uart2"
#define UART_ROUTING_UART3      "uart3"
#define UART_ROUTING_UART4      "uart4"
#define UART_ROUTING_UART5      "uart5"
#define UART_ROUTING_UART6      "uart6"
#define UART_ROUTING_UART10     "uart10"
#define UART_ROUTING_RES        "reserved"

struct aspeed_uart_routing {
        struct regmap *map;
        struct attribute_group const *attr_grp;
};

struct aspeed_uart_routing_selector {
        struct device_attribute dev_attr;
        uint8_t reg;
        uint8_t mask;
        uint8_t shift;
        const char *const options[];
};

#define to_routing_selector(_dev_attr)                                  \
        container_of(_dev_attr, struct aspeed_uart_routing_selector, dev_attr)

static ssize_t aspeed_uart_routing_show(struct device *dev,
                                        struct device_attribute *attr,
                                        char *buf);

static ssize_t aspeed_uart_routing_store(struct device *dev,
                                         struct device_attribute *attr,
                                         const char *buf, size_t count);

#define ROUTING_ATTR(_name) {                                   \
        .attr = {.name = _name,                                 \
                 .mode = VERIFY_OCTAL_PERMISSIONS(0644) },      \
        .show = aspeed_uart_routing_show,                       \
        .store = aspeed_uart_routing_store,                     \
}

/* routing selector for AST25xx */
static struct aspeed_uart_routing_selector ast2500_io6_sel = {
        .dev_attr = ROUTING_ATTR(UART_ROUTING_IO6),
        .reg = HICR9,
        .shift = 8,
        .mask = 0xf,
        .options = {
                    UART_ROUTING_UART1,
                    UART_ROUTING_UART2,
                    UART_ROUTING_UART3,
                    UART_ROUTING_UART4,
                    UART_ROUTING_UART5,
                    UART_ROUTING_IO1,
                    UART_ROUTING_IO2,
                    UART_ROUTING_IO3,
                    UART_ROUTING_IO4,
                    UART_ROUTING_IO5,
                    NULL,
                    },
};

static struct aspeed_uart_routing_selector ast2500_uart5_sel = {
        .dev_attr = ROUTING_ATTR(UART_ROUTING_UART5),
        .reg = HICRA,
        .shift = 28,
        .mask = 0xf,
        .options = {
                    UART_ROUTING_IO5,
                    UART_ROUTING_IO1,
                    UART_ROUTING_IO2,
                    UART_ROUTING_IO3,
                    UART_ROUTING_IO4,
                    UART_ROUTING_UART1,
                    UART_ROUTING_UART2,
                    UART_ROUTING_UART3,
                    UART_ROUTING_UART4,
                    UART_ROUTING_IO6,
                    NULL,
                    },
};

static struct aspeed_uart_routing_selector ast2500_uart4_sel = {
        .dev_attr = ROUTING_ATTR(UART_ROUTING_UART4),
        .reg = HICRA,
        .shift = 25,
        .mask = 0x7,
        .options = {
                    UART_ROUTING_IO4,
                    UART_ROUTING_IO1,
                    UART_ROUTING_IO2,
                    UART_ROUTING_IO3,
                    UART_ROUTING_UART1,
                    UART_ROUTING_UART2,
                    UART_ROUTING_UART3,
                    UART_ROUTING_IO6,
                    NULL,
        },
};

static struct aspeed_uart_routing_selector ast2500_uart3_sel = {
        .dev_attr = ROUTING_ATTR(UART_ROUTING_UART3),
        .reg = HICRA,
        .shift = 22,
        .mask = 0x7,
        .options = {
                    UART_ROUTING_IO3,
                    UART_ROUTING_IO4,
                    UART_ROUTING_IO1,
                    UART_ROUTING_IO2,
                    UART_ROUTING_UART4,
                    UART_ROUTING_UART1,
                    UART_ROUTING_UART2,
                    UART_ROUTING_IO6,
                    NULL,
                    },
};

static struct aspeed_uart_routing_selector ast2500_uart2_sel = {
        .dev_attr = ROUTING_ATTR(UART_ROUTING_UART2),
        .reg = HICRA,
        .shift = 19,
        .mask = 0x7,
        .options = {
                    UART_ROUTING_IO2,
                    UART_ROUTING_IO3,
                    UART_ROUTING_IO4,
                    UART_ROUTING_IO1,
                    UART_ROUTING_UART3,
                    UART_ROUTING_UART4,
                    UART_ROUTING_UART1,
                    UART_ROUTING_IO6,
                    NULL,
                    },
};

static struct aspeed_uart_routing_selector ast2500_uart1_sel = {
        .dev_attr = ROUTING_ATTR(UART_ROUTING_UART1),
        .reg = HICRA,
        .shift = 16,
        .mask = 0x7,
        .options = {
                    UART_ROUTING_IO1,
                    UART_ROUTING_IO2,
                    UART_ROUTING_IO3,
                    UART_ROUTING_IO4,
                    UART_ROUTING_UART2,
                    UART_ROUTING_UART3,
                    UART_ROUTING_UART4,
                    UART_ROUTING_IO6,
                    NULL,
                    },
};

static struct aspeed_uart_routing_selector ast2500_io5_sel = {
        .dev_attr = ROUTING_ATTR(UART_ROUTING_IO5),
        .reg = HICRA,
        .shift = 12,
        .mask = 0x7,
        .options = {
                    UART_ROUTING_UART5,
                    UART_ROUTING_UART1,
                    UART_ROUTING_UART2,
                    UART_ROUTING_UART3,
                    UART_ROUTING_UART4,
                    UART_ROUTING_IO1,
                    UART_ROUTING_IO3,
                    UART_ROUTING_IO6,
                    NULL,
                    },
};

static struct aspeed_uart_routing_selector ast2500_io4_sel = {
        .dev_attr = ROUTING_ATTR(UART_ROUTING_IO4),
        .reg = HICRA,
        .shift = 9,
        .mask = 0x7,
        .options = {
                    UART_ROUTING_UART4,
                    UART_ROUTING_UART5,
                    UART_ROUTING_UART1,
                    UART_ROUTING_UART2,
                    UART_ROUTING_UART3,
                    UART_ROUTING_IO1,
                    UART_ROUTING_IO2,
                    UART_ROUTING_IO6,
                    NULL,
                    },
};

static struct aspeed_uart_routing_selector ast2500_io3_sel = {
        .dev_attr = ROUTING_ATTR(UART_ROUTING_IO3),
        .reg = HICRA,
        .shift = 6,
        .mask = 0x7,
        .options = {
                    UART_ROUTING_UART3,
                    UART_ROUTING_UART4,
                    UART_ROUTING_UART5,
                    UART_ROUTING_UART1,
                    UART_ROUTING_UART2,
                    UART_ROUTING_IO1,
                    UART_ROUTING_IO2,
                    UART_ROUTING_IO6,
                    NULL,
                    },
};

static struct aspeed_uart_routing_selector ast2500_io2_sel = {
        .dev_attr = ROUTING_ATTR(UART_ROUTING_IO2),
        .reg = HICRA,
        .shift = 3,
        .mask = 0x7,
        .options = {
                    UART_ROUTING_UART2,
                    UART_ROUTING_UART3,
                    UART_ROUTING_UART4,
                    UART_ROUTING_UART5,
                    UART_ROUTING_UART1,
                    UART_ROUTING_IO3,
                    UART_ROUTING_IO4,
                    UART_ROUTING_IO6,
                    NULL,
                    },
};

static struct aspeed_uart_routing_selector ast2500_io1_sel = {
        .dev_attr = ROUTING_ATTR(UART_ROUTING_IO1),
        .reg = HICRA,
        .shift = 0,
        .mask = 0x7,
        .options = {
                    UART_ROUTING_UART1,
                    UART_ROUTING_UART2,
                    UART_ROUTING_UART3,
                    UART_ROUTING_UART4,
                    UART_ROUTING_UART5,
                    UART_ROUTING_IO3,
                    UART_ROUTING_IO4,
                    UART_ROUTING_IO6,
                    NULL,
                    },
};

static struct attribute *ast2500_uart_routing_attrs[] = {
        &ast2500_io6_sel.dev_attr.attr,
        &ast2500_uart5_sel.dev_attr.attr,
        &ast2500_uart4_sel.dev_attr.attr,
        &ast2500_uart3_sel.dev_attr.attr,
        &ast2500_uart2_sel.dev_attr.attr,
        &ast2500_uart1_sel.dev_attr.attr,
        &ast2500_io5_sel.dev_attr.attr,
        &ast2500_io4_sel.dev_attr.attr,
        &ast2500_io3_sel.dev_attr.attr,
        &ast2500_io2_sel.dev_attr.attr,
        &ast2500_io1_sel.dev_attr.attr,
        NULL,
};

static const struct attribute_group ast2500_uart_routing_attr_group = {
        .attrs = ast2500_uart_routing_attrs,
};

/* routing selector for AST26xx */
static struct aspeed_uart_routing_selector ast2600_uart10_sel = {
        .dev_attr = ROUTING_ATTR(UART_ROUTING_UART10),
        .reg = HICR9,
        .shift = 12,
        .mask = 0xf,
        .options = {
                    UART_ROUTING_IO10,
                    UART_ROUTING_IO1,
                    UART_ROUTING_IO2,
                    UART_ROUTING_IO3,
                    UART_ROUTING_IO4,
                        UART_ROUTING_RES,
                    UART_ROUTING_UART1,
                    UART_ROUTING_UART2,
                    UART_ROUTING_UART3,
                    UART_ROUTING_UART4,
                    NULL,
                    },
};

static struct aspeed_uart_routing_selector ast2600_io10_sel = {
        .dev_attr = ROUTING_ATTR(UART_ROUTING_IO10),
        .reg = HICR9,
        .shift = 8,
        .mask = 0xf,
        .options = {
                    UART_ROUTING_UART1,
                    UART_ROUTING_UART2,
                    UART_ROUTING_UART3,
                    UART_ROUTING_UART4,
                        UART_ROUTING_RES,
                    UART_ROUTING_IO1,
                    UART_ROUTING_IO2,
                    UART_ROUTING_IO3,
                    UART_ROUTING_IO4,
                        UART_ROUTING_RES,
                    UART_ROUTING_UART10,
                    NULL,
                    },
};

static struct aspeed_uart_routing_selector ast2600_uart4_sel = {
        .dev_attr = ROUTING_ATTR(UART_ROUTING_UART4),
        .reg = HICRA,
        .shift = 25,
        .mask = 0x7,
        .options = {
                    UART_ROUTING_IO4,
                    UART_ROUTING_IO1,
                    UART_ROUTING_IO2,
                    UART_ROUTING_IO3,
                    UART_ROUTING_UART1,
                    UART_ROUTING_UART2,
                    UART_ROUTING_UART3,
                    UART_ROUTING_IO10,
                    NULL,
        },
};

static struct aspeed_uart_routing_selector ast2600_uart3_sel = {
        .dev_attr = ROUTING_ATTR(UART_ROUTING_UART3),
        .reg = HICRA,
        .shift = 22,
        .mask = 0x7,
        .options = {
                    UART_ROUTING_IO3,
                    UART_ROUTING_IO4,
                    UART_ROUTING_IO1,
                    UART_ROUTING_IO2,
                    UART_ROUTING_UART4,
                    UART_ROUTING_UART1,
                    UART_ROUTING_UART2,
                    UART_ROUTING_IO10,
                    NULL,
                    },
};

static struct aspeed_uart_routing_selector ast2600_uart2_sel = {
        .dev_attr = ROUTING_ATTR(UART_ROUTING_UART2),
        .reg = HICRA,
        .shift = 19,
        .mask = 0x7,
        .options = {
                    UART_ROUTING_IO2,
                    UART_ROUTING_IO3,
                    UART_ROUTING_IO4,
                    UART_ROUTING_IO1,
                    UART_ROUTING_UART3,
                    UART_ROUTING_UART4,
                    UART_ROUTING_UART1,
                    UART_ROUTING_IO10,
                    NULL,
                    },
};

static struct aspeed_uart_routing_selector ast2600_uart1_sel = {
        .dev_attr = ROUTING_ATTR(UART_ROUTING_UART1),
        .reg = HICRA,
        .shift = 16,
        .mask = 0x7,
        .options = {
                    UART_ROUTING_IO1,
                    UART_ROUTING_IO2,
                    UART_ROUTING_IO3,
                    UART_ROUTING_IO4,
                    UART_ROUTING_UART2,
                    UART_ROUTING_UART3,
                    UART_ROUTING_UART4,
                    UART_ROUTING_IO10,
                    NULL,
                    },
};

static struct aspeed_uart_routing_selector ast2600_io4_sel = {
        .dev_attr = ROUTING_ATTR(UART_ROUTING_IO4),
        .reg = HICRA,
        .shift = 9,
        .mask = 0x7,
        .options = {
                    UART_ROUTING_UART4,
                    UART_ROUTING_UART10,
                    UART_ROUTING_UART1,
                    UART_ROUTING_UART2,
                    UART_ROUTING_UART3,
                    UART_ROUTING_IO1,
                    UART_ROUTING_IO2,
                    UART_ROUTING_IO10,
                    NULL,
                    },
};

static struct aspeed_uart_routing_selector ast2600_io3_sel = {
        .dev_attr = ROUTING_ATTR(UART_ROUTING_IO3),
        .reg = HICRA,
        .shift = 6,
        .mask = 0x7,
        .options = {
                    UART_ROUTING_UART3,
                    UART_ROUTING_UART4,
                    UART_ROUTING_UART10,
                    UART_ROUTING_UART1,
                    UART_ROUTING_UART2,
                    UART_ROUTING_IO1,
                    UART_ROUTING_IO2,
                    UART_ROUTING_IO10,
                    NULL,
                    },
};

static struct aspeed_uart_routing_selector ast2600_io2_sel = {
        .dev_attr = ROUTING_ATTR(UART_ROUTING_IO2),
        .reg = HICRA,
        .shift = 3,
        .mask = 0x7,
        .options = {
                    UART_ROUTING_UART2,
                    UART_ROUTING_UART3,
                    UART_ROUTING_UART4,
                    UART_ROUTING_UART10,
                    UART_ROUTING_UART1,
                    UART_ROUTING_IO3,
                    UART_ROUTING_IO4,
                    UART_ROUTING_IO10,
                    NULL,
                    },
};

static struct aspeed_uart_routing_selector ast2600_io1_sel = {
        .dev_attr = ROUTING_ATTR(UART_ROUTING_IO1),
        .reg = HICRA,
        .shift = 0,
        .mask = 0x7,
        .options = {
                    UART_ROUTING_UART1,
                    UART_ROUTING_UART2,
                    UART_ROUTING_UART3,
                    UART_ROUTING_UART4,
                    UART_ROUTING_UART10,
                    UART_ROUTING_IO3,
                    UART_ROUTING_IO4,
                    UART_ROUTING_IO10,
                    NULL,
                    },
};

static struct attribute *ast2600_uart_routing_attrs[] = {
        &ast2600_uart10_sel.dev_attr.attr,
        &ast2600_io10_sel.dev_attr.attr,
        &ast2600_uart4_sel.dev_attr.attr,
        &ast2600_uart3_sel.dev_attr.attr,
        &ast2600_uart2_sel.dev_attr.attr,
        &ast2600_uart1_sel.dev_attr.attr,
        &ast2600_io4_sel.dev_attr.attr,
        &ast2600_io3_sel.dev_attr.attr,
        &ast2600_io2_sel.dev_attr.attr,
        &ast2600_io1_sel.dev_attr.attr,
        NULL,
};

static const struct attribute_group ast2600_uart_routing_attr_group = {
        .attrs = ast2600_uart_routing_attrs,
};

static ssize_t aspeed_uart_routing_show(struct device *dev,
                                        struct device_attribute *attr,
                                        char *buf)
{
        struct aspeed_uart_routing *uart_routing = dev_get_drvdata(dev);
        struct aspeed_uart_routing_selector *sel = to_routing_selector(attr);
        int val, pos, len;

        regmap_read(uart_routing->map, sel->reg, &val);
        val = (val >> sel->shift) & sel->mask;

        len = 0;
        for (pos = 0; sel->options[pos] != NULL; ++pos) {
                if (pos == val)
                        len += sysfs_emit_at(buf, len, "[%s] ", sel->options[pos]);
                else
                        len += sysfs_emit_at(buf, len, "%s ", sel->options[pos]);
        }

        if (val >= pos)
                len += sysfs_emit_at(buf, len, "[unknown(%d)]", val);

        len += sysfs_emit_at(buf, len, "\n");

        return len;
}

static ssize_t aspeed_uart_routing_store(struct device *dev,
                                         struct device_attribute *attr,
                                         const char *buf, size_t count)
{
        struct aspeed_uart_routing *uart_routing = dev_get_drvdata(dev);
        struct aspeed_uart_routing_selector *sel = to_routing_selector(attr);
        int val;

        val = __sysfs_match_string(sel->options, -1, buf);
        if (val < 0) {
                dev_err(dev, "invalid value \"%s\"\n", buf);
                return -EINVAL;
        }

        regmap_update_bits(uart_routing->map, sel->reg,
                        (sel->mask << sel->shift),
                        (val & sel->mask) << sel->shift);

        return count;
}

static int aspeed_uart_routing_probe(struct platform_device *pdev)
{
        int rc;
        struct device *dev = &pdev->dev;
        struct aspeed_uart_routing *uart_routing;

        uart_routing = devm_kzalloc(&pdev->dev, sizeof(*uart_routing), GFP_KERNEL);
        if (!uart_routing)
                return -ENOMEM;

        uart_routing->map = syscon_node_to_regmap(dev->parent->of_node);
        if (IS_ERR(uart_routing->map)) {
                dev_err(dev, "cannot get regmap\n");
                return PTR_ERR(uart_routing->map);
        }

        uart_routing->attr_grp = of_device_get_match_data(dev);

        rc = sysfs_create_group(&dev->kobj, uart_routing->attr_grp);
        if (rc < 0)
                return rc;

        dev_set_drvdata(dev, uart_routing);

        dev_info(dev, "module loaded\n");

        return 0;
}

static void aspeed_uart_routing_remove(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        struct aspeed_uart_routing *uart_routing = platform_get_drvdata(pdev);

        sysfs_remove_group(&dev->kobj, uart_routing->attr_grp);
}

static const struct of_device_id aspeed_uart_routing_table[] = {
        { .compatible = "aspeed,ast2400-uart-routing",
          .data = &ast2500_uart_routing_attr_group },
        { .compatible = "aspeed,ast2500-uart-routing",
          .data = &ast2500_uart_routing_attr_group },
        { .compatible = "aspeed,ast2600-uart-routing",
          .data = &ast2600_uart_routing_attr_group },
        { },
};

static struct platform_driver aspeed_uart_routing_driver = {
        .driver = {
                .name = "aspeed-uart-routing",
                .of_match_table = aspeed_uart_routing_table,
        },
        .probe = aspeed_uart_routing_probe,
        .remove = aspeed_uart_routing_remove,
};

module_platform_driver(aspeed_uart_routing_driver);

MODULE_AUTHOR("Oskar Senft <osk@google.com>");
MODULE_AUTHOR("Chia-Wei Wang <chiawei_wang@aspeedtech.com>");
MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("Driver to configure Aspeed UART routing");