root/sound/soc/fsl/imx-audmux.c
// SPDX-License-Identifier: GPL-2.0+
//
// Copyright 2012 Freescale Semiconductor, Inc.
// Copyright 2012 Linaro Ltd.
// Copyright 2009 Pengutronix, Sascha Hauer <s.hauer@pengutronix.de>
//
// Initial development of this code was funded by
// Phytec Messtechnik GmbH, https://www.phytec.de

#include <linux/clk.h>
#include <linux/debugfs.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/slab.h>

#include "imx-audmux.h"

#define DRIVER_NAME "imx-audmux"

static struct clk *audmux_clk;
static void __iomem *audmux_base;
static u32 *regcache;
static u32 reg_max;

#define IMX_AUDMUX_V2_PTCR(x)           ((x) * 8)
#define IMX_AUDMUX_V2_PDCR(x)           ((x) * 8 + 4)

#ifdef CONFIG_DEBUG_FS
static struct dentry *audmux_debugfs_root;

/* There is an annoying discontinuity in the SSI numbering with regard
 * to the Linux number of the devices */
static const char *audmux_port_string(int port)
{
        switch (port) {
        case MX31_AUDMUX_PORT1_SSI0:
                return "imx-ssi.0";
        case MX31_AUDMUX_PORT2_SSI1:
                return "imx-ssi.1";
        case MX31_AUDMUX_PORT3_SSI_PINS_3:
                return "SSI3";
        case MX31_AUDMUX_PORT4_SSI_PINS_4:
                return "SSI4";
        case MX31_AUDMUX_PORT5_SSI_PINS_5:
                return "SSI5";
        case MX31_AUDMUX_PORT6_SSI_PINS_6:
                return "SSI6";
        default:
                return "UNKNOWN";
        }
}

static ssize_t audmux_read_file(struct file *file, char __user *user_buf,
                                size_t count, loff_t *ppos)
{
        ssize_t ret;
        char *buf;
        uintptr_t port = (uintptr_t)file->private_data;
        u32 pdcr, ptcr;

        ret = clk_prepare_enable(audmux_clk);
        if (ret)
                return ret;

        ptcr = readl(audmux_base + IMX_AUDMUX_V2_PTCR(port));
        pdcr = readl(audmux_base + IMX_AUDMUX_V2_PDCR(port));

        clk_disable_unprepare(audmux_clk);

        buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
        if (!buf)
                return -ENOMEM;

        ret = sysfs_emit(buf, "PDCR: %08x\nPTCR: %08x\n", pdcr, ptcr);

        if (ptcr & IMX_AUDMUX_V2_PTCR_TFSDIR)
                ret += scnprintf(buf + ret, PAGE_SIZE - ret,
                                "TxFS output from %s, ",
                                audmux_port_string((ptcr >> 27) & 0x7));
        else
                ret += scnprintf(buf + ret, PAGE_SIZE - ret,
                                "TxFS input, ");

        if (ptcr & IMX_AUDMUX_V2_PTCR_TCLKDIR)
                ret += scnprintf(buf + ret, PAGE_SIZE - ret,
                                "TxClk output from %s",
                                audmux_port_string((ptcr >> 22) & 0x7));
        else
                ret += scnprintf(buf + ret, PAGE_SIZE - ret,
                                "TxClk input");

        ret += scnprintf(buf + ret, PAGE_SIZE - ret, "\n");

        if (ptcr & IMX_AUDMUX_V2_PTCR_SYN) {
                ret += scnprintf(buf + ret, PAGE_SIZE - ret,
                                "Port is symmetric");
        } else {
                if (ptcr & IMX_AUDMUX_V2_PTCR_RFSDIR)
                        ret += scnprintf(buf + ret, PAGE_SIZE - ret,
                                        "RxFS output from %s, ",
                                        audmux_port_string((ptcr >> 17) & 0x7));
                else
                        ret += scnprintf(buf + ret, PAGE_SIZE - ret,
                                        "RxFS input, ");

                if (ptcr & IMX_AUDMUX_V2_PTCR_RCLKDIR)
                        ret += scnprintf(buf + ret, PAGE_SIZE - ret,
                                        "RxClk output from %s",
                                        audmux_port_string((ptcr >> 12) & 0x7));
                else
                        ret += scnprintf(buf + ret, PAGE_SIZE - ret,
                                        "RxClk input");
        }

        ret += scnprintf(buf + ret, PAGE_SIZE - ret,
                        "\nData received from %s\n",
                        audmux_port_string((pdcr >> 13) & 0x7));

        ret = simple_read_from_buffer(user_buf, count, ppos, buf, ret);

        kfree(buf);

        return ret;
}

static const struct file_operations audmux_debugfs_fops = {
        .open = simple_open,
        .read = audmux_read_file,
        .llseek = default_llseek,
};

static void audmux_debugfs_init(void)
{
        uintptr_t i;
        char buf[20];

        audmux_debugfs_root = debugfs_create_dir("audmux", NULL);

        for (i = 0; i < MX31_AUDMUX_PORT7_SSI_PINS_7 + 1; i++) {
                snprintf(buf, sizeof(buf), "ssi%lu", i);
                debugfs_create_file(buf, 0444, audmux_debugfs_root,
                                    (void *)i, &audmux_debugfs_fops);
        }
}

static void audmux_debugfs_remove(void)
{
        debugfs_remove_recursive(audmux_debugfs_root);
}
#else
static inline void audmux_debugfs_init(void)
{
}

static inline void audmux_debugfs_remove(void)
{
}
#endif

static enum imx_audmux_type {
        IMX21_AUDMUX,
        IMX31_AUDMUX,
} audmux_type;

static const struct of_device_id imx_audmux_dt_ids[] = {
        { .compatible = "fsl,imx21-audmux", .data = (void *)IMX21_AUDMUX, },
        { .compatible = "fsl,imx31-audmux", .data = (void *)IMX31_AUDMUX, },
        { /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, imx_audmux_dt_ids);

static const uint8_t port_mapping[] = {
        0x0, 0x4, 0x8, 0x10, 0x14, 0x1c,
};

int imx_audmux_v1_configure_port(unsigned int port, unsigned int pcr)
{
        if (audmux_type != IMX21_AUDMUX)
                return -EINVAL;

        if (!audmux_base)
                return -ENOSYS;

        if (port >= ARRAY_SIZE(port_mapping))
                return -EINVAL;

        writel(pcr, audmux_base + port_mapping[port]);

        return 0;
}
EXPORT_SYMBOL_GPL(imx_audmux_v1_configure_port);

int imx_audmux_v2_configure_port(unsigned int port, unsigned int ptcr,
                unsigned int pdcr)
{
        int ret;

        if (audmux_type != IMX31_AUDMUX)
                return -EINVAL;

        if (!audmux_base)
                return -ENOSYS;

        ret = clk_prepare_enable(audmux_clk);
        if (ret)
                return ret;

        writel(ptcr, audmux_base + IMX_AUDMUX_V2_PTCR(port));
        writel(pdcr, audmux_base + IMX_AUDMUX_V2_PDCR(port));

        clk_disable_unprepare(audmux_clk);

        return 0;
}
EXPORT_SYMBOL_GPL(imx_audmux_v2_configure_port);

static int imx_audmux_parse_dt_defaults(struct platform_device *pdev,
                struct device_node *of_node)
{
        struct device_node *child;

        for_each_available_child_of_node(of_node, child) {
                unsigned int port;
                unsigned int ptcr = 0;
                unsigned int pdcr = 0;
                unsigned int pcr = 0;
                unsigned int val;
                int ret;
                int i = 0;

                ret = of_property_read_u32(child, "fsl,audmux-port", &port);
                if (ret) {
                        dev_warn(&pdev->dev, "Failed to get fsl,audmux-port of child node \"%pOF\"\n",
                                        child);
                        continue;
                }
                if (!of_property_present(child, "fsl,port-config")) {
                        dev_warn(&pdev->dev, "child node \"%pOF\" does not have property fsl,port-config\n",
                                        child);
                        continue;
                }

                for (i = 0; (ret = of_property_read_u32_index(child,
                                        "fsl,port-config", i, &val)) == 0;
                                ++i) {
                        if (audmux_type == IMX31_AUDMUX) {
                                if (i % 2)
                                        pdcr |= val;
                                else
                                        ptcr |= val;
                        } else {
                                pcr |= val;
                        }
                }

                if (ret != -EOVERFLOW) {
                        dev_err(&pdev->dev, "Failed to read u32 at index %d of child %pOF\n",
                                        i, child);
                        continue;
                }

                if (audmux_type == IMX31_AUDMUX) {
                        if (i % 2) {
                                dev_err(&pdev->dev, "One pdcr value is missing in child node %pOF\n",
                                                child);
                                continue;
                        }
                        imx_audmux_v2_configure_port(port, ptcr, pdcr);
                } else {
                        imx_audmux_v1_configure_port(port, pcr);
                }
        }

        return 0;
}

static int imx_audmux_probe(struct platform_device *pdev)
{
        audmux_base = devm_platform_ioremap_resource(pdev, 0);
        if (IS_ERR(audmux_base))
                return PTR_ERR(audmux_base);

        audmux_clk = devm_clk_get(&pdev->dev, "audmux");
        if (IS_ERR(audmux_clk)) {
                dev_dbg(&pdev->dev, "cannot get clock: %ld\n",
                                PTR_ERR(audmux_clk));
                audmux_clk = NULL;
        }

        audmux_type = (uintptr_t)of_device_get_match_data(&pdev->dev);

        switch (audmux_type) {
        case IMX31_AUDMUX:
                audmux_debugfs_init();
                reg_max = 14;
                break;
        case IMX21_AUDMUX:
                reg_max = 6;
                break;
        default:
                dev_err(&pdev->dev, "unsupported version!\n");
                return -EINVAL;
        }

        regcache = devm_kcalloc(&pdev->dev, reg_max, sizeof(u32), GFP_KERNEL);
        if (!regcache)
                return -ENOMEM;

        imx_audmux_parse_dt_defaults(pdev, pdev->dev.of_node);

        return 0;
}

static void imx_audmux_remove(struct platform_device *pdev)
{
        if (audmux_type == IMX31_AUDMUX)
                audmux_debugfs_remove();
}

static int imx_audmux_suspend(struct device *dev)
{
        int i;

        clk_prepare_enable(audmux_clk);

        for (i = 0; i < reg_max; i++)
                regcache[i] = readl(audmux_base + i * 4);

        clk_disable_unprepare(audmux_clk);

        return 0;
}

static int imx_audmux_resume(struct device *dev)
{
        int i;

        clk_prepare_enable(audmux_clk);

        for (i = 0; i < reg_max; i++)
                writel(regcache[i], audmux_base + i * 4);

        clk_disable_unprepare(audmux_clk);

        return 0;
}

static const struct dev_pm_ops imx_audmux_pm = {
        SYSTEM_SLEEP_PM_OPS(imx_audmux_suspend, imx_audmux_resume)
};

static struct platform_driver imx_audmux_driver = {
        .probe          = imx_audmux_probe,
        .remove         = imx_audmux_remove,
        .driver = {
                .name   = DRIVER_NAME,
                .pm = pm_sleep_ptr(&imx_audmux_pm),
                .of_match_table = imx_audmux_dt_ids,
        }
};

static int __init imx_audmux_init(void)
{
        return platform_driver_register(&imx_audmux_driver);
}
subsys_initcall(imx_audmux_init);

static void __exit imx_audmux_exit(void)
{
        platform_driver_unregister(&imx_audmux_driver);
}
module_exit(imx_audmux_exit);

MODULE_DESCRIPTION("Freescale i.MX AUDMUX driver");
MODULE_AUTHOR("Sascha Hauer <s.hauer@pengutronix.de>");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:" DRIVER_NAME);