// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Driver for Allwinner sunXi IR controller
 *
 * Copyright (C) 2014 Alexsey Shestacov <wingrime@linux-sunxi.org>
 * Copyright (C) 2014 Alexander Bersenev <bay@hackerdom.ru>
 *
 * Based on sun5i-ir.c:
 * Copyright (C) 2007-2012 Daniel Wang
 * Allwinner Technology Co., Ltd. <www.allwinnertech.com>
 */

#include <linux/clk.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/reset.h>
#include <media/rc-core.h>

#define SUNXI_IR_DEV "sunxi-ir"

/* Registers */
/* IR Control */
#define SUNXI_IR_CTL_REG      0x00
/* Global Enable */
#define REG_CTL_GEN                     BIT(0)
/* RX block enable */
#define REG_CTL_RXEN                    BIT(1)
/* CIR mode */
#define REG_CTL_MD                      (BIT(4) | BIT(5))

/* Rx Config */
#define SUNXI_IR_RXCTL_REG    0x10
/* Pulse Polarity Invert flag */
#define REG_RXCTL_RPPI                  BIT(2)

/* Rx Data */
#define SUNXI_IR_RXFIFO_REG   0x20

/* Rx Interrupt Enable */
#define SUNXI_IR_RXINT_REG    0x2C
/* Rx FIFO Overflow Interrupt Enable */
#define REG_RXINT_ROI_EN                BIT(0)
/* Rx Packet End Interrupt Enable */
#define REG_RXINT_RPEI_EN               BIT(1)
/* Rx FIFO Data Available Interrupt Enable */
#define REG_RXINT_RAI_EN                BIT(4)

/* Rx FIFO available byte level */
#define REG_RXINT_RAL(val)    ((val) << 8)

/* Rx Interrupt Status */
#define SUNXI_IR_RXSTA_REG    0x30
/* Rx FIFO Overflow */
#define REG_RXSTA_ROI                   REG_RXINT_ROI_EN
/* Rx Packet End */
#define REG_RXSTA_RPE                   REG_RXINT_RPEI_EN
/* Rx FIFO Data Available */
#define REG_RXSTA_RA                    REG_RXINT_RAI_EN
/* RX FIFO Get Available Counter */
#define REG_RXSTA_GET_AC(val) (((val) >> 8) & (ir->fifo_size * 2 - 1))
/* Clear all interrupt status value */
#define REG_RXSTA_CLEARALL    0xff

/* IR Sample Config */
#define SUNXI_IR_CIR_REG      0x34
/* CIR_REG register noise threshold */
#define REG_CIR_NTHR(val)    (((val) << 2) & (GENMASK(7, 2)))
/* CIR_REG register idle threshold */
#define REG_CIR_ITHR(val)    (((val) << 8) & (GENMASK(15, 8)))

/* Required frequency for IR0 or IR1 clock in CIR mode (default) */
#define SUNXI_IR_BASE_CLK     8000000
/* Noise threshold in samples  */
#define SUNXI_IR_RXNOISE      1

/**
 * struct sunxi_ir_quirks - Differences between SoC variants.
 *
 * @has_reset: SoC needs reset deasserted.
 * @fifo_size: size of the fifo.
 */
struct sunxi_ir_quirks {
        bool            has_reset;
        int             fifo_size;
};

struct sunxi_ir {
        struct rc_dev   *rc;
        void __iomem    *base;
        int             irq;
        int             fifo_size;
        struct clk      *clk;
        struct clk      *apb_clk;
        struct reset_control *rst;
        const char      *map_name;
};

static irqreturn_t sunxi_ir_irq(int irqno, void *dev_id)
{
        unsigned long status;
        unsigned char dt;
        unsigned int cnt, rc;
        struct sunxi_ir *ir = dev_id;
        struct ir_raw_event rawir = {};

        status = readl(ir->base + SUNXI_IR_RXSTA_REG);

        /* clean all pending statuses */
        writel(status | REG_RXSTA_CLEARALL, ir->base + SUNXI_IR_RXSTA_REG);

        if (status & (REG_RXSTA_RA | REG_RXSTA_RPE)) {
                /* How many messages in fifo */
                rc  = REG_RXSTA_GET_AC(status);
                /* Sanity check */
                rc = rc > ir->fifo_size ? ir->fifo_size : rc;
                /* If we have data */
                for (cnt = 0; cnt < rc; cnt++) {
                        /* for each bit in fifo */
                        dt = readb(ir->base + SUNXI_IR_RXFIFO_REG);
                        rawir.pulse = (dt & 0x80) != 0;
                        rawir.duration = ((dt & 0x7f) + 1) *
                                         ir->rc->rx_resolution;
                        ir_raw_event_store_with_filter(ir->rc, &rawir);
                }
        }

        if (status & REG_RXSTA_ROI) {
                ir_raw_event_overflow(ir->rc);
        } else if (status & REG_RXSTA_RPE) {
                ir_raw_event_set_idle(ir->rc, true);
                ir_raw_event_handle(ir->rc);
        } else {
                ir_raw_event_handle(ir->rc);
        }

        return IRQ_HANDLED;
}

/* Convert idle threshold to usec */
static unsigned int sunxi_ithr_to_usec(unsigned int base_clk, unsigned int ithr)
{
        return DIV_ROUND_CLOSEST(USEC_PER_SEC * (ithr + 1),
                                 base_clk / (128 * 64));
}

/* Convert usec to idle threshold */
static unsigned int sunxi_usec_to_ithr(unsigned int base_clk, unsigned int usec)
{
        /* make sure we don't end up with a timeout less than requested */
        return DIV_ROUND_UP((base_clk / (128 * 64)) * usec,  USEC_PER_SEC) - 1;
}

static int sunxi_ir_set_timeout(struct rc_dev *rc_dev, unsigned int timeout)
{
        struct sunxi_ir *ir = rc_dev->priv;
        unsigned int base_clk = clk_get_rate(ir->clk);

        unsigned int ithr = sunxi_usec_to_ithr(base_clk, timeout);

        dev_dbg(rc_dev->dev.parent, "setting idle threshold to %u\n", ithr);

        /* Set noise threshold and idle threshold */
        writel(REG_CIR_NTHR(SUNXI_IR_RXNOISE) | REG_CIR_ITHR(ithr),
               ir->base + SUNXI_IR_CIR_REG);

        rc_dev->timeout = sunxi_ithr_to_usec(base_clk, ithr);

        return 0;
}

static int sunxi_ir_hw_init(struct device *dev)
{
        struct sunxi_ir *ir = dev_get_drvdata(dev);
        u32 tmp;
        int ret;

        ret = reset_control_deassert(ir->rst);
        if (ret)
                return ret;

        ret = clk_prepare_enable(ir->apb_clk);
        if (ret) {
                dev_err(dev, "failed to enable apb clk\n");
                goto exit_assert_reset;
        }

        ret = clk_prepare_enable(ir->clk);
        if (ret) {
                dev_err(dev, "failed to enable ir clk\n");
                goto exit_disable_apb_clk;
        }

        /* Enable CIR Mode */
        writel(REG_CTL_MD, ir->base + SUNXI_IR_CTL_REG);

        /* Set noise threshold and idle threshold */
        sunxi_ir_set_timeout(ir->rc, ir->rc->timeout);

        /* Invert Input Signal */
        writel(REG_RXCTL_RPPI, ir->base + SUNXI_IR_RXCTL_REG);

        /* Clear All Rx Interrupt Status */
        writel(REG_RXSTA_CLEARALL, ir->base + SUNXI_IR_RXSTA_REG);

        /*
         * Enable IRQ on overflow, packet end, FIFO available with trigger
         * level
         */
        writel(REG_RXINT_ROI_EN | REG_RXINT_RPEI_EN |
               REG_RXINT_RAI_EN | REG_RXINT_RAL(ir->fifo_size / 2 - 1),
               ir->base + SUNXI_IR_RXINT_REG);

        /* Enable IR Module */
        tmp = readl(ir->base + SUNXI_IR_CTL_REG);
        writel(tmp | REG_CTL_GEN | REG_CTL_RXEN, ir->base + SUNXI_IR_CTL_REG);

        return 0;

exit_disable_apb_clk:
        clk_disable_unprepare(ir->apb_clk);
exit_assert_reset:
        reset_control_assert(ir->rst);

        return ret;
}

static void sunxi_ir_hw_exit(struct device *dev)
{
        struct sunxi_ir *ir = dev_get_drvdata(dev);

        clk_disable_unprepare(ir->clk);
        clk_disable_unprepare(ir->apb_clk);
        reset_control_assert(ir->rst);
}

static int __maybe_unused sunxi_ir_suspend(struct device *dev)
{
        sunxi_ir_hw_exit(dev);

        return 0;
}

static int __maybe_unused sunxi_ir_resume(struct device *dev)
{
        return sunxi_ir_hw_init(dev);
}

static SIMPLE_DEV_PM_OPS(sunxi_ir_pm_ops, sunxi_ir_suspend, sunxi_ir_resume);

static int sunxi_ir_probe(struct platform_device *pdev)
{
        int ret = 0;

        struct device *dev = &pdev->dev;
        struct device_node *dn = dev->of_node;
        const struct sunxi_ir_quirks *quirks;
        struct sunxi_ir *ir;
        u32 b_clk_freq = SUNXI_IR_BASE_CLK;

        ir = devm_kzalloc(dev, sizeof(struct sunxi_ir), GFP_KERNEL);
        if (!ir)
                return -ENOMEM;

        quirks = of_device_get_match_data(&pdev->dev);
        if (!quirks) {
                dev_err(&pdev->dev, "Failed to determine the quirks to use\n");
                return -ENODEV;
        }

        ir->fifo_size = quirks->fifo_size;

        /* Clock */
        ir->apb_clk = devm_clk_get(dev, "apb");
        if (IS_ERR(ir->apb_clk)) {
                dev_err(dev, "failed to get a apb clock.\n");
                return PTR_ERR(ir->apb_clk);
        }
        ir->clk = devm_clk_get(dev, "ir");
        if (IS_ERR(ir->clk)) {
                dev_err(dev, "failed to get a ir clock.\n");
                return PTR_ERR(ir->clk);
        }

        /* Base clock frequency (optional) */
        of_property_read_u32(dn, "clock-frequency", &b_clk_freq);

        /* Reset */
        if (quirks->has_reset) {
                ir->rst = devm_reset_control_get_exclusive(dev, NULL);
                if (IS_ERR(ir->rst))
                        return PTR_ERR(ir->rst);
        }

        ret = clk_set_rate(ir->clk, b_clk_freq);
        if (ret) {
                dev_err(dev, "set ir base clock failed!\n");
                return ret;
        }
        dev_dbg(dev, "set base clock frequency to %d Hz.\n", b_clk_freq);

        /* IO */
        ir->base = devm_platform_ioremap_resource(pdev, 0);
        if (IS_ERR(ir->base)) {
                return PTR_ERR(ir->base);
        }

        ir->rc = rc_allocate_device(RC_DRIVER_IR_RAW);
        if (!ir->rc) {
                dev_err(dev, "failed to allocate device\n");
                return -ENOMEM;
        }

        ir->rc->priv = ir;
        ir->rc->device_name = SUNXI_IR_DEV;
        ir->rc->input_phys = "sunxi-ir/input0";
        ir->rc->input_id.bustype = BUS_HOST;
        ir->rc->input_id.vendor = 0x0001;
        ir->rc->input_id.product = 0x0001;
        ir->rc->input_id.version = 0x0100;
        ir->map_name = of_get_property(dn, "linux,rc-map-name", NULL);
        ir->rc->map_name = ir->map_name ?: RC_MAP_EMPTY;
        ir->rc->dev.parent = dev;
        ir->rc->allowed_protocols = RC_PROTO_BIT_ALL_IR_DECODER;
        /* Frequency after IR internal divider with sample period in us */
        ir->rc->rx_resolution = (USEC_PER_SEC / (b_clk_freq / 64));
        ir->rc->timeout = IR_DEFAULT_TIMEOUT;
        ir->rc->min_timeout = sunxi_ithr_to_usec(b_clk_freq, 0);
        ir->rc->max_timeout = sunxi_ithr_to_usec(b_clk_freq, 255);
        ir->rc->s_timeout = sunxi_ir_set_timeout;
        ir->rc->driver_name = SUNXI_IR_DEV;

        ret = rc_register_device(ir->rc);
        if (ret) {
                dev_err(dev, "failed to register rc device\n");
                goto exit_free_dev;
        }

        platform_set_drvdata(pdev, ir);

        /* IRQ */
        ir->irq = platform_get_irq(pdev, 0);
        if (ir->irq < 0) {
                ret = ir->irq;
                goto exit_free_dev;
        }

        ret = devm_request_irq(dev, ir->irq, sunxi_ir_irq, 0, SUNXI_IR_DEV, ir);
        if (ret) {
                dev_err(dev, "failed request irq\n");
                goto exit_free_dev;
        }

        ret = sunxi_ir_hw_init(dev);
        if (ret)
                goto exit_free_dev;

        dev_info(dev, "initialized sunXi IR driver\n");
        return 0;

exit_free_dev:
        rc_free_device(ir->rc);

        return ret;
}

static void sunxi_ir_remove(struct platform_device *pdev)
{
        struct sunxi_ir *ir = platform_get_drvdata(pdev);

        rc_unregister_device(ir->rc);
        sunxi_ir_hw_exit(&pdev->dev);
}

static void sunxi_ir_shutdown(struct platform_device *pdev)
{
        sunxi_ir_hw_exit(&pdev->dev);
}

static const struct sunxi_ir_quirks sun4i_a10_ir_quirks = {
        .has_reset = false,
        .fifo_size = 16,
};

static const struct sunxi_ir_quirks sun5i_a13_ir_quirks = {
        .has_reset = false,
        .fifo_size = 64,
};

static const struct sunxi_ir_quirks sun6i_a31_ir_quirks = {
        .has_reset = true,
        .fifo_size = 64,
};

static const struct of_device_id sunxi_ir_match[] = {
        {
                .compatible = "allwinner,sun4i-a10-ir",
                .data = &sun4i_a10_ir_quirks,
        },
        {
                .compatible = "allwinner,sun5i-a13-ir",
                .data = &sun5i_a13_ir_quirks,
        },
        {
                .compatible = "allwinner,sun6i-a31-ir",
                .data = &sun6i_a31_ir_quirks,
        },
        {}
};
MODULE_DEVICE_TABLE(of, sunxi_ir_match);

static struct platform_driver sunxi_ir_driver = {
        .probe          = sunxi_ir_probe,
        .remove         = sunxi_ir_remove,
        .shutdown       = sunxi_ir_shutdown,
        .driver = {
                .name = SUNXI_IR_DEV,
                .of_match_table = sunxi_ir_match,
                .pm = &sunxi_ir_pm_ops,
        },
};

module_platform_driver(sunxi_ir_driver);

MODULE_DESCRIPTION("Allwinner sunXi IR controller driver");
MODULE_AUTHOR("Alexsey Shestacov <wingrime@linux-sunxi.org>");
MODULE_LICENSE("GPL");