// SPDX-License-Identifier: GPL-2.0-only
/*
 * TI Touch Screen / ADC MFD driver
 *
 * Copyright (C) 2012 Texas Instruments Incorporated - https://www.ti.com/
 */

#include <linux/module.h>
#include <linux/slab.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/clk.h>
#include <linux/regmap.h>
#include <linux/mfd/core.h>
#include <linux/pm_runtime.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/sched.h>

#include <linux/mfd/ti_am335x_tscadc.h>

static const struct regmap_config tscadc_regmap_config = {
        .name = "ti_tscadc",
        .reg_bits = 32,
        .reg_stride = 4,
        .val_bits = 32,
};

void am335x_tsc_se_set_cache(struct ti_tscadc_dev *tscadc, u32 val)
{
        unsigned long flags;

        spin_lock_irqsave(&tscadc->reg_lock, flags);
        tscadc->reg_se_cache |= val;
        if (tscadc->adc_waiting)
                wake_up(&tscadc->reg_se_wait);
        else if (!tscadc->adc_in_use)
                regmap_write(tscadc->regmap, REG_SE, tscadc->reg_se_cache);

        spin_unlock_irqrestore(&tscadc->reg_lock, flags);
}
EXPORT_SYMBOL_GPL(am335x_tsc_se_set_cache);

static void am335x_tscadc_need_adc(struct ti_tscadc_dev *tscadc)
{
        DEFINE_WAIT(wait);
        u32 reg;

        regmap_read(tscadc->regmap, REG_ADCFSM, &reg);
        if (reg & SEQ_STATUS) {
                tscadc->adc_waiting = true;
                prepare_to_wait(&tscadc->reg_se_wait, &wait,
                                TASK_UNINTERRUPTIBLE);
                spin_unlock_irq(&tscadc->reg_lock);

                schedule();

                spin_lock_irq(&tscadc->reg_lock);
                finish_wait(&tscadc->reg_se_wait, &wait);

                /*
                 * Sequencer should either be idle or
                 * busy applying the charge step.
                 */
                regmap_read(tscadc->regmap, REG_ADCFSM, &reg);
                WARN_ON((reg & SEQ_STATUS) && !(reg & CHARGE_STEP));
                tscadc->adc_waiting = false;
        }
        tscadc->adc_in_use = true;
}

void am335x_tsc_se_set_once(struct ti_tscadc_dev *tscadc, u32 val)
{
        spin_lock_irq(&tscadc->reg_lock);
        am335x_tscadc_need_adc(tscadc);

        regmap_write(tscadc->regmap, REG_SE, val);
        spin_unlock_irq(&tscadc->reg_lock);
}
EXPORT_SYMBOL_GPL(am335x_tsc_se_set_once);

void am335x_tsc_se_adc_done(struct ti_tscadc_dev *tscadc)
{
        unsigned long flags;

        spin_lock_irqsave(&tscadc->reg_lock, flags);
        tscadc->adc_in_use = false;
        regmap_write(tscadc->regmap, REG_SE, tscadc->reg_se_cache);
        spin_unlock_irqrestore(&tscadc->reg_lock, flags);
}
EXPORT_SYMBOL_GPL(am335x_tsc_se_adc_done);

void am335x_tsc_se_clr(struct ti_tscadc_dev *tscadc, u32 val)
{
        unsigned long flags;

        spin_lock_irqsave(&tscadc->reg_lock, flags);
        tscadc->reg_se_cache &= ~val;
        regmap_write(tscadc->regmap, REG_SE, tscadc->reg_se_cache);
        spin_unlock_irqrestore(&tscadc->reg_lock, flags);
}
EXPORT_SYMBOL_GPL(am335x_tsc_se_clr);

static void tscadc_idle_config(struct ti_tscadc_dev *tscadc)
{
        unsigned int idleconfig;

        idleconfig = STEPCONFIG_INM_ADCREFM | STEPCONFIG_INP_ADCREFM;
        if (ti_adc_with_touchscreen(tscadc))
                idleconfig |= STEPCONFIG_YNN | STEPCONFIG_YPN;

        regmap_write(tscadc->regmap, REG_IDLECONFIG, idleconfig);
}

static  int ti_tscadc_probe(struct platform_device *pdev)
{
        struct ti_tscadc_dev *tscadc;
        struct resource *res;
        struct clk *clk;
        struct device_node *node;
        struct mfd_cell *cell;
        bool use_tsc = false, use_mag = false;
        u32 val;
        int err;
        int tscmag_wires = 0, adc_channels = 0, cell_idx = 0, total_channels;
        int readouts = 0, mag_tracks = 0;

        /* Allocate memory for device */
        tscadc = devm_kzalloc(&pdev->dev, sizeof(*tscadc), GFP_KERNEL);
        if (!tscadc)
                return -ENOMEM;

        tscadc->dev = &pdev->dev;

        if (!pdev->dev.of_node) {
                dev_err(&pdev->dev, "Could not find valid DT data.\n");
                return -EINVAL;
        }

        tscadc->data = of_device_get_match_data(&pdev->dev);

        if (ti_adc_with_touchscreen(tscadc)) {
                node = of_get_child_by_name(pdev->dev.of_node, "tsc");
                of_property_read_u32(node, "ti,wires", &tscmag_wires);
                err = of_property_read_u32(node, "ti,coordinate-readouts",
                                           &readouts);
                if (err < 0)
                        of_property_read_u32(node, "ti,coordiante-readouts",
                                             &readouts);

                of_node_put(node);

                if (tscmag_wires)
                        use_tsc = true;
        } else {
                /*
                 * When adding support for the magnetic stripe reader, here is
                 * the place to look for the number of tracks used from device
                 * tree. Let's default to 0 for now.
                 */
                mag_tracks = 0;
                tscmag_wires = mag_tracks * 2;
                if (tscmag_wires)
                        use_mag = true;
        }

        node = of_get_child_by_name(pdev->dev.of_node, "adc");
        of_property_for_each_u32(node, "ti,adc-channels", val) {
                adc_channels++;
                if (val > 7) {
                        dev_err(&pdev->dev, " PIN numbers are 0..7 (not %d)\n",
                                val);
                        of_node_put(node);
                        return -EINVAL;
                }
        }

        of_node_put(node);

        total_channels = tscmag_wires + adc_channels;
        if (total_channels > 8) {
                dev_err(&pdev->dev, "Number of i/p channels more than 8\n");
                return -EINVAL;
        }

        if (total_channels == 0) {
                dev_err(&pdev->dev, "Need at least one channel.\n");
                return -EINVAL;
        }

        if (use_tsc && (readouts * 2 + 2 + adc_channels > 16)) {
                dev_err(&pdev->dev, "Too many step configurations requested\n");
                return -EINVAL;
        }

        err = platform_get_irq(pdev, 0);
        if (err < 0)
                return err;
        else
                tscadc->irq = err;

        tscadc->tscadc_base = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
        if (IS_ERR(tscadc->tscadc_base))
                return PTR_ERR(tscadc->tscadc_base);

        tscadc->tscadc_phys_base = res->start;
        tscadc->regmap = devm_regmap_init_mmio(&pdev->dev,
                                               tscadc->tscadc_base,
                                               &tscadc_regmap_config);
        if (IS_ERR(tscadc->regmap)) {
                dev_err(&pdev->dev, "regmap init failed\n");
                return PTR_ERR(tscadc->regmap);
        }

        spin_lock_init(&tscadc->reg_lock);
        init_waitqueue_head(&tscadc->reg_se_wait);

        pm_runtime_enable(&pdev->dev);
        pm_runtime_get_sync(&pdev->dev);

        /*
         * The TSC_ADC_Subsystem has 2 clock domains: OCP_CLK and ADC_CLK.
         * ADCs produce a 12-bit sample every 15 ADC_CLK cycles.
         * am33xx ADCs expect to capture 200ksps.
         * am47xx ADCs expect to capture 867ksps.
         * We need ADC clocks respectively running at 3MHz and 13MHz.
         * These frequencies are valid since TSC_ADC_SS controller design
         * assumes the OCP clock is at least 6x faster than the ADC clock.
         */
        clk = devm_clk_get(&pdev->dev, NULL);
        if (IS_ERR(clk)) {
                dev_err(&pdev->dev, "failed to get fck\n");
                err = PTR_ERR(clk);
                goto err_disable_clk;
        }

        tscadc->clk_div = (clk_get_rate(clk) / tscadc->data->target_clk_rate) - 1;
        regmap_write(tscadc->regmap, REG_CLKDIV, tscadc->clk_div);

        /*
         * Set the control register bits. tscadc->ctrl stores the configuration
         * of the CTRL register but not the subsystem enable bit which must be
         * added manually when timely.
         */
        tscadc->ctrl = CNTRLREG_STEPID;
        if (ti_adc_with_touchscreen(tscadc)) {
                tscadc->ctrl |= CNTRLREG_TSC_STEPCONFIGWRT;
                if (use_tsc) {
                        tscadc->ctrl |= CNTRLREG_TSC_ENB;
                        if (tscmag_wires == 5)
                                tscadc->ctrl |= CNTRLREG_TSC_5WIRE;
                        else
                                tscadc->ctrl |= CNTRLREG_TSC_4WIRE;
                }
        } else {
                tscadc->ctrl |= CNTRLREG_MAG_PREAMP_PWRDOWN |
                                CNTRLREG_MAG_PREAMP_BYPASS;
        }
        regmap_write(tscadc->regmap, REG_CTRL, tscadc->ctrl);

        tscadc_idle_config(tscadc);

        /* Enable the TSC module enable bit */
        regmap_write(tscadc->regmap, REG_CTRL, tscadc->ctrl | CNTRLREG_SSENB);

        /* TSC or MAG Cell */
        if (use_tsc || use_mag) {
                cell = &tscadc->cells[cell_idx++];
                cell->name = tscadc->data->secondary_feature_name;
                cell->of_compatible = tscadc->data->secondary_feature_compatible;
                cell->platform_data = &tscadc;
                cell->pdata_size = sizeof(tscadc);
        }

        /* ADC Cell */
        if (adc_channels > 0) {
                cell = &tscadc->cells[cell_idx++];
                cell->name = tscadc->data->adc_feature_name;
                cell->of_compatible = tscadc->data->adc_feature_compatible;
                cell->platform_data = &tscadc;
                cell->pdata_size = sizeof(tscadc);
        }

        err = mfd_add_devices(&pdev->dev, PLATFORM_DEVID_AUTO,
                              tscadc->cells, cell_idx, NULL, 0, NULL);
        if (err < 0)
                goto err_disable_clk;

        platform_set_drvdata(pdev, tscadc);
        return 0;

err_disable_clk:
        pm_runtime_put_sync(&pdev->dev);
        pm_runtime_disable(&pdev->dev);

        return err;
}

static void ti_tscadc_remove(struct platform_device *pdev)
{
        struct ti_tscadc_dev *tscadc = platform_get_drvdata(pdev);

        regmap_write(tscadc->regmap, REG_SE, 0x00);

        pm_runtime_put_sync(&pdev->dev);
        pm_runtime_disable(&pdev->dev);

        mfd_remove_devices(tscadc->dev);
}

static int __maybe_unused ti_tscadc_can_wakeup(struct device *dev, void *data)
{
        return device_may_wakeup(dev);
}

static int __maybe_unused tscadc_suspend(struct device *dev)
{
        struct ti_tscadc_dev *tscadc = dev_get_drvdata(dev);

        regmap_write(tscadc->regmap, REG_SE, 0x00);
        if (device_for_each_child(dev, NULL, ti_tscadc_can_wakeup)) {
                u32 ctrl;

                regmap_read(tscadc->regmap, REG_CTRL, &ctrl);
                ctrl &= ~(CNTRLREG_POWERDOWN);
                ctrl |= CNTRLREG_SSENB;
                regmap_write(tscadc->regmap, REG_CTRL, ctrl);
        }
        pm_runtime_put_sync(dev);

        return 0;
}

static int __maybe_unused tscadc_resume(struct device *dev)
{
        struct ti_tscadc_dev *tscadc = dev_get_drvdata(dev);

        pm_runtime_get_sync(dev);

        regmap_write(tscadc->regmap, REG_CLKDIV, tscadc->clk_div);
        regmap_write(tscadc->regmap, REG_CTRL, tscadc->ctrl);
        tscadc_idle_config(tscadc);
        regmap_write(tscadc->regmap, REG_CTRL, tscadc->ctrl | CNTRLREG_SSENB);

        return 0;
}

static SIMPLE_DEV_PM_OPS(tscadc_pm_ops, tscadc_suspend, tscadc_resume);

static const struct ti_tscadc_data tscdata = {
        .adc_feature_name = "TI-am335x-adc",
        .adc_feature_compatible = "ti,am3359-adc",
        .secondary_feature_name = "TI-am335x-tsc",
        .secondary_feature_compatible = "ti,am3359-tsc",
        .target_clk_rate = TSC_ADC_CLK,
};

static const struct ti_tscadc_data magdata = {
        .adc_feature_name = "TI-am43xx-adc",
        .adc_feature_compatible = "ti,am4372-adc",
        .secondary_feature_name = "TI-am43xx-mag",
        .secondary_feature_compatible = "ti,am4372-mag",
        .target_clk_rate = MAG_ADC_CLK,
};

static const struct of_device_id ti_tscadc_dt_ids[] = {
        { .compatible = "ti,am3359-tscadc", .data = &tscdata },
        { .compatible = "ti,am4372-magadc", .data = &magdata },
        { }
};
MODULE_DEVICE_TABLE(of, ti_tscadc_dt_ids);

static struct platform_driver ti_tscadc_driver = {
        .driver = {
                .name   = "ti_am3359-tscadc",
                .pm     = &tscadc_pm_ops,
                .of_match_table = ti_tscadc_dt_ids,
        },
        .probe  = ti_tscadc_probe,
        .remove = ti_tscadc_remove,

};

module_platform_driver(ti_tscadc_driver);

MODULE_DESCRIPTION("TI touchscreen/magnetic stripe reader/ADC MFD controller driver");
MODULE_AUTHOR("Rachna Patil <rachna@ti.com>");
MODULE_LICENSE("GPL");