Quelle  ti_am335x_tscadc.c   Sprache: C

// 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, ®);
 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, ®);
  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 ");
MODULE_LICENSE("GPL");