Quelle  stm32-dac-core.c   Sprache: C

// SPDX-License-Identifier: GPL-2.0
/*
 * This file is part of STM32 DAC driver
 *
 * Copyright (C) 2017, STMicroelectronics - All Rights Reserved
 * Author: Fabrice Gasnier <fabrice.gasnier@st.com>.
 *
 */

#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/of_platform.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#include <linux/property.h>
#include <linux/regulator/consumer.h>
#include <linux/reset.h>

#include "stm32-dac-core.h"

/**
 * struct stm32_dac_priv - stm32 DAC core private data
 * @pclk: peripheral clock common for all DACs
 * @vref: regulator reference
 * @common: Common data for all DAC instances
 */
struct stm32_dac_priv {
 struct clk *pclk;
 struct regulator *vref;
 struct stm32_dac_common common;
};

/**
 * struct stm32_dac_cfg - DAC configuration
 * @has_hfsel: DAC has high frequency control
 */
struct stm32_dac_cfg {
 bool has_hfsel;
};

static struct stm32_dac_priv *to_stm32_dac_priv(struct stm32_dac_common *com)
{
 return container_of(com, struct stm32_dac_priv, common);
}

static const struct regmap_config stm32_dac_regmap_cfg = {
 .reg_bits = 32,
 .val_bits = 32,
 .reg_stride = sizeof(u32),
 .max_register = 0x3fc,
};

static int stm32_dac_core_hw_start(struct device *dev)
{
 struct stm32_dac_common *common = dev_get_drvdata(dev);
 struct stm32_dac_priv *priv = to_stm32_dac_priv(common);
 int ret;

 ret = regulator_enable(priv->vref);
 if (ret < 0) {
  dev_err(dev, "vref enable failed: %d\n", ret);
  return ret;
 }

 ret = clk_prepare_enable(priv->pclk);
 if (ret < 0) {
  dev_err(dev, "pclk enable failed: %d\n", ret);
  goto err_regulator_disable;
 }

 return 0;

err_regulator_disable:
 regulator_disable(priv->vref);

 return ret;
}

static void stm32_dac_core_hw_stop(struct device *dev)
{
 struct stm32_dac_common *common = dev_get_drvdata(dev);
 struct stm32_dac_priv *priv = to_stm32_dac_priv(common);

 clk_disable_unprepare(priv->pclk);
 regulator_disable(priv->vref);
}

static int stm32_dac_probe(struct platform_device *pdev)
{
 struct device *dev = &pdev->dev;
 const struct stm32_dac_cfg *cfg;
 struct stm32_dac_priv *priv;
 struct regmap *regmap;
 void __iomem *mmio;
 struct reset_control *rst;
 int ret;

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

 cfg = device_get_match_data(dev);

 mmio = devm_platform_ioremap_resource(pdev, 0);
 if (IS_ERR(mmio))
  return PTR_ERR(mmio);

 regmap = devm_regmap_init_mmio_clk(dev, "pclk", mmio,
        &stm32_dac_regmap_cfg);
 if (IS_ERR(regmap))
  return PTR_ERR(regmap);
 priv->common.regmap = regmap;

 priv->pclk = devm_clk_get(dev, "pclk");
 if (IS_ERR(priv->pclk))
  return dev_err_probe(dev, PTR_ERR(priv->pclk), "pclk get failed\n");

 priv->vref = devm_regulator_get(dev, "vref");
 if (IS_ERR(priv->vref))
  return dev_err_probe(dev, PTR_ERR(priv->vref), "vref get failed\n");

 pm_runtime_get_noresume(dev);
 pm_runtime_set_active(dev);
 pm_runtime_enable(dev);

 ret = stm32_dac_core_hw_start(dev);
 if (ret)
  goto err_pm_stop;

 ret = regulator_get_voltage(priv->vref);
 if (ret < 0) {
  dev_err(dev, "vref get voltage failed, %d\n", ret);
  goto err_hw_stop;
 }
 priv->common.vref_mv = ret / 1000;
 dev_dbg(dev, "vref+=%dmV\n", priv->common.vref_mv);

 rst = devm_reset_control_get_optional_exclusive(dev, NULL);
 if (rst) {
  if (IS_ERR(rst)) {
   ret = dev_err_probe(dev, PTR_ERR(rst), "reset get failed\n");
   goto err_hw_stop;
  }

  reset_control_assert(rst);
  udelay(2);
  reset_control_deassert(rst);
 }

 if (cfg && cfg->has_hfsel) {
  /* When clock speed is higher than 80MHz, set HFSEL */
  priv->common.hfsel = (clk_get_rate(priv->pclk) > 80000000UL);
  ret = regmap_update_bits(regmap, STM32_DAC_CR,
      STM32H7_DAC_CR_HFSEL,
      priv->common.hfsel ?
      STM32H7_DAC_CR_HFSEL : 0);
  if (ret)
   goto err_hw_stop;
 }


 ret = of_platform_populate(pdev->dev.of_node, NULL, NULL, dev);
 if (ret < 0) {
  dev_err(dev, "failed to populate DT children\n");
  goto err_hw_stop;
 }

 pm_runtime_put(dev);

 return 0;

err_hw_stop:
 stm32_dac_core_hw_stop(dev);
err_pm_stop:
 pm_runtime_disable(dev);
 pm_runtime_set_suspended(dev);
 pm_runtime_put_noidle(dev);

 return ret;
}

static void stm32_dac_remove(struct platform_device *pdev)
{
 pm_runtime_get_sync(&pdev->dev);
 of_platform_depopulate(&pdev->dev);
 stm32_dac_core_hw_stop(&pdev->dev);
 pm_runtime_disable(&pdev->dev);
 pm_runtime_set_suspended(&pdev->dev);
 pm_runtime_put_noidle(&pdev->dev);
}

static int stm32_dac_core_resume(struct device *dev)
{
 struct stm32_dac_common *common = dev_get_drvdata(dev);
 struct stm32_dac_priv *priv = to_stm32_dac_priv(common);
 int ret;

 if (priv->common.hfsel) {
  /* restore hfsel (maybe lost under low power state) */
  ret = regmap_set_bits(priv->common.regmap, STM32_DAC_CR,
          STM32H7_DAC_CR_HFSEL);
  if (ret)
   return ret;
 }

 return pm_runtime_force_resume(dev);
}

static int stm32_dac_core_runtime_suspend(struct device *dev)
{
 stm32_dac_core_hw_stop(dev);

 return 0;
}

static int stm32_dac_core_runtime_resume(struct device *dev)
{
 return stm32_dac_core_hw_start(dev);
}

static const struct dev_pm_ops stm32_dac_core_pm_ops = {
 SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend, stm32_dac_core_resume)
 RUNTIME_PM_OPS(stm32_dac_core_runtime_suspend,
         stm32_dac_core_runtime_resume,
         NULL)
};

static const struct stm32_dac_cfg stm32h7_dac_cfg = {
 .has_hfsel = true,
};

static const struct of_device_id stm32_dac_of_match[] = {
 {
  .compatible = "st,stm32f4-dac-core",
 }, {
  .compatible = "st,stm32h7-dac-core",
  .data = (void *)&stm32h7_dac_cfg,
 },
 { }
};
MODULE_DEVICE_TABLE(of, stm32_dac_of_match);

static struct platform_driver stm32_dac_driver = {
 .probe = stm32_dac_probe,
 .remove = stm32_dac_remove,
 .driver = {
  .name = "stm32-dac-core",
  .of_match_table = stm32_dac_of_match,
  .pm = pm_ptr(&stm32_dac_core_pm_ops),
 },
};
module_platform_driver(stm32_dac_driver);

MODULE_AUTHOR("Fabrice Gasnier ");
MODULE_DESCRIPTION("STMicroelectronics STM32 DAC core driver");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:stm32-dac-core");