Eric Lee / smarc-fsl-linux-kernel

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drivers/reset/reset-stm32mp1.c 2.83 KB
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197858b68   Gabriel Fernandez   reset: stm32mp1: ... 
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  // SPDX-License-Identifier: GPL-2.0
  /*
   * Copyright (C) STMicroelectronics 2018 - All Rights Reserved
   * Author: Gabriel Fernandez <gabriel.fernandez@st.com> for STMicroelectronics.
   */
  
  #include <linux/device.h>
  #include <linux/err.h>
  #include <linux/io.h>
  #include <linux/of.h>
  #include <linux/platform_device.h>
  #include <linux/reset-controller.h>
  
  #define CLR_OFFSET 0x4
  
  struct stm32_reset_data {
  	struct reset_controller_dev	rcdev;
  	void __iomem			*membase;
  };
  
  static inline struct stm32_reset_data *
  to_stm32_reset_data(struct reset_controller_dev *rcdev)
  {
  	return container_of(rcdev, struct stm32_reset_data, rcdev);
  }
  
  static int stm32_reset_update(struct reset_controller_dev *rcdev,
  			      unsigned long id, bool assert)
  {
  	struct stm32_reset_data *data = to_stm32_reset_data(rcdev);
  	int reg_width = sizeof(u32);
  	int bank = id / (reg_width * BITS_PER_BYTE);
  	int offset = id % (reg_width * BITS_PER_BYTE);
  	void __iomem *addr;
  
  	addr = data->membase + (bank * reg_width);
  	if (!assert)
  		addr += CLR_OFFSET;
  
  	writel(BIT(offset), addr);
  
  	return 0;
  }
  
  static int stm32_reset_assert(struct reset_controller_dev *rcdev,
  			      unsigned long id)
  {
  	return stm32_reset_update(rcdev, id, true);
  }
  
  static int stm32_reset_deassert(struct reset_controller_dev *rcdev,
  				unsigned long id)
  {
  	return stm32_reset_update(rcdev, id, false);
  }
  
  static int stm32_reset_status(struct reset_controller_dev *rcdev,
  			      unsigned long id)
  {
  	struct stm32_reset_data *data = to_stm32_reset_data(rcdev);
  	int reg_width = sizeof(u32);
  	int bank = id / (reg_width * BITS_PER_BYTE);
  	int offset = id % (reg_width * BITS_PER_BYTE);
  	u32 reg;
  
  	reg = readl(data->membase + (bank * reg_width));
  
  	return !!(reg & BIT(offset));
  }
  
  static const struct reset_control_ops stm32_reset_ops = {
  	.assert		= stm32_reset_assert,
  	.deassert	= stm32_reset_deassert,
  	.status		= stm32_reset_status,
  };
  
  static const struct of_device_id stm32_reset_dt_ids[] = {
  	{ .compatible = "st,stm32mp1-rcc"},
  	{ /* sentinel */ },
  };
  
  static int stm32_reset_probe(struct platform_device *pdev)
  {
  	struct device *dev = &pdev->dev;
  	struct stm32_reset_data *data;
  	void __iomem *membase;
  	struct resource *res;
  
  	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
  	if (!data)
  		return -ENOMEM;
  
  	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  	membase = devm_ioremap_resource(dev, res);
  	if (IS_ERR(membase))
  		return PTR_ERR(membase);
  
  	data->membase = membase;
  	data->rcdev.owner = THIS_MODULE;
  	data->rcdev.nr_resets = resource_size(res) * BITS_PER_BYTE;
  	data->rcdev.ops = &stm32_reset_ops;
  	data->rcdev.of_node = dev->of_node;
  
  	return devm_reset_controller_register(dev, &data->rcdev);
  }
  
  static struct platform_driver stm32_reset_driver = {
  	.probe	= stm32_reset_probe,
  	.driver = {
  		.name		= "stm32mp1-reset",
  		.of_match_table	= stm32_reset_dt_ids,
  	},
  };
  
  builtin_platform_driver(stm32_reset_driver);