cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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stm32-lptimer.c (2537B)

      1// SPDX-License-Identifier: GPL-2.0
      2/*
      3 * STM32 Low-Power Timer parent driver.
      4 * Copyright (C) STMicroelectronics 2017
      5 * Author: Fabrice Gasnier <fabrice.gasnier@st.com>
      6 * Inspired by Benjamin Gaignard's stm32-timers driver
      7 */
      8
      9#include <linux/mfd/stm32-lptimer.h>
     10#include <linux/module.h>
     11#include <linux/of_platform.h>
     12
     13#define STM32_LPTIM_MAX_REGISTER	0x3fc
     14
     15static const struct regmap_config stm32_lptimer_regmap_cfg = {
     16	.reg_bits = 32,
     17	.val_bits = 32,
     18	.reg_stride = sizeof(u32),
     19	.max_register = STM32_LPTIM_MAX_REGISTER,
     20	.fast_io = true,
     21};
     22
     23static int stm32_lptimer_detect_encoder(struct stm32_lptimer *ddata)
     24{
     25	u32 val;
     26	int ret;
     27
     28	/*
     29	 * Quadrature encoder mode bit can only be written and read back when
     30	 * Low-Power Timer supports it.
     31	 */
     32	ret = regmap_update_bits(ddata->regmap, STM32_LPTIM_CFGR,
     33				 STM32_LPTIM_ENC, STM32_LPTIM_ENC);
     34	if (ret)
     35		return ret;
     36
     37	ret = regmap_read(ddata->regmap, STM32_LPTIM_CFGR, &val);
     38	if (ret)
     39		return ret;
     40
     41	ret = regmap_update_bits(ddata->regmap, STM32_LPTIM_CFGR,
     42				 STM32_LPTIM_ENC, 0);
     43	if (ret)
     44		return ret;
     45
     46	ddata->has_encoder = !!(val & STM32_LPTIM_ENC);
     47
     48	return 0;
     49}
     50
     51static int stm32_lptimer_probe(struct platform_device *pdev)
     52{
     53	struct device *dev = &pdev->dev;
     54	struct stm32_lptimer *ddata;
     55	struct resource *res;
     56	void __iomem *mmio;
     57	int ret;
     58
     59	ddata = devm_kzalloc(dev, sizeof(*ddata), GFP_KERNEL);
     60	if (!ddata)
     61		return -ENOMEM;
     62
     63	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
     64	mmio = devm_ioremap_resource(dev, res);
     65	if (IS_ERR(mmio))
     66		return PTR_ERR(mmio);
     67
     68	ddata->regmap = devm_regmap_init_mmio_clk(dev, "mux", mmio,
     69						  &stm32_lptimer_regmap_cfg);
     70	if (IS_ERR(ddata->regmap))
     71		return PTR_ERR(ddata->regmap);
     72
     73	ddata->clk = devm_clk_get(dev, NULL);
     74	if (IS_ERR(ddata->clk))
     75		return PTR_ERR(ddata->clk);
     76
     77	ret = stm32_lptimer_detect_encoder(ddata);
     78	if (ret)
     79		return ret;
     80
     81	platform_set_drvdata(pdev, ddata);
     82
     83	return devm_of_platform_populate(&pdev->dev);
     84}
     85
     86static const struct of_device_id stm32_lptimer_of_match[] = {
     87	{ .compatible = "st,stm32-lptimer", },
     88	{},
     89};
     90MODULE_DEVICE_TABLE(of, stm32_lptimer_of_match);
     91
     92static struct platform_driver stm32_lptimer_driver = {
     93	.probe = stm32_lptimer_probe,
     94	.driver = {
     95		.name = "stm32-lptimer",
     96		.of_match_table = stm32_lptimer_of_match,
     97	},
     98};
     99module_platform_driver(stm32_lptimer_driver);
    100
    101MODULE_AUTHOR("Fabrice Gasnier <fabrice.gasnier@st.com>");
    102MODULE_DESCRIPTION("STMicroelectronics STM32 Low-Power Timer");
    103MODULE_ALIAS("platform:stm32-lptimer");
    104MODULE_LICENSE("GPL v2");