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104 lines
2.5 KiB
104 lines
2.5 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* STM32 Low-Power Timer parent driver. |
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* Copyright (C) STMicroelectronics 2017 |
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* Author: Fabrice Gasnier <[email protected]> |
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* Inspired by Benjamin Gaignard's stm32-timers driver |
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*/ |
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#include <linux/mfd/stm32-lptimer.h> |
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#include <linux/module.h> |
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#include <linux/of_platform.h> |
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#define STM32_LPTIM_MAX_REGISTER 0x3fc |
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static const struct regmap_config stm32_lptimer_regmap_cfg = { |
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.reg_bits = 32, |
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.val_bits = 32, |
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.reg_stride = sizeof(u32), |
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.max_register = STM32_LPTIM_MAX_REGISTER, |
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.fast_io = true, |
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}; |
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static int stm32_lptimer_detect_encoder(struct stm32_lptimer *ddata) |
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{ |
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u32 val; |
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int ret; |
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/* |
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* Quadrature encoder mode bit can only be written and read back when |
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* Low-Power Timer supports it. |
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*/ |
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ret = regmap_update_bits(ddata->regmap, STM32_LPTIM_CFGR, |
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STM32_LPTIM_ENC, STM32_LPTIM_ENC); |
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if (ret) |
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return ret; |
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ret = regmap_read(ddata->regmap, STM32_LPTIM_CFGR, &val); |
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if (ret) |
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return ret; |
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ret = regmap_update_bits(ddata->regmap, STM32_LPTIM_CFGR, |
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STM32_LPTIM_ENC, 0); |
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if (ret) |
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return ret; |
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ddata->has_encoder = !!(val & STM32_LPTIM_ENC); |
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return 0; |
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} |
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static int stm32_lptimer_probe(struct platform_device *pdev) |
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{ |
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struct device *dev = &pdev->dev; |
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struct stm32_lptimer *ddata; |
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struct resource *res; |
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void __iomem *mmio; |
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int ret; |
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ddata = devm_kzalloc(dev, sizeof(*ddata), GFP_KERNEL); |
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if (!ddata) |
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return -ENOMEM; |
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res = platform_get_resource(pdev, IORESOURCE_MEM, 0); |
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mmio = devm_ioremap_resource(dev, res); |
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if (IS_ERR(mmio)) |
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return PTR_ERR(mmio); |
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ddata->regmap = devm_regmap_init_mmio_clk(dev, "mux", mmio, |
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&stm32_lptimer_regmap_cfg); |
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if (IS_ERR(ddata->regmap)) |
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return PTR_ERR(ddata->regmap); |
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ddata->clk = devm_clk_get(dev, NULL); |
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if (IS_ERR(ddata->clk)) |
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return PTR_ERR(ddata->clk); |
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ret = stm32_lptimer_detect_encoder(ddata); |
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if (ret) |
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return ret; |
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platform_set_drvdata(pdev, ddata); |
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return devm_of_platform_populate(&pdev->dev); |
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} |
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static const struct of_device_id stm32_lptimer_of_match[] = { |
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{ .compatible = "st,stm32-lptimer", }, |
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{}, |
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}; |
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MODULE_DEVICE_TABLE(of, stm32_lptimer_of_match); |
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static struct platform_driver stm32_lptimer_driver = { |
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.probe = stm32_lptimer_probe, |
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.driver = { |
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.name = "stm32-lptimer", |
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.of_match_table = stm32_lptimer_of_match, |
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}, |
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}; |
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module_platform_driver(stm32_lptimer_driver); |
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MODULE_AUTHOR("Fabrice Gasnier <[email protected]>"); |
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MODULE_DESCRIPTION("STMicroelectronics STM32 Low-Power Timer"); |
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MODULE_ALIAS("platform:stm32-lptimer"); |
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MODULE_LICENSE("GPL v2");
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