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