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 15 static 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 23 static 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 51 static int stm32_lptimer_probe(struct platform_device *pdev) 52 { 53 struct device *dev = &pdev->dev; 54 struct stm32_lptimer *ddata; 55 void __iomem *mmio; 56 int ret; 57 58 ddata = devm_kzalloc(dev, sizeof(*ddata), GFP_KERNEL); 59 if (!ddata) 60 return -ENOMEM; 61 62 mmio = devm_platform_get_and_ioremap_resource(pdev, 0, NULL); 63 if (IS_ERR(mmio)) 64 return PTR_ERR(mmio); 65 66 ddata->regmap = devm_regmap_init_mmio_clk(dev, "mux", mmio, 67 &stm32_lptimer_regmap_cfg); 68 if (IS_ERR(ddata->regmap)) 69 return PTR_ERR(ddata->regmap); 70 71 ddata->clk = devm_clk_get(dev, NULL); 72 if (IS_ERR(ddata->clk)) 73 return PTR_ERR(ddata->clk); 74 75 ret = stm32_lptimer_detect_encoder(ddata); 76 if (ret) 77 return ret; 78 79 platform_set_drvdata(pdev, ddata); 80 81 return devm_of_platform_populate(&pdev->dev); 82 } 83 84 static const struct of_device_id stm32_lptimer_of_match[] = { 85 { .compatible = "st,stm32-lptimer", }, 86 {}, 87 }; 88 MODULE_DEVICE_TABLE(of, stm32_lptimer_of_match); 89 90 static struct platform_driver stm32_lptimer_driver = { 91 .probe = stm32_lptimer_probe, 92 .driver = { 93 .name = "stm32-lptimer", 94 .of_match_table = stm32_lptimer_of_match, 95 }, 96 }; 97 module_platform_driver(stm32_lptimer_driver); 98 99 MODULE_AUTHOR("Fabrice Gasnier <fabrice.gasnier@st.com>"); 100 MODULE_DESCRIPTION("STMicroelectronics STM32 Low-Power Timer"); 101 MODULE_ALIAS("platform:stm32-lptimer"); 102 MODULE_LICENSE("GPL v2"); 103