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/bitfield.h> 10 #include <linux/mfd/stm32-lptimer.h> 11 #include <linux/module.h> 12 #include <linux/of_platform.h> 13 #include <linux/platform_device.h> 14 15 #define STM32_LPTIM_MAX_REGISTER 0x3fc 16 17 static const struct regmap_config stm32_lptimer_regmap_cfg = { 18 .reg_bits = 32, 19 .val_bits = 32, 20 .reg_stride = sizeof(u32), 21 .max_register = STM32_LPTIM_MAX_REGISTER, 22 .fast_io = true, 23 }; 24 25 static int stm32_lptimer_detect_encoder(struct stm32_lptimer *ddata) 26 { 27 u32 val; 28 int ret; 29 30 /* 31 * Quadrature encoder mode bit can only be written and read back when 32 * Low-Power Timer supports it. 33 */ 34 ret = regmap_update_bits(ddata->regmap, STM32_LPTIM_CFGR, 35 STM32_LPTIM_ENC, STM32_LPTIM_ENC); 36 if (ret) 37 return ret; 38 39 ret = regmap_read(ddata->regmap, STM32_LPTIM_CFGR, &val); 40 if (ret) 41 return ret; 42 43 ret = regmap_update_bits(ddata->regmap, STM32_LPTIM_CFGR, 44 STM32_LPTIM_ENC, 0); 45 if (ret) 46 return ret; 47 48 ddata->has_encoder = !!(val & STM32_LPTIM_ENC); 49 50 return 0; 51 } 52 53 static int stm32_lptimer_detect_hwcfgr(struct stm32_lptimer *ddata) 54 { 55 u32 val; 56 int ret; 57 58 ret = regmap_read(ddata->regmap, STM32_LPTIM_VERR, &ddata->version); 59 if (ret) 60 return ret; 61 62 /* Try to guess parameters from HWCFGR: e.g. encoder mode (STM32MP15) */ 63 ret = regmap_read(ddata->regmap, STM32_LPTIM_HWCFGR1, &val); 64 if (ret) 65 return ret; 66 67 /* Fallback to legacy init if HWCFGR isn't present */ 68 if (!val) 69 return stm32_lptimer_detect_encoder(ddata); 70 71 ddata->has_encoder = FIELD_GET(STM32_LPTIM_HWCFGR1_ENCODER, val); 72 73 ret = regmap_read(ddata->regmap, STM32_LPTIM_HWCFGR2, &val); 74 if (ret) 75 return ret; 76 77 /* Number of capture/compare channels */ 78 ddata->num_cc_chans = FIELD_GET(STM32_LPTIM_HWCFGR2_CHAN_NUM, val); 79 80 return 0; 81 } 82 83 static int stm32_lptimer_probe(struct platform_device *pdev) 84 { 85 struct device *dev = &pdev->dev; 86 struct stm32_lptimer *ddata; 87 void __iomem *mmio; 88 int ret; 89 90 ddata = devm_kzalloc(dev, sizeof(*ddata), GFP_KERNEL); 91 if (!ddata) 92 return -ENOMEM; 93 94 mmio = devm_platform_get_and_ioremap_resource(pdev, 0, NULL); 95 if (IS_ERR(mmio)) 96 return PTR_ERR(mmio); 97 98 ddata->regmap = devm_regmap_init_mmio_clk(dev, "mux", mmio, 99 &stm32_lptimer_regmap_cfg); 100 if (IS_ERR(ddata->regmap)) 101 return PTR_ERR(ddata->regmap); 102 103 ddata->clk = devm_clk_get(dev, NULL); 104 if (IS_ERR(ddata->clk)) 105 return PTR_ERR(ddata->clk); 106 107 ret = stm32_lptimer_detect_hwcfgr(ddata); 108 if (ret) 109 return ret; 110 111 platform_set_drvdata(pdev, ddata); 112 113 return devm_of_platform_populate(&pdev->dev); 114 } 115 116 static const struct of_device_id stm32_lptimer_of_match[] = { 117 { .compatible = "st,stm32-lptimer", }, 118 {}, 119 }; 120 MODULE_DEVICE_TABLE(of, stm32_lptimer_of_match); 121 122 static struct platform_driver stm32_lptimer_driver = { 123 .probe = stm32_lptimer_probe, 124 .driver = { 125 .name = "stm32-lptimer", 126 .of_match_table = stm32_lptimer_of_match, 127 }, 128 }; 129 module_platform_driver(stm32_lptimer_driver); 130 131 MODULE_AUTHOR("Fabrice Gasnier <fabrice.gasnier@st.com>"); 132 MODULE_DESCRIPTION("STMicroelectronics STM32 Low-Power Timer"); 133 MODULE_ALIAS("platform:stm32-lptimer"); 134 MODULE_LICENSE("GPL v2"); 135