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