| Fabrice Gasnier | e892400 | 2017-08-28 12:04:07 +0200 | [diff] [blame^] | 1 | /* |
| 2 | * STM32 Low-Power Timer parent driver. |
| 3 | * |
| 4 | * Copyright (C) STMicroelectronics 2017 |
| 5 | * |
| 6 | * Author: Fabrice Gasnier <fabrice.gasnier@st.com> |
| 7 | * |
| 8 | * Inspired by Benjamin Gaignard's stm32-timers driver |
| 9 | * |
| 10 | * License terms: GNU General Public License (GPL), version 2 |
| 11 | */ |
| 12 | |
| 13 | #include <linux/mfd/stm32-lptimer.h> |
| 14 | #include <linux/module.h> |
| 15 | #include <linux/of_platform.h> |
| 16 | |
| 17 | #define STM32_LPTIM_MAX_REGISTER 0x3fc |
| 18 | |
| 19 | static const struct regmap_config stm32_lptimer_regmap_cfg = { |
| 20 | .reg_bits = 32, |
| 21 | .val_bits = 32, |
| 22 | .reg_stride = sizeof(u32), |
| 23 | .max_register = STM32_LPTIM_MAX_REGISTER, |
| 24 | }; |
| 25 | |
| 26 | static int stm32_lptimer_detect_encoder(struct stm32_lptimer *ddata) |
| 27 | { |
| 28 | u32 val; |
| 29 | int ret; |
| 30 | |
| 31 | /* |
| 32 | * Quadrature encoder mode bit can only be written and read back when |
| 33 | * Low-Power Timer supports it. |
| 34 | */ |
| 35 | ret = regmap_update_bits(ddata->regmap, STM32_LPTIM_CFGR, |
| 36 | STM32_LPTIM_ENC, STM32_LPTIM_ENC); |
| 37 | if (ret) |
| 38 | return ret; |
| 39 | |
| 40 | ret = regmap_read(ddata->regmap, STM32_LPTIM_CFGR, &val); |
| 41 | if (ret) |
| 42 | return ret; |
| 43 | |
| 44 | ret = regmap_update_bits(ddata->regmap, STM32_LPTIM_CFGR, |
| 45 | STM32_LPTIM_ENC, 0); |
| 46 | if (ret) |
| 47 | return ret; |
| 48 | |
| 49 | ddata->has_encoder = !!(val & STM32_LPTIM_ENC); |
| 50 | |
| 51 | return 0; |
| 52 | } |
| 53 | |
| 54 | static int stm32_lptimer_probe(struct platform_device *pdev) |
| 55 | { |
| 56 | struct device *dev = &pdev->dev; |
| 57 | struct stm32_lptimer *ddata; |
| 58 | struct resource *res; |
| 59 | void __iomem *mmio; |
| 60 | int ret; |
| 61 | |
| 62 | ddata = devm_kzalloc(dev, sizeof(*ddata), GFP_KERNEL); |
| 63 | if (!ddata) |
| 64 | return -ENOMEM; |
| 65 | |
| 66 | res = platform_get_resource(pdev, IORESOURCE_MEM, 0); |
| 67 | mmio = devm_ioremap_resource(dev, res); |
| 68 | if (IS_ERR(mmio)) |
| 69 | return PTR_ERR(mmio); |
| 70 | |
| 71 | ddata->regmap = devm_regmap_init_mmio_clk(dev, "mux", mmio, |
| 72 | &stm32_lptimer_regmap_cfg); |
| 73 | if (IS_ERR(ddata->regmap)) |
| 74 | return PTR_ERR(ddata->regmap); |
| 75 | |
| 76 | ddata->clk = devm_clk_get(dev, NULL); |
| 77 | if (IS_ERR(ddata->clk)) |
| 78 | return PTR_ERR(ddata->clk); |
| 79 | |
| 80 | ret = stm32_lptimer_detect_encoder(ddata); |
| 81 | if (ret) |
| 82 | return ret; |
| 83 | |
| 84 | platform_set_drvdata(pdev, ddata); |
| 85 | |
| 86 | return devm_of_platform_populate(&pdev->dev); |
| 87 | } |
| 88 | |
| 89 | static const struct of_device_id stm32_lptimer_of_match[] = { |
| 90 | { .compatible = "st,stm32-lptimer", }, |
| 91 | {}, |
| 92 | }; |
| 93 | MODULE_DEVICE_TABLE(of, stm32_lptimer_of_match); |
| 94 | |
| 95 | static struct platform_driver stm32_lptimer_driver = { |
| 96 | .probe = stm32_lptimer_probe, |
| 97 | .driver = { |
| 98 | .name = "stm32-lptimer", |
| 99 | .of_match_table = stm32_lptimer_of_match, |
| 100 | }, |
| 101 | }; |
| 102 | module_platform_driver(stm32_lptimer_driver); |
| 103 | |
| 104 | MODULE_AUTHOR("Fabrice Gasnier <fabrice.gasnier@st.com>"); |
| 105 | MODULE_DESCRIPTION("STMicroelectronics STM32 Low-Power Timer"); |
| 106 | MODULE_ALIAS("platform:stm32-lptimer"); |
| 107 | MODULE_LICENSE("GPL v2"); |