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fa93f5b7 | 1 | // SPDX-License-Identifier: GPL-2.0 |
e8924005 FG |
2 | /* |
3 | * STM32 Low-Power Timer parent driver. | |
e8924005 | 4 | * Copyright (C) STMicroelectronics 2017 |
e8924005 | 5 | * Author: Fabrice Gasnier <fabrice.gasnier@st.com> |
e8924005 | 6 | * Inspired by Benjamin Gaignard's stm32-timers driver |
e8924005 FG |
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, | |
45d93065 | 20 | .fast_io = true, |
e8924005 FG |
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 | struct resource *res; | |
56 | void __iomem *mmio; | |
57 | int ret; | |
58 | ||
59 | ddata = devm_kzalloc(dev, sizeof(*ddata), GFP_KERNEL); | |
60 | if (!ddata) | |
61 | return -ENOMEM; | |
62 | ||
63 | res = platform_get_resource(pdev, IORESOURCE_MEM, 0); | |
64 | mmio = devm_ioremap_resource(dev, res); | |
65 | if (IS_ERR(mmio)) | |
66 | return PTR_ERR(mmio); | |
67 | ||
68 | ddata->regmap = devm_regmap_init_mmio_clk(dev, "mux", mmio, | |
69 | &stm32_lptimer_regmap_cfg); | |
70 | if (IS_ERR(ddata->regmap)) | |
71 | return PTR_ERR(ddata->regmap); | |
72 | ||
73 | ddata->clk = devm_clk_get(dev, NULL); | |
74 | if (IS_ERR(ddata->clk)) | |
75 | return PTR_ERR(ddata->clk); | |
76 | ||
77 | ret = stm32_lptimer_detect_encoder(ddata); | |
78 | if (ret) | |
79 | return ret; | |
80 | ||
81 | platform_set_drvdata(pdev, ddata); | |
82 | ||
83 | return devm_of_platform_populate(&pdev->dev); | |
84 | } | |
85 | ||
86 | static const struct of_device_id stm32_lptimer_of_match[] = { | |
87 | { .compatible = "st,stm32-lptimer", }, | |
88 | {}, | |
89 | }; | |
90 | MODULE_DEVICE_TABLE(of, stm32_lptimer_of_match); | |
91 | ||
92 | static struct platform_driver stm32_lptimer_driver = { | |
93 | .probe = stm32_lptimer_probe, | |
94 | .driver = { | |
95 | .name = "stm32-lptimer", | |
96 | .of_match_table = stm32_lptimer_of_match, | |
97 | }, | |
98 | }; | |
99 | module_platform_driver(stm32_lptimer_driver); | |
100 | ||
101 | MODULE_AUTHOR("Fabrice Gasnier <fabrice.gasnier@st.com>"); | |
102 | MODULE_DESCRIPTION("STMicroelectronics STM32 Low-Power Timer"); | |
103 | MODULE_ALIAS("platform:stm32-lptimer"); | |
104 | MODULE_LICENSE("GPL v2"); |