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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"); |