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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> | |
dc0c386e | 12 | #include <linux/platform_device.h> |
e8924005 FG |
13 | |
14 | #define STM32_LPTIM_MAX_REGISTER 0x3fc | |
15 | ||
16 | static const struct regmap_config stm32_lptimer_regmap_cfg = { | |
17 | .reg_bits = 32, | |
18 | .val_bits = 32, | |
19 | .reg_stride = sizeof(u32), | |
20 | .max_register = STM32_LPTIM_MAX_REGISTER, | |
45d93065 | 21 | .fast_io = true, |
e8924005 FG |
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_probe(struct platform_device *pdev) | |
53 | { | |
54 | struct device *dev = &pdev->dev; | |
55 | struct stm32_lptimer *ddata; | |
e8924005 FG |
56 | void __iomem *mmio; |
57 | int ret; | |
58 | ||
59 | ddata = devm_kzalloc(dev, sizeof(*ddata), GFP_KERNEL); | |
60 | if (!ddata) | |
61 | return -ENOMEM; | |
62 | ||
f359c3e5 | 63 | mmio = devm_platform_get_and_ioremap_resource(pdev, 0, NULL); |
e8924005 FG |
64 | if (IS_ERR(mmio)) |
65 | return PTR_ERR(mmio); | |
66 | ||
67 | ddata->regmap = devm_regmap_init_mmio_clk(dev, "mux", mmio, | |
68 | &stm32_lptimer_regmap_cfg); | |
69 | if (IS_ERR(ddata->regmap)) | |
70 | return PTR_ERR(ddata->regmap); | |
71 | ||
72 | ddata->clk = devm_clk_get(dev, NULL); | |
73 | if (IS_ERR(ddata->clk)) | |
74 | return PTR_ERR(ddata->clk); | |
75 | ||
76 | ret = stm32_lptimer_detect_encoder(ddata); | |
77 | if (ret) | |
78 | return ret; | |
79 | ||
80 | platform_set_drvdata(pdev, ddata); | |
81 | ||
82 | return devm_of_platform_populate(&pdev->dev); | |
83 | } | |
84 | ||
85 | static const struct of_device_id stm32_lptimer_of_match[] = { | |
86 | { .compatible = "st,stm32-lptimer", }, | |
87 | {}, | |
88 | }; | |
89 | MODULE_DEVICE_TABLE(of, stm32_lptimer_of_match); | |
90 | ||
91 | static struct platform_driver stm32_lptimer_driver = { | |
92 | .probe = stm32_lptimer_probe, | |
93 | .driver = { | |
94 | .name = "stm32-lptimer", | |
95 | .of_match_table = stm32_lptimer_of_match, | |
96 | }, | |
97 | }; | |
98 | module_platform_driver(stm32_lptimer_driver); | |
99 | ||
100 | MODULE_AUTHOR("Fabrice Gasnier <fabrice.gasnier@st.com>"); | |
101 | MODULE_DESCRIPTION("STMicroelectronics STM32 Low-Power Timer"); | |
102 | MODULE_ALIAS("platform:stm32-lptimer"); | |
103 | MODULE_LICENSE("GPL v2"); |