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/mfd/stm32-lptimer.h> |
10 | #include <linux/module.h> |
11 | #include <linux/of_platform.h> |
12 | #include <linux/platform_device.h> |
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, |
21 | .fast_io = true, |
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(map: ddata->regmap, STM32_LPTIM_CFGR, |
34 | STM32_LPTIM_ENC, STM32_LPTIM_ENC); |
35 | if (ret) |
36 | return ret; |
37 | |
38 | ret = regmap_read(map: ddata->regmap, STM32_LPTIM_CFGR, val: &val); |
39 | if (ret) |
40 | return ret; |
41 | |
42 | ret = regmap_update_bits(map: ddata->regmap, STM32_LPTIM_CFGR, |
43 | STM32_LPTIM_ENC, val: 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; |
56 | void __iomem *mmio; |
57 | int ret; |
58 | |
59 | ddata = devm_kzalloc(dev, size: sizeof(*ddata), GFP_KERNEL); |
60 | if (!ddata) |
61 | return -ENOMEM; |
62 | |
63 | mmio = devm_platform_get_and_ioremap_resource(pdev, index: 0, NULL); |
64 | if (IS_ERR(ptr: mmio)) |
65 | return PTR_ERR(ptr: mmio); |
66 | |
67 | ddata->regmap = devm_regmap_init_mmio_clk(dev, "mux" , mmio, |
68 | &stm32_lptimer_regmap_cfg); |
69 | if (IS_ERR(ptr: ddata->regmap)) |
70 | return PTR_ERR(ptr: ddata->regmap); |
71 | |
72 | ddata->clk = devm_clk_get(dev, NULL); |
73 | if (IS_ERR(ptr: ddata->clk)) |
74 | return PTR_ERR(ptr: ddata->clk); |
75 | |
76 | ret = stm32_lptimer_detect_encoder(ddata); |
77 | if (ret) |
78 | return ret; |
79 | |
80 | platform_set_drvdata(pdev, data: ddata); |
81 | |
82 | return devm_of_platform_populate(dev: &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" ); |
104 | |