GNU Linux-libre 5.10.219-gnu1
[releases.git] / drivers / mfd / stm32-lptimer.c
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
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,
20         .fast_io = true,
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");