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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
16static 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
24static 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
52static 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, sizeof(*ddata), GFP_KERNEL);
60 if (!ddata)
61 return -ENOMEM;
62
63 mmio = devm_platform_get_and_ioremap_resource(pdev, 0, NULL);
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
85static const struct of_device_id stm32_lptimer_of_match[] = {
86 { .compatible = "st,stm32-lptimer", },
87 {},
88};
89MODULE_DEVICE_TABLE(of, stm32_lptimer_of_match);
90
91static 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};
98module_platform_driver(stm32_lptimer_driver);
99
100MODULE_AUTHOR("Fabrice Gasnier <fabrice.gasnier@st.com>");
101MODULE_DESCRIPTION("STMicroelectronics STM32 Low-Power Timer");
102MODULE_ALIAS("platform:stm32-lptimer");
103MODULE_LICENSE("GPL v2");