1fa93f5b7SBenjamin Gaignard // SPDX-License-Identifier: GPL-2.0
2e8924005SFabrice Gasnier /*
3e8924005SFabrice Gasnier * STM32 Low-Power Timer parent driver.
4e8924005SFabrice Gasnier * Copyright (C) STMicroelectronics 2017
5e8924005SFabrice Gasnier * Author: Fabrice Gasnier <fabrice.gasnier@st.com>
6e8924005SFabrice Gasnier * Inspired by Benjamin Gaignard's stm32-timers driver
7e8924005SFabrice Gasnier */
8e8924005SFabrice Gasnier
9e8924005SFabrice Gasnier #include <linux/mfd/stm32-lptimer.h>
10e8924005SFabrice Gasnier #include <linux/module.h>
11e8924005SFabrice Gasnier #include <linux/of_platform.h>
12*dc0c386eSRob Herring #include <linux/platform_device.h>
13e8924005SFabrice Gasnier
14e8924005SFabrice Gasnier #define STM32_LPTIM_MAX_REGISTER 0x3fc
15e8924005SFabrice Gasnier
16e8924005SFabrice Gasnier static const struct regmap_config stm32_lptimer_regmap_cfg = {
17e8924005SFabrice Gasnier .reg_bits = 32,
18e8924005SFabrice Gasnier .val_bits = 32,
19e8924005SFabrice Gasnier .reg_stride = sizeof(u32),
20e8924005SFabrice Gasnier .max_register = STM32_LPTIM_MAX_REGISTER,
2145d93065SBenjamin Gaignard .fast_io = true,
22e8924005SFabrice Gasnier };
23e8924005SFabrice Gasnier
stm32_lptimer_detect_encoder(struct stm32_lptimer * ddata)24e8924005SFabrice Gasnier static int stm32_lptimer_detect_encoder(struct stm32_lptimer *ddata)
25e8924005SFabrice Gasnier {
26e8924005SFabrice Gasnier u32 val;
27e8924005SFabrice Gasnier int ret;
28e8924005SFabrice Gasnier
29e8924005SFabrice Gasnier /*
30e8924005SFabrice Gasnier * Quadrature encoder mode bit can only be written and read back when
31e8924005SFabrice Gasnier * Low-Power Timer supports it.
32e8924005SFabrice Gasnier */
33e8924005SFabrice Gasnier ret = regmap_update_bits(ddata->regmap, STM32_LPTIM_CFGR,
34e8924005SFabrice Gasnier STM32_LPTIM_ENC, STM32_LPTIM_ENC);
35e8924005SFabrice Gasnier if (ret)
36e8924005SFabrice Gasnier return ret;
37e8924005SFabrice Gasnier
38e8924005SFabrice Gasnier ret = regmap_read(ddata->regmap, STM32_LPTIM_CFGR, &val);
39e8924005SFabrice Gasnier if (ret)
40e8924005SFabrice Gasnier return ret;
41e8924005SFabrice Gasnier
42e8924005SFabrice Gasnier ret = regmap_update_bits(ddata->regmap, STM32_LPTIM_CFGR,
43e8924005SFabrice Gasnier STM32_LPTIM_ENC, 0);
44e8924005SFabrice Gasnier if (ret)
45e8924005SFabrice Gasnier return ret;
46e8924005SFabrice Gasnier
47e8924005SFabrice Gasnier ddata->has_encoder = !!(val & STM32_LPTIM_ENC);
48e8924005SFabrice Gasnier
49e8924005SFabrice Gasnier return 0;
50e8924005SFabrice Gasnier }
51e8924005SFabrice Gasnier
stm32_lptimer_probe(struct platform_device * pdev)52e8924005SFabrice Gasnier static int stm32_lptimer_probe(struct platform_device *pdev)
53e8924005SFabrice Gasnier {
54e8924005SFabrice Gasnier struct device *dev = &pdev->dev;
55e8924005SFabrice Gasnier struct stm32_lptimer *ddata;
56e8924005SFabrice Gasnier void __iomem *mmio;
57e8924005SFabrice Gasnier int ret;
58e8924005SFabrice Gasnier
59e8924005SFabrice Gasnier ddata = devm_kzalloc(dev, sizeof(*ddata), GFP_KERNEL);
60e8924005SFabrice Gasnier if (!ddata)
61e8924005SFabrice Gasnier return -ENOMEM;
62e8924005SFabrice Gasnier
63f359c3e5SMinghao Chi mmio = devm_platform_get_and_ioremap_resource(pdev, 0, NULL);
64e8924005SFabrice Gasnier if (IS_ERR(mmio))
65e8924005SFabrice Gasnier return PTR_ERR(mmio);
66e8924005SFabrice Gasnier
67e8924005SFabrice Gasnier ddata->regmap = devm_regmap_init_mmio_clk(dev, "mux", mmio,
68e8924005SFabrice Gasnier &stm32_lptimer_regmap_cfg);
69e8924005SFabrice Gasnier if (IS_ERR(ddata->regmap))
70e8924005SFabrice Gasnier return PTR_ERR(ddata->regmap);
71e8924005SFabrice Gasnier
72e8924005SFabrice Gasnier ddata->clk = devm_clk_get(dev, NULL);
73e8924005SFabrice Gasnier if (IS_ERR(ddata->clk))
74e8924005SFabrice Gasnier return PTR_ERR(ddata->clk);
75e8924005SFabrice Gasnier
76e8924005SFabrice Gasnier ret = stm32_lptimer_detect_encoder(ddata);
77e8924005SFabrice Gasnier if (ret)
78e8924005SFabrice Gasnier return ret;
79e8924005SFabrice Gasnier
80e8924005SFabrice Gasnier platform_set_drvdata(pdev, ddata);
81e8924005SFabrice Gasnier
82e8924005SFabrice Gasnier return devm_of_platform_populate(&pdev->dev);
83e8924005SFabrice Gasnier }
84e8924005SFabrice Gasnier
85e8924005SFabrice Gasnier static const struct of_device_id stm32_lptimer_of_match[] = {
86e8924005SFabrice Gasnier { .compatible = "st,stm32-lptimer", },
87e8924005SFabrice Gasnier {},
88e8924005SFabrice Gasnier };
89e8924005SFabrice Gasnier MODULE_DEVICE_TABLE(of, stm32_lptimer_of_match);
90e8924005SFabrice Gasnier
91e8924005SFabrice Gasnier static struct platform_driver stm32_lptimer_driver = {
92e8924005SFabrice Gasnier .probe = stm32_lptimer_probe,
93e8924005SFabrice Gasnier .driver = {
94e8924005SFabrice Gasnier .name = "stm32-lptimer",
95e8924005SFabrice Gasnier .of_match_table = stm32_lptimer_of_match,
96e8924005SFabrice Gasnier },
97e8924005SFabrice Gasnier };
98e8924005SFabrice Gasnier module_platform_driver(stm32_lptimer_driver);
99e8924005SFabrice Gasnier
100e8924005SFabrice Gasnier MODULE_AUTHOR("Fabrice Gasnier <fabrice.gasnier@st.com>");
101e8924005SFabrice Gasnier MODULE_DESCRIPTION("STMicroelectronics STM32 Low-Power Timer");
102e8924005SFabrice Gasnier MODULE_ALIAS("platform:stm32-lptimer");
103e8924005SFabrice Gasnier MODULE_LICENSE("GPL v2");
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