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108 lines
2.5 KiB
C
108 lines
2.5 KiB
C
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/*
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* STM32 Low-Power Timer parent driver.
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*
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* Copyright (C) STMicroelectronics 2017
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*
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* Author: Fabrice Gasnier <fabrice.gasnier@st.com>
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*
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* Inspired by Benjamin Gaignard's stm32-timers driver
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*
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* License terms: GNU General Public License (GPL), version 2
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*/
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#include <linux/mfd/stm32-lptimer.h>
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#include <linux/module.h>
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#include <linux/of_platform.h>
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#define STM32_LPTIM_MAX_REGISTER 0x3fc
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static const struct regmap_config stm32_lptimer_regmap_cfg = {
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.reg_bits = 32,
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.val_bits = 32,
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.reg_stride = sizeof(u32),
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.max_register = STM32_LPTIM_MAX_REGISTER,
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};
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static int stm32_lptimer_detect_encoder(struct stm32_lptimer *ddata)
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{
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u32 val;
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int ret;
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/*
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* Quadrature encoder mode bit can only be written and read back when
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* Low-Power Timer supports it.
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*/
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ret = regmap_update_bits(ddata->regmap, STM32_LPTIM_CFGR,
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STM32_LPTIM_ENC, STM32_LPTIM_ENC);
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if (ret)
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return ret;
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ret = regmap_read(ddata->regmap, STM32_LPTIM_CFGR, &val);
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if (ret)
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return ret;
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ret = regmap_update_bits(ddata->regmap, STM32_LPTIM_CFGR,
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STM32_LPTIM_ENC, 0);
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if (ret)
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return ret;
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ddata->has_encoder = !!(val & STM32_LPTIM_ENC);
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return 0;
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}
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static int stm32_lptimer_probe(struct platform_device *pdev)
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{
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struct device *dev = &pdev->dev;
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struct stm32_lptimer *ddata;
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struct resource *res;
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void __iomem *mmio;
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int ret;
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ddata = devm_kzalloc(dev, sizeof(*ddata), GFP_KERNEL);
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if (!ddata)
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return -ENOMEM;
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res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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mmio = devm_ioremap_resource(dev, res);
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if (IS_ERR(mmio))
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return PTR_ERR(mmio);
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ddata->regmap = devm_regmap_init_mmio_clk(dev, "mux", mmio,
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&stm32_lptimer_regmap_cfg);
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if (IS_ERR(ddata->regmap))
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return PTR_ERR(ddata->regmap);
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ddata->clk = devm_clk_get(dev, NULL);
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if (IS_ERR(ddata->clk))
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return PTR_ERR(ddata->clk);
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ret = stm32_lptimer_detect_encoder(ddata);
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if (ret)
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return ret;
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platform_set_drvdata(pdev, ddata);
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return devm_of_platform_populate(&pdev->dev);
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}
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static const struct of_device_id stm32_lptimer_of_match[] = {
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{ .compatible = "st,stm32-lptimer", },
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{},
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};
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MODULE_DEVICE_TABLE(of, stm32_lptimer_of_match);
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static struct platform_driver stm32_lptimer_driver = {
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.probe = stm32_lptimer_probe,
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.driver = {
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.name = "stm32-lptimer",
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.of_match_table = stm32_lptimer_of_match,
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},
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};
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module_platform_driver(stm32_lptimer_driver);
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MODULE_AUTHOR("Fabrice Gasnier <fabrice.gasnier@st.com>");
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MODULE_DESCRIPTION("STMicroelectronics STM32 Low-Power Timer");
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MODULE_ALIAS("platform:stm32-lptimer");
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MODULE_LICENSE("GPL v2");
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