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// SPDX-License-Identifier: GPL-2.0
/*
* STM32 Low-Power Timer parent driver.
* Copyright (C) STMicroelectronics 2017
* Author: Fabrice Gasnier <fabrice.gasnier@st.com>
* Inspired by Benjamin Gaignard's stm32-timers driver
*/
#include <linux/bitfield.h>
#include <linux/mfd/stm32-lptimer.h>
#include <linux/module.h>
#include <linux/of_platform.h>
#include <linux/platform_device.h>
#define STM32_LPTIM_MAX_REGISTER 0x3fc
static const struct regmap_config stm32_lptimer_regmap_cfg = {
.reg_bits = 32,
.val_bits = 32,
.reg_stride = sizeof(u32),
.max_register = STM32_LPTIM_MAX_REGISTER,
};
static int stm32_lptimer_detect_encoder(struct stm32_lptimer *ddata)
{
u32 val;
int ret;
/*
* Quadrature encoder mode bit can only be written and read back when
* Low-Power Timer supports it.
*/
ret = regmap_update_bits(ddata->regmap, STM32_LPTIM_CFGR,
STM32_LPTIM_ENC, STM32_LPTIM_ENC);
if (ret)
return ret;
ret = regmap_read(ddata->regmap, STM32_LPTIM_CFGR, &val);
if (ret)
return ret;
ret = regmap_update_bits(ddata->regmap, STM32_LPTIM_CFGR,
STM32_LPTIM_ENC, 0);
if (ret)
return ret;
ddata->has_encoder = !!(val & STM32_LPTIM_ENC);
return 0;
}
static int stm32_lptimer_detect_hwcfgr(struct stm32_lptimer *ddata)
{
u32 val;
int ret;
ret = regmap_read(ddata->regmap, STM32_LPTIM_VERR, &ddata->version);
if (ret)
return ret;
/* Try to guess parameters from HWCFGR: e.g. encoder mode (STM32MP15) */
ret = regmap_read(ddata->regmap, STM32_LPTIM_HWCFGR1, &val);
if (ret)
return ret;
/* Fallback to legacy init if HWCFGR isn't present */
if (!val)
return stm32_lptimer_detect_encoder(ddata);
ddata->has_encoder = FIELD_GET(STM32_LPTIM_HWCFGR1_ENCODER, val);
ret = regmap_read(ddata->regmap, STM32_LPTIM_HWCFGR2, &val);
if (ret)
return ret;
/* Number of capture/compare channels */
ddata->num_cc_chans = FIELD_GET(STM32_LPTIM_HWCFGR2_CHAN_NUM, val);
return 0;
}
static int stm32_lptimer_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct stm32_lptimer *ddata;
void __iomem *mmio;
int ret;
ddata = devm_kzalloc(dev, sizeof(*ddata), GFP_KERNEL);
if (!ddata)
return -ENOMEM;
mmio = devm_platform_get_and_ioremap_resource(pdev, 0, NULL);
if (IS_ERR(mmio))
return PTR_ERR(mmio);
ddata->regmap = devm_regmap_init_mmio_clk(dev, "mux", mmio,
&stm32_lptimer_regmap_cfg);
if (IS_ERR(ddata->regmap))
return PTR_ERR(ddata->regmap);
ddata->clk = devm_clk_get(dev, NULL);
if (IS_ERR(ddata->clk))
return PTR_ERR(ddata->clk);
ret = stm32_lptimer_detect_hwcfgr(ddata);
if (ret)
return ret;
platform_set_drvdata(pdev, ddata);
return devm_of_platform_populate(&pdev->dev);
}
static const struct of_device_id stm32_lptimer_of_match[] = {
{ .compatible = "st,stm32-lptimer", },
{},
};
MODULE_DEVICE_TABLE(of, stm32_lptimer_of_match);
static struct platform_driver stm32_lptimer_driver = {
.probe = stm32_lptimer_probe,
.driver = {
.name = "stm32-lptimer",
.of_match_table = stm32_lptimer_of_match,
},
};
module_platform_driver(stm32_lptimer_driver);
MODULE_AUTHOR("Fabrice Gasnier <fabrice.gasnier@st.com>");
MODULE_DESCRIPTION("STMicroelectronics STM32 Low-Power Timer");
MODULE_ALIAS("platform:stm32-lptimer");
MODULE_LICENSE("GPL v2");
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