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221 lines
6.0 KiB
221 lines
6.0 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* Copyright (C) STMicroelectronics 2019 - All Rights Reserved |
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* Authors: Benjamin Gaignard <[email protected]> for STMicroelectronics. |
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* Pascal Paillet <[email protected]> for STMicroelectronics. |
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*/ |
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#include <linux/clk.h> |
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#include <linux/clockchips.h> |
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#include <linux/interrupt.h> |
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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_address.h> |
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#include <linux/of_irq.h> |
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#include <linux/platform_device.h> |
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#include <linux/pm_wakeirq.h> |
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#define CFGR_PSC_OFFSET 9 |
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#define STM32_LP_RATING 1000 |
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#define STM32_TARGET_CLKRATE (32000 * HZ) |
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#define STM32_LP_MAX_PSC 7 |
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struct stm32_lp_private { |
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struct regmap *reg; |
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struct clock_event_device clkevt; |
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unsigned long period; |
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struct device *dev; |
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}; |
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static struct stm32_lp_private* |
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to_priv(struct clock_event_device *clkevt) |
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{ |
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return container_of(clkevt, struct stm32_lp_private, clkevt); |
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} |
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static int stm32_clkevent_lp_shutdown(struct clock_event_device *clkevt) |
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{ |
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struct stm32_lp_private *priv = to_priv(clkevt); |
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regmap_write(priv->reg, STM32_LPTIM_CR, 0); |
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regmap_write(priv->reg, STM32_LPTIM_IER, 0); |
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/* clear pending flags */ |
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regmap_write(priv->reg, STM32_LPTIM_ICR, STM32_LPTIM_ARRMCF); |
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return 0; |
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} |
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static int stm32_clkevent_lp_set_timer(unsigned long evt, |
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struct clock_event_device *clkevt, |
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int is_periodic) |
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{ |
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struct stm32_lp_private *priv = to_priv(clkevt); |
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/* disable LPTIMER to be able to write into IER register*/ |
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regmap_write(priv->reg, STM32_LPTIM_CR, 0); |
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/* enable ARR interrupt */ |
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regmap_write(priv->reg, STM32_LPTIM_IER, STM32_LPTIM_ARRMIE); |
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/* enable LPTIMER to be able to write into ARR register */ |
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regmap_write(priv->reg, STM32_LPTIM_CR, STM32_LPTIM_ENABLE); |
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/* set next event counter */ |
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regmap_write(priv->reg, STM32_LPTIM_ARR, evt); |
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/* start counter */ |
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if (is_periodic) |
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regmap_write(priv->reg, STM32_LPTIM_CR, |
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STM32_LPTIM_CNTSTRT | STM32_LPTIM_ENABLE); |
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else |
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regmap_write(priv->reg, STM32_LPTIM_CR, |
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STM32_LPTIM_SNGSTRT | STM32_LPTIM_ENABLE); |
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return 0; |
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} |
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static int stm32_clkevent_lp_set_next_event(unsigned long evt, |
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struct clock_event_device *clkevt) |
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{ |
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return stm32_clkevent_lp_set_timer(evt, clkevt, |
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clockevent_state_periodic(clkevt)); |
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} |
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static int stm32_clkevent_lp_set_periodic(struct clock_event_device *clkevt) |
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{ |
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struct stm32_lp_private *priv = to_priv(clkevt); |
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return stm32_clkevent_lp_set_timer(priv->period, clkevt, true); |
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} |
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static int stm32_clkevent_lp_set_oneshot(struct clock_event_device *clkevt) |
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{ |
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struct stm32_lp_private *priv = to_priv(clkevt); |
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return stm32_clkevent_lp_set_timer(priv->period, clkevt, false); |
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} |
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static irqreturn_t stm32_clkevent_lp_irq_handler(int irq, void *dev_id) |
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{ |
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struct clock_event_device *clkevt = (struct clock_event_device *)dev_id; |
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struct stm32_lp_private *priv = to_priv(clkevt); |
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regmap_write(priv->reg, STM32_LPTIM_ICR, STM32_LPTIM_ARRMCF); |
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if (clkevt->event_handler) |
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clkevt->event_handler(clkevt); |
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return IRQ_HANDLED; |
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} |
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static void stm32_clkevent_lp_set_prescaler(struct stm32_lp_private *priv, |
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unsigned long *rate) |
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{ |
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int i; |
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for (i = 0; i <= STM32_LP_MAX_PSC; i++) { |
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if (DIV_ROUND_CLOSEST(*rate, 1 << i) < STM32_TARGET_CLKRATE) |
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break; |
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} |
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regmap_write(priv->reg, STM32_LPTIM_CFGR, i << CFGR_PSC_OFFSET); |
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/* Adjust rate and period given the prescaler value */ |
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*rate = DIV_ROUND_CLOSEST(*rate, (1 << i)); |
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priv->period = DIV_ROUND_UP(*rate, HZ); |
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} |
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static void stm32_clkevent_lp_init(struct stm32_lp_private *priv, |
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struct device_node *np, unsigned long rate) |
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{ |
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priv->clkevt.name = np->full_name; |
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priv->clkevt.cpumask = cpu_possible_mask; |
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priv->clkevt.features = CLOCK_EVT_FEAT_PERIODIC | |
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CLOCK_EVT_FEAT_ONESHOT; |
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priv->clkevt.set_state_shutdown = stm32_clkevent_lp_shutdown; |
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priv->clkevt.set_state_periodic = stm32_clkevent_lp_set_periodic; |
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priv->clkevt.set_state_oneshot = stm32_clkevent_lp_set_oneshot; |
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priv->clkevt.set_next_event = stm32_clkevent_lp_set_next_event; |
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priv->clkevt.rating = STM32_LP_RATING; |
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clockevents_config_and_register(&priv->clkevt, rate, 0x1, |
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STM32_LPTIM_MAX_ARR); |
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} |
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static int stm32_clkevent_lp_probe(struct platform_device *pdev) |
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{ |
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struct stm32_lptimer *ddata = dev_get_drvdata(pdev->dev.parent); |
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struct stm32_lp_private *priv; |
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unsigned long rate; |
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int ret, irq; |
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priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL); |
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if (!priv) |
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return -ENOMEM; |
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priv->reg = ddata->regmap; |
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ret = clk_prepare_enable(ddata->clk); |
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if (ret) |
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return -EINVAL; |
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rate = clk_get_rate(ddata->clk); |
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if (!rate) { |
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ret = -EINVAL; |
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goto out_clk_disable; |
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} |
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irq = platform_get_irq(to_platform_device(pdev->dev.parent), 0); |
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if (irq <= 0) { |
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ret = irq; |
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goto out_clk_disable; |
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} |
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if (of_property_read_bool(pdev->dev.parent->of_node, "wakeup-source")) { |
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ret = device_init_wakeup(&pdev->dev, true); |
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if (ret) |
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goto out_clk_disable; |
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ret = dev_pm_set_wake_irq(&pdev->dev, irq); |
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if (ret) |
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goto out_clk_disable; |
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} |
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ret = devm_request_irq(&pdev->dev, irq, stm32_clkevent_lp_irq_handler, |
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IRQF_TIMER, pdev->name, &priv->clkevt); |
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if (ret) |
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goto out_clk_disable; |
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stm32_clkevent_lp_set_prescaler(priv, &rate); |
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stm32_clkevent_lp_init(priv, pdev->dev.parent->of_node, rate); |
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priv->dev = &pdev->dev; |
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return 0; |
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out_clk_disable: |
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clk_disable_unprepare(ddata->clk); |
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return ret; |
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} |
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static int stm32_clkevent_lp_remove(struct platform_device *pdev) |
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{ |
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return -EBUSY; /* cannot unregister clockevent */ |
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} |
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static const struct of_device_id stm32_clkevent_lp_of_match[] = { |
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{ .compatible = "st,stm32-lptimer-timer", }, |
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{}, |
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}; |
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MODULE_DEVICE_TABLE(of, stm32_clkevent_lp_of_match); |
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static struct platform_driver stm32_clkevent_lp_driver = { |
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.probe = stm32_clkevent_lp_probe, |
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.remove = stm32_clkevent_lp_remove, |
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.driver = { |
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.name = "stm32-lptimer-timer", |
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.of_match_table = of_match_ptr(stm32_clkevent_lp_of_match), |
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}, |
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}; |
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module_platform_driver(stm32_clkevent_lp_driver); |
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MODULE_ALIAS("platform:stm32-lptimer-timer"); |
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MODULE_DESCRIPTION("STMicroelectronics STM32 clockevent low power driver"); |
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MODULE_LICENSE("GPL v2");
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