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Message-ID: <20140922154540.GS22877@ldesroches-Latitude-E6320>
Date: Mon, 22 Sep 2014 17:45:41 +0200
From: Ludovic Desroches <ludovic.desroches@...el.com>
To: Pramod Gurav <pramod.gurav@...rtplayin.com>
CC: <linux-kernel@...r.kernel.org>,
Ludovic Desroches <ludovic.desroches@...el.com>,
Chris Ball <chris@...ntf.net>,
Ulf Hansson <ulf.hansson@...aro.org>,
<linux-mmc@...r.kernel.org>
Subject: Re: [PATCH 1/2] mmc: atmel-mci: Switch to using managed resource in
probe
Hi Pramod,
Thanks for taking care of device managed resources conversion. My only
concern is about using devm_request_irq. There are several discussions
about races which can occur when using it.
Keeping request_irq and free_irq the time it takes to solve this issue
is probably better.
Regards
Ludovic
On Sat, Sep 20, 2014 at 12:22:30PM +0530, Pramod Gurav wrote:
> This change uses managed resource APIs to allocate resources such as,
> clk, gpio, irq in order to simplify the driver unload or failure cases.
> Hence does away with release statements of the same resorces in error
> lables and remove function.
>
> Cc: Ludovic Desroches <ludovic.desroches@...el.com>
> Cc: Chris Ball <chris@...ntf.net>
> Cc: Ulf Hansson <ulf.hansson@...aro.org>
> Cc: linux-mmc@...r.kernel.org
> Signed-off-by: Pramod Gurav <pramod.gurav@...rtplayin.com>
> ---
> drivers/mmc/host/atmel-mci.c | 57 ++++++++++++++++----------------------------
> 1 file changed, 20 insertions(+), 37 deletions(-)
>
> diff --git a/drivers/mmc/host/atmel-mci.c b/drivers/mmc/host/atmel-mci.c
> index bb585d9..21a222c 100644
> --- a/drivers/mmc/host/atmel-mci.c
> +++ b/drivers/mmc/host/atmel-mci.c
> @@ -17,6 +17,7 @@
> #include <linux/gpio.h>
> #include <linux/init.h>
> #include <linux/interrupt.h>
> +#include <linux/io.h>
> #include <linux/ioport.h>
> #include <linux/module.h>
> #include <linux/of.h>
> @@ -2195,7 +2196,8 @@ static int __init atmci_init_slot(struct atmel_mci *host,
> /* Assume card is present initially */
> set_bit(ATMCI_CARD_PRESENT, &slot->flags);
> if (gpio_is_valid(slot->detect_pin)) {
> - if (gpio_request(slot->detect_pin, "mmc_detect")) {
> + if (devm_gpio_request(&host->pdev->dev, slot->detect_pin,
> + "mmc_detect")) {
> dev_dbg(&mmc->class_dev, "no detect pin available\n");
> slot->detect_pin = -EBUSY;
> } else if (gpio_get_value(slot->detect_pin) ^
> @@ -2208,7 +2210,8 @@ static int __init atmci_init_slot(struct atmel_mci *host,
> mmc->caps |= MMC_CAP_NEEDS_POLL;
>
> if (gpio_is_valid(slot->wp_pin)) {
> - if (gpio_request(slot->wp_pin, "mmc_wp")) {
> + if (devm_gpio_request(&host->pdev->dev, slot->wp_pin,
> + "mmc_wp")) {
> dev_dbg(&mmc->class_dev, "no WP pin available\n");
> slot->wp_pin = -EBUSY;
> }
> @@ -2224,7 +2227,8 @@ static int __init atmci_init_slot(struct atmel_mci *host,
> setup_timer(&slot->detect_timer, atmci_detect_change,
> (unsigned long)slot);
>
> - ret = request_irq(gpio_to_irq(slot->detect_pin),
> + ret = devm_request_irq(&host->pdev->dev,
> + gpio_to_irq(slot->detect_pin),
> atmci_detect_interrupt,
> IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING,
> "mmc-detect", slot);
> @@ -2232,7 +2236,6 @@ static int __init atmci_init_slot(struct atmel_mci *host,
> dev_dbg(&mmc->class_dev,
> "could not request IRQ %d for detect pin\n",
> gpio_to_irq(slot->detect_pin));
> - gpio_free(slot->detect_pin);
> slot->detect_pin = -EBUSY;
> }
> }
> @@ -2252,15 +2255,8 @@ static void __exit atmci_cleanup_slot(struct atmel_mci_slot *slot,
>
> mmc_remove_host(slot->mmc);
>
> - if (gpio_is_valid(slot->detect_pin)) {
> - int pin = slot->detect_pin;
> -
> - free_irq(gpio_to_irq(pin), slot);
> + if (gpio_is_valid(slot->detect_pin))
> del_timer_sync(&slot->detect_timer);
> - gpio_free(pin);
> - }
> - if (gpio_is_valid(slot->wp_pin))
> - gpio_free(slot->wp_pin);
>
> slot->host->slot[id] = NULL;
> mmc_free_host(slot->mmc);
> @@ -2395,7 +2391,7 @@ static int __init atmci_probe(struct platform_device *pdev)
> if (irq < 0)
> return irq;
>
> - host = kzalloc(sizeof(struct atmel_mci), GFP_KERNEL);
> + host = devm_kzalloc(&pdev->dev, sizeof(*host), GFP_KERNEL);
> if (!host)
> return -ENOMEM;
>
> @@ -2403,20 +2399,18 @@ static int __init atmci_probe(struct platform_device *pdev)
> spin_lock_init(&host->lock);
> INIT_LIST_HEAD(&host->queue);
>
> - host->mck = clk_get(&pdev->dev, "mci_clk");
> - if (IS_ERR(host->mck)) {
> - ret = PTR_ERR(host->mck);
> - goto err_clk_get;
> - }
> + host->mck = devm_clk_get(&pdev->dev, "mci_clk");
> + if (IS_ERR(host->mck))
> + return PTR_ERR(host->mck);
>
> - ret = -ENOMEM;
> - host->regs = ioremap(regs->start, resource_size(regs));
> + host->regs = devm_ioremap(&pdev->dev, regs->start, resource_size(regs));
> if (!host->regs)
> - goto err_ioremap;
> + return -ENOMEM;
>
> ret = clk_prepare_enable(host->mck);
> if (ret)
> - goto err_request_irq;
> + return ret;
> +
> atmci_writel(host, ATMCI_CR, ATMCI_CR_SWRST);
> host->bus_hz = clk_get_rate(host->mck);
> clk_disable_unprepare(host->mck);
> @@ -2425,9 +2419,10 @@ static int __init atmci_probe(struct platform_device *pdev)
>
> tasklet_init(&host->tasklet, atmci_tasklet_func, (unsigned long)host);
>
> - ret = request_irq(irq, atmci_interrupt, 0, dev_name(&pdev->dev), host);
> + ret = devm_request_irq(&pdev->dev, irq, atmci_interrupt, 0,
> + dev_name(&pdev->dev), host);
> if (ret)
> - goto err_request_irq;
> + return ret;
>
> /* Get MCI capabilities and set operations according to it */
> atmci_get_cap(host);
> @@ -2498,13 +2493,7 @@ static int __init atmci_probe(struct platform_device *pdev)
> err_init_slot:
> if (host->dma.chan)
> dma_release_channel(host->dma.chan);
> - free_irq(irq, host);
> -err_request_irq:
> - iounmap(host->regs);
> -err_ioremap:
> - clk_put(host->mck);
> -err_clk_get:
> - kfree(host);
> +
> return ret;
> }
>
> @@ -2531,12 +2520,6 @@ static int __exit atmci_remove(struct platform_device *pdev)
> if (host->dma.chan)
> dma_release_channel(host->dma.chan);
>
> - free_irq(platform_get_irq(pdev, 0), host);
> - iounmap(host->regs);
> -
> - clk_put(host->mck);
> - kfree(host);
> -
> return 0;
> }
>
> --
> 1.8.3.2
>
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