Re: [PATCH 3/3] MMC: sdhci-dove: allow GPIOs to be used for card detection on Dove

Shawn Guo
2012-11-23T08:05:09Z

On Thu, Nov 22, 2012 at 11:55:51PM +0000, Russell King wrote:
> This commit taken from Rabeeh's Cubox kernel and re-worked for DT;
> Sebastian Hasselbrath is believed to be the original author.
>
> Some Cuboxes require a GPIO for card detection; this implements the
> optional GPIO support for card detection. This GPIO is logic 0 for
> card inserted.
>
> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
> ---
> drivers/mmc/host/sdhci-dove.c | 73 +++++++++++++++++++++++++++++++++++++---
> 1 files changed, 67 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/mmc/host/sdhci-dove.c b/drivers/mmc/host/sdhci-dove.c
> index 4af64f3..e621448 100644
> --- a/drivers/mmc/host/sdhci-dove.c
> +++ b/drivers/mmc/host/sdhci-dove.c
> @@ -19,20 +19,30 @@
> * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
> */
>
> -#include <linux/err.h>
> -#include <linux/io.h>
> #include <linux/clk.h>
> #include <linux/err.h>
> -#include <linux/module.h>
> +#include <linux/gpio.h>
> +#include <linux/io.h>
> #include <linux/mmc/host.h>
> +#include <linux/module.h>
> #include <linux/of.h>
> +#include <linux/of_gpio.h>
>
> #include "sdhci-pltfm.h"
>
> struct sdhci_dove_priv {
> struct clk *clk;
> + int gpio_cd;
> };
>
> +static irqreturn_t sdhci_dove_carddetect_irq(int irq, void *data)
> +{
> + struct sdhci_host *host = data;
> +
> + tasklet_schedule(&host->card_tasklet);
> + return IRQ_HANDLED;
> +}
> +
> static u16 sdhci_dove_readw(struct sdhci_host *host, int reg)
> {
> u16 ret;
> @@ -50,16 +60,25 @@ static u16 sdhci_dove_readw(struct sdhci_host *host, int reg)
>
> static u32 sdhci_dove_readl(struct sdhci_host *host, int reg)
> {
> + struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
> + struct sdhci_dove_priv *priv = pltfm_host->priv;
> u32 ret;
>
> + ret = readl(host->ioaddr + reg);
> +
> switch (reg) {
> case SDHCI_CAPABILITIES:
> - ret = readl(host->ioaddr + reg);
> /* Mask the support for 3.0V */
> ret &= ~SDHCI_CAN_VDD_300;
> break;
> - default:
> - ret = readl(host->ioaddr + reg);
> + case SDHCI_PRESENT_STATE:
> + if (gpio_is_valid(priv->gpio_cd)) {
> + if (gpio_get_value(priv->gpio_cd) == 0)
> + ret |= SDHCI_CARD_PRESENT;
> + else
> + ret &= ~SDHCI_CARD_PRESENT;
> + }
> + break;

It seems that the helpers in drivers/mmc/core/slot-gpio.c can help to
simplify the patch a lot. With sdhci core code being calling
mmc_gpio_get_cd() to query card present, the fake SDHCI_PRESENT_STATE
implementation above can be totally saved.

Shawn

> }
> return ret;
> }
> @@ -94,6 +113,23 @@ static int __devinit sdhci_dove_probe(struct platform_device *pdev)
>
> priv->clk = devm_clk_get(&pdev->dev, NULL);
>
> + if (pdev->dev.of_node) {
> + priv->gpio_cd = of_get_named_gpio(pdev->dev.of_node,
> + "cd-gpios", 0);
> + } else {
> + priv->gpio_cd = -EINVAL;
> + }
> +
> + if (gpio_is_valid(priv->gpio_cd)) {
> + ret = gpio_request(priv->gpio_cd, "sdhci-cd");
> + if (ret) {
> + dev_err(&pdev->dev, "card detect gpio request failed: %d\n",
> + ret);
> + return ret;
> + }
> + gpio_direction_input(priv->gpio_cd);
> + }
> +
> host = sdhci_pltfm_init(pdev, &sdhci_dove_pdata);
> if (IS_ERR(host)) {
> ret = PTR_ERR(host);
> @@ -112,13 +148,33 @@ static int __devinit sdhci_dove_probe(struct platform_device *pdev)
> if (ret)
> goto err_sdhci_add;
>
> + /*
> + * We must request the IRQ after sdhci_add_host(), as the tasklet only
> + * gets setup in sdhci_add_host() and we oops.
> + */
> + if (gpio_is_valid(priv->gpio_cd)) {
> + ret = request_irq(gpio_to_irq(priv->gpio_cd),
> + sdhci_dove_carddetect_irq,
> + IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING,
> + mmc_hostname(host->mmc), host);
> + if (ret) {
> + dev_err(&pdev->dev, "card detect irq request failed: %d\n",
> + ret);
> + goto err_request_irq;
> + }
> + }
> +
> return 0;
>
> +err_request_irq:
> + sdhci_remove_host(host, 0);
> err_sdhci_add:
> if (!IS_ERR(priv->clk))
> clk_disable_unprepare(priv->clk);
> sdhci_pltfm_free(pdev);
> err_sdhci_pltfm_init:
> + if (gpio_is_valid(priv->gpio_cd))
> + gpio_free(priv->gpio_cd);
> return ret;
> }
>
> @@ -130,6 +186,11 @@ static int __devexit sdhci_dove_remove(struct platform_device *pdev)
>
> sdhci_pltfm_unregister(pdev);
>
> + if (gpio_is_valid(priv->gpio_cd)) {
> + free_irq(gpio_to_irq(priv->gpio_cd), host);
> + gpio_free(priv->gpio_cd);
> + }
> +
> if (!IS_ERR(priv->clk))
> clk_disable_unprepare(priv->clk);
>
> --
> 1.7.4.4
>
> --
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