diff options
Diffstat (limited to 'drivers/mmc/core/slot-gpio.c')
| -rw-r--r-- | drivers/mmc/core/slot-gpio.c | 188 |
1 files changed, 188 insertions, 0 deletions
diff --git a/drivers/mmc/core/slot-gpio.c b/drivers/mmc/core/slot-gpio.c new file mode 100644 index 000000000000..058242916cef --- /dev/null +++ b/drivers/mmc/core/slot-gpio.c @@ -0,0 +1,188 @@ +/* + * Generic GPIO card-detect helper + * + * Copyright (C) 2011, Guennadi Liakhovetski <g.liakhovetski@gmx.de> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include <linux/err.h> +#include <linux/gpio.h> +#include <linux/interrupt.h> +#include <linux/jiffies.h> +#include <linux/mmc/host.h> +#include <linux/mmc/slot-gpio.h> +#include <linux/module.h> +#include <linux/slab.h> + +struct mmc_gpio { + int ro_gpio; + int cd_gpio; + char *ro_label; + char cd_label[0]; +}; + +static irqreturn_t mmc_gpio_cd_irqt(int irq, void *dev_id) +{ + /* Schedule a card detection after a debounce timeout */ + mmc_detect_change(dev_id, msecs_to_jiffies(100)); + return IRQ_HANDLED; +} + +static int mmc_gpio_alloc(struct mmc_host *host) +{ + size_t len = strlen(dev_name(host->parent)) + 4; + struct mmc_gpio *ctx; + + mutex_lock(&host->slot.lock); + + ctx = host->slot.handler_priv; + if (!ctx) { + /* + * devm_kzalloc() can be called after device_initialize(), even + * before device_add(), i.e., between mmc_alloc_host() and + * mmc_add_host() + */ + ctx = devm_kzalloc(&host->class_dev, sizeof(*ctx) + 2 * len, + GFP_KERNEL); + if (ctx) { + ctx->ro_label = ctx->cd_label + len; + snprintf(ctx->cd_label, len, "%s cd", dev_name(host->parent)); + snprintf(ctx->ro_label, len, "%s ro", dev_name(host->parent)); + ctx->cd_gpio = -EINVAL; + ctx->ro_gpio = -EINVAL; + host->slot.handler_priv = ctx; + } + } + + mutex_unlock(&host->slot.lock); + + return ctx ? 0 : -ENOMEM; +} + +int mmc_gpio_get_ro(struct mmc_host *host) +{ + struct mmc_gpio *ctx = host->slot.handler_priv; + + if (!ctx || !gpio_is_valid(ctx->ro_gpio)) + return -ENOSYS; + + return !gpio_get_value_cansleep(ctx->ro_gpio) ^ + !!(host->caps2 & MMC_CAP2_RO_ACTIVE_HIGH); +} +EXPORT_SYMBOL(mmc_gpio_get_ro); + +int mmc_gpio_get_cd(struct mmc_host *host) +{ + struct mmc_gpio *ctx = host->slot.handler_priv; + + if (!ctx || !gpio_is_valid(ctx->cd_gpio)) + return -ENOSYS; + + return !gpio_get_value_cansleep(ctx->cd_gpio) ^ + !!(host->caps2 & MMC_CAP2_CD_ACTIVE_HIGH); +} +EXPORT_SYMBOL(mmc_gpio_get_cd); + +int mmc_gpio_request_ro(struct mmc_host *host, unsigned int gpio) +{ + struct mmc_gpio *ctx; + int ret; + + if (!gpio_is_valid(gpio)) + return -EINVAL; + + ret = mmc_gpio_alloc(host); + if (ret < 0) + return ret; + + ctx = host->slot.handler_priv; + + return gpio_request_one(gpio, GPIOF_DIR_IN, ctx->ro_label); +} +EXPORT_SYMBOL(mmc_gpio_request_ro); + +int mmc_gpio_request_cd(struct mmc_host *host, unsigned int gpio) +{ + struct mmc_gpio *ctx; + int irq = gpio_to_irq(gpio); + int ret; + + ret = mmc_gpio_alloc(host); + if (ret < 0) + return ret; + + ctx = host->slot.handler_priv; + + ret = gpio_request_one(gpio, GPIOF_DIR_IN, ctx->cd_label); + if (ret < 0) + /* + * don't bother freeing memory. It might still get used by other + * slot functions, in any case it will be freed, when the device + * is destroyed. + */ + return ret; + + /* + * Even if gpio_to_irq() returns a valid IRQ number, the platform might + * still prefer to poll, e.g., because that IRQ number is already used + * by another unit and cannot be shared. + */ + if (irq >= 0 && host->caps & MMC_CAP_NEEDS_POLL) + irq = -EINVAL; + + if (irq >= 0) { + ret = request_threaded_irq(irq, NULL, mmc_gpio_cd_irqt, + IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING | IRQF_ONESHOT, + ctx->cd_label, host); + if (ret < 0) + irq = ret; + } + + host->slot.cd_irq = irq; + + if (irq < 0) + host->caps |= MMC_CAP_NEEDS_POLL; + + ctx->cd_gpio = gpio; + + return 0; +} +EXPORT_SYMBOL(mmc_gpio_request_cd); + +void mmc_gpio_free_ro(struct mmc_host *host) +{ + struct mmc_gpio *ctx = host->slot.handler_priv; + int gpio; + + if (!ctx || !gpio_is_valid(ctx->ro_gpio)) + return; + + gpio = ctx->ro_gpio; + ctx->ro_gpio = -EINVAL; + + gpio_free(gpio); +} +EXPORT_SYMBOL(mmc_gpio_free_ro); + +void mmc_gpio_free_cd(struct mmc_host *host) +{ + struct mmc_gpio *ctx = host->slot.handler_priv; + int gpio; + + if (!ctx || !gpio_is_valid(ctx->cd_gpio)) + return; + + if (host->slot.cd_irq >= 0) { + free_irq(host->slot.cd_irq, host); + host->slot.cd_irq = -EINVAL; + } + + gpio = ctx->cd_gpio; + ctx->cd_gpio = -EINVAL; + + gpio_free(gpio); +} +EXPORT_SYMBOL(mmc_gpio_free_cd); |