[1/2] mmc: core: allow a reset gpio to be configured.

Message ID	20141108001411.5629.25179.stgit@notabene.brown (mailing list archive)
State	New, archived
Headers	show Return-Path: <linux-mmc-owner@kernel.org> From: NeilBrown <neilb@suse.de> To: Ulf Hansson <ulf.hansson@linaro.org>, Chris Ball <chris@printf.net> Date: Sat, 08 Nov 2014 11:14:11 +1100 Subject: [PATCH 1/2] mmc: core: allow a reset gpio to be configured. Cc: devicetree@vger.kernel.org, linux-mmc@vger.kernel.org, linux-kernel@vger.kernel.org, GTA04 owners <gta04-owner@goldelico.com> Message-ID: <20141108001411.5629.25179.stgit@notabene.brown> In-Reply-To: <20141108000919.5629.55381.stgit@notabene.brown> References: <20141108000919.5629.55381.stgit@notabene.brown> User-Agent: StGit/0.17.1-dirty MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-mmc-owner@vger.kernel.org Precedence: bulk

diff --git a/Documentation/devicetree/bindings/mmc/mmc.txt b/Documentation/devicetree/bindings/mmc/mmc.txt index 431716e37a39..06b84b3bb3ee 100644 --- a/Documentation/devicetree/bindings/mmc/mmc.txt +++ b/Documentation/devicetree/bindings/mmc/mmc.txt @@ -21,6 +21,9 @@ Optional properties: below for the case, when a GPIO is used for the CD line - wp-inverted: when present, polarity on the WP line is inverted. See the note below for the case, when a GPIO is used for the WP line +- reset-gpios: Specify a GPIO to be asserted during power-up. This is + useful is power is not actually removed (e.g. due to shared + regulator) but a reset is needed before reconfiguration. - max-frequency: maximum operating clock frequency - no-1-8-v: when present, denotes that 1.8v card voltage is not supported on this system, even if the controller claims it is. diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c index d03a080fb9cd..64572c44f9b5 100644 --- a/drivers/mmc/core/core.c +++ b/drivers/mmc/core/core.c @@ -1533,6 +1533,8 @@ void mmc_power_up(struct mmc_host *host, u32 ocr) mmc_host_clk_hold(host); + /* Reset during power-off */ + mmc_gpio_set_rs(host, 1); host->ios.vdd = fls(ocr) - 1; if (mmc_host_is_spi(host)) host->ios.chip_select = MMC_CS_HIGH; @@ -1568,6 +1570,7 @@ void mmc_power_up(struct mmc_host *host, u32 ocr) * time required to reach a stable voltage. */ mmc_delay(10); + mmc_gpio_set_rs(host, 0); mmc_host_clk_release(host); } diff --git a/drivers/mmc/core/host.c b/drivers/mmc/core/host.c index 95cceae96944..42dbf7a521d4 100644 --- a/drivers/mmc/core/host.c +++ b/drivers/mmc/core/host.c @@ -415,6 +415,18 @@ int mmc_of_parse(struct mmc_host *host) if (explicit_inv_wp ^ gpio_inv_wp) host->caps2 |= MMC_CAP2_RO_ACTIVE_HIGH; + gpio = of_get_named_gpio_flags(np, "reset-gpios", 0, &flags); + if (gpio == -EPROBE_DEFER) { + ret = -EPROBE_DEFER; + goto out; + } + if (gpio_is_valid(gpio)) { + ret = mmc_gpio_request_rs(host, gpio, + flags & OF_GPIO_ACTIVE_LOW); + if (ret < 0) + goto out; + } + if (of_find_property(np, "cap-sd-highspeed", &len)) host->caps |= MMC_CAP_SD_HIGHSPEED; if (of_find_property(np, "cap-mmc-highspeed", &len)) diff --git a/drivers/mmc/core/slot-gpio.c b/drivers/mmc/core/slot-gpio.c index f3bc51f9aba9..354034a8519f 100644 --- a/drivers/mmc/core/slot-gpio.c +++ b/drivers/mmc/core/slot-gpio.c @@ -21,10 +21,12 @@ struct mmc_gpio { struct gpio_desc *ro_gpio; struct gpio_desc *cd_gpio; + struct gpio_desc *rs_gpio; /* reset line */ bool override_ro_active_level; bool override_cd_active_level; irqreturn_t (*cd_gpio_isr)(int irq, void *dev_id); char *ro_label; + char *rs_label; char cd_label[0]; }; @@ -53,12 +55,14 @@ static int mmc_gpio_alloc(struct mmc_host *host) * before device_add(), i.e., between mmc_alloc_host() and * mmc_add_host() */ - ctx = devm_kzalloc(&host->class_dev, sizeof(*ctx) + 2 * len, + ctx = devm_kzalloc(&host->class_dev, sizeof(*ctx) + 3 * len, GFP_KERNEL); if (ctx) { ctx->ro_label = ctx->cd_label + len; + ctx->rs_label = ctx->ro_label + len; snprintf(ctx->cd_label, len, "%s cd", dev_name(host->parent)); snprintf(ctx->ro_label, len, "%s ro", dev_name(host->parent)); + snprintf(ctx->rs_label, len, "%s rs", dev_name(host->parent)); host->slot.handler_priv = ctx; } } @@ -98,6 +102,18 @@ int mmc_gpio_get_cd(struct mmc_host *host) } EXPORT_SYMBOL(mmc_gpio_get_cd); +void mmc_gpio_set_rs(struct mmc_host *host, int state) +{ + struct mmc_gpio *ctx = host->slot.handler_priv; + + if (!ctx || !ctx->rs_gpio) + return; + + gpiod_set_value_cansleep(ctx->rs_gpio, state); +} +EXPORT_SYMBOL(mmc_gpio_set_rs); + + /** * mmc_gpio_request_ro - request a gpio for write-protection * @host: mmc host @@ -138,6 +154,36 @@ int mmc_gpio_request_ro(struct mmc_host *host, unsigned int gpio) } EXPORT_SYMBOL(mmc_gpio_request_ro); +int mmc_gpio_request_rs(struct mmc_host *host, unsigned int gpio, int low) +{ + struct mmc_gpio *ctx; + int ret; + int flags; + + if (!gpio_is_valid(gpio)) + return -EINVAL; + + ret = mmc_gpio_alloc(host); + if (ret < 0) + return ret; + + ctx = host->slot.handler_priv; + if (low) + flags = GPIOF_DIR_OUT | GPIOF_INIT_HIGH | GPIOF_ACTIVE_LOW; + else + flags = GPIOF_DIR_OUT | GPIOF_INIT_LOW; + + ret = devm_gpio_request_one(&host->class_dev, gpio, + flags, ctx->rs_label); + if (ret < 0) + return ret; + + ctx->rs_gpio = gpio_to_desc(gpio); + + return 0; +} +EXPORT_SYMBOL(mmc_gpio_request_rs); + void mmc_gpiod_request_cd_irq(struct mmc_host *host) { struct mmc_gpio *ctx = host->slot.handler_priv; @@ -269,6 +315,28 @@ void mmc_gpio_free_ro(struct mmc_host *host) EXPORT_SYMBOL(mmc_gpio_free_ro); /** + * mmc_gpio_free_rs - free the reset gpio + * @host: mmc host + * + * It's provided only for cases that client drivers need to manually free + * up the write-protection gpio requested by mmc_gpio_request_rs(). + */ +void mmc_gpio_free_rs(struct mmc_host *host) +{ + struct mmc_gpio *ctx = host->slot.handler_priv; + int gpio; + + if (!ctx || !ctx->rs_gpio) + return; + + gpio = desc_to_gpio(ctx->rs_gpio); + ctx->rs_gpio = NULL; + + devm_gpio_free(&host->class_dev, gpio); +} +EXPORT_SYMBOL(mmc_gpio_free_rs); + +/** * mmc_gpio_free_cd - free the card-detection gpio * @host: mmc host * diff --git a/include/linux/mmc/slot-gpio.h b/include/linux/mmc/slot-gpio.h index a119892cebdb..630e39af2035 100644 --- a/include/linux/mmc/slot-gpio.h +++ b/include/linux/mmc/slot-gpio.h @@ -22,6 +22,10 @@ int mmc_gpio_request_cd(struct mmc_host *host, unsigned int gpio, unsigned int debounce); void mmc_gpio_free_cd(struct mmc_host *host); +void mmc_gpio_set_rs(struct mmc_host *host, int state); +int mmc_gpio_request_rs(struct mmc_host *host, unsigned int gpio, int inv); +void mmc_gpio_free_rs(struct mmc_host *host); + int mmc_gpiod_request_cd(struct mmc_host *host, const char *con_id, unsigned int idx, bool override_active_level, unsigned int debounce);

[1/2] mmc: core: allow a reset gpio to be configured.

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