diff options
Diffstat (limited to 'drivers/mmc')
| -rw-r--r-- | drivers/mmc/core/host.c | 110 |
1 files changed, 110 insertions, 0 deletions
diff --git a/drivers/mmc/core/host.c b/drivers/mmc/core/host.c index ee2e16b17017..9c53452e73e1 100644 --- a/drivers/mmc/core/host.c +++ b/drivers/mmc/core/host.c @@ -15,6 +15,8 @@ #include <linux/device.h> #include <linux/err.h> #include <linux/idr.h> +#include <linux/of.h> +#include <linux/of_gpio.h> #include <linux/pagemap.h> #include <linux/export.h> #include <linux/leds.h> @@ -23,6 +25,7 @@ #include <linux/mmc/host.h> #include <linux/mmc/card.h> +#include <linux/mmc/slot-gpio.h> #include "core.h" #include "host.h" @@ -295,6 +298,113 @@ static inline void mmc_host_clk_sysfs_init(struct mmc_host *host) #endif /** + * mmc_of_parse() - parse host's device-tree node + * @host: host whose node should be parsed. + * + * To keep the rest of the MMC subsystem unaware of whether DT has been + * used to to instantiate and configure this host instance or not, we + * parse the properties and set respective generic mmc-host flags and + * parameters. + */ +void mmc_of_parse(struct mmc_host *host) +{ + struct device_node *np; + u32 bus_width; + bool explicit_inv_wp, gpio_inv_wp = false; + enum of_gpio_flags flags; + int len, ret, gpio; + + if (!host->parent || !host->parent->of_node) + return; + + np = host->parent->of_node; + + /* "bus-width" is translated to MMC_CAP_*_BIT_DATA flags */ + if (of_property_read_u32(np, "bus-width", &bus_width) < 0) { + dev_dbg(host->parent, + "\"bus-width\" property is missing, assuming 1 bit.\n"); + bus_width = 1; + } + + switch (bus_width) { + case 8: + host->caps |= MMC_CAP_8_BIT_DATA; + /* Hosts capable of 8-bit transfers can also do 4 bits */ + case 4: + host->caps |= MMC_CAP_4_BIT_DATA; + break; + case 1: + break; + default: + dev_err(host->parent, + "Invalid \"bus-width\" value %ud!\n", bus_width); + } + + /* f_max is obtained from the optional "max-frequency" property */ + of_property_read_u32(np, "max-frequency", &host->f_max); + + /* + * Configure CD and WP pins. They are both by default active low to + * match the SDHCI spec. If GPIOs are provided for CD and / or WP, the + * mmc-gpio helpers are used to attach, configure and use them. If + * polarity inversion is specified in DT, one of MMC_CAP2_CD_ACTIVE_HIGH + * and MMC_CAP2_RO_ACTIVE_HIGH capability-2 flags is set. If the + * "broken-cd" property is provided, the MMC_CAP_NEEDS_POLL capability + * is set. If the "non-removable" property is found, the + * MMC_CAP_NONREMOVABLE capability is set and no card-detection + * configuration is performed. + */ + + /* Parse Card Detection */ + if (of_find_property(np, "non-removable", &len)) { + host->caps |= MMC_CAP_NONREMOVABLE; + } else { + bool explicit_inv_cd, gpio_inv_cd = false; + + explicit_inv_cd = of_property_read_bool(np, "cd-inverted"); + + if (of_find_property(np, "broken-cd", &len)) + host->caps |= MMC_CAP_NEEDS_POLL; + + gpio = of_get_named_gpio_flags(np, "cd-gpios", 0, &flags); + if (gpio_is_valid(gpio)) { + if (!(flags & OF_GPIO_ACTIVE_LOW)) + gpio_inv_cd = true; + + ret = mmc_gpio_request_cd(host, gpio); + if (ret < 0) + dev_err(host->parent, + "Failed to request CD GPIO #%d: %d!\n", + gpio, ret); + else + dev_info(host->parent, "Got CD GPIO #%d.\n", + gpio); + } + + if (explicit_inv_cd ^ gpio_inv_cd) + host->caps2 |= MMC_CAP2_CD_ACTIVE_HIGH; + } + + /* Parse Write Protection */ + explicit_inv_wp = of_property_read_bool(np, "wp-inverted"); + + gpio = of_get_named_gpio_flags(np, "wp-gpios", 0, &flags); + if (gpio_is_valid(gpio)) { + if (!(flags & OF_GPIO_ACTIVE_LOW)) + gpio_inv_wp = true; + + ret = mmc_gpio_request_ro(host, gpio); + if (ret < 0) + dev_err(host->parent, + "Failed to request WP GPIO: %d!\n", ret); + } + if (explicit_inv_wp ^ gpio_inv_wp) + host->caps2 |= MMC_CAP2_RO_ACTIVE_HIGH; +} + +EXPORT_SYMBOL(mmc_of_parse); + +/** * mmc_alloc_host - initialise the per-host structure. * @extra: sizeof private data structure * @dev: pointer to host device model structure |