On Fri, Feb 15, 2013 at 04:13:52PM +0100, Guennadi Liakhovetski wrote:
> MMC defines a number of standard DT bindings. Having each driver parse
> them individually adds code redundancy and is error prone. Provide a
> standard function to unify the parsing. After all drivers are converted
> to using it instead of their own parsers, this function can be integrated
> into mmc_alloc_host().
>
> Cc: Markus Pargmann <mpa@xxxxxxxxxxxxxx>
> Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@xxxxxx>
> ---
>
> v4: make the bus-width property optional to match a recent change to
> mmc.txt, use of_property_read_bool() to obtain a boolean value of a DT
> property, add comments.
>
> drivers/mmc/core/host.c | 108 ++++++++++++++++++++++++++++++++++++++++++++++
> include/linux/mmc/host.h | 1 +
> 2 files changed, 109 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/mmc/core/host.c b/drivers/mmc/core/host.c
> index ee2e16b..daa2ed1 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 +298,111 @@ 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 the fact, 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_array(np, "bus-width", &bus_width, 1) < 0)
> + dev_dbg(host->parent,
> + "\"bus-width\" property is missing, assuming 1 bit.\n");
> +
> + switch (bus_width) {
kbuild tells me that gcc thinks that bus_width is used without being
initialised here. Assuming that of_property_read_u32_array always
initialises bus_width if it returns zero then perhaps it would be worth
considering using uninitialized_var().
> + 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_array(np, "max-frequency", &host->f_max, 1);
> +
> + /*
> + * 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
> diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
> index 61a10c1..13c0c8d 100644
> --- a/include/linux/mmc/host.h
> +++ b/include/linux/mmc/host.h
> @@ -345,6 +345,7 @@ extern struct mmc_host *mmc_alloc_host(int extra, struct device *);
> extern int mmc_add_host(struct mmc_host *);
> extern void mmc_remove_host(struct mmc_host *);
> extern void mmc_free_host(struct mmc_host *);
> +void mmc_of_parse(struct mmc_host *host);
>
> static inline void *mmc_priv(struct mmc_host *host)
> {
> --
> 1.7.2.5
>
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