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().
Signed-off-by: Guennadi Liakhovetski <g.liakhovet...@gmx.de>
---
v5:
1. fix an uninitialised variable warning. Note, I don't actually know,
whether this will fix the error, reported by the kbuild test robot. None
of my compilers reports an error there, at most, I've got a warning with
one of them, and, surprisingly, it is gone after this change.
Surprisingly, because I only add the bus_width initialisation in the error
case - exactly as it actually has to be done. In the success case it is
assigned set by the function. But the compiler cannot know that! So, I'm
surprised... I can only try this version, and see what the robot says
now... If it's still unhappy, I'll have to initialise the variable in any
case at definition, which I don't want to do, because it isn't really
required.
2. replace of_property_read_u32_array(..., 1) with of_property_read_u32()
drivers/mmc/core/host.c | 110 ++++++++++++++++++++++++++++++++++++++++++++++
include/linux/mmc/host.h | 1 +
2 files changed, 111 insertions(+), 0 deletions(-)
diff --git a/drivers/mmc/core/host.c b/drivers/mmc/core/host.c
index ee2e16b..304e549 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 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(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
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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