| Message ID | 1360941242-18153-4-git-send-email-g.liakhovetski@gmx.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
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@pengutronix.de> > Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de> > --- > > 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 > -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Saturday 16 February 2013, Simon Horman wrote: > > +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(). I think this is a false positive that I encountered before and that should be gone with gcc-4.7 or higher when using -O2 instead of -Os. I have a patch to disable -Wmaybe-uninitialized when builing with -Os. If that gets rid of the warning, I'd prefer not annotating it here. There was some discussion about removing uninitialized_var() recently after it was found to hide some real bugs. Arnd -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Sat, Feb 16, 2013 at 10:54:36AM +0000, Arnd Bergmann wrote: > On Saturday 16 February 2013, Simon Horman wrote: > > > +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(). > > I think this is a false positive that I encountered before and that should be gone > with gcc-4.7 or higher when using -O2 instead of -Os. I have a patch to disable > -Wmaybe-uninitialized when builing with -Os. If that gets rid of the warning, > I'd prefer not annotating it here. > > There was some discussion about removing uninitialized_var() recently after it > was found to hide some real bugs. Thanks. I agree that using uninitialized_var() may not be the best idea. -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Sat, 16 Feb 2013, Arnd Bergmann wrote: > On Saturday 16 February 2013, Simon Horman wrote: > > > +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(). > > I think this is a false positive that I encountered before and that should be gone > with gcc-4.7 or higher when using -O2 instead of -Os. I have a patch to disable > -Wmaybe-uninitialized when builing with -Os. If that gets rid of the warning, > I'd prefer not annotating it here. Unfortunately, this does seem to be a real bug, I lost the default initialisation to one somewhere along the way... I'll send a trivial update. Stupidly, my cross-toolchain doesn't report this error. Thanks Guennadi > There was some discussion about removing uninitialized_var() recently after it > was found to hide some real bugs. > > Arnd --- Guennadi Liakhovetski, Ph.D. Freelance Open-Source Software Developer http://www.open-technology.de/ -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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) { + 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) {
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@pengutronix.de> Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de> --- 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(-)