| Message ID | Pine.LNX.4.64.1302161613450.20044@axis700.grange (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Hi Guennadi, On Sat, Feb 16, 2013 at 04:21:16PM +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(). > > Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@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! Maybe the build robot builds with devicetree disabled? In this case of_property_read_u32_array expands to a static inline function and the compiler indeed knows that &bus_width is unitialized. It also knows that this function always returns an error, so what you did below should silence the compiler. Sascha
On Sat, Feb 16, 2013 at 05:58:25PM +0100, Sascha Hauer wrote: > Hi Guennadi, > > On Sat, Feb 16, 2013 at 04:21:16PM +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(). > > > > Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@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! > > Maybe the build robot builds with devicetree disabled? In this case > of_property_read_u32_array expands to a static inline function and the > compiler indeed knows that &bus_width is unitialized. It also knows that > this function always returns an error, so what you did below should > silence the compiler. It seems so. The configuration that flagged the error was atngw100_defconfig. ARCH=avr32 make atngw100_defconfig grep USE_OF .config [nothing] -- 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 Sun, Feb 17, 2013 at 04:52:16PM +0900, Simon Horman wrote: > On Sat, Feb 16, 2013 at 05:58:25PM +0100, Sascha Hauer wrote: > > Hi Guennadi, > > > > On Sat, Feb 16, 2013 at 04:21:16PM +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(). > > > > > > Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@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! > > > > Maybe the build robot builds with devicetree disabled? In this case > > of_property_read_u32_array expands to a static inline function and the > > compiler indeed knows that &bus_width is unitialized. It also knows that > > this function always returns an error, so what you did below should > > silence the compiler. > > It seems so. The configuration that flagged the error was atngw100_defconfig. > > ARCH=avr32 make atngw100_defconfig > grep USE_OF .config > [nothing] In that vein I managed to reproduce the warning using ap4evb_defconfig and then enabled MMC. I have also verified that v5 does not produce the same warning. I chose this as I don't have a avr32 cross-compile environment but I do have one for ARM and I know that ap4evb doesn't use DT. I will update topic/mmc with v5. -- 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 Sun, 17 Feb 2013, Simon Horman wrote: > On Sun, Feb 17, 2013 at 04:52:16PM +0900, Simon Horman wrote: > > On Sat, Feb 16, 2013 at 05:58:25PM +0100, Sascha Hauer wrote: > > > Hi Guennadi, > > > > > > On Sat, Feb 16, 2013 at 04:21:16PM +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(). > > > > > > > > Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@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! > > > > > > Maybe the build robot builds with devicetree disabled? In this case > > > of_property_read_u32_array expands to a static inline function and the > > > compiler indeed knows that &bus_width is unitialized. It also knows that > > > this function always returns an error, so what you did below should > > > silence the compiler. > > > > It seems so. The configuration that flagged the error was atngw100_defconfig. > > > > ARCH=avr32 make atngw100_defconfig > > grep USE_OF .config > > [nothing] > > In that vein I managed to reproduce the warning using ap4evb_defconfig > and then enabled MMC. I have also verified that v5 does not produce > the same warning. > > I chose this as I don't have a avr32 cross-compile environment > but I do have one for ARM and I know that ap4evb doesn't use DT. > > I will update topic/mmc with v5. Very good, thanks! So, this way I think, v5 should be ok. Thanks Guennadi --- 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..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) {
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.liakhovetski@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(-)