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[220.235.109.115]) by smtp.gmail.com with ESMTPSA id q26sm20330059pff.143.2019.11.18.06.48.28 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Mon, 18 Nov 2019 06:48:29 -0800 (PST) Date: Mon, 18 Nov 2019 22:48:25 +0800 From: Kent Gibson To: Bartosz Golaszewski Cc: linux-gpio Subject: Re: [libgpiod] [PATCH 11/19] API: add support for SET_CONFIG Message-ID: <20191118144825.GE27359@sol> References: <20191115144355.975-1-warthog618@gmail.com> <20191115144355.975-12-warthog618@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-gpio-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-gpio@vger.kernel.org On Mon, Nov 18, 2019 at 02:52:04PM +0100, Bartosz Golaszewski wrote: > pt., 15 lis 2019 o 15:45 Kent Gibson napisał(a): > > > > Extend the libgpiod API to support the setting line configuration using the > > GPIO GPIOHANDLE_SET_CONFIG_IOCTL uAPI ioctl. > > > > The core change is the addition of gpiod_line_set_config, which provides a > > low level wrapper around the ioctl. > > > > Additionally, higher level helper functions, gpiod_line_set_flags, > > gpiod_line_set_direction_input, and gpiod_line_set_direction_output provide > > slightly simplified APIs for common use cases. > > > > Bulk forms of all functions are also provided. > > > > Signed-off-by: Kent Gibson > > --- > > include/gpiod.h | 115 ++++++++++++++++++++++++++++ > > lib/core.c | 196 +++++++++++++++++++++++++++++++++++++++++++++--- > > 2 files changed, 300 insertions(+), 11 deletions(-) > > > > diff --git a/include/gpiod.h b/include/gpiod.h > > index 159d745..4053fd2 100644 > > --- a/include/gpiod.h > > +++ b/include/gpiod.h > > @@ -1252,6 +1252,14 @@ void gpiod_line_release_bulk(struct gpiod_line_bulk *bulk) GPIOD_API; > > */ > > bool gpiod_line_is_requested(struct gpiod_line *line) GPIOD_API; > > > > +/** > > + * @brief Check if the calling user has ownership of this line for values, > > + * not events. > > + * @param line GPIO line object. > > + * @return True if given line was requested, false otherwise. > > I'd clarify: "requested for reading/setting values". > > > + */ > > +bool gpiod_line_is_requested_values(struct gpiod_line *line) GPIOD_API; > > + > > /** > > * @brief Check if the calling user has neither requested ownership of this > > * line nor configured any event notifications. > > @@ -1311,6 +1319,113 @@ int gpiod_line_set_value(struct gpiod_line *line, int value) GPIOD_API; > > int gpiod_line_set_value_bulk(struct gpiod_line_bulk *bulk, > > const int *values) GPIOD_API; > > > > +/** > > + * @} > > + * > > + * @defgroup __line_config__ Setting line configuration > > + * @{ > > + */ > > + > > +/** > > + * @brief Update the configuration of a single GPIO line. > > + * @param line GPIO line object. > > + * @param direction Updated direction which may be one of > > + * GPIOD_LINE_REQUEST_DIRECTION_AS_IS, GPIOD_LINE_REQUEST_DIRECTION_INPUT, > > + * or GPIOD_LINE_REQUEST_DIRECTION_OUTPUT. > > + * @param flags Replacement flags. > > + * @param value The new output value for the line when direction is > > + * GPIOD_LINE_REQUEST_DIRECTION_OUTPUT. > > + * @return 0 is the operation succeeds. In case of an error this routine > > + * returns -1 and sets the last error number. > > + */ > > +int gpiod_line_set_config(struct gpiod_line *line, int direction, > > + int flags, int value) GPIOD_API; > > + > > +/** > > + * @brief Update the configuration of a set of GPIO lines. > > + * @param bulk Set of GPIO lines. > > + * @param direction Updated direction which may be one of > > + * GPIOD_LINE_REQUEST_DIRECTION_AS_IS, GPIOD_LINE_REQUEST_DIRECTION_INPUT, > > + * or GPIOD_LINE_REQUEST_DIRECTION_OUTPUT. > > + * @param flags Replacement flags. > > + * @param values An array holding line_bulk->num_lines new logical values > > + * for lines when direction is GPIOD_LINE_REQUEST_DIRECTION_OUTPUT. > > + * @return 0 is the operation succeeds. In case of an error this routine > > + * returns -1 and sets the last error number. > > + * > > + * If the lines were not previously requested together, the behavior is > > + * undefined. > > + */ > > +int gpiod_line_set_config_bulk(struct gpiod_line_bulk *bulk, > > + int direction, int flags, > > + const int *values) GPIOD_API; > > + > > + > > +/** > > + * @brief Update the configuration flags of a single GPIO line. > > + * @param line GPIO line object. > > + * @param flags Replacement flags. > > + * @return 0 is the operation succeeds. In case of an error this routine > > + * returns -1 and sets the last error number. > > + */ > > +int gpiod_line_set_flags(struct gpiod_line *line, int flags) GPIOD_API; > > + > > +/** > > + * @brief Update the configuration flags of a set of GPIO lines. > > + * @param bulk Set of GPIO lines. > > + * @param flags Replacement flags. > > + * @return 0 is the operation succeeds. In case of an error this routine > > + * returns -1 and sets the last error number. > > + * > > + * If the lines were not previously requested together, the behavior is > > + * undefined. > > + */ > > +int gpiod_line_set_flags_bulk(struct gpiod_line_bulk *bulk, > > + int flags) GPIOD_API; > > + > > +/** > > + * @brief Set the direction of a single GPIO line to input. > > + * @param line GPIO line object. > > + * @return 0 is the operation succeeds. In case of an error this routine > > + * returns -1 and sets the last error number. > > + */ > > +int gpiod_line_set_direction_input(struct gpiod_line *line) GPIOD_API; > > + > > +/** > > + * @brief Set the direction of a set of GPIO lines to input. > > + * @param bulk Set of GPIO lines. > > + * @return 0 is the operation succeeds. In case of an error this routine > > + * returns -1 and sets the last error number. > > + * > > + * If the lines were not previously requested together, the behavior is > > + * undefined. > > + */ > > +int gpiod_line_set_direction_bulk_input(struct gpiod_line_bulk *bulk > > + ) GPIOD_API; > > Please stick to the current convention of having "_bulk" at the end of > the function name. > That would be clearer. Not sure why I went with those names - maybe taking the lead from gpiod_line_request_bulk_falling_edge_events_flags? Maybe I originally had a core set_direction function, and these were to be wrappers around that? Anyway - will change it. > > + > > +/** > > + * @brief Set the direction of a single GPIO line to output. > > + * @param line GPIO line object. > > + * @param value The logical value output on the line. > > + * @return 0 is the operation succeeds. In case of an error this routine > > + * returns -1 and sets the last error number. > > + */ > > +int gpiod_line_set_direction_output(struct gpiod_line *line, > > + int value) GPIOD_API; > > + > > +/** > > + * @brief Set the direction of a set of GPIO lines to output. > > + * @param bulk Set of GPIO lines. > > + * @values The logical value to output for each line. > > + * @return 0 is the operation succeeds. In case of an error this routine > > + * returns -1 and sets the last error number. > > + * > > + * If the lines were not previously requested together, the behavior is > > + * undefined. > > + */ > > +int gpiod_line_set_direction_bulk_output(struct gpiod_line_bulk *bulk, > > + const int *values) GPIOD_API; > > + > > /** > > * @} > > * > > diff --git a/lib/core.c b/lib/core.c > > index 9b7d88f..c42cda5 100644 > > --- a/lib/core.c > > +++ b/lib/core.c > > @@ -36,10 +36,13 @@ struct gpiod_line { > > unsigned int offset; > > int direction; > > int active_state; > > - __u32 flags; > > + int output_value; > > + __u32 lflags; > > + __u32 cflags; > > Ugh, these aren't very fortunate names - at first glance I have no > idea what they mean. Either document those or change the names to > something more obvious. > Yeah - not the best - lflags are line_flags (those returned by LINEINFO_IOCTL) and cflags is config_flags (those set in the initial line request). So maybe rename lflags to line_flags or info_flags, and rename cflags to handle_flags or req_flags? And add some documentation as well. > > > > int state; > > bool needs_update; > > + bool as_is; > > > > struct gpiod_chip *chip; > > struct line_fd_handle *fd_handle; > > @@ -359,11 +362,11 @@ int gpiod_line_active_state(struct gpiod_line *line) > > > > int gpiod_line_bias(struct gpiod_line *line) > > { > > - if (line->flags & GPIOLINE_FLAG_BIAS_DISABLE) > > + if (line->lflags & GPIOLINE_FLAG_BIAS_DISABLE) > > return GPIOD_LINE_BIAS_DISABLE; > > - if (line->flags & GPIOLINE_FLAG_BIAS_PULL_UP) > > + if (line->lflags & GPIOLINE_FLAG_BIAS_PULL_UP) > > return GPIOD_LINE_BIAS_PULL_UP; > > - if (line->flags & GPIOLINE_FLAG_BIAS_PULL_DOWN) > > + if (line->lflags & GPIOLINE_FLAG_BIAS_PULL_DOWN) > > return GPIOD_LINE_BIAS_PULL_DOWN; > > > > return GPIOD_LINE_BIAS_AS_IS; > > @@ -371,17 +374,17 @@ int gpiod_line_bias(struct gpiod_line *line) > > > > bool gpiod_line_is_used(struct gpiod_line *line) > > { > > - return line->flags & GPIOLINE_FLAG_KERNEL; > > + return line->lflags & GPIOLINE_FLAG_KERNEL; > > } > > > > bool gpiod_line_is_open_drain(struct gpiod_line *line) > > { > > - return line->flags & GPIOLINE_FLAG_OPEN_DRAIN; > > + return line->lflags & GPIOLINE_FLAG_OPEN_DRAIN; > > } > > > > bool gpiod_line_is_open_source(struct gpiod_line *line) > > { > > - return line->flags & GPIOLINE_FLAG_OPEN_SOURCE; > > + return line->lflags & GPIOLINE_FLAG_OPEN_SOURCE; > > } > > > > bool gpiod_line_needs_update(struct gpiod_line *line) > > @@ -408,7 +411,7 @@ int gpiod_line_update(struct gpiod_line *line) > > ? GPIOD_LINE_ACTIVE_STATE_LOW > > : GPIOD_LINE_ACTIVE_STATE_HIGH; > > > > - line->flags = info.flags; > > + line->lflags = info.flags; > > > > strncpy(line->name, info.name, sizeof(line->name)); > > strncpy(line->consumer, info.consumer, sizeof(line->consumer)); > > @@ -457,6 +460,20 @@ static bool line_bulk_all_requested(struct gpiod_line_bulk *bulk) > > return true; > > } > > > > +static bool line_bulk_all_requested_values(struct gpiod_line_bulk *bulk) > > +{ > > + struct gpiod_line *line, **lineptr; > > + > > + gpiod_line_bulk_foreach_line(bulk, line, lineptr) { > > + if (!gpiod_line_is_requested_values(line)) { > > + errno = EPERM; > > + return false; > > + } > > + } > > + > > + return true; > > +} > > + > > static bool line_bulk_all_free(struct gpiod_line_bulk *bulk) > > { > > struct gpiod_line *line, **lineptr; > > @@ -471,6 +488,27 @@ static bool line_bulk_all_free(struct gpiod_line_bulk *bulk) > > return true; > > } > > > > +static bool line_request_direction_is_valid(int direction) > > +{ > > + if ((direction == GPIOD_LINE_REQUEST_DIRECTION_AS_IS) || > > + (direction == GPIOD_LINE_REQUEST_DIRECTION_INPUT) || > > + (direction == GPIOD_LINE_REQUEST_DIRECTION_OUTPUT)) > > + return true; > > + > > + errno = EINVAL; > > + return false; > > +} > > + > > +static __u32 line_request_direction_to_gpio_handleflag(int direction) > > +{ > > + if (direction == GPIOD_LINE_REQUEST_DIRECTION_INPUT) > > + return GPIOHANDLE_REQUEST_INPUT; > > + if (direction == GPIOD_LINE_REQUEST_DIRECTION_OUTPUT) > > + return GPIOHANDLE_REQUEST_OUTPUT; > > + > > + return 0; > > +} > > + > > static __u32 line_request_flag_to_gpio_handleflag(int flags) > > { > > int hflags = 0; > > @@ -495,7 +533,7 @@ static int line_request_values(struct gpiod_line_bulk *bulk, > > const struct gpiod_line_request_config *config, > > const int *default_vals) > > { > > - struct gpiod_line *line, **lineptr; > > + struct gpiod_line *line; > > struct line_fd_handle *line_fd; > > struct gpiohandle_request req; > > unsigned int i; > > @@ -524,7 +562,6 @@ static int line_request_values(struct gpiod_line_bulk *bulk, > > else if (config->request_type == GPIOD_LINE_REQUEST_DIRECTION_OUTPUT) > > req.flags |= GPIOHANDLE_REQUEST_OUTPUT; > > > > - > > gpiod_line_bulk_foreach_line_off(bulk, line, i) { > > req.lineoffsets[i] = gpiod_line_offset(line); > > if (config->request_type == > > @@ -548,8 +585,14 @@ static int line_request_values(struct gpiod_line_bulk *bulk, > > if (!line_fd) > > return -1; > > > > - gpiod_line_bulk_foreach_line(bulk, line, lineptr) { > > + gpiod_line_bulk_foreach_line_off(bulk, line, i) { > > line->state = LINE_REQUESTED_VALUES; > > + line->cflags = config->flags; > > + if (config->request_type == > > + GPIOD_LINE_REQUEST_DIRECTION_OUTPUT) > > + line->output_value = req.default_values[i]; > > + if (config->request_type == GPIOD_LINE_REQUEST_DIRECTION_AS_IS) > > + line->as_is = true; > > line_set_fd(line, line_fd); > > line_maybe_update(line); > > } > > @@ -590,6 +633,7 @@ static int line_request_event_single(struct gpiod_line *line, > > return -1; > > > > line->state = LINE_REQUESTED_EVENTS; > > + line->cflags = config->flags; > > line_set_fd(line, line_fd); > > line_maybe_update(line); > > > > @@ -688,6 +732,11 @@ bool gpiod_line_is_requested(struct gpiod_line *line) > > line->state == LINE_REQUESTED_EVENTS); > > } > > > > +bool gpiod_line_is_requested_values(struct gpiod_line *line) > > +{ > > + return (line->state == LINE_REQUESTED_VALUES); > > +} > > + > > bool gpiod_line_is_free(struct gpiod_line *line) > > { > > return line->state == LINE_FREE; > > @@ -766,9 +815,134 @@ int gpiod_line_set_value_bulk(struct gpiod_line_bulk *bulk, const int *values) > > if (rv < 0) > > return -1; > > > > + gpiod_line_bulk_foreach_line_off(bulk, line, i) > > + line->output_value = data.values[i]; > > + > > + return 0; > > +} > > + > > +int gpiod_line_set_config(struct gpiod_line *line, int direction, > > + int flags, int value) > > +{ > > + struct gpiod_line_bulk bulk; > > + > > + gpiod_line_bulk_init(&bulk); > > + gpiod_line_bulk_add(&bulk, line); > > + > > + return gpiod_line_set_config_bulk(&bulk, direction, flags, &value); > > +} > > + > > +int gpiod_line_set_config_bulk(struct gpiod_line_bulk *bulk, > > + int direction, int flags, > > + const int *values) > > +{ > > + struct gpiohandle_config hcfg; > > + struct gpiod_line *line; > > + unsigned int i; > > + int rv, fd; > > + bool as_is; > > + > > + if (!line_bulk_same_chip(bulk) || > > + !line_bulk_all_requested_values(bulk)) > > + return -1; > > + > > + if (!line_request_direction_is_valid(direction)) > > + return -1; > > + > > + memset(&hcfg, 0, sizeof(hcfg)); > > + > > + hcfg.flags = line_request_flag_to_gpio_handleflag(flags); > > + hcfg.flags |= line_request_direction_to_gpio_handleflag(direction); > > + if (direction == GPIOD_LINE_REQUEST_DIRECTION_OUTPUT && values) { > > + for (i = 0; i < gpiod_line_bulk_num_lines(bulk); i++) > > + hcfg.default_values[i] = (uint8_t)!!values[i]; > > + } > > + > > + line = gpiod_line_bulk_get_line(bulk, 0); > > + fd = line_get_fd(line); > > + > > + rv = ioctl(fd, GPIOHANDLE_SET_CONFIG_IOCTL, &hcfg); > > + if (rv < 0) > > + return -1; > > + > > + as_is = line->as_is && direction == GPIOD_LINE_REQUEST_DIRECTION_AS_IS; > > + gpiod_line_bulk_foreach_line_off(bulk, line, i) { > > + line->cflags = flags; > > + if (direction == GPIOD_LINE_REQUEST_DIRECTION_OUTPUT) > > + line->output_value = hcfg.default_values[i]; > > + line->as_is = as_is; > > + line_maybe_update(line); > > + } > > return 0; > > } > > > > +int gpiod_line_set_flags(struct gpiod_line *line, int flags) > > +{ > > + struct gpiod_line_bulk bulk; > > + > > + gpiod_line_bulk_init(&bulk); > > + gpiod_line_bulk_add(&bulk, line); > > + > > + return gpiod_line_set_flags_bulk(&bulk, flags); > > +} > > + > > +int gpiod_line_set_flags_bulk(struct gpiod_line_bulk *bulk, int flags) > > +{ > > + struct gpiod_line *line; > > + int values[GPIOD_LINE_BULK_MAX_LINES]; > > + unsigned int i; > > + int direction; > > + > > + line = gpiod_line_bulk_get_line(bulk, 0); > > + if (line->as_is) { > > Can you explain the purpose of this as_is field? I'm not sure this is > really needed. > It is there for gpiod_set_flags, which has to populate the direction flags in the SET_CONFIG ioctl. The existing line->direction is either input or output. It is drawn from GPIOLINE_FLAG_IS_OUT, so as-is is gets mapped to input. I didn't want to change the existing line->direction, and adding the as-is seemed clearer than adding another flavour of direction that contained all three. Happy to entertain alternatives... Cheers, Kent.