diff options
| -rw-r--r-- | Documentation/devicetree/bindings/pwm/pwm-omap-dmtimer.txt | 18 | ||||
| -rw-r--r-- | drivers/pwm/Kconfig | 9 | ||||
| -rw-r--r-- | drivers/pwm/Makefile | 1 | ||||
| -rw-r--r-- | drivers/pwm/pwm-omap-dmtimer.c | 327 | ||||
| -rw-r--r-- | include/linux/platform_data/pwm_omap_dmtimer.h | 69 |
5 files changed, 424 insertions, 0 deletions
diff --git a/Documentation/devicetree/bindings/pwm/pwm-omap-dmtimer.txt b/Documentation/devicetree/bindings/pwm/pwm-omap-dmtimer.txt new file mode 100644 index 000000000000..5befb538db95 --- /dev/null +++ b/Documentation/devicetree/bindings/pwm/pwm-omap-dmtimer.txt @@ -0,0 +1,18 @@ +* OMAP PWM for dual-mode timers + +Required properties: +- compatible: Shall contain "ti,omap-dmtimer-pwm". +- ti,timers: phandle to PWM capable OMAP timer. See arm/omap/timer.txt for info + about these timers. +- #pwm-cells: Should be 3. See pwm.txt in this directory for a description of + the cells format. + +Optional properties: +- ti,prescaler: Should be a value between 0 and 7, see the timers datasheet + +Example: + pwm9: dmtimer-pwm@9 { + compatible = "ti,omap-dmtimer-pwm"; + ti,timers = <&timer9>; + #pwm-cells = <3>; + }; diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig index aef635b7e2d1..3513ff833305 100644 --- a/drivers/pwm/Kconfig +++ b/drivers/pwm/Kconfig @@ -265,6 +265,15 @@ config PWM_MXS To compile this driver as a module, choose M here: the module will be called pwm-mxs. +config PWM_OMAP_DMTIMER + tristate "OMAP Dual-Mode Timer PWM support" + depends on OF && ARCH_OMAP && OMAP_DM_TIMER + help + Generic PWM framework driver for OMAP Dual-Mode Timer PWM output + + To compile this driver as a module, choose M here: the module + will be called pwm-omap-dmtimer + config PWM_PCA9685 tristate "NXP PCA9685 PWM driver" depends on I2C diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile index 69b8275f3c08..dd35bc121a18 100644 --- a/drivers/pwm/Makefile +++ b/drivers/pwm/Makefile @@ -24,6 +24,7 @@ obj-$(CONFIG_PWM_LPSS_PCI) += pwm-lpss-pci.o obj-$(CONFIG_PWM_LPSS_PLATFORM) += pwm-lpss-platform.o obj-$(CONFIG_PWM_MTK_DISP) += pwm-mtk-disp.o obj-$(CONFIG_PWM_MXS) += pwm-mxs.o +obj-$(CONFIG_PWM_OMAP_DMTIMER) += pwm-omap-dmtimer.o obj-$(CONFIG_PWM_PCA9685) += pwm-pca9685.o obj-$(CONFIG_PWM_PUV3) += pwm-puv3.o obj-$(CONFIG_PWM_PXA) += pwm-pxa.o diff --git a/drivers/pwm/pwm-omap-dmtimer.c b/drivers/pwm/pwm-omap-dmtimer.c new file mode 100644 index 000000000000..c453b3360605 --- /dev/null +++ b/drivers/pwm/pwm-omap-dmtimer.c @@ -0,0 +1,327 @@ +/* + * Copyright (c) 2015 Neil Armstrong <narmstrong@baylibre.com> + * Copyright (c) 2014 Joachim Eastwood <manabian@gmail.com> + * Copyright (c) 2012 NeilBrown <neilb@suse.de> + * Heavily based on earlier code which is: + * Copyright (c) 2010 Grant Erickson <marathon96@gmail.com> + * + * Also based on pwm-samsung.c + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * version 2 as published by the Free Software Foundation. + * + * Description: + * This file is the core OMAP support for the generic, Linux + * PWM driver / controller, using the OMAP's dual-mode timers. + */ + +#include <linux/clk.h> +#include <linux/err.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/mutex.h> +#include <linux/of.h> +#include <linux/of_platform.h> +#include <linux/platform_data/pwm_omap_dmtimer.h> +#include <linux/platform_device.h> +#include <linux/pm_runtime.h> +#include <linux/pwm.h> +#include <linux/slab.h> +#include <linux/time.h> + +#define DM_TIMER_LOAD_MIN 0xfffffffe + +struct pwm_omap_dmtimer_chip { + struct pwm_chip chip; + struct mutex mutex; + pwm_omap_dmtimer *dm_timer; + struct pwm_omap_dmtimer_pdata *pdata; + struct platform_device *dm_timer_pdev; +}; + +static inline struct pwm_omap_dmtimer_chip * +to_pwm_omap_dmtimer_chip(struct pwm_chip *chip) +{ + return container_of(chip, struct pwm_omap_dmtimer_chip, chip); +} + +static int pwm_omap_dmtimer_calc_value(unsigned long clk_rate, int ns) +{ + u64 c = (u64)clk_rate * ns; + + do_div(c, NSEC_PER_SEC); + + return DM_TIMER_LOAD_MIN - c; +} + +static void pwm_omap_dmtimer_start(struct pwm_omap_dmtimer_chip *omap) +{ + /* + * According to OMAP 4 TRM section 22.2.4.10 the counter should be + * started at 0xFFFFFFFE when overflow and match is used to ensure + * that the PWM line is toggled on the first event. + * + * Note that omap_dm_timer_enable/disable is for register access and + * not the timer counter itself. + */ + omap->pdata->enable(omap->dm_timer); + omap->pdata->write_counter(omap->dm_timer, DM_TIMER_LOAD_MIN); + omap->pdata->disable(omap->dm_timer); + + omap->pdata->start(omap->dm_timer); +} + +static int pwm_omap_dmtimer_enable(struct pwm_chip *chip, + struct pwm_device *pwm) +{ + struct pwm_omap_dmtimer_chip *omap = to_pwm_omap_dmtimer_chip(chip); + + mutex_lock(&omap->mutex); + pwm_omap_dmtimer_start(omap); + mutex_unlock(&omap->mutex); + + return 0; +} + +static void pwm_omap_dmtimer_disable(struct pwm_chip *chip, + struct pwm_device *pwm) +{ + struct pwm_omap_dmtimer_chip *omap = to_pwm_omap_dmtimer_chip(chip); + + mutex_lock(&omap->mutex); + omap->pdata->stop(omap->dm_timer); + mutex_unlock(&omap->mutex); +} + +static int pwm_omap_dmtimer_config(struct pwm_chip *chip, + struct pwm_device *pwm, + int duty_ns, int period_ns) +{ + struct pwm_omap_dmtimer_chip *omap = to_pwm_omap_dmtimer_chip(chip); + int load_value, match_value; + struct clk *fclk; + unsigned long clk_rate; + bool timer_active; + + dev_dbg(chip->dev, "duty cycle: %d, period %d\n", duty_ns, period_ns); + + mutex_lock(&omap->mutex); + if (duty_ns == pwm_get_duty_cycle(pwm) && + period_ns == pwm_get_period(pwm)) { + /* No change - don't cause any transients. */ + mutex_unlock(&omap->mutex); + return 0; + } + + fclk = omap->pdata->get_fclk(omap->dm_timer); + if (!fclk) { + dev_err(chip->dev, "invalid pmtimer fclk\n"); + mutex_unlock(&omap->mutex); + return -EINVAL; + } + + clk_rate = clk_get_rate(fclk); + if (!clk_rate) { + dev_err(chip->dev, "invalid pmtimer fclk rate\n"); + mutex_unlock(&omap->mutex); + return -EINVAL; + } + + dev_dbg(chip->dev, "clk rate: %luHz\n", clk_rate); + + /* + * Calculate the appropriate load and match values based on the + * specified period and duty cycle. The load value determines the + * cycle time and the match value determines the duty cycle. + */ + load_value = pwm_omap_dmtimer_calc_value(clk_rate, period_ns); + match_value = pwm_omap_dmtimer_calc_value(clk_rate, + period_ns - duty_ns); + + /* + * We MUST stop the associated dual-mode timer before attempting to + * write its registers, but calls to omap_dm_timer_start/stop must + * be balanced so check if timer is active before calling timer_stop. + */ + timer_active = pm_runtime_active(&omap->dm_timer_pdev->dev); + if (timer_active) + omap->pdata->stop(omap->dm_timer); + + omap->pdata->set_load(omap->dm_timer, true, load_value); + omap->pdata->set_match(omap->dm_timer, true, match_value); + + dev_dbg(chip->dev, "load value: %#08x (%d), match value: %#08x (%d)\n", + load_value, load_value, match_value, match_value); + + omap->pdata->set_pwm(omap->dm_timer, + pwm->polarity == PWM_POLARITY_INVERSED, + true, + PWM_OMAP_DMTIMER_TRIGGER_OVERFLOW_AND_COMPARE); + + /* If config was called while timer was running it must be reenabled. */ + if (timer_active) + pwm_omap_dmtimer_start(omap); + + mutex_unlock(&omap->mutex); + + return 0; +} + +static int pwm_omap_dmtimer_set_polarity(struct pwm_chip *chip, + struct pwm_device *pwm, + enum pwm_polarity polarity) +{ + struct pwm_omap_dmtimer_chip *omap = to_pwm_omap_dmtimer_chip(chip); + + /* + * PWM core will not call set_polarity while PWM is enabled so it's + * safe to reconfigure the timer here without stopping it first. + */ + mutex_lock(&omap->mutex); + omap->pdata->set_pwm(omap->dm_timer, + polarity == PWM_POLARITY_INVERSED, + true, + PWM_OMAP_DMTIMER_TRIGGER_OVERFLOW_AND_COMPARE); + mutex_unlock(&omap->mutex); + + return 0; +} + +static const struct pwm_ops pwm_omap_dmtimer_ops = { + .enable = pwm_omap_dmtimer_enable, + .disable = pwm_omap_dmtimer_disable, + .config = pwm_omap_dmtimer_config, + .set_polarity = pwm_omap_dmtimer_set_polarity, + .owner = THIS_MODULE, +}; + +static int pwm_omap_dmtimer_probe(struct platform_device *pdev) +{ + struct device_node *np = pdev->dev.of_node; + struct device_node *timer; + struct pwm_omap_dmtimer_chip *omap; + struct pwm_omap_dmtimer_pdata *pdata; + pwm_omap_dmtimer *dm_timer; + u32 prescaler; + int status; + + pdata = dev_get_platdata(&pdev->dev); + if (!pdata) { + dev_err(&pdev->dev, "Missing dmtimer platform data\n"); + return -EINVAL; + } + + if (!pdata->request_by_node || + !pdata->free || + !pdata->enable || + !pdata->disable || + !pdata->get_fclk || + !pdata->start || + !pdata->stop || + !pdata->set_load || + !pdata->set_match || + !pdata->set_pwm || + !pdata->set_prescaler || + !pdata->write_counter) { + dev_err(&pdev->dev, "Incomplete dmtimer pdata structure\n"); + return -EINVAL; + } + + timer = of_parse_phandle(np, "ti,timers", 0); + if (!timer) + return -ENODEV; + + if (!of_get_property(timer, "ti,timer-pwm", NULL)) { + dev_err(&pdev->dev, "Missing ti,timer-pwm capability\n"); + return -ENODEV; + } + + dm_timer = pdata->request_by_node(timer); + if (!dm_timer) + return -EPROBE_DEFER; + + omap = devm_kzalloc(&pdev->dev, sizeof(*omap), GFP_KERNEL); + if (!omap) { + omap->pdata->free(dm_timer); + return -ENOMEM; + } + + omap->pdata = pdata; + omap->dm_timer = dm_timer; + + omap->dm_timer_pdev = of_find_device_by_node(timer); + if (!omap->dm_timer_pdev) { + dev_err(&pdev->dev, "Unable to find timer pdev\n"); + omap->pdata->free(dm_timer); + return -EINVAL; + } + + /* + * Ensure that the timer is stopped before we allow PWM core to call + * pwm_enable. + */ + if (pm_runtime_active(&omap->dm_timer_pdev->dev)) + omap->pdata->stop(omap->dm_timer); + + /* setup dmtimer prescaler */ + if (!of_property_read_u32(pdev->dev.of_node, "ti,prescaler", + &prescaler)) + omap->pdata->set_prescaler(omap->dm_timer, prescaler); + + omap->chip.dev = &pdev->dev; + omap->chip.ops = &pwm_omap_dmtimer_ops; + omap->chip.base = -1; + omap->chip.npwm = 1; + omap->chip.of_xlate = of_pwm_xlate_with_flags; + omap->chip.of_pwm_n_cells = 3; + + mutex_init(&omap->mutex); + + status = pwmchip_add(&omap->chip); + if (status < 0) { + dev_err(&pdev->dev, "failed to register PWM\n"); + omap->pdata->free(omap->dm_timer); + return status; + } + + platform_set_drvdata(pdev, omap); + + return 0; +} + +static int pwm_omap_dmtimer_remove(struct platform_device *pdev) +{ + struct pwm_omap_dmtimer_chip *omap = platform_get_drvdata(pdev); + + if (pm_runtime_active(&omap->dm_timer_pdev->dev)) + omap->pdata->stop(omap->dm_timer); + + omap->pdata->free(omap->dm_timer); + + mutex_destroy(&omap->mutex); + + return pwmchip_remove(&omap->chip); +} + +static const struct of_device_id pwm_omap_dmtimer_of_match[] = { + {.compatible = "ti,omap-dmtimer-pwm"}, + {} +}; +MODULE_DEVICE_TABLE(of, pwm_omap_dmtimer_of_match); + +static struct platform_driver pwm_omap_dmtimer_driver = { + .driver = { + .name = "omap-dmtimer-pwm", + .of_match_table = of_match_ptr(pwm_omap_dmtimer_of_match), + }, + .probe = pwm_omap_dmtimer_probe, + .remove = pwm_omap_dmtimer_remove, +}; +module_platform_driver(pwm_omap_dmtimer_driver); + +MODULE_AUTHOR("Grant Erickson <marathon96@gmail.com>"); +MODULE_AUTHOR("NeilBrown <neilb@suse.de>"); +MODULE_AUTHOR("Neil Armstrong <narmstrong@baylibre.com>"); +MODULE_LICENSE("GPL v2"); +MODULE_DESCRIPTION("OMAP PWM Driver using Dual-mode Timers"); diff --git a/include/linux/platform_data/pwm_omap_dmtimer.h b/include/linux/platform_data/pwm_omap_dmtimer.h new file mode 100644 index 000000000000..59384217208f --- /dev/null +++ b/include/linux/platform_data/pwm_omap_dmtimer.h @@ -0,0 +1,69 @@ +/* + * include/linux/platform_data/pwm_omap_dmtimer.h + * + * OMAP Dual-Mode Timer PWM platform data + * + * Copyright (C) 2010 Texas Instruments Incorporated - http://www.ti.com/ + * Tarun Kanti DebBarma <tarun.kanti@ti.com> + * Thara Gopinath <thara@ti.com> + * + * Platform device conversion and hwmod support. + * + * Copyright (C) 2005 Nokia Corporation + * Author: Lauri Leukkunen <lauri.leukkunen@nokia.com> + * PWM and clock framework support by Timo Teras. + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License as published by the + * Free Software Foundation; either version 2 of the License, or (at your + * option) any later version. + * + * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED + * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF + * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN + * NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, + * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT + * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF + * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + * + * You should have received a copy of the GNU General Public License along + * with this program; if not, write to the Free Software Foundation, Inc., + * 675 Mass Ave, Cambridge, MA 02139, USA. + */ + +#ifndef __PWM_OMAP_DMTIMER_PDATA_H +#define __PWM_OMAP_DMTIMER_PDATA_H + +/* trigger types */ +#define PWM_OMAP_DMTIMER_TRIGGER_NONE 0x00 +#define PWM_OMAP_DMTIMER_TRIGGER_OVERFLOW 0x01 +#define PWM_OMAP_DMTIMER_TRIGGER_OVERFLOW_AND_COMPARE 0x02 + +struct omap_dm_timer; +typedef struct omap_dm_timer pwm_omap_dmtimer; + +struct pwm_omap_dmtimer_pdata { + pwm_omap_dmtimer *(*request_by_node)(struct device_node *np); + int (*free)(pwm_omap_dmtimer *timer); + + void (*enable)(pwm_omap_dmtimer *timer); + void (*disable)(pwm_omap_dmtimer *timer); + + struct clk *(*get_fclk)(pwm_omap_dmtimer *timer); + + int (*start)(pwm_omap_dmtimer *timer); + int (*stop)(pwm_omap_dmtimer *timer); + + int (*set_load)(pwm_omap_dmtimer *timer, int autoreload, + unsigned int value); + int (*set_match)(pwm_omap_dmtimer *timer, int enable, + unsigned int match); + int (*set_pwm)(pwm_omap_dmtimer *timer, int def_on, + int toggle, int trigger); + int (*set_prescaler)(pwm_omap_dmtimer *timer, int prescaler); + + int (*write_counter)(pwm_omap_dmtimer *timer, unsigned int value); +}; + +#endif /* __PWM_OMAP_DMTIMER_PDATA_H */ |