This patch is based on an earlier patch by Grant Erickson
which provided pwm devices using the 'legacy' interface.
This driver instead uses the new framework interface.
Cc: Grant Erickson <marathon96@xxxxxxxxx>
Signed-off-by: NeilBrown <neilb@xxxxxxx>
diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
index ed81720..7df573a 100644
--- a/drivers/pwm/Kconfig
+++ b/drivers/pwm/Kconfig
@@ -85,6 +85,15 @@ config PWM_MXS
To compile this driver as a module, choose M here: the module
will be called pwm-mxs.
+config PWM_OMAP
+ tristate "OMAP pwm support"
+ depends on ARCH_OMAP
+ help
+ Generic PWM framework driver for OMAP
+
+ To compile this driver as a module, choose M here: the module
+ will be called pwm-omap
+
config PWM_PUV3
tristate "PKUnity NetBook-0916 PWM support"
depends on ARCH_PUV3
diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile
index acfe482..f5d200d 100644
--- a/drivers/pwm/Makefile
+++ b/drivers/pwm/Makefile
@@ -5,6 +5,7 @@ obj-$(CONFIG_PWM_IMX) += pwm-imx.o
obj-$(CONFIG_PWM_JZ4740) += pwm-jz4740.o
obj-$(CONFIG_PWM_LPC32XX) += pwm-lpc32xx.o
obj-$(CONFIG_PWM_MXS) += pwm-mxs.o
+obj-$(CONFIG_PWM_OMAP) += pwm-omap.o
obj-$(CONFIG_PWM_PUV3) += pwm-puv3.o
obj-$(CONFIG_PWM_PXA) += pwm-pxa.o
obj-$(CONFIG_PWM_SAMSUNG) += pwm-samsung.o
diff --git a/drivers/pwm/pwm-omap.c b/drivers/pwm/pwm-omap.c
new file mode 100644
index 0000000..e3dbce3
--- /dev/null
+++ b/drivers/pwm/pwm-omap.c
@@ -0,0 +1,318 @@
+/*
+ * Copyright (c) 2012 NeilBrown <neilb@xxxxxxx>
+ * Heavily based on earlier code which is:
+ * Copyright (c) 2010 Grant Erickson <marathon96@xxxxxxxxx>
+ *
+ * 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 OMAP2/3 support for the generic, Linux
+ * PWM driver / controller, using the OMAP's dual-mode timers.
+ *
+ * The 'id' number for the device encodes the number of the dm timer
+ * to use, and the polarity of the output.
+ * lsb is '1' of active-high, and '0' for active low
+ * remaining bit a timer number and need to be shifted down before use.
+ */
+
+#define pr_fmt(fmt) "pwm-omap: " fmt
+
+#include <linux/export.h>
+#include <linux/kernel.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/err.h>
+#include <linux/clk.h>
+#include <linux/io.h>
+#include <linux/pwm.h>
+#include <linux/module.h>
+
+#include <plat/dmtimer.h>
+
+#define DM_TIMER_LOAD_MIN 0xFFFFFFFE
+
+struct omap_chip {
+ struct platform_device *pdev;
+
+ struct omap_dm_timer *dm_timer;
+ unsigned int polarity;
+ const char *label;
+
+ unsigned int duty_ns, period_ns;
+ struct pwm_chip chip;
+};
+
+#define to_omap_chip(chip) container_of(chip, struct omap_chip, chip)
+
+#define pwm_dbg(_pwm, msg...) dev_dbg(&(_pwm)->pdev->dev, msg)
+
+/**
+ * pwm_calc_value - determines the counter value for a clock rate and period.
+ * @clk_rate: The clock rate, in Hz, of the PWM's clock source to compute the
+ * counter value for.
+ * @ns: The period, in nanoseconds, to computer the counter value for.
+ *
+ * Returns the PWM counter value for the specified clock rate and period.
+ */
+static inline int pwm_calc_value(unsigned long clk_rate, int ns)
+{
+ const unsigned long nanoseconds_per_second = 1000000000;
+ int cycles;
+ __u64 c;
+
+ c = (__u64)clk_rate * ns;
+ do_div(c, nanoseconds_per_second);
+ cycles = c;
+
+ return DM_TIMER_LOAD_MIN - cycles;
+}
+
+static int omap_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+ struct omap_chip *omap = to_omap_chip(chip);
+ int status = 0;
+
+ /* Enable the counter--always--before attempting to write its
+ * registers and then set the timer to its minimum load value to
+ * ensure we get an overflow event right away once we start it.
+ */
+
+ omap_dm_timer_enable(omap->dm_timer);
+ omap_dm_timer_write_counter(omap->dm_timer, DM_TIMER_LOAD_MIN);
+ omap_dm_timer_start(omap->dm_timer);
+ omap_dm_timer_disable(omap->dm_timer);
+
+ return status;
+}
+
+static void omap_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
+{
+ struct omap_chip *omap = to_omap_chip(chip);
+
+ omap_dm_timer_stop(omap->dm_timer);
+}
+
+static int omap_pwm_config(struct pwm_chip *chip, struct pwm_device *pwm,
+ int duty_ns, int period_ns)
+{
+ struct omap_chip *omap = to_omap_chip(chip);
+ int status = 0;
+ const bool enable = true;
+ const bool autoreload = true;
+ const bool toggle = true;
+ const int trigger = OMAP_TIMER_TRIGGER_OVERFLOW_AND_COMPARE;
+ int load_value, match_value;
+ unsigned long clk_rate;
+
+ dev_dbg(chip->dev,
+ "duty cycle: %d, period %d\n",
+ duty_ns, period_ns);
+
+ if (omap->duty_ns == duty_ns &&
+ omap->period_ns == period_ns)
+ /* No change - don't cause any transients */
+ return 0;
+
+ clk_rate = clk_get_rate(omap_dm_timer_get_fclk(omap->dm_timer));
+
+ /* 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_calc_value(clk_rate, period_ns);
+ match_value = pwm_calc_value(clk_rate, period_ns - duty_ns);
+
+ /* We MUST enable yet stop the associated dual-mode timer before
+ * attempting to write its registers. Hopefully it is already
+ * disabled, but call the (idempotent) pwm_disable just in case
+ */
+
+ pwm_disable(pwm);
+
+ omap_dm_timer_enable(omap->dm_timer);
+
+ omap_dm_timer_set_load(omap->dm_timer, autoreload, load_value);
+ omap_dm_timer_set_match(omap->dm_timer, enable, match_value);
+
+ dev_dbg(chip->dev,
+ "load value: %#08x (%d), "
+ "match value: %#08x (%d)\n",
+ load_value, load_value,
+ match_value, match_value);
+
+ omap_dm_timer_set_pwm(omap->dm_timer,
+ !omap->polarity,
+ toggle,
+ trigger);
+
+ /* Set the counter to generate an overflow event immediately. */
+
+ omap_dm_timer_write_counter(omap->dm_timer, DM_TIMER_LOAD_MIN);
+
+ /* Now that we're done configuring the dual-mode timer, disable it
+ * again. We'll enable and start it later, when requested.
+ */
+
+ omap_dm_timer_disable(omap->dm_timer);
+ omap->duty_ns = duty_ns;
+ omap->period_ns = period_ns;
+
+ return status;
+}
+
+
+static struct pwm_ops omap_pwm_ops = {
+ .enable = omap_pwm_enable,
+ .disable= omap_pwm_disable,
+ .config = omap_pwm_config,
+ .owner = THIS_MODULE,
+};
+
+/**
+ * omap_pwm_probe - check for the PWM and bind it to the driver.
+ * @pdev: A pointer to the platform device node associated with the
+ * PWM instance to be probed for driver binding.
+ *
+ * Returns 0 if the PWM instance was successfully bound to the driver;
+ * otherwise, < 0 on error.
+ */
+static int __devinit omap_pwm_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct omap_chip *omap;
+ int status = 0;
+ unsigned int id = pdev->id;
+ unsigned int timer = id >> 1; /* lsb is polarity */
+
+ omap = kzalloc(sizeof(struct pwm_device), GFP_KERNEL);
+
+ if (omap == NULL) {
+ dev_err(dev, "Could not allocate memory.\n");
+ status = -ENOMEM;
+ goto done;
+ }
+
+ /* Request the OMAP dual-mode timer that will be bound to and
+ * associated with this generic PWM.
+ */
+
+ omap->dm_timer = omap_dm_timer_request_specific(timer);
+
+ if (omap->dm_timer == NULL) {
+ status = -EPROBE_DEFER;
+ goto err_free;
+ }
+
+ /* Configure the source for the dual-mode timer backing this
+ * generic PWM device. The clock source will ultimately determine
+ * how small or large the PWM frequency can be.
+ *
+ * At some point, it's probably worth revisiting moving this to
+ * the configure method and choosing either the slow- or
+ * system-clock source as appropriate for the desired PWM period.
+ */
+
+ omap_dm_timer_set_source(omap->dm_timer, OMAP_TIMER_SRC_SYS_CLK);
+
+ /* Cache away other miscellaneous driver-private data and state
+ * information and add the driver-private data to the platform
+ * device.
+ */
+
+ omap->chip.dev = dev;
+ omap->chip.ops = &omap_pwm_ops;
+ omap->chip.base = -1;
+ omap->chip.npwm = 1;
+ omap->polarity = id & 1;
+
+ status = pwmchip_add(&omap->chip);
+ if (status < 0) {
+ dev_err(dev, "failed to register pwm\n");
+ omap_dm_timer_free(omap->dm_timer);
+ goto err_free;
+ }
+
+ platform_set_drvdata(pdev, omap);
+
+ status = 0;
+ goto done;
+
+ err_free:
+ kfree(omap);
+ done:
+ return status;
+}
+
+/**
+ * omap_pwm_remove - unbind the specified PWM platform device from the driver.
+ * @pdev: A pointer to the platform device node associated with the
+ * PWM instance to be unbound/removed.
+ *
+ * Returns 0 if the PWM was successfully removed as a platform device;
+ * otherwise, < 0 on error.
+ */
+static int __devexit omap_pwm_remove(struct platform_device *pdev)
+{
+ struct omap_chip *omap = platform_get_drvdata(pdev);
+ int status = 0;
+
+ status = pwmchip_remove(&omap->chip);
+ if (status < 0)
+ goto done;
+
+ omap_dm_timer_free(omap->dm_timer);
+
+ kfree(omap);
+
+ done:
+ return status;
+}
+
+#if CONFIG_PM
+static int omap_pwm_suspend(struct platform_device *pdev, pm_message_t state)
+{
+ struct omap_chip *omap = platform_get_drvdata(pdev);
+ /* No one preserve these values during suspend so reset them
+ * Otherwise driver leaves PWM unconfigured if same values
+ * passed to pwm_config
+ */
+ omap->period_ns = 0;
+ omap->duty_ns = 0;
+
+ return 0;
+}
+#else
+#define omap_pwm_suspend NULL
+#endif
+
+static struct platform_driver omap_pwm_driver = {
+ .driver.name = "omap-pwm",
+ .driver.owner = THIS_MODULE,
+ .probe = omap_pwm_probe,
+ .remove = __devexit_p(omap_pwm_remove),
+ .suspend = omap_pwm_suspend,
+ .resume = NULL,
+};
+
+static int __init omap_pwm_init(void)
+{
+ return platform_driver_register(&omap_pwm_driver);
+}
+
+static void __exit omap_pwm_exit(void)
+{
+ platform_driver_unregister(&omap_pwm_driver);
+}
+
+arch_initcall(omap_pwm_init);
+module_exit(omap_pwm_exit);
+
+MODULE_AUTHOR("Grant Erickson <marathon96@xxxxxxxxx>");
+MODULE_AUTHOR("NeilBrown <neilb@xxxxxxx>");
+MODULE_LICENSE("GPLv2");
+MODULE_VERSION("2012-12-01");
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