[PATCH 3/9] pwm: Add Renesas Mobile TPU PWM driver
From: Laurent Pinchart
Date: Tue Apr 23 2013 - 20:08:28 EST
The Timer Pulse Unit (TPU is a 4-channels 16-bit timer used to generate
waveforms. This driver exposes PWM functions through the PWM API for
other drivers to use.
The code is loosely based on the leds-renesas-tpu driver by Magnus Damm
and the TPU PWM driver shipped in the Armadillo EVA 800 kernel sources.
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@xxxxxxxxxxxxxxxx>
Tested-by: Simon Horman <horms@xxxxxxxxxxxx>
---
drivers/pwm/Kconfig | 7 +
drivers/pwm/Makefile | 1 +
drivers/pwm/pwm-rmob.c | 462 +++++++++++++++++++++++++++++++++
include/linux/platform_data/pwm-rmob.h | 18 ++
4 files changed, 488 insertions(+)
create mode 100644 drivers/pwm/pwm-rmob.c
create mode 100644 include/linux/platform_data/pwm-rmob.h
diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig
index 0e0bfa0..23281f2 100644
--- a/drivers/pwm/Kconfig
+++ b/drivers/pwm/Kconfig
@@ -115,6 +115,13 @@ config PWM_PXA
To compile this driver as a module, choose M here: the module
will be called pwm-pxa.
+config PWM_RMOB
+ tristate "R-Mobile TPU PWM support"
+ depends on ARCH_SHMOBILE
+ help
+ This driver exposes the Timer Pulse Unit (TPU) PWM controller found
+ in R-Mobile and SH-Mobile chips through the PWM API.
+
config PWM_SAMSUNG
tristate "Samsung PWM support"
depends on PLAT_SAMSUNG
diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile
index 94ba21e..63742d9 100644
--- a/drivers/pwm/Makefile
+++ b/drivers/pwm/Makefile
@@ -8,6 +8,7 @@ obj-$(CONFIG_PWM_LPC32XX) += pwm-lpc32xx.o
obj-$(CONFIG_PWM_MXS) += pwm-mxs.o
obj-$(CONFIG_PWM_PUV3) += pwm-puv3.o
obj-$(CONFIG_PWM_PXA) += pwm-pxa.o
+obj-$(CONFIG_PWM_RMOB) += pwm-rmob.o
obj-$(CONFIG_PWM_SAMSUNG) += pwm-samsung.o
obj-$(CONFIG_PWM_SPEAR) += pwm-spear.o
obj-$(CONFIG_PWM_TEGRA) += pwm-tegra.o
diff --git a/drivers/pwm/pwm-rmob.c b/drivers/pwm/pwm-rmob.c
new file mode 100644
index 0000000..c00f76d
--- /dev/null
+++ b/drivers/pwm/pwm-rmob.c
@@ -0,0 +1,462 @@
+/*
+ * R-Mobile TPU PWM driver
+ *
+ * Copyright (C) 2012 Renesas Solutions Corp.
+ *
+ * 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
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/init.h>
+#include <linux/ioport.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/platform_data/pwm-rmob.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/pwm.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+
+#define TPU_TSTR 0x00 /* Timer start register (shared) */
+
+#define TPU_TCRn 0x00 /* Timer control register */
+#define TPU_TCR_CCLR_NONE (0 << 5)
+#define TPU_TCR_CCLR_TGRA (1 << 5)
+#define TPU_TCR_CCLR_TGRB (2 << 5)
+#define TPU_TCR_CCLR_TGRC (5 << 5)
+#define TPU_TCR_CCLR_TGRD (6 << 5)
+#define TPU_TCR_CKEG_RISING (0 << 3)
+#define TPU_TCR_CKEG_FALLING (1 << 3)
+#define TPU_TCR_CKEG_BOTH (2 << 3)
+#define TPU_TMDRn 0x04 /* Timer mode register */
+#define TPU_TMDR_BFWT (1 << 6)
+#define TPU_TMDR_BFB (1 << 5)
+#define TPU_TMDR_BFA (1 << 4)
+#define TPU_TMDR_MD_NORMAL (0 << 0)
+#define TPU_TMDR_MD_PWM (2 << 0)
+#define TPU_TIORn 0x08 /* Timer I/O control register */
+#define TPU_TIOR_IOA_0 (0 << 0)
+#define TPU_TIOR_IOA_0_CLR (1 << 0)
+#define TPU_TIOR_IOA_0_SET (2 << 0)
+#define TPU_TIOR_IOA_0_TOGGLE (3 << 0)
+#define TPU_TIOR_IOA_1 (4 << 0)
+#define TPU_TIOR_IOA_1_CLR (5 << 0)
+#define TPU_TIOR_IOA_1_SET (6 << 0)
+#define TPU_TIOR_IOA_1_TOGGLE (7 << 0)
+#define TPU_TIERn 0x0c /* Timer interrupt enable register */
+#define TPU_TSRn 0x10 /* Timer status register */
+#define TPU_TCNTn 0x14 /* Timer counter */
+#define TPU_TGRAn 0x18 /* Timer general register A */
+#define TPU_TGRBn 0x1c /* Timer general register B */
+#define TPU_TGRCn 0x20 /* Timer general register C */
+#define TPU_TGRDn 0x24 /* Timer general register D */
+
+#define TPU_CHANNEL_OFFSET 0x10
+#define TPU_CHANNEL_SIZE 0x40
+
+enum tpu_pin_state {
+ TPU_PIN_INACTIVE, /* Pin is driven inactive */
+ TPU_PIN_PWM, /* Pin is driven by PWM */
+ TPU_PIN_ACTIVE, /* Pin is driven active */
+};
+
+struct tpu_device;
+
+struct tpu_pwm_device {
+ bool timer_on; /* Whether the timer is running */
+
+ struct rmob_tpu_pwm_channel_data *pdata;
+ struct tpu_device *tpu;
+ unsigned int channel; /* Channel number in the TPU */
+
+ unsigned int prescaler;
+ u16 period;
+ u16 duty;
+};
+
+struct tpu_device {
+ struct platform_device *pdev;
+ struct pwm_chip chip;
+ spinlock_t lock;
+
+ void __iomem *base;
+ struct clk *clk;
+
+ struct tpu_pwm_device pwms[RMOB_TPU_CHANNEL_MAX];
+};
+
+#define to_tpu_device(c) container_of(c, struct tpu_device, chip)
+
+static void tpu_pwm_write(struct tpu_pwm_device *pwm, int reg_nr, u16 value)
+{
+ void __iomem *base = pwm->tpu->base + TPU_CHANNEL_OFFSET
+ + pwm->channel * TPU_CHANNEL_SIZE;
+
+ iowrite16(value, base + reg_nr);
+}
+
+static void tpu_pwm_set_pin(struct tpu_pwm_device *pwm,
+ enum tpu_pin_state state)
+{
+ static const char * const states[] = { "inactive", "PWM", "active" };
+
+ dev_dbg(&pwm->tpu->pdev->dev, "%u: configuring pin as %s\n",
+ pwm->channel, states[state]);
+
+ switch (state) {
+ case TPU_PIN_INACTIVE:
+ tpu_pwm_write(pwm, TPU_TIORn, pwm->pdata->active_low ?
+ TPU_TIOR_IOA_1 : TPU_TIOR_IOA_0);
+ break;
+ case TPU_PIN_PWM:
+ tpu_pwm_write(pwm, TPU_TIORn, pwm->pdata->active_low ?
+ TPU_TIOR_IOA_0_SET : TPU_TIOR_IOA_1_CLR);
+ break;
+ case TPU_PIN_ACTIVE:
+ tpu_pwm_write(pwm, TPU_TIORn, pwm->pdata->active_low ?
+ TPU_TIOR_IOA_0 : TPU_TIOR_IOA_1);
+ break;
+ }
+}
+
+static void tpu_pwm_start_stop(struct tpu_pwm_device *pwm, int start)
+{
+ unsigned long flags;
+ u16 value;
+
+ spin_lock_irqsave(&pwm->tpu->lock, flags);
+ value = ioread16(pwm->tpu->base + TPU_TSTR);
+
+ if (start)
+ value |= 1 << pwm->channel;
+ else
+ value &= ~(1 << pwm->channel);
+
+ iowrite16(value, pwm->tpu->base + TPU_TSTR);
+ spin_unlock_irqrestore(&pwm->tpu->lock, flags);
+}
+
+static int tpu_pwm_timer_start(struct tpu_pwm_device *pwm)
+{
+ int ret;
+
+ if (!pwm->timer_on) {
+ /* Wake up device and enable clock. */
+ pm_runtime_get_sync(&pwm->tpu->pdev->dev);
+ ret = clk_prepare_enable(pwm->tpu->clk);
+ if (ret) {
+ dev_err(&pwm->tpu->pdev->dev, "cannot enable clock\n");
+ return ret;
+ }
+ pwm->timer_on = true;
+ }
+
+ /* Make sure the channel is stopped, as we need to reconfigure it
+ * completely. First drive the pin to the inactive state to avoid
+ * glitches.
+ */
+ tpu_pwm_set_pin(pwm, TPU_PIN_INACTIVE);
+ tpu_pwm_start_stop(pwm, false);
+
+ /*
+ * - Clear TCNT on TGRB match
+ * - Count on rising edge
+ * - Set prescaler
+ * - Output 0 until TGRA, output 1 until TGRB (active low polarity)
+ * - Output 1 until TGRA, output 0 until TGRB (active high polarity
+ * - PWM mode
+ */
+ tpu_pwm_write(pwm, TPU_TCRn, TPU_TCR_CCLR_TGRB | TPU_TCR_CKEG_RISING |
+ pwm->prescaler);
+ tpu_pwm_write(pwm, TPU_TMDRn, TPU_TMDR_MD_PWM);
+ tpu_pwm_set_pin(pwm, TPU_PIN_PWM);
+ tpu_pwm_write(pwm, TPU_TGRAn, pwm->duty);
+ tpu_pwm_write(pwm, TPU_TGRBn, pwm->period);
+
+ dev_dbg(&pwm->tpu->pdev->dev, "%u: TGRA 0x%04x TGRB 0x%04x\n",
+ pwm->channel, pwm->duty, pwm->period);
+
+ /* Start the channel. */
+ tpu_pwm_start_stop(pwm, true);
+
+ return 0;
+}
+
+static void tpu_pwm_timer_stop(struct tpu_pwm_device *pwm)
+{
+ if (!pwm->timer_on)
+ return;
+
+ /* Disable channel. */
+ tpu_pwm_start_stop(pwm, false);
+
+ /* Stop clock and mark device as idle. */
+ clk_disable_unprepare(pwm->tpu->clk);
+ pm_runtime_put(&pwm->tpu->pdev->dev);
+
+ pwm->timer_on = false;
+}
+
+/* -----------------------------------------------------------------------------
+ * PWM API
+ */
+
+static int tpu_pwm_request(struct pwm_chip *chip, struct pwm_device *_pwm)
+{
+ struct tpu_device *tpu = to_tpu_device(chip);
+ struct tpu_pwm_device *pwm = &tpu->pwms[_pwm->hwpwm];
+
+ return pwm->pdata == NULL ? -EPROBE_DEFER : 0;
+}
+
+static int tpu_pwm_config(struct pwm_chip *chip, struct pwm_device *_pwm,
+ int duty_ns, int period_ns)
+{
+ static const unsigned int prescalers[] = { 1, 4, 16, 64 };
+ struct tpu_device *tpu = to_tpu_device(chip);
+ struct tpu_pwm_device *pwm = &tpu->pwms[_pwm->hwpwm];
+ unsigned int prescaler;
+ bool duty_only;
+ u32 clk_rate;
+ u32 period;
+ u32 duty;
+ int ret;
+
+ if (period_ns <= 0 || duty_ns < 0 || duty_ns > period_ns)
+ return -EINVAL;
+
+ /* Pick a prescaler to avoid overflowing the counter.
+ * TODO: Pick the highest acceptable prescaler.
+ */
+ clk_prepare_enable(tpu->clk);
+ clk_rate = clk_get_rate(tpu->clk);
+ clk_disable_unprepare(pwm->tpu->clk);
+
+ for (prescaler = 0; prescaler < ARRAY_SIZE(prescalers); ++prescaler) {
+ period = clk_rate / prescalers[prescaler]
+ / (NSEC_PER_SEC / period_ns);
+ if (period <= 0xffff)
+ break;
+ }
+
+ if (prescaler == ARRAY_SIZE(prescalers) || period == 0) {
+ dev_err(&tpu->pdev->dev, "clock rate mismatch\n");
+ return -ENOTSUPP;
+ }
+
+ if (duty_ns) {
+ duty = clk_rate / prescalers[prescaler]
+ / (NSEC_PER_SEC / duty_ns);
+ if (duty > period)
+ return -EINVAL;
+ } else {
+ duty = 0;
+ }
+
+ dev_dbg(&tpu->pdev->dev,
+ "rate %u, prescaler %u, period %u, duty %u\n",
+ clk_rate, prescalers[prescaler], period, duty);
+
+ duty_only = pwm->prescaler == prescaler && pwm->period == period;
+
+ pwm->prescaler = prescaler;
+ pwm->period = period;
+ pwm->duty = duty;
+
+ /* If the channel is disabled we're done. */
+ if (!test_bit(PWMF_ENABLED, &_pwm->flags))
+ return 0;
+
+ if (duty_only && pwm->timer_on) {
+ /* If only the duty cycle changed and the timer is already
+ * running, there's no need to reconfigure it completely, Just
+ * modify the duty cycle.
+ */
+ tpu_pwm_write(pwm, TPU_TGRAn, pwm->duty);
+ dev_dbg(&tpu->pdev->dev, "%u: TGRA 0x%04x\n", pwm->channel,
+ pwm->duty);
+ } else {
+ /* Otherwise perform a full reconfiguration. */
+ ret = tpu_pwm_timer_start(pwm);
+ if (ret < 0)
+ return ret;
+ }
+
+ if (duty == 0 || duty == period) {
+ /* To avoid running the timer when not strictly required, handle
+ * 0% and 100% duty cycles as fixed levels and stop the timer.
+ */
+ tpu_pwm_set_pin(pwm, duty ? TPU_PIN_ACTIVE : TPU_PIN_INACTIVE);
+ tpu_pwm_timer_stop(pwm);
+ }
+
+ return 0;
+}
+
+static int tpu_pwm_enable(struct pwm_chip *chip, struct pwm_device *_pwm)
+{
+ struct tpu_device *tpu = to_tpu_device(chip);
+ struct tpu_pwm_device *pwm = &tpu->pwms[_pwm->hwpwm];
+ int ret;
+
+ ret = tpu_pwm_timer_start(pwm);
+ if (ret < 0)
+ return ret;
+
+ /* To avoid running the timer when not strictly required, handle 0% and
+ * 100% duty cycles as fixed levels and stop the timer.
+ */
+ if (pwm->duty == 0 || pwm->duty == pwm->period) {
+ tpu_pwm_set_pin(pwm, pwm->duty ?
+ TPU_PIN_ACTIVE : TPU_PIN_INACTIVE);
+ tpu_pwm_timer_stop(pwm);
+ }
+
+ return 0;
+}
+
+static void tpu_pwm_disable(struct pwm_chip *chip, struct pwm_device *_pwm)
+{
+ struct tpu_device *tpu = to_tpu_device(chip);
+ struct tpu_pwm_device *pwm = &tpu->pwms[_pwm->hwpwm];
+
+ /* The timer must be running to modify the pin output configuration. */
+ tpu_pwm_timer_start(pwm);
+ tpu_pwm_set_pin(pwm, TPU_PIN_INACTIVE);
+ tpu_pwm_timer_stop(pwm);
+}
+
+static const struct pwm_ops tpu_pwm_ops = {
+ .request = tpu_pwm_request,
+ .config = tpu_pwm_config,
+ .enable = tpu_pwm_enable,
+ .disable = tpu_pwm_disable,
+ .owner = THIS_MODULE,
+};
+
+/* -----------------------------------------------------------------------------
+ * Probe and remove
+ */
+
+static int tpu_probe(struct platform_device *pdev)
+{
+ struct rmob_tpu_pwm_platform_data *pdata = pdev->dev.platform_data;
+ struct tpu_device *tpu;
+ struct resource *res;
+ unsigned int i;
+ int ret;
+
+ if (!pdata) {
+ dev_err(&pdev->dev, "missing platform data\n");
+ return -ENXIO;
+ }
+
+ tpu = devm_kzalloc(&pdev->dev, sizeof(*tpu), GFP_KERNEL);
+ if (tpu == NULL) {
+ dev_err(&pdev->dev, "failed to allocate driver data\n");
+ return -ENOMEM;
+ }
+
+ /* Map memory, get clock and pin control. */
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!res) {
+ dev_err(&pdev->dev, "failed to get I/O memory\n");
+ return -ENXIO;
+ }
+
+ tpu->base = devm_ioremap_nocache(&pdev->dev, res->start,
+ resource_size(res));
+ if (tpu->base == NULL) {
+ dev_err(&pdev->dev, "failed to remap I/O memory\n");
+ return -ENXIO;
+ }
+
+ tpu->clk = devm_clk_get(&pdev->dev, NULL);
+ if (IS_ERR(tpu->clk)) {
+ dev_err(&pdev->dev, "cannot get clock\n");
+ return PTR_ERR(tpu->clk);
+ }
+
+ /* Initialize and register the device. */
+ platform_set_drvdata(pdev, tpu);
+
+ spin_lock_init(&tpu->lock);
+ tpu->pdev = pdev;
+
+ for (i = 0; i < ARRAY_SIZE(tpu->pwms); ++i) {
+ struct tpu_pwm_device *pwm = &tpu->pwms[i];
+
+ if (!pdata->channels[i].enabled)
+ continue;
+
+ pwm->tpu = tpu;
+ pwm->channel = i;
+ pwm->pdata = &pdata->channels[i];
+
+ pwm->prescaler = 0;
+ pwm->period = 0;
+ pwm->duty = 0;
+
+ pwm->timer_on = false;
+ }
+
+ tpu->chip.dev = &pdev->dev;
+ tpu->chip.ops = &tpu_pwm_ops;
+ tpu->chip.base = -1;
+ tpu->chip.npwm = RMOB_TPU_CHANNEL_MAX;
+
+ ret = pwmchip_add(&tpu->chip);
+ if (ret < 0) {
+ dev_err(&pdev->dev, "failed to register PWM chip\n");
+ return ret;
+ }
+
+ dev_info(&pdev->dev, "TPU PWM %d registered\n", tpu->pdev->id);
+
+ pm_runtime_enable(&pdev->dev);
+
+ return 0;
+}
+
+static int tpu_remove(struct platform_device *pdev)
+{
+ struct tpu_device *tpu = platform_get_drvdata(pdev);
+ unsigned int i;
+
+ for (i = 0; i < ARRAY_SIZE(tpu->pwms); ++i) {
+ struct tpu_pwm_device *pwm = &tpu->pwms[i];
+
+ if (!pwm->tpu)
+ continue;
+
+ tpu_pwm_timer_stop(pwm);
+ }
+
+ pm_runtime_disable(&pdev->dev);
+
+ return 0;
+}
+
+static struct platform_driver tpu_driver = {
+ .probe = tpu_probe,
+ .remove = tpu_remove,
+ .driver = {
+ .name = "rmob_tpu_pwm",
+ }
+};
+
+module_platform_driver(tpu_driver);
+
+MODULE_AUTHOR("Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>");
+MODULE_DESCRIPTION("R-Mobile TPU PWM Driver");
+MODULE_LICENSE("GPL v2");
diff --git a/include/linux/platform_data/pwm-rmob.h b/include/linux/platform_data/pwm-rmob.h
new file mode 100644
index 0000000..dd422ef
--- /dev/null
+++ b/include/linux/platform_data/pwm-rmob.h
@@ -0,0 +1,18 @@
+#ifndef __PWM_RMOB_TPU_H__
+#define __PWM_RMOB_TPU_H__
+
+#define RMOB_TPU_CHANNEL_MAX 4
+
+#define RMOB_TPU_PWM_ID(device, channel) \
+ ((device) * RMOB_TPU_CHANNEL_MAX + (channel))
+
+struct rmob_tpu_pwm_channel_data {
+ bool enabled;
+ bool active_low;
+};
+
+struct rmob_tpu_pwm_platform_data {
+ struct rmob_tpu_pwm_channel_data channels[RMOB_TPU_CHANNEL_MAX];
+};
+
+#endif /* __PWM_RMOB_TPU_H__ */
--
1.8.1.5
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/