--- /dev/null
+/*
+ * LED control using Renesas TPU
+ *
+ * Copyright (C) 2011 Magnus Damm
+ *
+ * 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.
+ *
+ * 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#include <linux/init.h>
+#include <linux/platform_device.h>
+#include <linux/spinlock.h>
+#include <linux/printk.h>
+#include <linux/ioport.h>
+#include <linux/io.h>
+#include <linux/clk.h>
+#include <linux/leds.h>
+#include <linux/leds-renesas-tpu.h>
+#include <linux/gpio.h>
+#include <linux/err.h>
+#include <linux/slab.h>
+#include <linux/pm_runtime.h>
+
+enum r_tpu_pin { R_TPU_PIN_UNUSED, R_TPU_PIN_GPIO, R_TPU_PIN_GPIO_FN };
+enum r_tpu_timer { R_TPU_TIMER_UNUSED, R_TPU_TIMER_ON };
+
+struct r_tpu_priv {
+ struct led_classdev ldev;
+ void __iomem *mapbase;
+ struct clk *clk;
+ struct platform_device *pdev;
+ enum r_tpu_pin pin_state;
+ enum r_tpu_timer timer_state;
+ unsigned long min_rate;
+ unsigned int refresh_rate;
+};
+
+static DEFINE_SPINLOCK(r_tpu_lock);
+
+#define TSTR -1 /* Timer start register (shared register) */
+#define TCR 0 /* Timer control register (+0x00) */
+#define TMDR 1 /* Timer mode register (+0x04) */
+#define TIOR 2 /* Timer I/O control register (+0x08) */
+#define TIER 3 /* Timer interrupt enable register (+0x0c) */
+#define TSR 4 /* Timer status register (+0x10) */
+#define TCNT 5 /* Timer counter (+0x14) */
+#define TGRA 6 /* Timer general register A (+0x18) */
+#define TGRB 7 /* Timer general register B (+0x1c) */
+#define TGRC 8 /* Timer general register C (+0x20) */
+#define TGRD 9 /* Timer general register D (+0x24) */
+
+static inline unsigned short r_tpu_read(struct r_tpu_priv *p, int reg_nr)
+{
+ struct led_renesas_tpu_config *cfg = p->pdev->dev.platform_data;
+ void __iomem *base = p->mapbase;
+ unsigned long offs = reg_nr << 2;
+
+ if (reg_nr == TSTR)
+ return ioread16(base - cfg->channel_offset);
+
+ return ioread16(base + offs);
+}
+
+static inline void r_tpu_write(struct r_tpu_priv *p, int reg_nr,
+ unsigned short value)
+{
+ struct led_renesas_tpu_config *cfg = p->pdev->dev.platform_data;
+ void __iomem *base = p->mapbase;
+ unsigned long offs = reg_nr << 2;
+
+ if (reg_nr == TSTR) {
+ iowrite16(value, base - cfg->channel_offset);
+ return;
+ }
+
+ iowrite16(value, base + offs);
+}
+
+static void r_tpu_start_stop_ch(struct r_tpu_priv *p, int start)
+{
+ struct led_renesas_tpu_config *cfg = p->pdev->dev.platform_data;
+ unsigned long flags, value;
+
+ /* start stop register shared by multiple timer channels */
+ spin_lock_irqsave(&r_tpu_lock, flags);
+ value = r_tpu_read(p, TSTR);
+
+ if (start)
+ value |= 1 << cfg->timer_bit;
+ else
+ value &= ~(1 << cfg->timer_bit);
+
+ r_tpu_write(p, TSTR, value);
+ spin_unlock_irqrestore(&r_tpu_lock, flags);
+}
+
+static int r_tpu_enable(struct r_tpu_priv *p, enum led_brightness brightness)
+{
+ struct led_renesas_tpu_config *cfg = p->pdev->dev.platform_data;
+ int prescaler[] = { 1, 4, 16, 64 };
+ int k, ret;
+ unsigned long rate, tmp;
+
+ if (p->timer_state == R_TPU_TIMER_ON)
+ return 0;
+
+ /* wake up device and enable clock */
+ pm_runtime_get_sync(&p->pdev->dev);
+ ret = clk_enable(p->clk);
+ if (ret) {
+ dev_err(&p->pdev->dev, "cannot enable clock\n");
+ return ret;
+ }
+
+ /* make sure channel is disabled */
+ r_tpu_start_stop_ch(p, 0);
+
+ /* get clock rate after enabling it */
+ rate = clk_get_rate(p->clk);
+
+ /* pick the lowest acceptable rate */
+ for (k = 0; k < ARRAY_SIZE(prescaler); k++)
+ if ((rate / prescaler[k]) < p->min_rate)
+ break;
+
+ if (!k) {
+ dev_err(&p->pdev->dev, "clock rate mismatch\n");
+ goto err0;
+ }
+ dev_dbg(&p->pdev->dev, "rate = %lu, prescaler %u\n",
+ rate, prescaler[k - 1]);
+
+ /* clear TCNT on TGRB match, count on rising edge, set prescaler */
+ r_tpu_write(p, TCR, 0x0040 | (k - 1));
+
+ /* output 0 until TGRA, output 1 until TGRB */
+ r_tpu_write(p, TIOR, 0x0002);
+
+ rate /= prescaler[k - 1] * p->refresh_rate;
+ r_tpu_write(p, TGRB, rate);
+ dev_dbg(&p->pdev->dev, "TRGB = 0x%04lx\n", rate);
+
+ tmp = (cfg->max_brightness - brightness) * rate;
+ r_tpu_write(p, TGRA, tmp / cfg->max_brightness);
+ dev_dbg(&p->pdev->dev, "TRGA = 0x%04lx\n", tmp / cfg->max_brightness);
+
+ /* PWM mode */
+ r_tpu_write(p, TMDR, 0x0002);
+
+ /* enable channel */
+ r_tpu_start_stop_ch(p, 1);
+
+ p->timer_state = R_TPU_TIMER_ON;
+ return 0;
+ err0:
+ clk_disable(p->clk);
+ pm_runtime_put_sync(&p->pdev->dev);
+ return -ENOTSUPP;
+}
+
+static void r_tpu_disable(struct r_tpu_priv *p)
+{
+ if (p->timer_state == R_TPU_TIMER_UNUSED)
+ return;
+
+ /* disable channel */
+ r_tpu_start_stop_ch(p, 0);
+
+ /* stop clock and mark device as idle */
+ clk_disable(p->clk);
+ pm_runtime_put_sync(&p->pdev->dev);
+
+ p->timer_state = R_TPU_TIMER_UNUSED;
+}
+
+static void r_tpu_set_pin(struct r_tpu_priv *p, enum r_tpu_pin new_state,
+ enum led_brightness brightness)
+{
+ struct led_renesas_tpu_config *cfg = p->pdev->dev.platform_data;
+
+ if (p->pin_state == new_state) {
+ if (p->pin_state == R_TPU_PIN_GPIO)
+ gpio_set_value(cfg->pin_gpio, brightness);
+ return;
+ }
+
+ if (p->pin_state == R_TPU_PIN_GPIO)
+ gpio_free(cfg->pin_gpio);
+
+ if (p->pin_state == R_TPU_PIN_GPIO_FN)
+ gpio_free(cfg->pin_gpio_fn);
+
+ if (new_state == R_TPU_PIN_GPIO) {
+ gpio_request(cfg->pin_gpio, cfg->name);
+ gpio_direction_output(cfg->pin_gpio, !!brightness);
+ }
+ if (new_state == R_TPU_PIN_GPIO_FN)
+ gpio_request(cfg->pin_gpio_fn, cfg->name);
+
+ p->pin_state = new_state;
+}
+
+static void r_tpu_set_brightness(struct led_classdev *ldev,
+ enum led_brightness brightness)
+{
+ struct r_tpu_priv *p = container_of(ldev, struct r_tpu_priv, ldev);
+
+ r_tpu_disable(p);
+
+ /* off and maximum are handled as GPIO pins, in between PWM */
+ if ((brightness == 0) || (brightness == ldev->max_brightness))
+ r_tpu_set_pin(p, R_TPU_PIN_GPIO, brightness);
+ else {
+ r_tpu_set_pin(p, R_TPU_PIN_GPIO_FN, 0);
+ r_tpu_enable(p, brightness);
+ }
+}
+
+static int __devinit r_tpu_probe(struct platform_device *pdev)
+{
+ struct led_renesas_tpu_config *cfg = pdev->dev.platform_data;
+ struct r_tpu_priv *p;
+ struct resource *res;
+ int ret = -ENXIO;
+
+ if (!cfg) {
+ dev_err(&pdev->dev, "missing platform data\n");
+ goto err0;
+ }
+
+ p = kzalloc(sizeof(*p), GFP_KERNEL);
+ if (p == NULL) {
+ dev_err(&pdev->dev, "failed to allocate driver data\n");
+ ret = -ENOMEM;
+ goto err0;
+ }
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!res) {
+ dev_err(&pdev->dev, "failed to get I/O memory\n");
+ goto err1;
+ }
+
+ /* map memory, let mapbase point to our channel */
+ p->mapbase = ioremap_nocache(res->start, resource_size(res));
+ if (p->mapbase == NULL) {
+ dev_err(&pdev->dev, "failed to remap I/O memory\n");
+ goto err1;
+ }
+
+ /* get hold of clock */
+ p->clk = clk_get(&pdev->dev, NULL);
+ if (IS_ERR(p->clk)) {
+ dev_err(&pdev->dev, "cannot get clock\n");
+ ret = PTR_ERR(p->clk);
+ goto err2;
+ }
+
+ p->pdev = pdev;
+ p->pin_state = R_TPU_PIN_UNUSED;
+ p->timer_state = R_TPU_TIMER_UNUSED;
+ p->refresh_rate = cfg->refresh_rate ? cfg->refresh_rate : 100;
+ r_tpu_set_pin(p, R_TPU_PIN_GPIO, LED_OFF);
+ platform_set_drvdata(pdev, p);
+
+
+ p->ldev.name = cfg->name;
+ p->ldev.brightness = LED_OFF;
+ p->ldev.max_brightness = cfg->max_brightness;
+ p->ldev.brightness_set = r_tpu_set_brightness;
+ p->ldev.flags |= LED_CORE_SUSPENDRESUME;
+ ret = led_classdev_register(&pdev->dev, &p->ldev);
+ if (ret < 0)
+ goto err3;
+
+ /* max_brightness may be updated by the LED core code */
+ p->min_rate = p->ldev.max_brightness * p->refresh_rate;
+
+ pm_runtime_enable(&pdev->dev);
+ return 0;
+
+ err3:
+ r_tpu_set_pin(p, R_TPU_PIN_UNUSED, LED_OFF);
+ clk_put(p->clk);
+ err2:
+ iounmap(p->mapbase);
+ err1:
+ kfree(p);
+ err0:
+ return ret;
+}
+
+static int __devexit r_tpu_remove(struct platform_device *pdev)
+{
+ struct r_tpu_priv *p = platform_get_drvdata(pdev);
+
+ r_tpu_set_brightness(&p->ldev, LED_OFF);
+ led_classdev_unregister(&p->ldev);
+ r_tpu_disable(p);
+ r_tpu_set_pin(p, R_TPU_PIN_UNUSED, LED_OFF);
+
+ pm_runtime_disable(&pdev->dev);
+ clk_put(p->clk);
+
+ iounmap(p->mapbase);
+ kfree(p);
+ return 0;
+}
+
+static struct platform_driver r_tpu_device_driver = {
+ .probe = r_tpu_probe,
+ .remove = __devexit_p(r_tpu_remove),
+ .driver = {
+ .name = "leds-renesas-tpu",
+ }
+};
+
+static int __init r_tpu_init(void)
+{
+ return platform_driver_register(&r_tpu_device_driver);
+}
+
+static void __exit r_tpu_exit(void)
+{
+ platform_driver_unregister(&r_tpu_device_driver);
+}
+
+module_init(r_tpu_init);
+module_exit(r_tpu_exit);
+
+MODULE_AUTHOR("Magnus Damm");
+MODULE_DESCRIPTION("Renesas TPU LED Driver");
+MODULE_LICENSE("GPL v2");
projects / karo-tx-linux.git / commitdiff