337 lines
8.8 KiB
C
337 lines
8.8 KiB
C
/*
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* LED control using Renesas TPU
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*
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* Copyright (C) 2011 Magnus Damm
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#include <linux/module.h>
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#include <linux/init.h>
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#include <linux/platform_device.h>
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#include <linux/spinlock.h>
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#include <linux/printk.h>
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#include <linux/ioport.h>
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#include <linux/io.h>
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#include <linux/clk.h>
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#include <linux/leds.h>
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#include <linux/platform_data/leds-renesas-tpu.h>
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#include <linux/gpio.h>
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#include <linux/err.h>
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#include <linux/slab.h>
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#include <linux/pm_runtime.h>
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#include <linux/workqueue.h>
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enum r_tpu_pin { R_TPU_PIN_UNUSED, R_TPU_PIN_GPIO, R_TPU_PIN_GPIO_FN };
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enum r_tpu_timer { R_TPU_TIMER_UNUSED, R_TPU_TIMER_ON };
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struct r_tpu_priv {
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struct led_classdev ldev;
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void __iomem *mapbase;
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struct clk *clk;
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struct platform_device *pdev;
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enum r_tpu_pin pin_state;
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enum r_tpu_timer timer_state;
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unsigned long min_rate;
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unsigned int refresh_rate;
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struct work_struct work;
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enum led_brightness new_brightness;
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};
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static DEFINE_SPINLOCK(r_tpu_lock);
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#define TSTR -1 /* Timer start register (shared register) */
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#define TCR 0 /* Timer control register (+0x00) */
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#define TMDR 1 /* Timer mode register (+0x04) */
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#define TIOR 2 /* Timer I/O control register (+0x08) */
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#define TIER 3 /* Timer interrupt enable register (+0x0c) */
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#define TSR 4 /* Timer status register (+0x10) */
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#define TCNT 5 /* Timer counter (+0x14) */
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#define TGRA 6 /* Timer general register A (+0x18) */
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#define TGRB 7 /* Timer general register B (+0x1c) */
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#define TGRC 8 /* Timer general register C (+0x20) */
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#define TGRD 9 /* Timer general register D (+0x24) */
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static inline unsigned short r_tpu_read(struct r_tpu_priv *p, int reg_nr)
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{
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struct led_renesas_tpu_config *cfg = p->pdev->dev.platform_data;
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void __iomem *base = p->mapbase;
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unsigned long offs = reg_nr << 2;
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if (reg_nr == TSTR)
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return ioread16(base - cfg->channel_offset);
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return ioread16(base + offs);
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}
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static inline void r_tpu_write(struct r_tpu_priv *p, int reg_nr,
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unsigned short value)
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{
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struct led_renesas_tpu_config *cfg = p->pdev->dev.platform_data;
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void __iomem *base = p->mapbase;
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unsigned long offs = reg_nr << 2;
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if (reg_nr == TSTR) {
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iowrite16(value, base - cfg->channel_offset);
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return;
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}
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iowrite16(value, base + offs);
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}
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static void r_tpu_start_stop_ch(struct r_tpu_priv *p, int start)
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{
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struct led_renesas_tpu_config *cfg = p->pdev->dev.platform_data;
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unsigned long flags, value;
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/* start stop register shared by multiple timer channels */
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spin_lock_irqsave(&r_tpu_lock, flags);
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value = r_tpu_read(p, TSTR);
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if (start)
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value |= 1 << cfg->timer_bit;
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else
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value &= ~(1 << cfg->timer_bit);
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r_tpu_write(p, TSTR, value);
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spin_unlock_irqrestore(&r_tpu_lock, flags);
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}
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static int r_tpu_enable(struct r_tpu_priv *p, enum led_brightness brightness)
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{
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struct led_renesas_tpu_config *cfg = p->pdev->dev.platform_data;
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int prescaler[] = { 1, 4, 16, 64 };
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int k, ret;
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unsigned long rate, tmp;
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if (p->timer_state == R_TPU_TIMER_ON)
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return 0;
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/* wake up device and enable clock */
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pm_runtime_get_sync(&p->pdev->dev);
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ret = clk_enable(p->clk);
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if (ret) {
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dev_err(&p->pdev->dev, "cannot enable clock\n");
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return ret;
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}
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/* make sure channel is disabled */
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r_tpu_start_stop_ch(p, 0);
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/* get clock rate after enabling it */
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rate = clk_get_rate(p->clk);
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/* pick the lowest acceptable rate */
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for (k = ARRAY_SIZE(prescaler) - 1; k >= 0; k--)
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if ((rate / prescaler[k]) >= p->min_rate)
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break;
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if (k < 0) {
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dev_err(&p->pdev->dev, "clock rate mismatch\n");
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goto err0;
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}
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dev_dbg(&p->pdev->dev, "rate = %lu, prescaler %u\n",
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rate, prescaler[k]);
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/* clear TCNT on TGRB match, count on rising edge, set prescaler */
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r_tpu_write(p, TCR, 0x0040 | k);
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/* output 0 until TGRA, output 1 until TGRB */
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r_tpu_write(p, TIOR, 0x0002);
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rate /= prescaler[k] * p->refresh_rate;
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r_tpu_write(p, TGRB, rate);
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dev_dbg(&p->pdev->dev, "TRGB = 0x%04lx\n", rate);
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tmp = (cfg->max_brightness - brightness) * rate;
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r_tpu_write(p, TGRA, tmp / cfg->max_brightness);
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dev_dbg(&p->pdev->dev, "TRGA = 0x%04lx\n", tmp / cfg->max_brightness);
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/* PWM mode */
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r_tpu_write(p, TMDR, 0x0002);
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/* enable channel */
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r_tpu_start_stop_ch(p, 1);
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p->timer_state = R_TPU_TIMER_ON;
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return 0;
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err0:
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clk_disable(p->clk);
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pm_runtime_put_sync(&p->pdev->dev);
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return -ENOTSUPP;
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}
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static void r_tpu_disable(struct r_tpu_priv *p)
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{
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if (p->timer_state == R_TPU_TIMER_UNUSED)
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return;
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/* disable channel */
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r_tpu_start_stop_ch(p, 0);
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/* stop clock and mark device as idle */
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clk_disable(p->clk);
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pm_runtime_put_sync(&p->pdev->dev);
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p->timer_state = R_TPU_TIMER_UNUSED;
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}
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static void r_tpu_set_pin(struct r_tpu_priv *p, enum r_tpu_pin new_state,
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enum led_brightness brightness)
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{
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struct led_renesas_tpu_config *cfg = p->pdev->dev.platform_data;
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if (p->pin_state == new_state) {
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if (p->pin_state == R_TPU_PIN_GPIO)
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gpio_set_value(cfg->pin_gpio, brightness);
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return;
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}
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if (p->pin_state == R_TPU_PIN_GPIO)
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gpio_free(cfg->pin_gpio);
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if (p->pin_state == R_TPU_PIN_GPIO_FN)
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gpio_free(cfg->pin_gpio_fn);
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if (new_state == R_TPU_PIN_GPIO)
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gpio_request_one(cfg->pin_gpio, GPIOF_DIR_OUT | !!brightness,
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cfg->name);
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if (new_state == R_TPU_PIN_GPIO_FN)
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gpio_request(cfg->pin_gpio_fn, cfg->name);
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p->pin_state = new_state;
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}
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static void r_tpu_work(struct work_struct *work)
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{
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struct r_tpu_priv *p = container_of(work, struct r_tpu_priv, work);
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enum led_brightness brightness = p->new_brightness;
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r_tpu_disable(p);
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/* off and maximum are handled as GPIO pins, in between PWM */
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if ((brightness == 0) || (brightness == p->ldev.max_brightness))
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r_tpu_set_pin(p, R_TPU_PIN_GPIO, brightness);
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else {
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r_tpu_set_pin(p, R_TPU_PIN_GPIO_FN, 0);
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r_tpu_enable(p, brightness);
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}
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}
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static void r_tpu_set_brightness(struct led_classdev *ldev,
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enum led_brightness brightness)
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{
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struct r_tpu_priv *p = container_of(ldev, struct r_tpu_priv, ldev);
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p->new_brightness = brightness;
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schedule_work(&p->work);
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}
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static int r_tpu_probe(struct platform_device *pdev)
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{
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struct led_renesas_tpu_config *cfg = pdev->dev.platform_data;
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struct r_tpu_priv *p;
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struct resource *res;
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int ret;
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if (!cfg) {
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dev_err(&pdev->dev, "missing platform data\n");
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return -ENODEV;
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}
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p = devm_kzalloc(&pdev->dev, sizeof(*p), GFP_KERNEL);
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if (p == NULL) {
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dev_err(&pdev->dev, "failed to allocate driver data\n");
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return -ENOMEM;
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}
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res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
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if (!res) {
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dev_err(&pdev->dev, "failed to get I/O memory\n");
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return -ENXIO;
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}
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/* map memory, let mapbase point to our channel */
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p->mapbase = devm_ioremap_nocache(&pdev->dev, res->start,
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resource_size(res));
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if (p->mapbase == NULL) {
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dev_err(&pdev->dev, "failed to remap I/O memory\n");
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return -ENXIO;
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}
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/* get hold of clock */
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p->clk = devm_clk_get(&pdev->dev, NULL);
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if (IS_ERR(p->clk)) {
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dev_err(&pdev->dev, "cannot get clock\n");
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return PTR_ERR(p->clk);
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}
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p->pdev = pdev;
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p->pin_state = R_TPU_PIN_UNUSED;
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p->timer_state = R_TPU_TIMER_UNUSED;
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p->refresh_rate = cfg->refresh_rate ? cfg->refresh_rate : 100;
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r_tpu_set_pin(p, R_TPU_PIN_GPIO, LED_OFF);
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platform_set_drvdata(pdev, p);
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INIT_WORK(&p->work, r_tpu_work);
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p->ldev.name = cfg->name;
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p->ldev.brightness = LED_OFF;
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p->ldev.max_brightness = cfg->max_brightness;
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p->ldev.brightness_set = r_tpu_set_brightness;
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p->ldev.flags |= LED_CORE_SUSPENDRESUME;
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ret = led_classdev_register(&pdev->dev, &p->ldev);
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if (ret < 0)
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goto err0;
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/* max_brightness may be updated by the LED core code */
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p->min_rate = p->ldev.max_brightness * p->refresh_rate;
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pm_runtime_enable(&pdev->dev);
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return 0;
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err0:
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r_tpu_set_pin(p, R_TPU_PIN_UNUSED, LED_OFF);
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return ret;
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}
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static int r_tpu_remove(struct platform_device *pdev)
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{
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struct r_tpu_priv *p = platform_get_drvdata(pdev);
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r_tpu_set_brightness(&p->ldev, LED_OFF);
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led_classdev_unregister(&p->ldev);
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cancel_work_sync(&p->work);
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r_tpu_disable(p);
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r_tpu_set_pin(p, R_TPU_PIN_UNUSED, LED_OFF);
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pm_runtime_disable(&pdev->dev);
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return 0;
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}
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static struct platform_driver r_tpu_device_driver = {
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.probe = r_tpu_probe,
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.remove = r_tpu_remove,
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.driver = {
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.name = "leds-renesas-tpu",
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}
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};
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module_platform_driver(r_tpu_device_driver);
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MODULE_AUTHOR("Magnus Damm");
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MODULE_DESCRIPTION("Renesas TPU LED Driver");
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MODULE_LICENSE("GPL v2");
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