| /* |
| * 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/module.h> |
| #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/platform_data/leds-renesas-tpu.h> |
| #include <linux/gpio.h> |
| #include <linux/err.h> |
| #include <linux/slab.h> |
| #include <linux/pm_runtime.h> |
| #include <linux/workqueue.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; |
| struct work_struct work; |
| enum led_brightness new_brightness; |
| }; |
| |
| 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_work(struct work_struct *work) |
| { |
| struct r_tpu_priv *p = container_of(work, struct r_tpu_priv, work); |
| enum led_brightness brightness = p->new_brightness; |
| |
| r_tpu_disable(p); |
| |
| /* off and maximum are handled as GPIO pins, in between PWM */ |
| if ((brightness == 0) || (brightness == p->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 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); |
| p->new_brightness = brightness; |
| schedule_work(&p->work); |
| } |
| |
| 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); |
| |
| INIT_WORK(&p->work, r_tpu_work); |
| |
| 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); |
| cancel_work_sync(&p->work); |
| 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", |
| } |
| }; |
| |
| module_platform_driver(r_tpu_device_driver); |
| |
| MODULE_AUTHOR("Magnus Damm"); |
| MODULE_DESCRIPTION("Renesas TPU LED Driver"); |
| MODULE_LICENSE("GPL v2"); |