Re: [PATCH 2/2] leds: sunxi: New driver for the R329/D1 LED controller

From: Maxime Ripard
Date: Fri Sep 03 2021 - 06:36:47 EST

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In reply to: kernel test robot: "Re: [PATCH 2/2] leds: sunxi: New driver for the R329/D1 LED controller"
Next in thread: Samuel Holland: "Re: [PATCH 2/2] leds: sunxi: New driver for the R329/D1 LED controller"
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On Thu, Sep 02, 2021 at 06:42:28PM -0500, Samuel Holland wrote:
> Some Allwinner sunxi SoCs, starting with the R329, contain an LED
> controller designed to drive RGB LED pixels. Add a driver for it using
> the multicolor LED framework, and with LEDs defined in the device tree.
>
> Signed-off-by: Samuel Holland <samuel@xxxxxxxxxxxx>
> ---
> drivers/leds/Kconfig | 8 +
> drivers/leds/Makefile | 1 +
> drivers/leds/leds-sunxi.c | 562 ++++++++++++++++++++++++++++++++++++++
> 3 files changed, 571 insertions(+)
> create mode 100644 drivers/leds/leds-sunxi.c
>
> diff --git a/drivers/leds/Kconfig b/drivers/leds/Kconfig
> index ed800f5da7d8..559d2ca0a7f4 100644
> --- a/drivers/leds/Kconfig
> +++ b/drivers/leds/Kconfig
> @@ -297,6 +297,14 @@ config LEDS_SUNFIRE
> This option enables support for the Left, Middle, and Right
> LEDs on the I/O and CPU boards of SunFire UltraSPARC servers.
>
> +config LEDS_SUNXI
> + tristate "LED support for Allwinner sunxi LED controller"
> + depends on LEDS_CLASS
> + depends on ARCH_SUNXI || COMPILE_TEST
> + help
> + This option enables support for the LED controller provided in
> + some Allwinner sunxi SoCs.
> +

Same comment for the name

> config LEDS_IPAQ_MICRO
> tristate "LED Support for the Compaq iPAQ h3xxx"
> depends on LEDS_CLASS
> diff --git a/drivers/leds/Makefile b/drivers/leds/Makefile
> index c636ec069612..3395f188e5bf 100644
> --- a/drivers/leds/Makefile
> +++ b/drivers/leds/Makefile
> @@ -77,6 +77,7 @@ obj-$(CONFIG_LEDS_PWM) += leds-pwm.o
> obj-$(CONFIG_LEDS_REGULATOR) += leds-regulator.o
> obj-$(CONFIG_LEDS_S3C24XX) += leds-s3c24xx.o
> obj-$(CONFIG_LEDS_SC27XX_BLTC) += leds-sc27xx-bltc.o
> +obj-$(CONFIG_LEDS_SUNXI) += leds-sunxi.o
> obj-$(CONFIG_LEDS_SUNFIRE) += leds-sunfire.o
> obj-$(CONFIG_LEDS_SYSCON) += leds-syscon.o
> obj-$(CONFIG_LEDS_TCA6507) += leds-tca6507.o
> diff --git a/drivers/leds/leds-sunxi.c b/drivers/leds/leds-sunxi.c
> new file mode 100644
> index 000000000000..6569d64e0c76
> --- /dev/null
> +++ b/drivers/leds/leds-sunxi.c
> @@ -0,0 +1,562 @@
> +// SPDX-License-Identifier: GPL-2.0
> +//
> +// Copyright (c) 2021 Samuel Holland <samuel@xxxxxxxxxxxx>
> +//
> +// Partly based on drivers/leds/leds-turris-omnia.c, which is:
> +// Copyright (c) 2020 by Marek Behún <kabel@xxxxxxxxxx>
> +//
> +
> +#include <linux/clk.h>
> +#include <linux/dma-mapping.h>
> +#include <linux/dmaengine.h>
> +#include <linux/interrupt.h>
> +#include <linux/io.h>
> +#include <linux/led-class-multicolor.h>
> +#include <linux/leds.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/platform_device.h>
> +#include <linux/pm.h>
> +#include <linux/regulator/consumer.h>
> +#include <linux/reset.h>
> +#include <linux/spinlock.h>
> +
> +#define LEDC_CTRL_REG 0x0000
> +#define LEDC_CTRL_REG_DATA_LENGTH (0x1fff << 16)
> +#define LEDC_CTRL_REG_RGB_MODE (0x7 << 6)
> +#define LEDC_CTRL_REG_LEDC_EN BIT(0)
> +#define LEDC_T01_TIMING_CTRL_REG 0x0004
> +#define LEDC_T01_TIMING_CTRL_REG_T1H (0x3f << 21)
> +#define LEDC_T01_TIMING_CTRL_REG_T1L (0x1f << 16)
> +#define LEDC_T01_TIMING_CTRL_REG_T0H (0x1f << 6)
> +#define LEDC_T01_TIMING_CTRL_REG_T0L (0x3f << 0)
> +#define LEDC_RESET_TIMING_CTRL_REG 0x000c
> +#define LEDC_RESET_TIMING_CTRL_REG_LED_NUM (0x3ff << 0)
> +#define LEDC_DATA_REG 0x0014
> +#define LEDC_DMA_CTRL_REG 0x0018
> +#define LEDC_DMA_CTRL_REG_FIFO_TRIG_LEVEL (0x1f << 0)
> +#define LEDC_INT_CTRL_REG 0x001c
> +#define LEDC_INT_CTRL_REG_GLOBAL_INT_EN BIT(5)
> +#define LEDC_INT_CTRL_REG_FIFO_CPUREQ_INT_EN BIT(1)
> +#define LEDC_INT_CTRL_REG_TRANS_FINISH_INT_EN BIT(0)
> +#define LEDC_INT_STS_REG 0x0020
> +#define LEDC_INT_STS_REG_FIFO_CPUREQ_INT BIT(1)
> +#define LEDC_INT_STS_REG_TRANS_FINISH_INT BIT(0)
> +
> +#define LEDC_FIFO_DEPTH 32
> +#define LEDC_MAX_LEDS 1024
> +
> +#define LEDS_TO_BYTES(n) ((n) * sizeof(u32))
> +
> +struct sunxi_ledc_led {
> + struct led_classdev_mc mc_cdev;
> + struct mc_subled subled_info[3];
> +};
> +#define to_ledc_led(mc) container_of(mc, struct sunxi_ledc_led, mc_cdev)
> +
> +struct sunxi_ledc_timing {
> + u32 t0h_ns;
> + u32 t0l_ns;
> + u32 t1h_ns;
> + u32 t1l_ns;
> + u32 treset_ns;
> +};
> +
> +struct sunxi_ledc {
> + struct device *dev;
> + void __iomem *base;
> + struct clk *bus_clk;
> + struct clk *mod_clk;
> + struct reset_control *reset;
> + struct regulator *vled;
> +
> + u32 *buffer;
> + struct dma_chan *dma_chan;
> + dma_addr_t dma_handle;
> + int pio_length;
> + int pio_offset;
> +
> + spinlock_t lock;
> + int next_length;
> + bool xfer_active;
> +
> + u32 format;
> + struct sunxi_ledc_timing timing;
> +
> + int num_leds;
> + struct sunxi_ledc_led leds[];
> +};
> +
> +static int sunxi_ledc_dma_xfer(struct sunxi_ledc *priv, int length)
> +{
> + struct dma_async_tx_descriptor *desc;
> + dma_cookie_t cookie;
> +
> + desc = dmaengine_prep_slave_single(priv->dma_chan, priv->dma_handle,
> + LEDS_TO_BYTES(length),
> + DMA_MEM_TO_DEV, 0);
> + if (!desc)
> + return -ENOMEM;
> +
> + cookie = dmaengine_submit(desc);
> + if (dma_submit_error(cookie))
> + return -EIO;
> +
> + dma_async_issue_pending(priv->dma_chan);
> +
> + return 0;
> +}
> +
> +static void sunxi_ledc_pio_xfer(struct sunxi_ledc *priv, int length)
> +{
> + u32 burst, offset, val;
> +
> + if (length) {
> + /* New transfer (FIFO is empty). */
> + offset = 0;
> + burst = min(length, LEDC_FIFO_DEPTH);
> + } else {
> + /* Existing transfer (FIFO is half-full). */
> + length = priv->pio_length;
> + offset = priv->pio_offset;
> + burst = min(length, LEDC_FIFO_DEPTH / 2);
> + }
> +
> + writesl(priv->base + LEDC_DATA_REG, priv->buffer + offset, burst);
> +
> + if (burst < length) {
> + priv->pio_length = length - burst;
> + priv->pio_offset = offset + burst;
> +
> + if (!offset) {
> + val = readl(priv->base + LEDC_INT_CTRL_REG);
> + val |= LEDC_INT_CTRL_REG_FIFO_CPUREQ_INT_EN;
> + writel(val, priv->base + LEDC_INT_CTRL_REG);
> + }
> + } else {
> + /* Disable the request IRQ once all data is written. */
> + val = readl(priv->base + LEDC_INT_CTRL_REG);
> + val &= ~LEDC_INT_CTRL_REG_FIFO_CPUREQ_INT_EN;
> + writel(val, priv->base + LEDC_INT_CTRL_REG);
> + }
> +}
> +
> +static void sunxi_ledc_start_xfer(struct sunxi_ledc *priv, int length)
> +{
> + u32 val;
> +
> + dev_dbg(priv->dev, "Updating %d LEDs\n", length);
> +
> + val = readl(priv->base + LEDC_CTRL_REG);
> + val &= ~LEDC_CTRL_REG_DATA_LENGTH;
> + val |= length << 16 | LEDC_CTRL_REG_LEDC_EN;
> + writel(val, priv->base + LEDC_CTRL_REG);
> +
> + if (length > LEDC_FIFO_DEPTH) {
> + int ret = sunxi_ledc_dma_xfer(priv, length);
> +
> + if (!ret)
> + return;
> +
> + dev_warn(priv->dev, "Failed to set up DMA: %d\n", ret);
> + }
> +
> + sunxi_ledc_pio_xfer(priv, length);
> +}
> +
> +static irqreturn_t sunxi_ledc_irq(int irq, void *dev_id)
> +{
> + struct sunxi_ledc *priv = dev_id;
> + u32 val;
> +
> + val = readl(priv->base + LEDC_INT_STS_REG);
> +
> + if (val & LEDC_INT_STS_REG_TRANS_FINISH_INT) {
> + int next_length;
> +
> + /* Start the next transfer if needed. */
> + spin_lock(&priv->lock);
> + next_length = priv->next_length;
> + if (next_length)
> + priv->next_length = 0;
> + else
> + priv->xfer_active = false;
> + spin_unlock(&priv->lock);
> +
> + if (next_length)
> + sunxi_ledc_start_xfer(priv, next_length);
> + } else if (val & LEDC_INT_STS_REG_FIFO_CPUREQ_INT) {
> + /* Continue the current transfer. */
> + sunxi_ledc_pio_xfer(priv, 0);
> + }
> +
> + writel(val, priv->base + LEDC_INT_STS_REG);
> +
> + return IRQ_HANDLED;
> +}
> +
> +static void sunxi_ledc_brightness_set(struct led_classdev *cdev,
> + enum led_brightness brightness)
> +{
> + struct sunxi_ledc *priv = dev_get_drvdata(cdev->dev->parent);
> + struct led_classdev_mc *mc_cdev = lcdev_to_mccdev(cdev);
> + struct sunxi_ledc_led *led = to_ledc_led(mc_cdev);
> + int addr = led - priv->leds;
> + unsigned long flags;
> + bool xfer_active;
> + int next_length;
> +
> + led_mc_calc_color_components(mc_cdev, brightness);
> +
> + priv->buffer[addr] = led->subled_info[0].brightness << 16 |
> + led->subled_info[1].brightness << 8 |
> + led->subled_info[2].brightness;
> +
> + dev_dbg(priv->dev, "LED %d -> #%06x\n", addr, priv->buffer[addr]);
> +
> + spin_lock_irqsave(&priv->lock, flags);
> + next_length = max(priv->next_length, addr + 1);
> + xfer_active = priv->xfer_active;
> + if (xfer_active)
> + priv->next_length = next_length;
> + else
> + priv->xfer_active = true;
> + spin_unlock_irqrestore(&priv->lock, flags);
> +
> + if (!xfer_active)
> + sunxi_ledc_start_xfer(priv, next_length);
> +}
> +
> +static const char *const sunxi_ledc_formats[] = {
> + "rgb",
> + "rbg",
> + "grb",
> + "gbr",
> + "brg",
> + "bgr",
> +};
> +
> +static int sunxi_ledc_parse_format(const struct device_node *np,
> + struct sunxi_ledc *priv)
> +{
> + const char *format = "grb";
> + u32 i;
> +
> + of_property_read_string(np, "format", &format);
> +
> + for (i = 0; i < ARRAY_SIZE(sunxi_ledc_formats); ++i) {
> + if (!strcmp(format, sunxi_ledc_formats[i])) {
> + priv->format = i;
> + return 0;
> + }
> + }
> +
> + dev_err(priv->dev, "Bad pixel format '%s'\n", format);
> +
> + return -EINVAL;
> +}
> +
> +static void sunxi_ledc_set_format(struct sunxi_ledc *priv)
> +{
> + u32 val;
> +
> + val = readl(priv->base + LEDC_CTRL_REG);
> + val &= ~LEDC_CTRL_REG_RGB_MODE;
> + val |= priv->format << 6;
> + writel(val, priv->base + LEDC_CTRL_REG);
> +}
> +
> +static const struct sunxi_ledc_timing sunxi_ledc_default_timing = {
> + .t0h_ns = 336,
> + .t0l_ns = 840,
> + .t1h_ns = 882,
> + .t1l_ns = 294,
> + .treset_ns = 300000,
> +};
> +
> +static int sunxi_ledc_parse_timing(const struct device_node *np,
> + struct sunxi_ledc *priv)
> +{
> + struct sunxi_ledc_timing *timing = &priv->timing;
> +
> + *timing = sunxi_ledc_default_timing;
> +
> + of_property_read_u32(np, "t0h-ns", &timing->t0h_ns);
> + of_property_read_u32(np, "t0l-ns", &timing->t0l_ns);
> + of_property_read_u32(np, "t1h-ns", &timing->t1h_ns);
> + of_property_read_u32(np, "t1l-ns", &timing->t1l_ns);
> + of_property_read_u32(np, "treset-ns", &timing->treset_ns);
> +
> + return 0;
> +}
> +
> +static void sunxi_ledc_set_timing(struct sunxi_ledc *priv)
> +{
> + const struct sunxi_ledc_timing *timing = &priv->timing;
> + unsigned long mod_freq = clk_get_rate(priv->mod_clk);
> + u32 cycle_ns = NSEC_PER_SEC / mod_freq;
> + u32 val;
> +
> + val = (timing->t1h_ns / cycle_ns) << 21 |
> + (timing->t1l_ns / cycle_ns) << 16 |
> + (timing->t0h_ns / cycle_ns) << 6 |
> + (timing->t0l_ns / cycle_ns);
> + writel(val, priv->base + LEDC_T01_TIMING_CTRL_REG);
> +
> + val = (timing->treset_ns / cycle_ns) << 16 |
> + (priv->num_leds - 1);
> + writel(val, priv->base + LEDC_RESET_TIMING_CTRL_REG);
> +}
> +
> +static int sunxi_ledc_resume(struct device *dev)
> +{
> + struct sunxi_ledc *priv = dev_get_drvdata(dev);
> + u32 val;
> + int ret;
> +
> + ret = regulator_enable(priv->vled);
> + if (ret)
> + return ret;
> +
> + ret = reset_control_deassert(priv->reset);
> + if (ret)
> + goto err_disable_regulator;
> +
> + ret = clk_prepare_enable(priv->bus_clk);
> + if (ret)
> + goto err_assert_reset;
> +
> + ret = clk_prepare_enable(priv->mod_clk);
> + if (ret)
> + goto err_disable_bus_clk;
> +
> + sunxi_ledc_set_format(priv);
> + sunxi_ledc_set_timing(priv);
> +
> + /* The trigger level must be at least the burst length. */
> + val = readl(priv->base + LEDC_DMA_CTRL_REG);
> + val &= ~LEDC_DMA_CTRL_REG_FIFO_TRIG_LEVEL;
> + val |= LEDC_FIFO_DEPTH / 2;
> + writel(val, priv->base + LEDC_DMA_CTRL_REG);
> +
> + val = LEDC_INT_CTRL_REG_GLOBAL_INT_EN |
> + LEDC_INT_CTRL_REG_TRANS_FINISH_INT_EN;
> + writel(val, priv->base + LEDC_INT_CTRL_REG);
> +
> + return 0;
> +
> +err_disable_bus_clk:
> + clk_disable_unprepare(priv->bus_clk);
> +err_assert_reset:
> + reset_control_assert(priv->reset);
> +err_disable_regulator:
> + regulator_disable(priv->vled);
> +
> + return ret;
> +}
> +
> +static int sunxi_ledc_suspend(struct device *dev)
> +{
> + struct sunxi_ledc *priv = dev_get_drvdata(dev);
> +
> + clk_disable_unprepare(priv->mod_clk);
> + clk_disable_unprepare(priv->bus_clk);
> + reset_control_assert(priv->reset);
> + regulator_disable(priv->vled);
> +
> + return 0;
> +}
> +
> +static void sunxi_ledc_dma_cleanup(void *data)
> +{
> + struct sunxi_ledc *priv = data;
> + struct device *dma_dev = dmaengine_get_dma_device(priv->dma_chan);
> +
> + if (priv->buffer)
> + dma_free_wc(dma_dev, LEDS_TO_BYTES(priv->num_leds),
> + priv->buffer, priv->dma_handle);
> + dma_release_channel(priv->dma_chan);
> +}
> +
> +static int sunxi_ledc_probe(struct platform_device *pdev)
> +{
> + const struct device_node *np = pdev->dev.of_node;
> + struct dma_slave_config dma_cfg = {};
> + struct led_init_data init_data = {};
> + struct device *dev = &pdev->dev;
> + struct device_node *child;
> + struct sunxi_ledc *priv;
> + struct resource *mem;
> + int count, irq, ret;
> +
> + count = of_get_available_child_count(np);
> + if (!count)
> + return -ENODEV;
> + if (count > LEDC_MAX_LEDS) {
> + dev_err(dev, "Too many LEDs! (max is %d)\n", LEDC_MAX_LEDS);
> + return -EINVAL;
> + }
> +
> + priv = devm_kzalloc(dev, struct_size(priv, leds, count), GFP_KERNEL);
> + if (!priv)
> + return -ENOMEM;
> +
> + priv->dev = dev;
> + priv->num_leds = count;
> + spin_lock_init(&priv->lock);
> + dev_set_drvdata(dev, priv);
> +
> + ret = sunxi_ledc_parse_format(np, priv);
> + if (ret)
> + return ret;
> +
> + ret = sunxi_ledc_parse_timing(np, priv);
> + if (ret)
> + return ret;
> +
> + priv->base = devm_platform_get_and_ioremap_resource(pdev, 0, &mem);
> + if (IS_ERR(priv->base))
> + return PTR_ERR(priv->base);
> +
> + priv->bus_clk = devm_clk_get(dev, "bus");
> + if (IS_ERR(priv->bus_clk))
> + return PTR_ERR(priv->bus_clk);
> +
> + priv->mod_clk = devm_clk_get(dev, "mod");
> + if (IS_ERR(priv->mod_clk))
> + return PTR_ERR(priv->mod_clk);
> +
> + priv->reset = devm_reset_control_get_exclusive(dev, NULL);
> + if (IS_ERR(priv->reset))
> + return PTR_ERR(priv->reset);
> +
> + priv->vled = devm_regulator_get(dev, "vled");
> + if (IS_ERR(priv->vled))
> + return PTR_ERR(priv->vled);
> +
> + priv->dma_chan = dma_request_chan(dev, "tx");
> + if (IS_ERR(priv->dma_chan))
> + return PTR_ERR(priv->dma_chan);
> +
> + ret = devm_add_action_or_reset(dev, sunxi_ledc_dma_cleanup, priv);
> + if (ret)
> + return ret;
> +
> + dma_cfg.dst_addr = mem->start + LEDC_DATA_REG;
> + dma_cfg.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
> + dma_cfg.dst_maxburst = LEDC_FIFO_DEPTH / 2;
> + ret = dmaengine_slave_config(priv->dma_chan, &dma_cfg);
> + if (ret)
> + return ret;
> +
> + priv->buffer = dma_alloc_wc(dmaengine_get_dma_device(priv->dma_chan),
> + LEDS_TO_BYTES(priv->num_leds),
> + &priv->dma_handle, GFP_KERNEL);
> + if (!priv->buffer)
> + return -ENOMEM;
> +
> + irq = platform_get_irq(pdev, 0);
> + if (irq < 0)
> + return irq;
> +
> + ret = devm_request_irq(dev, irq, sunxi_ledc_irq, 0, dev_name(dev), priv);
> + if (ret)
> + return ret;

Starting here, you can get interrupts. I couldn't spot anything wrong in
the handler, but would that cause any trouble if an interrupt was coming
right here?

> + ret = sunxi_ledc_resume(dev);
> + if (ret)
> + return ret;

It's not clear to me what is done here. I assume from the rest of the
driver that you want to use runtime_pm, but it's never enabled for that
driver and the active count will be off here

Maxime

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