drm/i2c: tda998x: add CEC support

The TDA998x is a HDMI transmitter with a TDA9950 CEC engine integrated
onto the same die. Add support for the TDA9950 CEC engine to the
TDA998x driver.

Reviewed-by: Hans Verkuil <[e-mail]>
Signed-off-by: Russell King <[e-mail]>

drivers/gpu/drm/i2c/Kconfig

···
 config DRM_I2C_NXP_TDA998X
 	tristate "NXP Semiconductors TDA998X HDMI encoder"
 	default m if DRM_TILCDC
+	select CEC_CORE if CEC_NOTIFIER
 	select SND_SOC_HDMI_CODEC if SND_SOC
 	help
 	  Support for NXP Semiconductors TDA998X HDMI encoders.

drivers/gpu/drm/i2c/tda998x_drv.c

···
  */
 
 #include <linux/component.h>
+#include <linux/gpio/consumer.h>
 #include <linux/hdmi.h>
 #include <linux/module.h>
+#include <linux/platform_data/tda9950.h>
 #include <linux/irq.h>
 #include <sound/asoundef.h>
 #include <sound/hdmi-codec.h>
···
 #include <drm/drm_edid.h>
 #include <drm/drm_of.h>
 #include <drm/i2c/tda998x.h>
+
+#include <media/cec-notifier.h>
 
 #define DBG(fmt, ...) DRM_DEBUG(fmt"\n", ##__VA_ARGS__)
 
···
 	struct platform_device *audio_pdev;
 	struct mutex audio_mutex;
 
+	struct mutex edid_mutex;
 	wait_queue_head_t wq_edid;
 	volatile int wq_edid_wait;
 
···
 	struct drm_connector connector;
 
 	struct tda998x_audio_port audio_port[2];
+	struct tda9950_glue cec_glue;
+	struct gpio_desc *calib;
+	struct cec_notifier *cec_notify;
 };
 
 #define conn_to_tda998x_priv(x) \
···
 #define REG_CEC_INTSTATUS	  0xee		      /* read */
 # define CEC_INTSTATUS_CEC	  (1 << 0)
 # define CEC_INTSTATUS_HDMI	  (1 << 1)
+#define REG_CEC_CAL_XOSC_CTRL1    0xf2
+# define CEC_CAL_XOSC_CTRL1_ENA_CAL	BIT(0)
+#define REG_CEC_DES_FREQ2         0xf5
+# define CEC_DES_FREQ2_DIS_AUTOCAL BIT(7)
+#define REG_CEC_CLK               0xf6
+# define CEC_CLK_FRO              0x11
 #define REG_CEC_FRO_IM_CLK_CTRL   0xfb                /* read/write */
 # define CEC_FRO_IM_CLK_CTRL_GHOST_DIS (1 << 7)
 # define CEC_FRO_IM_CLK_CTRL_ENA_OTP   (1 << 6)
···
 # define CEC_RXSHPDLEV_HPD        (1 << 1)
 
 #define REG_CEC_ENAMODS           0xff                /* read/write */
+# define CEC_ENAMODS_EN_CEC_CLK   (1 << 7)
 # define CEC_ENAMODS_DIS_FRO      (1 << 6)
 # define CEC_ENAMODS_DIS_CCLK     (1 << 5)
 # define CEC_ENAMODS_EN_RXSENS    (1 << 2)
···
 	}
 
 	return val;
+}
+
+static void cec_enamods(struct tda998x_priv *priv, u8 mods, bool enable)
+{
+	int val = cec_read(priv, REG_CEC_ENAMODS);
+
+	if (val < 0)
+		return;
+
+	if (enable)
+		val |= mods;
+	else
+		val &= ~mods;
+
+	cec_write(priv, REG_CEC_ENAMODS, val);
+}
+
+static void tda998x_cec_set_calibration(struct tda998x_priv *priv, bool enable)
+{
+	if (enable) {
+		u8 val;
+
+		cec_write(priv, 0xf3, 0xc0);
+		cec_write(priv, 0xf4, 0xd4);
+
+		/* Enable automatic calibration mode */
+		val = cec_read(priv, REG_CEC_DES_FREQ2);
+		val &= ~CEC_DES_FREQ2_DIS_AUTOCAL;
+		cec_write(priv, REG_CEC_DES_FREQ2, val);
+
+		/* Enable free running oscillator */
+		cec_write(priv, REG_CEC_CLK, CEC_CLK_FRO);
+		cec_enamods(priv, CEC_ENAMODS_DIS_FRO, false);
+
+		cec_write(priv, REG_CEC_CAL_XOSC_CTRL1,
+			  CEC_CAL_XOSC_CTRL1_ENA_CAL);
+	} else {
+		cec_write(priv, REG_CEC_CAL_XOSC_CTRL1, 0);
+	}
+}
+
+/*
+ * Calibration for the internal oscillator: we need to set calibration mode,
+ * and then pulse the IRQ line low for a 10ms ± 1% period.
+ */
+static void tda998x_cec_calibration(struct tda998x_priv *priv)
+{
+	struct gpio_desc *calib = priv->calib;
+
+	mutex_lock(&priv->edid_mutex);
+	if (priv->hdmi->irq > 0)
+		disable_irq(priv->hdmi->irq);
+	gpiod_direction_output(calib, 1);
+	tda998x_cec_set_calibration(priv, true);
+
+	local_irq_disable();
+	gpiod_set_value(calib, 0);
+	mdelay(10);
+	gpiod_set_value(calib, 1);
+	local_irq_enable();
+
+	tda998x_cec_set_calibration(priv, false);
+	gpiod_direction_input(calib);
+	if (priv->hdmi->irq > 0)
+		enable_irq(priv->hdmi->irq);
+	mutex_unlock(&priv->edid_mutex);
+}
+
+static int tda998x_cec_hook_init(void *data)
+{
+	struct tda998x_priv *priv = data;
+	struct gpio_desc *calib;
+
+	calib = gpiod_get(&priv->hdmi->dev, "nxp,calib", GPIOD_ASIS);
+	if (IS_ERR(calib)) {
+		dev_warn(&priv->hdmi->dev, "failed to get calibration gpio: %ld\n",
+			 PTR_ERR(calib));
+		return PTR_ERR(calib);
+	}
+
+	priv->calib = calib;
+
+	return 0;
+}
+
+static void tda998x_cec_hook_exit(void *data)
+{
+	struct tda998x_priv *priv = data;
+
+	gpiod_put(priv->calib);
+	priv->calib = NULL;
+}
+
+static int tda998x_cec_hook_open(void *data)
+{
+	struct tda998x_priv *priv = data;
+
+	cec_enamods(priv, CEC_ENAMODS_EN_CEC_CLK | CEC_ENAMODS_EN_CEC, true);
+	tda998x_cec_calibration(priv);
+
+	return 0;
+}
+
+static void tda998x_cec_hook_release(void *data)
+{
+	struct tda998x_priv *priv = data;
+
+	cec_enamods(priv, CEC_ENAMODS_EN_CEC_CLK | CEC_ENAMODS_EN_CEC, false);
 }
 
 static int
···
 			sta, cec, lvl, flag0, flag1, flag2);
 
 		if (cec & CEC_RXSHPDINT_HPD) {
-			if (lvl & CEC_RXSHPDLEV_HPD)
+			if (lvl & CEC_RXSHPDLEV_HPD) {
 				tda998x_edid_delay_start(priv);
-			else
+			} else {
 				schedule_work(&priv->detect_work);
+				cec_notifier_set_phys_addr(priv->cec_notify,
+						   CEC_PHYS_ADDR_INVALID);
+			}
 
 			handled = true;
 		}
···
 	if (connector->edid_blob_ptr) {
 		struct edid *edid = (void *)connector->edid_blob_ptr->data;
 
+		cec_notifier_set_phys_addr_from_edid(priv->cec_notify, edid);
+
 		priv->sink_has_audio = drm_detect_monitor_audio(edid);
 	} else {
 		priv->sink_has_audio = false;
···
 	offset = (blk & 1) ? 128 : 0;
 	segptr = blk / 2;
 
+	mutex_lock(&priv->edid_mutex);
+
 	reg_write(priv, REG_DDC_ADDR, 0xa0);
 	reg_write(priv, REG_DDC_OFFS, offset);
 	reg_write(priv, REG_DDC_SEGM_ADDR, 0x60);
···
 					msecs_to_jiffies(100));
 		if (i < 0) {
 			dev_err(&priv->hdmi->dev, "read edid wait err %d\n", i);
-			return i;
+			ret = i;
+			goto failed;
 		}
 	} else {
 		for (i = 100; i > 0; i--) {
 			msleep(1);
 			ret = reg_read(priv, REG_INT_FLAGS_2);
 			if (ret < 0)
-				return ret;
+				goto failed;
 			if (ret & INT_FLAGS_2_EDID_BLK_RD)
 				break;
 		}
···
 
 	if (i == 0) {
 		dev_err(&priv->hdmi->dev, "read edid timeout\n");
-		return -ETIMEDOUT;
+		ret = -ETIMEDOUT;
+		goto failed;
 	}
 
 	ret = reg_read_range(priv, REG_EDID_DATA_0, buf, length);
 	if (ret != length) {
 		dev_err(&priv->hdmi->dev, "failed to read edid block %d: %d\n",
 			blk, ret);
-		return ret;
+		goto failed;
 	}
 
-	return 0;
+	ret = 0;
+
+ failed:
+	mutex_unlock(&priv->edid_mutex);
+	return ret;
 }
 
 static int tda998x_connector_get_modes(struct drm_connector *connector)
···
 	cancel_work_sync(&priv->detect_work);
 
 	i2c_unregister_device(priv->cec);
+
+	if (priv->cec_notify)
+		cec_notifier_put(priv->cec_notify);
 }
 
 /* I2C driver functions */
···
 static int tda998x_create(struct i2c_client *client, struct tda998x_priv *priv)
 {
 	struct device_node *np = client->dev.of_node;
+	struct i2c_board_info cec_info;
 	u32 video;
 	int rev_lo, rev_hi, ret;
 
 	mutex_init(&priv->mutex);	/* protect the page access */
 	mutex_init(&priv->audio_mutex); /* protect access from audio thread */
+	mutex_init(&priv->edid_mutex);
 	init_waitqueue_head(&priv->edid_delay_waitq);
 	timer_setup(&priv->edid_delay_timer, tda998x_edid_delay_done, 0);
 	INIT_WORK(&priv->detect_work, tda998x_detect_work);
···
 
 		irq_flags =
 			irqd_get_trigger_type(irq_get_irq_data(client->irq));
+
+		priv->cec_glue.irq_flags = irq_flags;
+
 		irq_flags |= IRQF_SHARED | IRQF_ONESHOT;
 		ret = request_threaded_irq(client->irq, NULL,
 					   tda998x_irq_thread, irq_flags,
···
 		cec_write(priv, REG_CEC_RXSHPDINTENA, CEC_RXSHPDLEV_HPD);
 	}
 
-	priv->cec = i2c_new_dummy(client->adapter, priv->cec_addr);
+	priv->cec_notify = cec_notifier_get(&client->dev);
+	if (!priv->cec_notify) {
+		ret = -ENOMEM;
+		goto fail;
+	}
+
+	priv->cec_glue.parent = &client->dev;
+	priv->cec_glue.data = priv;
+	priv->cec_glue.init = tda998x_cec_hook_init;
+	priv->cec_glue.exit = tda998x_cec_hook_exit;
+	priv->cec_glue.open = tda998x_cec_hook_open;
+	priv->cec_glue.release = tda998x_cec_hook_release;
+
+	/*
+	 * Some TDA998x are actually two I2C devices merged onto one piece
+	 * of silicon: TDA9989 and TDA19989 combine the HDMI transmitter
+	 * with a slightly modified TDA9950 CEC device.  The CEC device
+	 * is at the TDA9950 address, with the address pins strapped across
+	 * to the TDA998x address pins.  Hence, it always has the same
+	 * offset.
+	 */
+	memset(&cec_info, 0, sizeof(cec_info));
+	strlcpy(cec_info.type, "tda9950", sizeof(cec_info.type));
+	cec_info.addr = priv->cec_addr;
+	cec_info.platform_data = &priv->cec_glue;
+	cec_info.irq = client->irq;
+
+	priv->cec = i2c_new_device(client->adapter, &cec_info);
 	if (!priv->cec) {
 		ret = -ENODEV;
 		goto fail;
···
 	return 0;
 
 fail:
+	/* if encoder_init fails, the encoder slave is never registered,
+	 * so cleanup here:
+	 */
+	if (priv->cec)
+		i2c_unregister_device(priv->cec);
+	if (priv->cec_notify)
+		cec_notifier_put(priv->cec_notify);
 	if (client->irq)
 		free_irq(client->irq, priv);
 err_irq:
-	i2c_unregister_device(priv->cec);
 	return ret;
 }