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 <hans.verkuil@cisco.com>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>

2 files changed, 187 insertions, 9 deletions

diff --git a/drivers/gpu/drm/i2c/Kconfig b/drivers/gpu/drm/i2c/Kconfig
index 3a232f5ff0a1..65d3acb61c03 100644
--- a/drivers/gpu/drm/i2c/Kconfig
+++ b/drivers/gpu/drm/i2c/Kconfig
@@ -22,6 +22,7 @@ config DRM_I2C_SIL164
 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.
diff --git a/drivers/gpu/drm/i2c/tda998x_drv.c b/drivers/gpu/drm/i2c/tda998x_drv.c
index 16e0439cad44..eb9916bd84a4 100644
--- a/drivers/gpu/drm/i2c/tda998x_drv.c
+++ b/drivers/gpu/drm/i2c/tda998x_drv.c
@@ -16,8 +16,10 @@
  */
 
 #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>
@@ -29,6 +31,8 @@
 #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 tda998x_audio_port {
@@ -55,6 +59,7 @@ struct tda998x_priv {
         struct platform_device *audio_pdev;
         struct mutex audio_mutex;
 
+        struct mutex edid_mutex;
         wait_queue_head_t wq_edid;
         volatile int wq_edid_wait;
 
@@ -67,6 +72,9 @@ struct tda998x_priv {
         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) \
@@ -345,6 +353,12 @@ struct tda998x_priv {
 #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)
@@ -359,6 +373,7 @@ struct tda998x_priv {
 # 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)
@@ -417,6 +432,114 @@ cec_read(struct tda998x_priv *priv, u8 addr)
         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
 set_page(struct tda998x_priv *priv, u16 reg)
 {
@@ -657,10 +780,13 @@ static irqreturn_t tda998x_irq_thread(int irq, void *data)
                         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;
                 }
@@ -981,6 +1107,8 @@ static int tda998x_connector_fill_modes(struct drm_connector *connector,
         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;
@@ -1024,6 +1152,8 @@ static int read_edid_block(void *data, u8 *buf, unsigned int blk, size_t length)
         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);
@@ -1043,14 +1173,15 @@ static int read_edid_block(void *data, u8 *buf, unsigned int blk, size_t length)
                                         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;
                 }
@@ -1058,17 +1189,22 @@ static int read_edid_block(void *data, u8 *buf, unsigned int blk, size_t length)
 
         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)
@@ -1423,6 +1559,9 @@ static void tda998x_destroy(struct tda998x_priv *priv)
         cancel_work_sync(&priv->detect_work);
 
         i2c_unregister_device(priv->cec);
+
+        if (priv->cec_notify)
+                cec_notifier_put(priv->cec_notify);
 }
 
 /* I2C driver functions */
@@ -1472,11 +1611,13 @@ static int tda998x_get_audio_ports(struct tda998x_priv *priv,
 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);
@@ -1564,6 +1705,9 @@ static int tda998x_create(struct i2c_client *client, struct tda998x_priv *priv)
 
                 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,
@@ -1579,7 +1723,34 @@ static int tda998x_create(struct i2c_client *client, struct tda998x_priv *priv)
                 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;
@@ -1609,10 +1780,16 @@ static int tda998x_create(struct i2c_client *client, struct tda998x_priv *priv)
         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;
 }