[PATCH v3 5/7] drm/i2c: tda9950: add CEC driver
Russell King - ARM Linux
linux at armlinux.org.uk
Fri Apr 20 15:31:37 UTC 2018
Hi Hans,
Any comments?
Thanks.
On Mon, Apr 09, 2018 at 01:16:32PM +0100, Russell King wrote:
> Add a CEC driver for the TDA9950, which is a stand-alone I2C CEC device,
> but is also integrated into HDMI transceivers such as the TDA9989 and
> TDA19989.
>
> The TDA9950 contains a command processor which handles retransmissions
> and the low level bus protocol. The driver just has to read and write
> the messages, and handle error conditions.
>
> Signed-off-by: Russell King <rmk+kernel at armlinux.org.uk>
> ---
> drivers/gpu/drm/i2c/Kconfig | 5 +
> drivers/gpu/drm/i2c/Makefile | 1 +
> drivers/gpu/drm/i2c/tda9950.c | 509 ++++++++++++++++++++++++++++++++++
> include/linux/platform_data/tda9950.h | 16 ++
> 4 files changed, 531 insertions(+)
> create mode 100644 drivers/gpu/drm/i2c/tda9950.c
> create mode 100644 include/linux/platform_data/tda9950.h
>
> diff --git a/drivers/gpu/drm/i2c/Kconfig b/drivers/gpu/drm/i2c/Kconfig
> index a6c92beb410a..3a232f5ff0a1 100644
> --- a/drivers/gpu/drm/i2c/Kconfig
> +++ b/drivers/gpu/drm/i2c/Kconfig
> @@ -26,4 +26,9 @@ config DRM_I2C_NXP_TDA998X
> help
> Support for NXP Semiconductors TDA998X HDMI encoders.
>
> +config DRM_I2C_NXP_TDA9950
> + tristate "NXP Semiconductors TDA9950/TDA998X HDMI CEC"
> + select CEC_NOTIFIER
> + select CEC_CORE
> +
> endmenu
> diff --git a/drivers/gpu/drm/i2c/Makefile b/drivers/gpu/drm/i2c/Makefile
> index b20100c18ffb..a962f6f08568 100644
> --- a/drivers/gpu/drm/i2c/Makefile
> +++ b/drivers/gpu/drm/i2c/Makefile
> @@ -7,3 +7,4 @@ obj-$(CONFIG_DRM_I2C_SIL164) += sil164.o
>
> tda998x-y := tda998x_drv.o
> obj-$(CONFIG_DRM_I2C_NXP_TDA998X) += tda998x.o
> +obj-$(CONFIG_DRM_I2C_NXP_TDA9950) += tda9950.o
> diff --git a/drivers/gpu/drm/i2c/tda9950.c b/drivers/gpu/drm/i2c/tda9950.c
> new file mode 100644
> index 000000000000..3f7396caad48
> --- /dev/null
> +++ b/drivers/gpu/drm/i2c/tda9950.c
> @@ -0,0 +1,509 @@
> +/*
> + * TDA9950 Consumer Electronics Control driver
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + *
> + * The NXP TDA9950 implements the HDMI Consumer Electronics Control
> + * interface. The host interface is similar to a mailbox: the data
> + * registers starting at REG_CDR0 are written to send a command to the
> + * internal CPU, and replies are read from these registers.
> + *
> + * As the data registers represent a mailbox, they must be accessed
> + * as a single I2C transaction. See the TDA9950 data sheet for details.
> + */
> +#include <linux/delay.h>
> +#include <linux/i2c.h>
> +#include <linux/interrupt.h>
> +#include <linux/module.h>
> +#include <linux/platform_data/tda9950.h>
> +#include <linux/slab.h>
> +#include <drm/drm_edid.h>
> +#include <media/cec.h>
> +#include <media/cec-notifier.h>
> +
> +enum {
> + REG_CSR = 0x00,
> + CSR_BUSY = BIT(7),
> + CSR_INT = BIT(6),
> + CSR_ERR = BIT(5),
> +
> + REG_CER = 0x01,
> +
> + REG_CVR = 0x02,
> +
> + REG_CCR = 0x03,
> + CCR_RESET = BIT(7),
> + CCR_ON = BIT(6),
> +
> + REG_ACKH = 0x04,
> + REG_ACKL = 0x05,
> +
> + REG_CCONR = 0x06,
> + CCONR_ENABLE_ERROR = BIT(4),
> + CCONR_RETRY_MASK = 7,
> +
> + REG_CDR0 = 0x07,
> +
> + CDR1_REQ = 0x00,
> + CDR1_CNF = 0x01,
> + CDR1_IND = 0x81,
> + CDR1_ERR = 0x82,
> + CDR1_IER = 0x83,
> +
> + CDR2_CNF_SUCCESS = 0x00,
> + CDR2_CNF_OFF_STATE = 0x80,
> + CDR2_CNF_BAD_REQ = 0x81,
> + CDR2_CNF_CEC_ACCESS = 0x82,
> + CDR2_CNF_ARB_ERROR = 0x83,
> + CDR2_CNF_BAD_TIMING = 0x84,
> + CDR2_CNF_NACK_ADDR = 0x85,
> + CDR2_CNF_NACK_DATA = 0x86,
> +};
> +
> +struct tda9950_priv {
> + struct i2c_client *client;
> + struct device *hdmi;
> + struct cec_adapter *adap;
> + struct tda9950_glue *glue;
> + u16 addresses;
> + struct cec_msg rx_msg;
> + struct cec_notifier *notify;
> + bool open;
> +};
> +
> +static int tda9950_write_range(struct i2c_client *client, u8 addr, u8 *p, int cnt)
> +{
> + struct i2c_msg msg;
> + u8 buf[cnt + 1];
> + int ret;
> +
> + buf[0] = addr;
> + memcpy(buf + 1, p, cnt);
> +
> + msg.addr = client->addr;
> + msg.flags = 0;
> + msg.len = cnt + 1;
> + msg.buf = buf;
> +
> + dev_dbg(&client->dev, "wr 0x%02x: %*ph\n", addr, cnt, p);
> +
> + ret = i2c_transfer(client->adapter, &msg, 1);
> + if (ret < 0)
> + dev_err(&client->dev, "Error %d writing to cec:0x%x\n", ret, addr);
> + return ret < 0 ? ret : 0;
> +}
> +
> +static void tda9950_write(struct i2c_client *client, u8 addr, u8 val)
> +{
> + tda9950_write_range(client, addr, &val, 1);
> +}
> +
> +static int tda9950_read_range(struct i2c_client *client, u8 addr, u8 *p, int cnt)
> +{
> + struct i2c_msg msg[2];
> + int ret;
> +
> + msg[0].addr = client->addr;
> + msg[0].flags = 0;
> + msg[0].len = 1;
> + msg[0].buf = &addr;
> + msg[1].addr = client->addr;
> + msg[1].flags = I2C_M_RD;
> + msg[1].len = cnt;
> + msg[1].buf = p;
> +
> + ret = i2c_transfer(client->adapter, msg, 2);
> + if (ret < 0)
> + dev_err(&client->dev, "Error %d reading from cec:0x%x\n", ret, addr);
> +
> + dev_dbg(&client->dev, "rd 0x%02x: %*ph\n", addr, cnt, p);
> +
> + return ret;
> +}
> +
> +static u8 tda9950_read(struct i2c_client *client, u8 addr)
> +{
> + int ret;
> + u8 val;
> +
> + ret = tda9950_read_range(client, addr, &val, 1);
> + if (ret < 0)
> + val = 0;
> +
> + return val;
> +}
> +
> +static irqreturn_t tda9950_irq(int irq, void *data)
> +{
> + struct tda9950_priv *priv = data;
> + unsigned int tx_status;
> + u8 csr, cconr, buf[19];
> + u8 arb_lost_cnt, nack_cnt, err_cnt;
> +
> + if (!priv->open)
> + return IRQ_NONE;
> +
> + csr = tda9950_read(priv->client, REG_CSR);
> + if (!(csr & CSR_INT))
> + return IRQ_NONE;
> +
> + cconr = tda9950_read(priv->client, REG_CCONR) & CCONR_RETRY_MASK;
> +
> + tda9950_read_range(priv->client, REG_CDR0, buf, sizeof(buf));
> +
> + /*
> + * This should never happen: the data sheet says that there will
> + * always be a valid message if the interrupt line is asserted.
> + */
> + if (buf[0] == 0) {
> + dev_warn(&priv->client->dev, "interrupt pending, but no message?\n");
> + return IRQ_NONE;
> + }
> +
> + switch (buf[1]) {
> + case CDR1_CNF: /* transmit result */
> + arb_lost_cnt = nack_cnt = err_cnt = 0;
> + switch (buf[2]) {
> + case CDR2_CNF_SUCCESS:
> + tx_status = CEC_TX_STATUS_OK;
> + break;
> +
> + case CDR2_CNF_ARB_ERROR:
> + tx_status = CEC_TX_STATUS_ARB_LOST;
> + arb_lost_cnt = cconr;
> + break;
> +
> + case CDR2_CNF_NACK_ADDR:
> + tx_status = CEC_TX_STATUS_NACK;
> + nack_cnt = cconr;
> + break;
> +
> + default: /* some other error, refer to TDA9950 docs */
> + dev_err(&priv->client->dev, "CNF reply error 0x%02x\n",
> + buf[2]);
> + tx_status = CEC_TX_STATUS_ERROR;
> + err_cnt = cconr;
> + break;
> + }
> + /* TDA9950 executes all retries for us */
> + tx_status |= CEC_TX_STATUS_MAX_RETRIES;
> + cec_transmit_done(priv->adap, tx_status, arb_lost_cnt,
> + nack_cnt, 0, err_cnt);
> + break;
> +
> + case CDR1_IND:
> + priv->rx_msg.len = buf[0] - 2;
> + if (priv->rx_msg.len > CEC_MAX_MSG_SIZE)
> + priv->rx_msg.len = CEC_MAX_MSG_SIZE;
> +
> + memcpy(priv->rx_msg.msg, buf + 2, priv->rx_msg.len);
> + cec_received_msg(priv->adap, &priv->rx_msg);
> + break;
> +
> + default: /* unknown */
> + dev_err(&priv->client->dev, "unknown service id 0x%02x\n",
> + buf[1]);
> + break;
> + }
> +
> + return IRQ_HANDLED;
> +}
> +
> +static int tda9950_cec_transmit(struct cec_adapter *adap, u8 attempts,
> + u32 signal_free_time, struct cec_msg *msg)
> +{
> + struct tda9950_priv *priv = adap->priv;
> + u8 buf[CEC_MAX_MSG_SIZE + 2];
> +
> + buf[0] = 2 + msg->len;
> + buf[1] = CDR1_REQ;
> + memcpy(buf + 2, msg->msg, msg->len);
> +
> + if (attempts > 5)
> + attempts = 5;
> +
> + tda9950_write(priv->client, REG_CCONR, attempts);
> +
> + return tda9950_write_range(priv->client, REG_CDR0, buf, 2 + msg->len);
> +}
> +
> +static int tda9950_cec_adap_log_addr(struct cec_adapter *adap, u8 addr)
> +{
> + struct tda9950_priv *priv = adap->priv;
> + u16 addresses;
> + u8 buf[2];
> +
> + if (addr == CEC_LOG_ADDR_INVALID)
> + addresses = priv->addresses = 0;
> + else
> + addresses = priv->addresses |= BIT(addr);
> +
> + /* TDA9950 doesn't want address 15 set */
> + addresses &= 0x7fff;
> + buf[0] = addresses >> 8;
> + buf[1] = addresses;
> +
> + return tda9950_write_range(priv->client, REG_ACKH, buf, 2);
> +}
> +
> +/*
> + * When operating as part of the TDA998x, we need additional handling
> + * to initialise and shut down the TDA9950 part of the device. These
> + * two hooks are provided to allow the TDA998x code to perform those
> + * activities.
> + */
> +static int tda9950_glue_open(struct tda9950_priv *priv)
> +{
> + int ret = 0;
> +
> + if (priv->glue && priv->glue->open)
> + ret = priv->glue->open(priv->glue->data);
> +
> + priv->open = true;
> +
> + return ret;
> +}
> +
> +static void tda9950_glue_release(struct tda9950_priv *priv)
> +{
> + priv->open = false;
> +
> + if (priv->glue && priv->glue->release)
> + priv->glue->release(priv->glue->data);
> +}
> +
> +static int tda9950_open(struct tda9950_priv *priv)
> +{
> + struct i2c_client *client = priv->client;
> + int ret;
> +
> + ret = tda9950_glue_open(priv);
> + if (ret)
> + return ret;
> +
> + /* Reset the TDA9950, and wait 250ms for it to recover */
> + tda9950_write(client, REG_CCR, CCR_RESET);
> + msleep(250);
> +
> + tda9950_cec_adap_log_addr(priv->adap, CEC_LOG_ADDR_INVALID);
> +
> + /* Start the command processor */
> + tda9950_write(client, REG_CCR, CCR_ON);
> +
> + return 0;
> +}
> +
> +static void tda9950_release(struct tda9950_priv *priv)
> +{
> + struct i2c_client *client = priv->client;
> + int timeout = 50;
> + u8 csr;
> +
> + /* Stop the command processor */
> + tda9950_write(client, REG_CCR, 0);
> +
> + /* Wait up to .5s for it to signal non-busy */
> + do {
> + csr = tda9950_read(client, REG_CSR);
> + if (!(csr & CSR_BUSY) || --timeout)
> + break;
> + msleep(10);
> + } while (1);
> +
> + /* Warn the user that their IRQ may die if it's shared. */
> + if (csr & CSR_BUSY)
> + dev_warn(&client->dev, "command processor failed to stop, irq%d may die (csr=0x%02x)\n",
> + client->irq, csr);
> +
> + tda9950_glue_release(priv);
> +}
> +
> +static int tda9950_cec_adap_enable(struct cec_adapter *adap, bool enable)
> +{
> + struct tda9950_priv *priv = adap->priv;
> +
> + if (!enable) {
> + tda9950_release(priv);
> + return 0;
> + } else {
> + return tda9950_open(priv);
> + }
> +}
> +
> +static const struct cec_adap_ops tda9950_cec_ops = {
> + .adap_enable = tda9950_cec_adap_enable,
> + .adap_log_addr = tda9950_cec_adap_log_addr,
> + .adap_transmit = tda9950_cec_transmit,
> +};
> +
> +/*
> + * When operating as part of the TDA998x, we need to claim additional
> + * resources. These two hooks permit the management of those resources.
> + */
> +static void tda9950_devm_glue_exit(void *data)
> +{
> + struct tda9950_glue *glue = data;
> +
> + if (glue && glue->exit)
> + glue->exit(glue->data);
> +}
> +
> +static int tda9950_devm_glue_init(struct device *dev, struct tda9950_glue *glue)
> +{
> + int ret;
> +
> + if (glue && glue->init) {
> + ret = glue->init(glue->data);
> + if (ret)
> + return ret;
> + }
> +
> + ret = devm_add_action(dev, tda9950_devm_glue_exit, glue);
> + if (ret)
> + tda9950_devm_glue_exit(glue);
> +
> + return ret;
> +}
> +
> +static void tda9950_cec_del(void *data)
> +{
> + struct tda9950_priv *priv = data;
> +
> + cec_delete_adapter(priv->adap);
> +}
> +
> +static int tda9950_probe(struct i2c_client *client,
> + const struct i2c_device_id *id)
> +{
> + struct tda9950_glue *glue = client->dev.platform_data;
> + struct device *dev = &client->dev;
> + struct tda9950_priv *priv;
> + unsigned long irqflags;
> + int ret;
> + u8 cvr;
> +
> + /*
> + * We must have I2C functionality: our multi-byte accesses
> + * must be performed as a single contiguous transaction.
> + */
> + if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
> + dev_err(&client->dev,
> + "adapter does not support I2C functionality\n");
> + return -ENXIO;
> + }
> +
> + /* We must have an interrupt to be functional. */
> + if (client->irq <= 0) {
> + dev_err(&client->dev, "driver requires an interrupt\n");
> + return -ENXIO;
> + }
> +
> + priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
> + if (!priv)
> + return -ENOMEM;
> +
> + priv->client = client;
> + priv->glue = glue;
> +
> + i2c_set_clientdata(client, priv);
> +
> + /*
> + * If we're part of a TDA998x, we want the class devices to be
> + * associated with the HDMI Tx so we have a tight relationship
> + * between the HDMI interface and the CEC interface.
> + */
> + priv->hdmi = dev;
> + if (glue && glue->parent)
> + priv->hdmi = glue->parent;
> +
> + priv->adap = cec_allocate_adapter(&tda9950_cec_ops, priv, "tda9950",
> + CEC_CAP_DEFAULTS,
> + CEC_MAX_LOG_ADDRS);
> + if (IS_ERR(priv->adap))
> + return PTR_ERR(priv->adap);
> +
> + ret = devm_add_action(dev, tda9950_cec_del, priv);
> + if (ret) {
> + cec_delete_adapter(priv->adap);
> + return ret;
> + }
> +
> + ret = tda9950_devm_glue_init(dev, glue);
> + if (ret)
> + return ret;
> +
> + ret = tda9950_glue_open(priv);
> + if (ret)
> + return ret;
> +
> + cvr = tda9950_read(client, REG_CVR);
> +
> + dev_info(&client->dev,
> + "TDA9950 CEC interface, hardware version %u.%u\n",
> + cvr >> 4, cvr & 15);
> +
> + tda9950_glue_release(priv);
> +
> + irqflags = IRQF_TRIGGER_FALLING;
> + if (glue)
> + irqflags = glue->irq_flags;
> +
> + ret = devm_request_threaded_irq(dev, client->irq, NULL, tda9950_irq,
> + irqflags | IRQF_SHARED | IRQF_ONESHOT,
> + dev_name(&client->dev), priv);
> + if (ret < 0)
> + return ret;
> +
> + priv->notify = cec_notifier_get(priv->hdmi);
> + if (!priv->notify)
> + return -ENOMEM;
> +
> + ret = cec_register_adapter(priv->adap, priv->hdmi);
> + if (ret < 0) {
> + cec_notifier_put(priv->notify);
> + return ret;
> + }
> +
> + /*
> + * CEC documentation says we must not call cec_delete_adapter
> + * after a successful call to cec_register_adapter().
> + */
> + devm_remove_action(dev, tda9950_cec_del, priv);
> +
> + cec_register_cec_notifier(priv->adap, priv->notify);
> +
> + return 0;
> +}
> +
> +static int tda9950_remove(struct i2c_client *client)
> +{
> + struct tda9950_priv *priv = i2c_get_clientdata(client);
> +
> + cec_unregister_adapter(priv->adap);
> + cec_notifier_put(priv->notify);
> +
> + return 0;
> +}
> +
> +static struct i2c_device_id tda9950_ids[] = {
> + { "tda9950", 0 },
> + { },
> +};
> +MODULE_DEVICE_TABLE(i2c, tda9950_ids);
> +
> +static struct i2c_driver tda9950_driver = {
> + .probe = tda9950_probe,
> + .remove = tda9950_remove,
> + .driver = {
> + .name = "tda9950",
> + },
> + .id_table = tda9950_ids,
> +};
> +
> +module_i2c_driver(tda9950_driver);
> +
> +MODULE_AUTHOR("Russell King <rmk+kernel at armlinux.org.uk>");
> +MODULE_DESCRIPTION("TDA9950/TDA998x Consumer Electronics Control Driver");
> +MODULE_LICENSE("GPL v2");
> diff --git a/include/linux/platform_data/tda9950.h b/include/linux/platform_data/tda9950.h
> new file mode 100644
> index 000000000000..c65efd461102
> --- /dev/null
> +++ b/include/linux/platform_data/tda9950.h
> @@ -0,0 +1,16 @@
> +#ifndef LINUX_PLATFORM_DATA_TDA9950_H
> +#define LINUX_PLATFORM_DATA_TDA9950_H
> +
> +struct device;
> +
> +struct tda9950_glue {
> + struct device *parent;
> + unsigned long irq_flags;
> + void *data;
> + int (*init)(void *);
> + void (*exit)(void *);
> + int (*open)(void *);
> + void (*release)(void *);
> +};
> +
> +#endif
> --
> 2.7.4
>
--
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