--- /dev/null
+/*
+ * drivers/staging/media/st-cec/stih-cec.c
+ *
+ * STIH4xx CEC driver
+ * Copyright (C) STMicroelectronic SA 2016
+ *
+ * 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, or
+ * (at your option) any later version.
+ */
+#include <linux/clk.h>
+#include <linux/interrupt.h>
+#include <linux/kernel.h>
+#include <linux/mfd/syscon.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/version.h>
+
+#include <media/cec.h>
+
+#define CEC_NAME "stih-cec"
+
+/* CEC registers */
+#define CEC_CLK_DIV 0x0
+#define CEC_CTRL 0x4
+#define CEC_IRQ_CTRL 0x8
+#define CEC_STATUS 0xC
+#define CEC_EXT_STATUS 0x10
+#define CEC_TX_CTRL 0x14
+#define CEC_FREE_TIME_THRESH 0x18
+#define CEC_BIT_TOUT_THRESH 0x1C
+#define CEC_BIT_PULSE_THRESH 0x20
+#define CEC_DATA 0x24
+#define CEC_TX_ARRAY_CTRL 0x28
+#define CEC_CTRL2 0x2C
+#define CEC_TX_ERROR_STS 0x30
+#define CEC_ADDR_TABLE 0x34
+#define CEC_DATA_ARRAY_CTRL 0x38
+#define CEC_DATA_ARRAY_STATUS 0x3C
+#define CEC_TX_DATA_BASE 0x40
+#define CEC_TX_DATA_TOP 0x50
+#define CEC_TX_DATA_SIZE 0x1
+#define CEC_RX_DATA_BASE 0x54
+#define CEC_RX_DATA_TOP 0x64
+#define CEC_RX_DATA_SIZE 0x1
+
+/* CEC_CTRL2 */
+#define CEC_LINE_INACTIVE_EN BIT(0)
+#define CEC_AUTO_BUS_ERR_EN BIT(1)
+#define CEC_STOP_ON_ARB_ERR_EN BIT(2)
+#define CEC_TX_REQ_WAIT_EN BIT(3)
+
+/* CEC_DATA_ARRAY_CTRL */
+#define CEC_TX_ARRAY_EN BIT(0)
+#define CEC_RX_ARRAY_EN BIT(1)
+#define CEC_TX_ARRAY_RESET BIT(2)
+#define CEC_RX_ARRAY_RESET BIT(3)
+#define CEC_TX_N_OF_BYTES_IRQ_EN BIT(4)
+#define CEC_TX_STOP_ON_NACK BIT(7)
+
+/* CEC_TX_ARRAY_CTRL */
+#define CEC_TX_N_OF_BYTES 0x1F
+#define CEC_TX_START BIT(5)
+#define CEC_TX_AUTO_SOM_EN BIT(6)
+#define CEC_TX_AUTO_EOM_EN BIT(7)
+
+/* CEC_IRQ_CTRL */
+#define CEC_TX_DONE_IRQ_EN BIT(0)
+#define CEC_ERROR_IRQ_EN BIT(2)
+#define CEC_RX_DONE_IRQ_EN BIT(3)
+#define CEC_RX_SOM_IRQ_EN BIT(4)
+#define CEC_RX_EOM_IRQ_EN BIT(5)
+#define CEC_FREE_TIME_IRQ_EN BIT(6)
+#define CEC_PIN_STS_IRQ_EN BIT(7)
+
+/* CEC_CTRL */
+#define CEC_IN_FILTER_EN BIT(0)
+#define CEC_PWR_SAVE_EN BIT(1)
+#define CEC_EN BIT(4)
+#define CEC_ACK_CTRL BIT(5)
+#define CEC_RX_RESET_EN BIT(6)
+#define CEC_IGNORE_RX_ERROR BIT(7)
+
+/* CEC_STATUS */
+#define CEC_TX_DONE_STS BIT(0)
+#define CEC_TX_ACK_GET_STS BIT(1)
+#define CEC_ERROR_STS BIT(2)
+#define CEC_RX_DONE_STS BIT(3)
+#define CEC_RX_SOM_STS BIT(4)
+#define CEC_RX_EOM_STS BIT(5)
+#define CEC_FREE_TIME_IRQ_STS BIT(6)
+#define CEC_PIN_STS BIT(7)
+#define CEC_SBIT_TOUT_STS BIT(8)
+#define CEC_DBIT_TOUT_STS BIT(9)
+#define CEC_LPULSE_ERROR_STS BIT(10)
+#define CEC_HPULSE_ERROR_STS BIT(11)
+#define CEC_TX_ERROR BIT(12)
+#define CEC_TX_ARB_ERROR BIT(13)
+#define CEC_RX_ERROR_MIN BIT(14)
+#define CEC_RX_ERROR_MAX BIT(15)
+
+/* Signal free time in bit periods (2.4ms) */
+#define CEC_PRESENT_INIT_SFT 7
+#define CEC_NEW_INIT_SFT 5
+#define CEC_RETRANSMIT_SFT 3
+
+/* Constants for CEC_BIT_TOUT_THRESH register */
+#define CEC_SBIT_TOUT_47MS BIT(1)
+#define CEC_SBIT_TOUT_48MS BIT(0) | BIT(1)
+#define CEC_SBIT_TOUT_50MS BIT(2)
+#define CEC_DBIT_TOUT_27MS BIT(0)
+#define CEC_DBIT_TOUT_28MS BIT(1)
+#define CEC_DBIT_TOUT_29MS BIT(0) | BIT(1)
+
+/* Constants for CEC_BIT_PULSE_THRESH register */
+#define CEC_BIT_LPULSE_03MS BIT(1)
+#define CEC_BIT_HPULSE_03MS BIT(3)
+
+/* Constants for CEC_DATA_ARRAY_STATUS register */
+#define CEC_RX_N_OF_BYTES 0x1F
+#define CEC_TX_N_OF_BYTES_SENT BIT(5)
+#define CEC_RX_OVERRUN BIT(6)
+
+struct stih_cec {
+ struct cec_adapter *adap;
+ struct device *dev;
+ struct clk *clk;
+ void __iomem *regs;
+ int irq;
+ u32 irq_status;
+};
+
+static int stih_cec_adap_enable(struct cec_adapter *adap, bool enable)
+{
+ struct stih_cec *cec = adap->priv;
+
+ if (enable) {
+ /* The doc says (input TCLK_PERIOD * CEC_CLK_DIV) = 0.1ms */
+ unsigned long clk_freq = clk_get_rate(cec->clk);
+ u32 cec_clk_div = clk_freq / 10000;
+
+ writel(cec_clk_div, cec->regs + CEC_CLK_DIV);
+
+ /* Configuration of the durations activating a timeout */
+ writel(CEC_SBIT_TOUT_47MS | (CEC_DBIT_TOUT_28MS << 4),
+ cec->regs + CEC_BIT_TOUT_THRESH);
+
+ /* Configuration of the smallest allowed duration for pulses */
+ writel(CEC_BIT_LPULSE_03MS | CEC_BIT_HPULSE_03MS,
+ cec->regs + CEC_BIT_PULSE_THRESH);
+
+ /* Minimum received bit period threshold */
+ writel(BIT(5) | BIT(7), cec->regs + CEC_TX_CTRL);
+
+ /* Configuration of transceiver data arrays */
+ writel(CEC_TX_ARRAY_EN | CEC_RX_ARRAY_EN | CEC_TX_STOP_ON_NACK,
+ cec->regs + CEC_DATA_ARRAY_CTRL);
+
+ /* Configuration of the control bits for CEC Transceiver */
+ writel(CEC_IN_FILTER_EN | CEC_EN | CEC_RX_RESET_EN,
+ cec->regs + CEC_CTRL);
+
+ /* Clear logical addresses */
+ writel(0, cec->regs + CEC_ADDR_TABLE);
+
+ /* Clear the status register */
+ writel(0x0, cec->regs + CEC_STATUS);
+
+ /* Enable the interrupts */
+ writel(CEC_TX_DONE_IRQ_EN | CEC_RX_DONE_IRQ_EN |
+ CEC_RX_SOM_IRQ_EN | CEC_RX_EOM_IRQ_EN |
+ CEC_ERROR_IRQ_EN,
+ cec->regs + CEC_IRQ_CTRL);
+
+ } else {
+ /* Clear logical addresses */
+ writel(0, cec->regs + CEC_ADDR_TABLE);
+
+ /* Clear the status register */
+ writel(0x0, cec->regs + CEC_STATUS);
+
+ /* Disable the interrupts */
+ writel(0, cec->regs + CEC_IRQ_CTRL);
+ }
+
+ return 0;
+}
+
+static int stih_cec_adap_log_addr(struct cec_adapter *adap, u8 logical_addr)
+{
+ struct stih_cec *cec = adap->priv;
+ u32 reg = readl(cec->regs + CEC_ADDR_TABLE);
+
+ reg |= 1 << logical_addr;
+
+ if (logical_addr == CEC_LOG_ADDR_INVALID)
+ reg = 0;
+
+ writel(reg, cec->regs + CEC_ADDR_TABLE);
+
+ return 0;
+}
+
+static int stih_cec_adap_transmit(struct cec_adapter *adap, u8 attempts,
+ u32 signal_free_time, struct cec_msg *msg)
+{
+ struct stih_cec *cec = adap->priv;
+ int i;
+
+ /* Copy message into registers */
+ for (i = 0; i < msg->len; i++)
+ writeb(msg->msg[i], cec->regs + CEC_TX_DATA_BASE + i);
+
+ /* Start transmission, configure hardware to add start and stop bits
+ * Signal free time is handled by the hardware
+ */
+ writel(CEC_TX_AUTO_SOM_EN | CEC_TX_AUTO_EOM_EN | CEC_TX_START |
+ msg->len, cec->regs + CEC_TX_ARRAY_CTRL);
+
+ return 0;
+}
+
+static void stih_tx_done(struct stih_cec *cec, u32 status)
+{
+ if (status & CEC_TX_ERROR) {
+ cec_transmit_done(cec->adap, CEC_TX_STATUS_ERROR, 0, 0, 0, 1);
+ return;
+ }
+
+ if (status & CEC_TX_ARB_ERROR) {
+ cec_transmit_done(cec->adap,
+ CEC_TX_STATUS_ARB_LOST, 1, 0, 0, 0);
+ return;
+ }
+
+ if (!(status & CEC_TX_ACK_GET_STS)) {
+ cec_transmit_done(cec->adap, CEC_TX_STATUS_NACK, 0, 1, 0, 0);
+ return;
+ }
+
+ cec_transmit_done(cec->adap, CEC_TX_STATUS_OK, 0, 0, 0, 0);
+}
+
+static void stih_rx_done(struct stih_cec *cec, u32 status)
+{
+ struct cec_msg msg = {};
+ u8 i;
+
+ if (status & CEC_RX_ERROR_MIN)
+ return;
+
+ if (status & CEC_RX_ERROR_MAX)
+ return;
+
+ msg.len = readl(cec->regs + CEC_DATA_ARRAY_STATUS) & 0x1f;
+
+ if (!msg.len)
+ return;
+
+ if (msg.len > 16)
+ msg.len = 16;
+
+ for (i = 0; i < msg.len; i++)
+ msg.msg[i] = readl(cec->regs + CEC_RX_DATA_BASE + i);
+
+ cec_received_msg(cec->adap, &msg);
+}
+
+static irqreturn_t stih_cec_irq_handler_thread(int irq, void *priv)
+{
+ struct stih_cec *cec = priv;
+
+ if (cec->irq_status & CEC_TX_DONE_STS)
+ stih_tx_done(cec, cec->irq_status);
+
+ if (cec->irq_status & CEC_RX_DONE_STS)
+ stih_rx_done(cec, cec->irq_status);
+
+ cec->irq_status = 0;
+
+ return IRQ_HANDLED;
+}
+
+static irqreturn_t stih_cec_irq_handler(int irq, void *priv)
+{
+ struct stih_cec *cec = priv;
+
+ cec->irq_status = readl(cec->regs + CEC_STATUS);
+ writel(cec->irq_status, cec->regs + CEC_STATUS);
+
+ return IRQ_WAKE_THREAD;
+}
+
+static const struct cec_adap_ops sti_cec_adap_ops = {
+ .adap_enable = stih_cec_adap_enable,
+ .adap_log_addr = stih_cec_adap_log_addr,
+ .adap_transmit = stih_cec_adap_transmit,
+};
+
+static int stih_cec_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct resource *res;
+ struct stih_cec *cec;
+ int ret;
+
+ cec = devm_kzalloc(dev, sizeof(*cec), GFP_KERNEL);
+ if (!cec)
+ return -ENOMEM;
+
+ cec->dev = dev;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ cec->regs = devm_ioremap_resource(dev, res);
+ if (IS_ERR(cec->regs))
+ return PTR_ERR(cec->regs);
+
+ cec->irq = platform_get_irq(pdev, 0);
+ if (cec->irq < 0)
+ return cec->irq;
+
+ ret = devm_request_threaded_irq(dev, cec->irq, stih_cec_irq_handler,
+ stih_cec_irq_handler_thread, 0,
+ pdev->name, cec);
+ if (ret)
+ return ret;
+
+ cec->clk = devm_clk_get(dev, "cec-clk");
+ if (IS_ERR(cec->clk)) {
+ dev_err(dev, "Cannot get cec clock\n");
+ return PTR_ERR(cec->clk);
+ }
+
+ cec->adap = cec_allocate_adapter(&sti_cec_adap_ops, cec,
+ CEC_NAME,
+ CEC_CAP_LOG_ADDRS | CEC_CAP_PASSTHROUGH |
+ CEC_CAP_PHYS_ADDR | CEC_CAP_TRANSMIT,
+ 1, &pdev->dev);
+ ret = PTR_ERR_OR_ZERO(cec->adap);
+ if (ret)
+ return ret;
+
+ ret = cec_register_adapter(cec->adap);
+ if (ret) {
+ cec_delete_adapter(cec->adap);
+ return ret;
+ }
+
+ platform_set_drvdata(pdev, cec);
+ return 0;
+}
+
+static int stih_cec_remove(struct platform_device *pdev)
+{
+ return 0;
+}
+
+static const struct of_device_id stih_cec_match[] = {
+ {
+ .compatible = "st,stih-cec",
+ },
+ {},
+};
+
+static struct platform_driver stih_cec_pdrv = {
+ .probe = stih_cec_probe,
+ .remove = stih_cec_remove,
+ .driver = {
+ .name = CEC_NAME,
+ .of_match_table = stih_cec_match,
+ },
+};
+
+module_platform_driver(stih_cec_pdrv);
+
+MODULE_AUTHOR("Benjamin Gaignard <benjamin.gaignard@linaro.org>");
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("STIH4xx CEC driver");
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