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Diffstat (limited to 'drivers/i2c/busses/i2c-designware-slave.c')
-rw-r--r--drivers/i2c/busses/i2c-designware-slave.c296
1 files changed, 296 insertions, 0 deletions
diff --git a/drivers/i2c/busses/i2c-designware-slave.c b/drivers/i2c/busses/i2c-designware-slave.c
new file mode 100644
index 000000000..0d15f4c1e
--- /dev/null
+++ b/drivers/i2c/busses/i2c-designware-slave.c
@@ -0,0 +1,296 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Synopsys DesignWare I2C adapter driver (slave only).
+ *
+ * Based on the Synopsys DesignWare I2C adapter driver (master).
+ *
+ * Copyright (C) 2016 Synopsys Inc.
+ */
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/errno.h>
+#include <linux/i2c.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/pm_runtime.h>
+#include <linux/regmap.h>
+
+#include "i2c-designware-core.h"
+
+static void i2c_dw_configure_fifo_slave(struct dw_i2c_dev *dev)
+{
+ /* Configure Tx/Rx FIFO threshold levels. */
+ regmap_write(dev->map, DW_IC_TX_TL, 0);
+ regmap_write(dev->map, DW_IC_RX_TL, 0);
+
+ /* Configure the I2C slave. */
+ regmap_write(dev->map, DW_IC_CON, dev->slave_cfg);
+ regmap_write(dev->map, DW_IC_INTR_MASK, DW_IC_INTR_SLAVE_MASK);
+}
+
+/**
+ * i2c_dw_init_slave() - Initialize the designware i2c slave hardware
+ * @dev: device private data
+ *
+ * This function configures and enables the I2C in slave mode.
+ * This function is called during I2C init function, and in case of timeout at
+ * run time.
+ */
+static int i2c_dw_init_slave(struct dw_i2c_dev *dev)
+{
+ int ret;
+
+ ret = i2c_dw_acquire_lock(dev);
+ if (ret)
+ return ret;
+
+ /* Disable the adapter. */
+ __i2c_dw_disable(dev);
+
+ /* Write SDA hold time if supported */
+ if (dev->sda_hold_time)
+ regmap_write(dev->map, DW_IC_SDA_HOLD, dev->sda_hold_time);
+
+ i2c_dw_configure_fifo_slave(dev);
+ i2c_dw_release_lock(dev);
+
+ return 0;
+}
+
+static int i2c_dw_reg_slave(struct i2c_client *slave)
+{
+ struct dw_i2c_dev *dev = i2c_get_adapdata(slave->adapter);
+
+ if (dev->slave)
+ return -EBUSY;
+ if (slave->flags & I2C_CLIENT_TEN)
+ return -EAFNOSUPPORT;
+ pm_runtime_get_sync(dev->dev);
+
+ /*
+ * Set slave address in the IC_SAR register,
+ * the address to which the DW_apb_i2c responds.
+ */
+ __i2c_dw_disable_nowait(dev);
+ regmap_write(dev->map, DW_IC_SAR, slave->addr);
+ dev->slave = slave;
+
+ __i2c_dw_enable(dev);
+
+ dev->cmd_err = 0;
+ dev->msg_write_idx = 0;
+ dev->msg_read_idx = 0;
+ dev->msg_err = 0;
+ dev->status = STATUS_IDLE;
+ dev->abort_source = 0;
+ dev->rx_outstanding = 0;
+
+ return 0;
+}
+
+static int i2c_dw_unreg_slave(struct i2c_client *slave)
+{
+ struct dw_i2c_dev *dev = i2c_get_adapdata(slave->adapter);
+
+ dev->disable_int(dev);
+ dev->disable(dev);
+ synchronize_irq(dev->irq);
+ dev->slave = NULL;
+ pm_runtime_put(dev->dev);
+
+ return 0;
+}
+
+static u32 i2c_dw_read_clear_intrbits_slave(struct dw_i2c_dev *dev)
+{
+ u32 stat, dummy;
+
+ /*
+ * The IC_INTR_STAT register just indicates "enabled" interrupts.
+ * The unmasked raw version of interrupt status bits is available
+ * in the IC_RAW_INTR_STAT register.
+ *
+ * That is,
+ * stat = readl(IC_INTR_STAT);
+ * equals to,
+ * stat = readl(IC_RAW_INTR_STAT) & readl(IC_INTR_MASK);
+ *
+ * The raw version might be useful for debugging purposes.
+ */
+ regmap_read(dev->map, DW_IC_INTR_STAT, &stat);
+
+ /*
+ * Do not use the IC_CLR_INTR register to clear interrupts, or
+ * you'll miss some interrupts, triggered during the period from
+ * readl(IC_INTR_STAT) to readl(IC_CLR_INTR).
+ *
+ * Instead, use the separately-prepared IC_CLR_* registers.
+ */
+ if (stat & DW_IC_INTR_TX_ABRT)
+ regmap_read(dev->map, DW_IC_CLR_TX_ABRT, &dummy);
+ if (stat & DW_IC_INTR_RX_UNDER)
+ regmap_read(dev->map, DW_IC_CLR_RX_UNDER, &dummy);
+ if (stat & DW_IC_INTR_RX_OVER)
+ regmap_read(dev->map, DW_IC_CLR_RX_OVER, &dummy);
+ if (stat & DW_IC_INTR_TX_OVER)
+ regmap_read(dev->map, DW_IC_CLR_TX_OVER, &dummy);
+ if (stat & DW_IC_INTR_RX_DONE)
+ regmap_read(dev->map, DW_IC_CLR_RX_DONE, &dummy);
+ if (stat & DW_IC_INTR_ACTIVITY)
+ regmap_read(dev->map, DW_IC_CLR_ACTIVITY, &dummy);
+ if (stat & DW_IC_INTR_STOP_DET)
+ regmap_read(dev->map, DW_IC_CLR_STOP_DET, &dummy);
+ if (stat & DW_IC_INTR_START_DET)
+ regmap_read(dev->map, DW_IC_CLR_START_DET, &dummy);
+ if (stat & DW_IC_INTR_GEN_CALL)
+ regmap_read(dev->map, DW_IC_CLR_GEN_CALL, &dummy);
+
+ return stat;
+}
+
+/*
+ * Interrupt service routine. This gets called whenever an I2C slave interrupt
+ * occurs.
+ */
+
+static int i2c_dw_irq_handler_slave(struct dw_i2c_dev *dev)
+{
+ u32 raw_stat, stat, enabled, tmp;
+ u8 val = 0, slave_activity;
+
+ regmap_read(dev->map, DW_IC_ENABLE, &enabled);
+ regmap_read(dev->map, DW_IC_RAW_INTR_STAT, &raw_stat);
+ regmap_read(dev->map, DW_IC_STATUS, &tmp);
+ slave_activity = ((tmp & DW_IC_STATUS_SLAVE_ACTIVITY) >> 6);
+
+ if (!enabled || !(raw_stat & ~DW_IC_INTR_ACTIVITY) || !dev->slave)
+ return 0;
+
+ stat = i2c_dw_read_clear_intrbits_slave(dev);
+ dev_dbg(dev->dev,
+ "%#x STATUS SLAVE_ACTIVITY=%#x : RAW_INTR_STAT=%#x : INTR_STAT=%#x\n",
+ enabled, slave_activity, raw_stat, stat);
+
+ if (stat & DW_IC_INTR_RX_FULL) {
+ if (dev->status != STATUS_WRITE_IN_PROGRESS) {
+ dev->status = STATUS_WRITE_IN_PROGRESS;
+ i2c_slave_event(dev->slave, I2C_SLAVE_WRITE_REQUESTED,
+ &val);
+ }
+
+ regmap_read(dev->map, DW_IC_DATA_CMD, &tmp);
+ val = tmp;
+ if (!i2c_slave_event(dev->slave, I2C_SLAVE_WRITE_RECEIVED,
+ &val))
+ dev_vdbg(dev->dev, "Byte %X acked!", val);
+ }
+
+ if (stat & DW_IC_INTR_RD_REQ) {
+ if (slave_activity) {
+ regmap_read(dev->map, DW_IC_CLR_RD_REQ, &tmp);
+
+ dev->status = STATUS_READ_IN_PROGRESS;
+ if (!i2c_slave_event(dev->slave,
+ I2C_SLAVE_READ_REQUESTED,
+ &val))
+ regmap_write(dev->map, DW_IC_DATA_CMD, val);
+ }
+ }
+
+ if (stat & DW_IC_INTR_RX_DONE) {
+ if (!i2c_slave_event(dev->slave, I2C_SLAVE_READ_PROCESSED,
+ &val))
+ regmap_read(dev->map, DW_IC_CLR_RX_DONE, &tmp);
+ }
+
+ if (stat & DW_IC_INTR_STOP_DET) {
+ dev->status = STATUS_IDLE;
+ i2c_slave_event(dev->slave, I2C_SLAVE_STOP, &val);
+ }
+
+ return 1;
+}
+
+static irqreturn_t i2c_dw_isr_slave(int this_irq, void *dev_id)
+{
+ struct dw_i2c_dev *dev = dev_id;
+ int ret;
+
+ ret = i2c_dw_irq_handler_slave(dev);
+ if (ret > 0)
+ complete(&dev->cmd_complete);
+
+ return IRQ_RETVAL(ret);
+}
+
+static const struct i2c_algorithm i2c_dw_algo = {
+ .functionality = i2c_dw_func,
+ .reg_slave = i2c_dw_reg_slave,
+ .unreg_slave = i2c_dw_unreg_slave,
+};
+
+void i2c_dw_configure_slave(struct dw_i2c_dev *dev)
+{
+ dev->functionality = I2C_FUNC_SLAVE | DW_IC_DEFAULT_FUNCTIONALITY;
+
+ dev->slave_cfg = DW_IC_CON_RX_FIFO_FULL_HLD_CTRL |
+ DW_IC_CON_RESTART_EN | DW_IC_CON_STOP_DET_IFADDRESSED;
+
+ dev->mode = DW_IC_SLAVE;
+}
+EXPORT_SYMBOL_GPL(i2c_dw_configure_slave);
+
+int i2c_dw_probe_slave(struct dw_i2c_dev *dev)
+{
+ struct i2c_adapter *adap = &dev->adapter;
+ int ret;
+
+ init_completion(&dev->cmd_complete);
+
+ dev->init = i2c_dw_init_slave;
+ dev->disable = i2c_dw_disable;
+ dev->disable_int = i2c_dw_disable_int;
+
+ ret = i2c_dw_init_regmap(dev);
+ if (ret)
+ return ret;
+
+ ret = i2c_dw_set_sda_hold(dev);
+ if (ret)
+ return ret;
+
+ ret = i2c_dw_set_fifo_size(dev);
+ if (ret)
+ return ret;
+
+ ret = dev->init(dev);
+ if (ret)
+ return ret;
+
+ snprintf(adap->name, sizeof(adap->name),
+ "Synopsys DesignWare I2C Slave adapter");
+ adap->retries = 3;
+ adap->algo = &i2c_dw_algo;
+ adap->dev.parent = dev->dev;
+ i2c_set_adapdata(adap, dev);
+
+ ret = devm_request_irq(dev->dev, dev->irq, i2c_dw_isr_slave,
+ IRQF_SHARED, dev_name(dev->dev), dev);
+ if (ret) {
+ dev_err(dev->dev, "failure requesting irq %i: %d\n",
+ dev->irq, ret);
+ return ret;
+ }
+
+ ret = i2c_add_numbered_adapter(adap);
+ if (ret)
+ dev_err(dev->dev, "failure adding adapter: %d\n", ret);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(i2c_dw_probe_slave);
+
+MODULE_AUTHOR("Luis Oliveira <lolivei@synopsys.com>");
+MODULE_DESCRIPTION("Synopsys DesignWare I2C bus slave adapter");
+MODULE_LICENSE("GPL v2");