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From 865433df5d11aef7cfe5d51b362b6276bddb7a15 Mon Sep 17 00:00:00 2001
From: Biwen Li <biwen.li@nxp.com>
Date: Fri, 2 Aug 2019 17:45:56 +0800
Subject: [PATCH] i2c: imx: support slave mode for imx I2C driver
The patch supports slave mode for imx I2C driver
Reviewed-by: Clark Wang <xiaoning.wang@nxp.com>
Signed-off-by: Biwen Li <biwen.li@nxp.com>
---
drivers/i2c/busses/i2c-imx.c | 219 +++++++++++++++++++++++++++++++++++++++----
1 file changed, 201 insertions(+), 18 deletions(-)
--- a/drivers/i2c/busses/i2c-imx.c
+++ b/drivers/i2c/busses/i2c-imx.c
@@ -265,6 +265,9 @@ struct imx_i2c_struct {
int pmuxcr_set;
int pmuxcr_endian;
void __iomem *pmuxcr_addr;
+#if IS_ENABLED(CONFIG_I2C_SLAVE)
+ struct i2c_client *slave;
+#endif
};
static const struct imx_i2c_hwdata imx1_i2c_hwdata = {
@@ -357,6 +360,14 @@ static inline unsigned char imx_i2c_read
return readb(i2c_imx->base + (reg << i2c_imx->hwdata->regshift));
}
+/* Set up i2c controller register and i2c status register to default value. */
+static void i2c_imx_reset_regs(struct imx_i2c_struct *i2c_imx)
+{
+ imx_i2c_write_reg(i2c_imx->hwdata->i2cr_ien_opcode ^ I2CR_IEN,
+ i2c_imx, IMX_I2C_I2CR);
+ imx_i2c_write_reg(i2c_imx->hwdata->i2sr_clr_opcode, i2c_imx, IMX_I2C_I2SR);
+}
+
/* Functions for DMA support */
static void i2c_imx_dma_request(struct imx_i2c_struct *i2c_imx,
dma_addr_t phy_addr)
@@ -705,21 +716,33 @@ static void i2c_imx_stop(struct imx_i2c_
imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR);
}
-static irqreturn_t i2c_imx_isr(int irq, void *dev_id)
+/* Clear interrupt flag bit */
+static void i2c_imx_clr_if_bit(unsigned int status, struct imx_i2c_struct *i2c_imx)
{
- struct imx_i2c_struct *i2c_imx = dev_id;
- unsigned int temp;
+ status &= ~I2SR_IIF;
+ status |= (i2c_imx->hwdata->i2sr_clr_opcode & I2SR_IIF);
+ imx_i2c_write_reg(status, i2c_imx, IMX_I2C_I2SR);
+}
- temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2SR);
- if (temp & I2SR_IIF) {
- /* save status register */
- i2c_imx->i2csr = temp;
- i2c_imx_clear_irq(i2c_imx, I2SR_IIF);
- wake_up(&i2c_imx->queue);
- return IRQ_HANDLED;
- }
+/* Clear arbitration lost bit */
+static void i2c_imx_clr_al_bit(unsigned int status, struct imx_i2c_struct *i2c_imx)
+{
+ status &= ~I2SR_IAL;
+ status |= (i2c_imx->hwdata->i2sr_clr_opcode & I2SR_IAL);
+ imx_i2c_write_reg(status, i2c_imx, IMX_I2C_I2SR);
+}
+
+static irqreturn_t i2c_imx_master_isr(struct imx_i2c_struct *i2c_imx)
+{
+ unsigned int status;
+
+ /* Save status register */
+ status = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2SR);
+ i2c_imx->i2csr = status | I2SR_IIF;
+
+ wake_up(&i2c_imx->queue);
- return IRQ_NONE;
+ return IRQ_HANDLED;
}
static int i2c_imx_dma_write(struct imx_i2c_struct *i2c_imx,
@@ -1094,6 +1117,13 @@ static int i2c_imx_xfer(struct i2c_adapt
dev_dbg(&i2c_imx->adapter.dev, "<%s>\n", __func__);
+#if IS_ENABLED(CONFIG_I2C_SLAVE)
+ if (i2c_imx->slave) {
+ dev_err(&i2c_imx->adapter.dev, "Please not do operations of master mode in slave mode");
+ return -EBUSY;
+ }
+#endif
+
if (!pm_runtime_enabled(i2c_imx->adapter.dev.parent)) {
pm_runtime_enable(i2c_imx->adapter.dev.parent);
enable_runtime_pm = true;
@@ -1307,11 +1337,169 @@ static u32 i2c_imx_func(struct i2c_adapt
| I2C_FUNC_SMBUS_READ_BLOCK_DATA;
}
+#if IS_ENABLED(CONFIG_I2C_SLAVE)
+static int i2c_imx_slave_init(struct imx_i2c_struct *i2c_imx)
+{
+ int temp;
+
+ /* Resume */
+ temp = pm_runtime_get_sync(i2c_imx->adapter.dev.parent);
+ if (temp < 0) {
+ dev_err(&i2c_imx->adapter.dev, "failed to resume i2c controller");
+ return temp;
+ }
+
+ /* Set slave addr. */
+ imx_i2c_write_reg((i2c_imx->slave->addr << 1), i2c_imx, IMX_I2C_IADR);
+
+ i2c_imx_reset_regs(i2c_imx);
+
+ /* Enable module */
+ temp = i2c_imx->hwdata->i2cr_ien_opcode;
+ imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR);
+
+ /* Enable interrupt from i2c module */
+ temp |= I2CR_IIEN;
+ imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR);
+
+ /* Wait controller to be stable */
+ usleep_range(50, 150);
+ return 0;
+}
+
+static irqreturn_t i2c_imx_slave_isr(struct imx_i2c_struct *i2c_imx)
+{
+ unsigned int status, ctl;
+ u8 value;
+
+ if (!i2c_imx->slave) {
+ dev_err(&i2c_imx->adapter.dev, "cannot deal with slave irq,i2c_imx->slave is null");
+ return IRQ_NONE;
+ }
+
+ status = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2SR);
+ ctl = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR);
+ if (status & I2SR_IAL) { /* Arbitration lost */
+ i2c_imx_clr_al_bit(status, i2c_imx);
+ } else if (status & I2SR_IAAS) { /* Addressed as a slave */
+ if (status & I2SR_SRW) { /* Master wants to read from us*/
+ dev_dbg(&i2c_imx->adapter.dev, "read requested");
+ i2c_slave_event(i2c_imx->slave, I2C_SLAVE_READ_REQUESTED, &value);
+
+ /* Slave transmit */
+ ctl |= I2CR_MTX;
+ imx_i2c_write_reg(ctl, i2c_imx, IMX_I2C_I2CR);
+
+ /* Send data */
+ imx_i2c_write_reg(value, i2c_imx, IMX_I2C_I2DR);
+ } else { /* Master wants to write to us */
+ dev_dbg(&i2c_imx->adapter.dev, "write requested");
+ i2c_slave_event(i2c_imx->slave, I2C_SLAVE_WRITE_REQUESTED, &value);
+
+ /* Slave receive */
+ ctl &= ~I2CR_MTX;
+ imx_i2c_write_reg(ctl, i2c_imx, IMX_I2C_I2CR);
+ /* Dummy read */
+ imx_i2c_read_reg(i2c_imx, IMX_I2C_I2DR);
+ }
+ } else if (!(ctl & I2CR_MTX)) { /* Receive mode */
+ if (status & I2SR_IBB) { /* No STOP signal detected */
+ ctl &= ~I2CR_MTX;
+ imx_i2c_write_reg(ctl, i2c_imx, IMX_I2C_I2CR);
+
+ value = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2DR);
+ i2c_slave_event(i2c_imx->slave, I2C_SLAVE_WRITE_RECEIVED, &value);
+ } else { /* STOP signal is detected */
+ dev_dbg(&i2c_imx->adapter.dev,
+ "STOP signal detected");
+ i2c_slave_event(i2c_imx->slave, I2C_SLAVE_STOP, &value);
+ }
+ } else if (!(status & I2SR_RXAK)) { /* Transmit mode received ACK */
+ ctl |= I2CR_MTX;
+ imx_i2c_write_reg(ctl, i2c_imx, IMX_I2C_I2CR);
+
+ i2c_slave_event(i2c_imx->slave, I2C_SLAVE_READ_PROCESSED, &value);
+
+ imx_i2c_write_reg(value, i2c_imx, IMX_I2C_I2DR);
+ } else { /* Transmit mode received NAK */
+ ctl &= ~I2CR_MTX;
+ imx_i2c_write_reg(ctl, i2c_imx, IMX_I2C_I2CR);
+ imx_i2c_read_reg(i2c_imx, IMX_I2C_I2DR);
+ }
+ return IRQ_HANDLED;
+}
+
+static int i2c_imx_reg_slave(struct i2c_client *client)
+{
+ struct imx_i2c_struct *i2c_imx = i2c_get_adapdata(client->adapter);
+ int ret;
+ if (i2c_imx->slave)
+ return -EBUSY;
+
+ i2c_imx->slave = client;
+
+ ret = i2c_imx_slave_init(i2c_imx);
+ if (ret < 0)
+ dev_err(&i2c_imx->adapter.dev, "failed to switch to slave mode");
+
+ return ret;
+}
+
+static int i2c_imx_unreg_slave(struct i2c_client *client)
+{
+ struct imx_i2c_struct *i2c_imx = i2c_get_adapdata(client->adapter);
+ int ret;
+
+ if (!i2c_imx->slave)
+ return -EINVAL;
+
+ /* Reset slave address. */
+ imx_i2c_write_reg(0, i2c_imx, IMX_I2C_IADR);
+
+ i2c_imx_reset_regs(i2c_imx);
+
+ i2c_imx->slave = NULL;
+
+ /* Suspend */
+ ret = pm_runtime_put_sync(i2c_imx->adapter.dev.parent);
+ if (ret < 0)
+ dev_err(&i2c_imx->adapter.dev, "failed to suspend i2c controller");
+
+ return ret;
+}
+#endif
+
static const struct i2c_algorithm i2c_imx_algo = {
.master_xfer = i2c_imx_xfer,
.functionality = i2c_imx_func,
+#if IS_ENABLED(CONFIG_I2C_SLAVE)
+ .reg_slave = i2c_imx_reg_slave,
+ .unreg_slave = i2c_imx_unreg_slave,
+#endif
};
+static irqreturn_t i2c_imx_isr(int irq, void *dev_id)
+{
+ struct imx_i2c_struct *i2c_imx = dev_id;
+ unsigned int status, ctl;
+ irqreturn_t irq_status = IRQ_NONE;
+
+ status = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2SR);
+ ctl = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR);
+
+ if (status & I2SR_IIF) {
+ i2c_imx_clr_if_bit(status, i2c_imx);
+ if (ctl & I2CR_MSTA)
+ irq_status = i2c_imx_master_isr(i2c_imx);
+#if IS_ENABLED(CONFIG_I2C_SLAVE)
+ else
+ irq_status = i2c_imx_slave_isr(i2c_imx);
+#endif
+ }
+
+ return irq_status;
+}
+
static int i2c_imx_probe(struct platform_device *pdev)
{
struct imx_i2c_struct *i2c_imx;
@@ -1420,10 +1608,7 @@ static int i2c_imx_probe(struct platform
if (is_imx7d_i2c(i2c_imx) && i2c_imx->bitrate > IMX_I2C_MAX_E_BIT_RATE)
i2c_imx->bitrate = IMX_I2C_MAX_E_BIT_RATE;
- /* Set up chip registers to defaults */
- imx_i2c_write_reg(i2c_imx->hwdata->i2cr_ien_opcode ^ I2CR_IEN,
- i2c_imx, IMX_I2C_I2CR);
- imx_i2c_write_reg(i2c_imx->hwdata->i2sr_clr_opcode, i2c_imx, IMX_I2C_I2SR);
+ i2c_imx_reset_regs(i2c_imx);
/* Init optional bus recovery */
if (of_match_node(pinmux_of_match, pdev->dev.of_node))
|
