RE: [v10] i2c: imx: support slave mode for imx I2C driver

From: Biwen Li (OSS)
Date: Mon Nov 30 2020 - 00:27:48 EST

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> >
> > The patch supports slave mode for imx I2C driver
> >
> > Signed-off-by: Biwen Li <biwen.li@xxxxxxx>
>
> Thank you for your work!
>
> Acked-by: Oleksij Rempel <o.rempel@xxxxxxxxxxxxxx>

>
> @Wolfram, Christian Eggers I2SR_IAL patches should go before this one.
Hi Wolfram,

Any progress?

Regards,
Biwen Li
>
> > ---
> > Change in v10:
> > - totally remove CONFIG_I2C_SLAVE
> > - replace api with i2c_imx_clart_irq()
> > - remove robust code
> > - place pm_runtime_get in i2c_imx_slave_init()
> > to i2c_imx_reg_slave()
> > - apply the patch on top of this patch set:
> > [PATCH v6 0/3] i2c: imx: Fix handling of arbitration loss
> > https://lkml.org/lkml/2020/10/9/407
> >
> > Change in v9:
> > - remove #ifdef after select I2C_SLAVE by default
> >
> > Change in v8:
> > - fix build issue
> >
> > Change in v7:
> > - support auto switch mode between master and slave
> > - enable interrupt when idle in slave mode
> > - remove #ifdef
> >
> > Change in v6:
> > - delete robust logs and comments
> > - not read status register again in master isr.
> >
> > Change in v5:
> > - fix a bug that cannot determine in what mode(master mode or
> > slave mode)
> >
> > Change in v4:
> > - add MACRO CONFIG_I2C_SLAVE to fix compilation issue
> >
> > Change in v3:
> > - support layerscape and i.mx platform
> >
> > Change in v2:
> > - remove MACRO CONFIG_I2C_SLAVE
> >
> > drivers/i2c/busses/Kconfig | 1 +
> > drivers/i2c/busses/i2c-imx.c | 219
> > +++++++++++++++++++++++++++++++----
> > 2 files changed, 196 insertions(+), 24 deletions(-)
> >
> > diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
> > index a97a9d058198..e2ad62481f25 100644
> > --- a/drivers/i2c/busses/Kconfig
> > +++ b/drivers/i2c/busses/Kconfig
> > @@ -675,6 +675,7 @@ config I2C_IMG
> > config I2C_IMX
> > tristate "IMX I2C interface"
> > depends on ARCH_MXC || ARCH_LAYERSCAPE || COLDFIRE
> > + select I2C_SLAVE
> > help
> > Say Y here if you want to use the IIC bus controller on
> > the Freescale i.MX/MXC, Layerscape or ColdFire processors.
> > diff --git a/drivers/i2c/busses/i2c-imx.c
> > b/drivers/i2c/busses/i2c-imx.c index e6f8d6e45a15..a8e8af57e33f 100644
> > --- a/drivers/i2c/busses/i2c-imx.c
> > +++ b/drivers/i2c/busses/i2c-imx.c
> > @@ -17,6 +17,7 @@
> > * Copyright (C) 2008 Darius Augulis <darius.augulis at teltonika.lt>
> > *
> > * Copyright 2013 Freescale Semiconductor, Inc.
> > + * Copyright 2020 NXP
> > *
> > */
> >
> > @@ -73,6 +74,11 @@
> > #define IMX_I2C_I2SR 0x03 /* i2c status */
> > #define IMX_I2C_I2DR 0x04 /* i2c transfer data */
> >
> > +/*
> > + * All of the layerscape series SoCs support IBIC register.
> > + */
> > +#define IMX_I2C_IBIC 0x05 /* i2c bus interrupt config */
> > +
> > #define IMX_I2C_REGSHIFT 2
> > #define VF610_I2C_REGSHIFT 0
> >
> > @@ -91,6 +97,7 @@
> > #define I2CR_MSTA 0x20
> > #define I2CR_IIEN 0x40
> > #define I2CR_IEN 0x80
> > +#define IBIC_BIIE 0x80 /* Bus idle interrupt enable */
> >
> > /* register bits different operating codes definition:
> > * 1) I2SR: Interrupt flags clear operation differ between SoCs:
> > @@ -201,6 +208,7 @@ struct imx_i2c_struct {
> > struct pinctrl_state *pinctrl_pins_gpio;
> >
> > struct imx_i2c_dma *dma;
> > + struct i2c_client *slave;
> > };
> >
> > static const struct imx_i2c_hwdata imx1_i2c_hwdata = { @@ -265,6
> > +273,11 @@ static inline int is_imx1_i2c(struct imx_i2c_struct *i2c_imx)
> > return i2c_imx->hwdata->devtype == IMX1_I2C; }
> >
> > +static inline int is_vf610_i2c(struct imx_i2c_struct *i2c_imx) {
> > + return i2c_imx->hwdata->devtype == VF610_I2C; }
> > +
> > static inline void imx_i2c_write_reg(unsigned int val,
> > struct imx_i2c_struct *i2c_imx, unsigned int reg) { @@ -277,6
> > +290,27 @@ static inline unsigned char imx_i2c_read_reg(struct
> imx_i2c_struct *i2c_imx,
> > return readb(i2c_imx->base + (reg << i2c_imx->hwdata->regshift)); }
> >
> > +static void i2c_imx_clear_irq(struct imx_i2c_struct *i2c_imx,
> > +unsigned int bits) {
> > + unsigned int temp;
> > +
> > + /*
> > + * i2sr_clr_opcode is the value to clear all interrupts. Here we want to
> > + * clear only <bits>, so we write ~i2sr_clr_opcode with just <bits>
> > + * toggled. This is required because i.MX needs W0C and Vybrid uses W1C.
> > + */
> > + temp = ~i2c_imx->hwdata->i2sr_clr_opcode ^ bits;
> > + imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2SR); }
> > +
> > +/* 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);
> > + i2c_imx_clear_irq(i2c_imx, I2SR_IIF | I2SR_IAL); }
> > +
> > /* Functions for DMA support */
> > static void i2c_imx_dma_request(struct imx_i2c_struct *i2c_imx,
> > dma_addr_t phy_addr)
> > @@ -412,19 +446,6 @@ static void i2c_imx_dma_free(struct imx_i2c_struct
> *i2c_imx)
> > dma->chan_using = NULL;
> > }
> >
> > -static void i2c_imx_clear_irq(struct imx_i2c_struct *i2c_imx,
> > unsigned int bits) -{
> > - unsigned int temp;
> > -
> > - /*
> > - * i2sr_clr_opcode is the value to clear all interrupts. Here we want to
> > - * clear only <bits>, so we write ~i2sr_clr_opcode with just <bits>
> > - * toggled. This is required because i.MX needs W0C and Vybrid uses W1C.
> > - */
> > - temp = ~i2c_imx->hwdata->i2sr_clr_opcode ^ bits;
> > - imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2SR);
> > -}
> > -
> > static int i2c_imx_bus_busy(struct imx_i2c_struct *i2c_imx, int
> > for_busy, bool atomic) {
> > unsigned long orig_jiffies = jiffies; @@ -638,18 +659,165 @@ static
> > void i2c_imx_stop(struct imx_i2c_struct *i2c_imx, bool atomic)
> > imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR); }
> >
> > +/*
> > + * Enable bus idle interrupts
> > + * Note: IBIC register will be cleared after disabled i2c module.
> > + * All of layerscape series SoCs support IBIC register.
> > + */
> > +static void i2c_imx_enable_bus_idle(struct imx_i2c_struct *i2c_imx) {
> > + if (is_vf610_i2c(i2c_imx)) {
> > + unsigned int temp;
> > +
> > + temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_IBIC);
> > + temp |= IBIC_BIIE;
> > + imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_IBIC);
> > + }
> > +}
> > +
> > +static irqreturn_t i2c_imx_slave_isr(struct imx_i2c_struct *i2c_imx,
> > + unsigned int status, unsigned int ctl) {
> > + u8 value;
> > +
> > + if (status & I2SR_IAL) { /* Arbitration lost */
> > + i2c_imx_clear_irq(i2c_imx, I2SR_IAL);
> > + if (!(status & I2SR_IAAS))
> > + return IRQ_HANDLED;
> > + }
> > +
> > + 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 */
> > + 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 void i2c_imx_slave_init(struct imx_i2c_struct *i2c_imx) {
> > + int 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);
> > +
> > + i2c_imx_enable_bus_idle(i2c_imx);
> > +}
> > +
> > +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;
> > +
> > + /* Resume */
> > + ret = pm_runtime_get_sync(i2c_imx->adapter.dev.parent);
> > + if (ret < 0) {
> > + dev_err(&i2c_imx->adapter.dev, "failed to resume i2c controller");
> > + return ret;
> > + }
> > +
> > + i2c_imx_slave_init(i2c_imx);
> > +
> > + return 0;
> > +}
> > +
> > +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;
> > +}
> > +
> > +static irqreturn_t i2c_imx_master_isr(struct imx_i2c_struct *i2c_imx,
> > +unsigned int status) {
> > + /* save status register */
> > + i2c_imx->i2csr = status;
> > + wake_up(&i2c_imx->queue);
> > +
> > + return IRQ_HANDLED;
> > +}
> > +
> > static irqreturn_t i2c_imx_isr(int irq, void *dev_id) {
> > struct imx_i2c_struct *i2c_imx = dev_id;
> > - unsigned int temp;
> > + unsigned int ctl, status;
> >
> > - temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2SR);
> > - if (temp & I2SR_IIF) {
> > - /* save status register */
> > - i2c_imx->i2csr = temp;
> > + 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_clear_irq(i2c_imx, I2SR_IIF);
> > - wake_up(&i2c_imx->queue);
> > - return IRQ_HANDLED;
> > + if (i2c_imx->slave && !(ctl & I2CR_MSTA))
> > + return i2c_imx_slave_isr(i2c_imx, status, ctl);
> > + return i2c_imx_master_isr(i2c_imx, status);
> > }
> >
> > return IRQ_NONE;
> > @@ -1027,6 +1195,10 @@ static int i2c_imx_xfer_common(struct
> i2c_adapter *adapter,
> > dev_dbg(&i2c_imx->adapter.dev, "<%s> exit with: %s: %d\n", __func__,
> > (result < 0) ? "error" : "success msg",
> > (result < 0) ? result : num);
> > + /* After data is transferred, switch to slave mode(as a receiver) */
> > + if (i2c_imx->slave)
> > + i2c_imx_slave_init(i2c_imx);
> > +
> > return (result < 0) ? result : num;
> > }
> >
> > @@ -1140,6 +1312,8 @@ static const struct i2c_algorithm i2c_imx_algo = {
> > .master_xfer = i2c_imx_xfer,
> > .master_xfer_atomic = i2c_imx_xfer_atomic,
> > .functionality = i2c_imx_func,
> > + .reg_slave = i2c_imx_reg_slave,
> > + .unreg_slave = i2c_imx_unreg_slave,
> > };
> >
> > static int i2c_imx_probe(struct platform_device *pdev) @@ -1233,10
> > +1407,7 @@ static int i2c_imx_probe(struct platform_device *pdev)
> > clk_notifier_register(i2c_imx->clk, &i2c_imx->clk_change_nb);
> > i2c_imx_set_clk(i2c_imx, clk_get_rate(i2c_imx->clk));
> >
> > - /* 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 function */
> > ret = i2c_imx_init_recovery_info(i2c_imx, pdev);
> > --
> > 2.17.1
> >
> >
>
> --
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> |
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