5.15-stable review patch. If anyone has any objections, please let me know.
------------------
From: Corey Minyard minyard@acm.org
[ Upstream commit f89bf95632b41695402996d96476c44c641d23d7 ]
Most IMX I2C interfaces don't generate an interrupt on a stop condition, so it won't generate a timely stop event on a slave mode transfer. Some users, like IPMB, need a timely stop event to work properly.
So, add a timer and add the proper handling to generate a stop event in slave mode if the interface goes idle.
Signed-off-by: Corey Minyard minyard@acm.org Tested-by: Andrew Manley andrew.manley@sealingtech.com Reviewed-by: Andrew Manley andrew.manley@sealingtech.com Reviewed-by: Oleksij Rempel o.rempel@pengutronix.de Signed-off-by: Wolfram Sang wsa@kernel.org Stable-dep-of: 87aec499368d ("i2c: imx: when being a target, mark the last read as processed") Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/i2c/busses/i2c-imx.c | 92 ++++++++++++++++++++++++++++-------- 1 file changed, 73 insertions(+), 19 deletions(-)
diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c index 5e8853d3f8da7..d545547c89ca7 100644 --- a/drivers/i2c/busses/i2c-imx.c +++ b/drivers/i2c/busses/i2c-imx.c @@ -37,6 +37,8 @@ #include <linux/io.h> #include <linux/iopoll.h> #include <linux/kernel.h> +#include <linux/spinlock.h> +#include <linux/hrtimer.h> #include <linux/module.h> #include <linux/of.h> #include <linux/of_device.h> @@ -51,6 +53,8 @@ /* This will be the driver name the kernel reports */ #define DRIVER_NAME "imx-i2c"
+#define I2C_IMX_CHECK_DELAY 30000 /* Time to check for bus idle, in NS */ + /* * Enable DMA if transfer byte size is bigger than this threshold. * As the hardware request, it must bigger than 4 bytes.\ @@ -210,6 +214,10 @@ struct imx_i2c_struct { struct imx_i2c_dma *dma; struct i2c_client *slave; enum i2c_slave_event last_slave_event; + + /* For checking slave events. */ + spinlock_t slave_lock; + struct hrtimer slave_timer; };
static const struct imx_i2c_hwdata imx1_i2c_hwdata = { @@ -680,7 +688,7 @@ static void i2c_imx_slave_event(struct imx_i2c_struct *i2c_imx,
static void i2c_imx_slave_finish_op(struct imx_i2c_struct *i2c_imx) { - u8 val; + u8 val = 0;
while (i2c_imx->last_slave_event != I2C_SLAVE_STOP) { switch (i2c_imx->last_slave_event) { @@ -701,10 +709,11 @@ static void i2c_imx_slave_finish_op(struct imx_i2c_struct *i2c_imx) } }
-static irqreturn_t i2c_imx_slave_isr(struct imx_i2c_struct *i2c_imx, - unsigned int status, unsigned int ctl) +/* Returns true if the timer should be restarted, false if not. */ +static irqreturn_t i2c_imx_slave_handle(struct imx_i2c_struct *i2c_imx, + unsigned int status, unsigned int ctl) { - u8 value; + u8 value = 0;
if (status & I2SR_IAL) { /* Arbitration lost */ i2c_imx_clear_irq(i2c_imx, I2SR_IAL); @@ -712,6 +721,16 @@ static irqreturn_t i2c_imx_slave_isr(struct imx_i2c_struct *i2c_imx, return IRQ_HANDLED; }
+ if (!(status & I2SR_IBB)) { + /* No master on the bus, that could mean a stop condition. */ + i2c_imx_slave_finish_op(i2c_imx); + return IRQ_HANDLED; + } + + if (!(status & I2SR_ICF)) + /* Data transfer still in progress, ignore this. */ + goto out; + if (status & I2SR_IAAS) { /* Addressed as a slave */ i2c_imx_slave_finish_op(i2c_imx); if (status & I2SR_SRW) { /* Master wants to read from us*/ @@ -737,16 +756,9 @@ static irqreturn_t i2c_imx_slave_isr(struct imx_i2c_struct *i2c_imx, 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_imx_slave_event(i2c_imx, - I2C_SLAVE_WRITE_RECEIVED, &value); - } else { /* STOP signal is detected */ - dev_dbg(&i2c_imx->adapter.dev, - "STOP signal detected"); - i2c_imx_slave_event(i2c_imx, - I2C_SLAVE_STOP, &value); - } + value = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2DR); + i2c_imx_slave_event(i2c_imx, + I2C_SLAVE_WRITE_RECEIVED, &value); } else if (!(status & I2SR_RXAK)) { /* Transmit mode received ACK */ ctl |= I2CR_MTX; imx_i2c_write_reg(ctl, i2c_imx, IMX_I2C_I2CR); @@ -755,15 +767,43 @@ static irqreturn_t i2c_imx_slave_isr(struct imx_i2c_struct *i2c_imx, I2C_SLAVE_READ_PROCESSED, &value);
imx_i2c_write_reg(value, i2c_imx, IMX_I2C_I2DR); - } else { /* Transmit mode received NAK */ + } else { /* Transmit mode received NAK, operation is done */ ctl &= ~I2CR_MTX; imx_i2c_write_reg(ctl, i2c_imx, IMX_I2C_I2CR); imx_i2c_read_reg(i2c_imx, IMX_I2C_I2DR); + i2c_imx_slave_finish_op(i2c_imx); + return IRQ_HANDLED; }
+out: + /* + * No need to check the return value here. If it returns 0 or + * 1, then everything is fine. If it returns -1, then the + * timer is running in the handler. This will still work, + * though it may be redone (or already have been done) by the + * timer function. + */ + hrtimer_try_to_cancel(&i2c_imx->slave_timer); + hrtimer_forward_now(&i2c_imx->slave_timer, I2C_IMX_CHECK_DELAY); + hrtimer_restart(&i2c_imx->slave_timer); return IRQ_HANDLED; }
+static enum hrtimer_restart i2c_imx_slave_timeout(struct hrtimer *t) +{ + struct imx_i2c_struct *i2c_imx = container_of(t, struct imx_i2c_struct, + slave_timer); + unsigned int ctl, status; + unsigned long flags; + + spin_lock_irqsave(&i2c_imx->slave_lock, flags); + status = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2SR); + ctl = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR); + i2c_imx_slave_handle(i2c_imx, status, ctl); + spin_unlock_irqrestore(&i2c_imx->slave_lock, flags); + return HRTIMER_NORESTART; +} + static void i2c_imx_slave_init(struct imx_i2c_struct *i2c_imx) { int temp; @@ -843,7 +883,9 @@ static irqreturn_t i2c_imx_isr(int irq, void *dev_id) { struct imx_i2c_struct *i2c_imx = dev_id; unsigned int ctl, status; + unsigned long flags;
+ spin_lock_irqsave(&i2c_imx->slave_lock, flags); status = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2SR); ctl = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR);
@@ -851,14 +893,20 @@ static irqreturn_t i2c_imx_isr(int irq, void *dev_id) i2c_imx_clear_irq(i2c_imx, I2SR_IIF); if (i2c_imx->slave) { if (!(ctl & I2CR_MSTA)) { - return i2c_imx_slave_isr(i2c_imx, status, ctl); - } else if (i2c_imx->last_slave_event != - I2C_SLAVE_STOP) { - i2c_imx_slave_finish_op(i2c_imx); + irqreturn_t ret; + + ret = i2c_imx_slave_handle(i2c_imx, + status, ctl); + spin_unlock_irqrestore(&i2c_imx->slave_lock, + flags); + return ret; } + i2c_imx_slave_finish_op(i2c_imx); } + spin_unlock_irqrestore(&i2c_imx->slave_lock, flags); return i2c_imx_master_isr(i2c_imx, status); } + spin_unlock_irqrestore(&i2c_imx->slave_lock, flags);
return IRQ_NONE; } @@ -1380,6 +1428,10 @@ static int i2c_imx_probe(struct platform_device *pdev) if (!i2c_imx) return -ENOMEM;
+ spin_lock_init(&i2c_imx->slave_lock); + hrtimer_init(&i2c_imx->slave_timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS); + i2c_imx->slave_timer.function = i2c_imx_slave_timeout; + match = device_get_match_data(&pdev->dev); if (match) i2c_imx->hwdata = match; @@ -1491,6 +1543,8 @@ static int i2c_imx_remove(struct platform_device *pdev)
ret = pm_runtime_get_sync(&pdev->dev);
+ hrtimer_cancel(&i2c_imx->slave_timer); + /* remove adapter */ dev_dbg(&i2c_imx->adapter.dev, "adapter removed\n"); i2c_del_adapter(&i2c_imx->adapter);