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i2c: removed work arounds in i2c driver for Zynq Ultrascale+ MPSoC
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Cadence 1.0 version has bugs which have been fixed in the cadence 1.4 version.
This patch removes the quirks present in the driver for cadence 1.4 version.

Signed-off-by: Anurag Kumar Vulisha <anuragku@xilinx.com>
[wsa: fixed indentation issues in r1p10_i2c_def]
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
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Anurag Kumar Vulisha authored and Wolfram Sang committed Aug 10, 2015
1 parent d57f5de commit 63cab19
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Showing 2 changed files with 62 additions and 12 deletions.
6 changes: 5 additions & 1 deletion Documentation/devicetree/bindings/i2c/i2c-cadence.txt
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Original file line number Diff line number Diff line change
Expand Up @@ -2,7 +2,11 @@ Binding for the Cadence I2C controller

Required properties:
- reg: Physical base address and size of the controller's register area.
- compatible: Compatibility string. Must be 'cdns,i2c-r1p10'.
- compatible: Should contain one of:
* "cdns,i2c-r1p10"
Note: Use this when cadence i2c controller version 1.0 is used.
* "cdns,i2c-r1p14"
Note: Use this when cadence i2c controller version 1.4 is used.
- clocks: Input clock specifier. Refer to common clock bindings.
- interrupts: Interrupt specifier. Refer to interrupt bindings.
- #address-cells: Should be 1.
Expand Down
68 changes: 57 additions & 11 deletions drivers/i2c/busses/i2c-cadence.c
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Original file line number Diff line number Diff line change
Expand Up @@ -17,6 +17,7 @@
#include <linux/io.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/of.h>

/* Register offsets for the I2C device. */
#define CDNS_I2C_CR_OFFSET 0x00 /* Control Register, RW */
Expand Down Expand Up @@ -113,6 +114,8 @@

#define CDNS_I2C_TIMEOUT_MAX 0xFF

#define CDNS_I2C_BROKEN_HOLD_BIT BIT(0)

#define cdns_i2c_readreg(offset) readl_relaxed(id->membase + offset)
#define cdns_i2c_writereg(val, offset) writel_relaxed(val, id->membase + offset)

Expand All @@ -135,6 +138,7 @@
* @bus_hold_flag: Flag used in repeated start for clearing HOLD bit
* @clk: Pointer to struct clk
* @clk_rate_change_nb: Notifier block for clock rate changes
* @quirks: flag for broken hold bit usage in r1p10
*/
struct cdns_i2c {
void __iomem *membase;
Expand All @@ -154,6 +158,11 @@ struct cdns_i2c {
unsigned int bus_hold_flag;
struct clk *clk;
struct notifier_block clk_rate_change_nb;
u32 quirks;
};

struct cdns_platform_data {
u32 quirks;
};

#define to_cdns_i2c(_nb) container_of(_nb, struct cdns_i2c, \
Expand All @@ -172,6 +181,12 @@ static void cdns_i2c_clear_bus_hold(struct cdns_i2c *id)
cdns_i2c_writereg(reg & ~CDNS_I2C_CR_HOLD, CDNS_I2C_CR_OFFSET);
}

static inline bool cdns_is_holdquirk(struct cdns_i2c *id, bool hold_wrkaround)
{
return (hold_wrkaround &&
(id->curr_recv_count == CDNS_I2C_FIFO_DEPTH + 1));
}

/**
* cdns_i2c_isr - Interrupt handler for the I2C device
* @irq: irq number for the I2C device
Expand All @@ -186,6 +201,7 @@ static irqreturn_t cdns_i2c_isr(int irq, void *ptr)
{
unsigned int isr_status, avail_bytes, updatetx;
unsigned int bytes_to_send;
bool hold_quirk;
struct cdns_i2c *id = ptr;
/* Signal completion only after everything is updated */
int done_flag = 0;
Expand All @@ -208,6 +224,8 @@ static irqreturn_t cdns_i2c_isr(int irq, void *ptr)
if (id->recv_count > id->curr_recv_count)
updatetx = 1;

hold_quirk = (id->quirks & CDNS_I2C_BROKEN_HOLD_BIT) && updatetx;

/* When receiving, handle data interrupt and completion interrupt */
if (id->p_recv_buf &&
((isr_status & CDNS_I2C_IXR_COMP) ||
Expand All @@ -229,8 +247,7 @@ static irqreturn_t cdns_i2c_isr(int irq, void *ptr)
id->recv_count--;
id->curr_recv_count--;

if (updatetx &&
(id->curr_recv_count == CDNS_I2C_FIFO_DEPTH + 1))
if (cdns_is_holdquirk(id, hold_quirk))
break;
}

Expand All @@ -241,8 +258,7 @@ static irqreturn_t cdns_i2c_isr(int irq, void *ptr)
* maintain transfer size non-zero while performing a large
* receive operation.
*/
if (updatetx &&
(id->curr_recv_count == CDNS_I2C_FIFO_DEPTH + 1)) {
if (cdns_is_holdquirk(id, hold_quirk)) {
/* wait while fifo is full */
while (cdns_i2c_readreg(CDNS_I2C_XFER_SIZE_OFFSET) !=
(id->curr_recv_count - CDNS_I2C_FIFO_DEPTH))
Expand All @@ -264,6 +280,22 @@ static irqreturn_t cdns_i2c_isr(int irq, void *ptr)
CDNS_I2C_XFER_SIZE_OFFSET);
id->curr_recv_count = id->recv_count;
}
} else if (id->recv_count && !hold_quirk &&
!id->curr_recv_count) {

/* Set the slave address in address register*/
cdns_i2c_writereg(id->p_msg->addr & CDNS_I2C_ADDR_MASK,
CDNS_I2C_ADDR_OFFSET);

if (id->recv_count > CDNS_I2C_TRANSFER_SIZE) {
cdns_i2c_writereg(CDNS_I2C_TRANSFER_SIZE,
CDNS_I2C_XFER_SIZE_OFFSET);
id->curr_recv_count = CDNS_I2C_TRANSFER_SIZE;
} else {
cdns_i2c_writereg(id->recv_count,
CDNS_I2C_XFER_SIZE_OFFSET);
id->curr_recv_count = id->recv_count;
}
}

/* Clear hold (if not repeated start) and signal completion */
Expand Down Expand Up @@ -535,11 +567,13 @@ static int cdns_i2c_master_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
int ret, count;
u32 reg;
struct cdns_i2c *id = adap->algo_data;
bool hold_quirk;

/* Check if the bus is free */
if (cdns_i2c_readreg(CDNS_I2C_SR_OFFSET) & CDNS_I2C_SR_BA)
return -EAGAIN;

hold_quirk = !!(id->quirks & CDNS_I2C_BROKEN_HOLD_BIT);
/*
* Set the flag to one when multiple messages are to be
* processed with a repeated start.
Expand All @@ -552,7 +586,7 @@ static int cdns_i2c_master_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
* followed by any other message, an error is returned
* indicating that this sequence is not supported.
*/
for (count = 0; count < num - 1; count++) {
for (count = 0; (count < num - 1 && hold_quirk); count++) {
if (msgs[count].flags & I2C_M_RD) {
dev_warn(adap->dev.parent,
"Can't do repeated start after a receive message\n");
Expand Down Expand Up @@ -815,6 +849,17 @@ static int __maybe_unused cdns_i2c_resume(struct device *_dev)
static SIMPLE_DEV_PM_OPS(cdns_i2c_dev_pm_ops, cdns_i2c_suspend,
cdns_i2c_resume);

static const struct cdns_platform_data r1p10_i2c_def = {
.quirks = CDNS_I2C_BROKEN_HOLD_BIT,
};

static const struct of_device_id cdns_i2c_of_match[] = {
{ .compatible = "cdns,i2c-r1p10", .data = &r1p10_i2c_def },
{ .compatible = "cdns,i2c-r1p14",},
{ /* end of table */ }
};
MODULE_DEVICE_TABLE(of, cdns_i2c_of_match);

/**
* cdns_i2c_probe - Platform registration call
* @pdev: Handle to the platform device structure
Expand All @@ -830,13 +875,20 @@ static int cdns_i2c_probe(struct platform_device *pdev)
struct resource *r_mem;
struct cdns_i2c *id;
int ret;
const struct of_device_id *match;

id = devm_kzalloc(&pdev->dev, sizeof(*id), GFP_KERNEL);
if (!id)
return -ENOMEM;

platform_set_drvdata(pdev, id);

match = of_match_node(cdns_i2c_of_match, pdev->dev.of_node);
if (match && match->data) {
const struct cdns_platform_data *data = match->data;
id->quirks = data->quirks;
}

r_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
id->membase = devm_ioremap_resource(&pdev->dev, r_mem);
if (IS_ERR(id->membase))
Expand Down Expand Up @@ -935,12 +987,6 @@ static int cdns_i2c_remove(struct platform_device *pdev)
return 0;
}

static const struct of_device_id cdns_i2c_of_match[] = {
{ .compatible = "cdns,i2c-r1p10", },
{ /* end of table */ }
};
MODULE_DEVICE_TABLE(of, cdns_i2c_of_match);

static struct platform_driver cdns_i2c_drv = {
.driver = {
.name = DRIVER_NAME,
Expand Down

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