[PATCH] i2c: removed work arounds in i2c driver for Zynq Ultrascale+ MPSoC
Anurag Kumar Vulisha
anurag.kumar.vulisha at xilinx.com
Thu Jun 18 09:19:42 PDT 2015
Removed the workarounds present in the cadence i2c driver for
Zynq Ultrascale+ MPSoC
Signed-off-by: Anurag Kumar Vulisha <anuragku at xilinx.com>
---
.../devicetree/bindings/i2c/i2c-cadence.txt | 2 +-
drivers/i2c/busses/i2c-cadence.c | 67 ++++++++++++++++---
2 files changed, 57 insertions(+), 12 deletions(-)
diff --git a/Documentation/devicetree/bindings/i2c/i2c-cadence.txt b/Documentation/devicetree/bindings/i2c/i2c-cadence.txt
index 7cb0b56..11ef7f2 100644
--- a/Documentation/devicetree/bindings/i2c/i2c-cadence.txt
+++ b/Documentation/devicetree/bindings/i2c/i2c-cadence.txt
@@ -2,7 +2,7 @@ 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: Compatibility string.Use 'cdns,i2c-r1p10' or 'cdns,i2c-r1p14'
- clocks: Input clock specifier. Refer to common clock bindings.
- interrupts: Interrupt specifier. Refer to interrupt bindings.
- #address-cells: Should be 1.
diff --git a/drivers/i2c/busses/i2c-cadence.c b/drivers/i2c/busses/i2c-cadence.c
index 2ee78e0..6ad1571 100644
--- a/drivers/i2c/busses/i2c-cadence.c
+++ b/drivers/i2c/busses/i2c-cadence.c
@@ -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 */
@@ -113,6 +114,8 @@
#define CDNS_I2C_TIMEOUT_MAX 0xFF
+#define CDNS_I2C_BROKEN_HOLD_BIT 0x00000001
+
#define cdns_i2c_readreg(offset) readl_relaxed(id->membase + offset)
#define cdns_i2c_writereg(val, offset) writel_relaxed(val, id->membase + offset)
@@ -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;
@@ -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, \
@@ -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
@@ -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;
@@ -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) ||
@@ -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;
}
@@ -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))
@@ -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 */
@@ -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.
@@ -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");
@@ -815,6 +849,16 @@ 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
@@ -830,6 +874,7 @@ 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)
@@ -837,6 +882,12 @@ static int cdns_i2c_probe(struct platform_device *pdev)
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))
@@ -935,12 +986,6 @@ 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,
--
1.7.4
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