[PATCH v2 05/10] i2c-octeon: Add support for cn78XX chips

From: Jan Glauber
Date: Fri Mar 04 2016 - 13:00:58 EST


From: David Daney <ddaney@xxxxxxxxxxxxxxxxxx>

cn78XX has a different interrupt architecture, so we have to manage
the interrupts differently.

Signed-off-by: David Daney <ddaney@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Jan Glauber <jglauber@xxxxxxxxxx>
---
drivers/i2c/busses/i2c-octeon.c | 156 ++++++++++++++++++++++++++++++++++------
1 file changed, 136 insertions(+), 20 deletions(-)

diff --git a/drivers/i2c/busses/i2c-octeon.c b/drivers/i2c/busses/i2c-octeon.c
index d48456a..0b28d8c 100644
--- a/drivers/i2c/busses/i2c-octeon.c
+++ b/drivers/i2c/busses/i2c-octeon.c
@@ -15,6 +15,7 @@
#include <linux/interrupt.h>
#include <linux/kernel.h>
#include <linux/module.h>
+#include <linux/atomic.h>
#include <linux/delay.h>
#include <linux/sched.h>
#include <linux/slab.h>
@@ -109,11 +110,18 @@ struct octeon_i2c {
wait_queue_head_t queue;
struct i2c_adapter adap;
int irq;
+ int hlc_irq; /* For cn7890 only */
u32 twsi_freq;
int sys_freq;
void __iomem *twsi_base;
struct device *dev;
bool hlc_enabled;
+ void (*int_en) (struct octeon_i2c *);
+ void (*int_dis) (struct octeon_i2c *);
+ void (*hlc_int_en) (struct octeon_i2c *);
+ void (*hlc_int_dis) (struct octeon_i2c *);
+ atomic_t int_en_cnt;
+ atomic_t hlc_int_en_cnt;
};

static int reset_how;
@@ -215,6 +223,58 @@ static void octeon_i2c_disable_hlc(struct octeon_i2c *i2c)
}

/**
+ * octeon_i2c_int_enable78 - enable the CORE interrupt
+ * @i2c: The struct octeon_i2c
+ *
+ * The interrupt will be asserted when there is non-STAT_IDLE state in the
+ * SW_TWSI_EOP_TWSI_STAT register.
+ */
+static void octeon_i2c_int_enable78(struct octeon_i2c *i2c)
+{
+ atomic_inc_return(&i2c->int_en_cnt);
+ enable_irq(i2c->irq);
+}
+
+static void __octeon_i2c_irq_disable(atomic_t *cnt, int irq)
+{
+ int count;
+
+ /*
+ * The interrupt can be disabled in two places, but we only
+ * want to make the disable_irq_nosync() call once, so keep
+ * track with the atomic variable.
+ */
+ count = atomic_dec_if_positive(cnt);
+ if (count >= 0)
+ disable_irq_nosync(irq);
+}
+
+/* disable the CORE interrupt */
+static void octeon_i2c_int_disable78(struct octeon_i2c *i2c)
+{
+ __octeon_i2c_irq_disable(&i2c->int_en_cnt, i2c->irq);
+}
+
+/**
+ * octeon_i2c_hlc_int_enable78 - enable the ST interrupt
+ * @i2c: The struct octeon_i2c
+ *
+ * The interrupt will be asserted when there is non-STAT_IDLE state in
+ * the SW_TWSI_EOP_TWSI_STAT register.
+ */
+static void octeon_i2c_hlc_int_enable78(struct octeon_i2c *i2c)
+{
+ atomic_inc_return(&i2c->hlc_int_en_cnt);
+ enable_irq(i2c->hlc_irq);
+}
+
+/* disable the ST interrupt */
+static void octeon_i2c_hlc_int_disable78(struct octeon_i2c *i2c)
+{
+ __octeon_i2c_irq_disable(&i2c->hlc_int_en_cnt, i2c->hlc_irq);
+}
+
+/**
* bitbang_unblock - unblock the bus
* @i2c: The struct octeon_i2c
*
@@ -251,7 +311,18 @@ static irqreturn_t octeon_i2c_isr(int irq, void *dev_id)
{
struct octeon_i2c *i2c = dev_id;

- octeon_i2c_int_disable(i2c);
+ i2c->int_dis(i2c);
+ wake_up(&i2c->queue);
+
+ return IRQ_HANDLED;
+}
+
+/* interrupt service routine */
+static irqreturn_t octeon_i2c_hlc_isr78(int irq, void *dev_id)
+{
+ struct octeon_i2c *i2c = dev_id;
+
+ i2c->hlc_int_dis(i2c);
wake_up(&i2c->queue);

return IRQ_HANDLED;
@@ -277,10 +348,10 @@ static int octeon_i2c_wait(struct octeon_i2c *i2c)
{
long result;

- octeon_i2c_int_enable(i2c);
+ i2c->int_en(i2c);
result = wait_event_timeout(i2c->queue, octeon_i2c_test_iflg(i2c),
i2c->adap.timeout);
- octeon_i2c_int_disable(i2c);
+ i2c->int_dis(i2c);
if (!result) {
dev_dbg(i2c->dev, "%s: timeout\n", __func__);
return -ETIMEDOUT;
@@ -300,8 +371,8 @@ static int octeon_i2c_enable_hlc(struct octeon_i2c *i2c)

if (i2c->hlc_enabled)
return 0;
- else
- i2c->hlc_enabled = true;
+
+ i2c->hlc_enabled = true;

while (1) {
val = octeon_i2c_read_ctl(i2c) & (TWSI_CTL_STA | TWSI_CTL_STP);
@@ -635,11 +706,10 @@ static int octeon_i2c_hlc_wait(struct octeon_i2c *i2c)
{
int result;

- octeon_i2c_hlc_int_enable(i2c);
+ i2c->hlc_int_en(i2c);
result = wait_event_interruptible_timeout(i2c->queue,
- octeon_i2c_hlc_test_ready(i2c),
- i2c->adap.timeout);
- octeon_i2c_int_disable(i2c);
+ octeon_i2c_hlc_test_ready(i2c), i2c->adap.timeout);
+ i2c->hlc_int_dis(i2c);
if (!result)
octeon_i2c_hlc_int_clear(i2c);

@@ -972,14 +1042,26 @@ static void octeon_i2c_setclock(struct octeon_i2c *i2c)
static int octeon_i2c_probe(struct platform_device *pdev)
{
struct device_node *node = pdev->dev.of_node;
- int irq, result = 0;
+ int irq, hlc_irq = 0, result = 0;
struct resource *res_mem;
struct octeon_i2c *i2c;
-
- /* All adaptors have an irq. */
- irq = platform_get_irq(pdev, 0);
- if (irq < 0)
- return irq;
+ bool cn78xx_style;
+
+ cn78xx_style = of_device_is_compatible(node, "cavium,octeon-7890-twsi");
+ if (cn78xx_style) {
+ hlc_irq = platform_get_irq(pdev, 0);
+ if (hlc_irq < 0)
+ return hlc_irq;
+
+ irq = platform_get_irq(pdev, 2);
+ if (irq < 0)
+ return irq;
+ } else {
+ /* All adaptors have an irq. */
+ irq = platform_get_irq(pdev, 0);
+ if (irq < 0)
+ return irq;
+ }

i2c = devm_kzalloc(&pdev->dev, sizeof(*i2c), GFP_KERNEL);
if (!i2c) {
@@ -1022,11 +1104,44 @@ static int octeon_i2c_probe(struct platform_device *pdev)
init_waitqueue_head(&i2c->queue);
i2c->irq = irq;

- result = devm_request_irq(&pdev->dev, i2c->irq,
- octeon_i2c_isr, 0, DRV_NAME, i2c);
- if (result < 0) {
- dev_err(i2c->dev, "failed to attach interrupt\n");
- goto out;
+ if (cn78xx_style) {
+ i2c->hlc_irq = hlc_irq;
+
+ i2c->int_en = octeon_i2c_int_enable78;
+ i2c->int_dis = octeon_i2c_int_disable78;
+ i2c->hlc_int_en = octeon_i2c_hlc_int_enable78;
+ i2c->hlc_int_dis = octeon_i2c_hlc_int_disable78;
+
+ irq_set_status_flags(i2c->irq, IRQ_NOAUTOEN);
+ irq_set_status_flags(i2c->hlc_irq, IRQ_NOAUTOEN);
+
+ result = devm_request_irq(&pdev->dev, i2c->irq,
+ octeon_i2c_isr, 0, DRV_NAME, i2c);
+
+ if (result < 0) {
+ dev_err(i2c->dev, "failed to attach interrupt\n");
+ goto out;
+ }
+ result = devm_request_irq(&pdev->dev, i2c->hlc_irq,
+ octeon_i2c_hlc_isr78, 0,
+ DRV_NAME, i2c);
+
+ if (result < 0) {
+ dev_err(i2c->dev, "failed to attach interrupt\n");
+ goto out;
+ }
+ } else {
+ i2c->int_en = octeon_i2c_int_enable;
+ i2c->int_dis = octeon_i2c_int_disable;
+ i2c->hlc_int_en = octeon_i2c_hlc_int_enable;
+ i2c->hlc_int_dis = octeon_i2c_int_disable;
+
+ result = devm_request_irq(&pdev->dev, i2c->irq,
+ octeon_i2c_isr, 0, DRV_NAME, i2c);
+ if (result < 0) {
+ dev_err(i2c->dev, "failed to attach interrupt\n");
+ goto out;
+ }
}

result = octeon_i2c_initlowlevel(i2c);
@@ -1067,6 +1182,7 @@ static int octeon_i2c_remove(struct platform_device *pdev)

static const struct of_device_id octeon_i2c_match[] = {
{ .compatible = "cavium,octeon-3860-twsi", },
+ { .compatible = "cavium,octeon-7890-twsi", },
{},
};
MODULE_DEVICE_TABLE(of, octeon_i2c_match);
--
1.9.1