[PATCH v7 07/15] i2c: octeon: Add support for cn78xx chips

Jan Glauber
2016-04-25T14:34:08Z

From: David Daney <david.daney@cavium.com>

cn78xx has a different interrupt architecture, so we have to manage
the interrupts differently.

Signed-off-by: David Daney <ddaney@caviumnetworks.com>
Signed-off-by: Jan Glauber <jglauber@cavium.com>
---
drivers/i2c/busses/i2c-octeon.c | 131 ++++++++++++++++++++++++++++++++++++----
1 file changed, 120 insertions(+), 11 deletions(-)

diff --git a/drivers/i2c/busses/i2c-octeon.c b/drivers/i2c/busses/i2c-octeon.c
index 9520f78..76fa479 100644
--- a/drivers/i2c/busses/i2c-octeon.c
+++ b/drivers/i2c/busses/i2c-octeon.c
@@ -11,6 +11,7 @@
* warranty of any kind, whether express or implied.
*/

+#include <linux/atomic.h>
#include <linux/platform_device.h>
#include <linux/interrupt.h>
#include <linux/kernel.h>
@@ -112,11 +113,18 @@ 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_enable)(struct octeon_i2c *);
+ void (*int_disable)(struct octeon_i2c *);
+ void (*hlc_int_enable)(struct octeon_i2c *);
+ void (*hlc_int_disable)(struct octeon_i2c *);
+ atomic_t int_enable_cnt;
+ atomic_t hlc_int_enable_cnt;
};

static void octeon_i2c_writeq_flush(u64 val, void __iomem *addr)
@@ -217,6 +225,58 @@ static void octeon_i2c_int_disable(struct octeon_i2c *i2c)
octeon_i2c_write_int(i2c, 0);
}

+/**
+ * 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_enable_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_enable_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_enable_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_enable_cnt, i2c->hlc_irq);
+}
+
/*
* Cleanup low-level state & enable high-level controller.
*/
@@ -263,7 +323,18 @@ static irqreturn_t octeon_i2c_isr(int irq, void *dev_id)
{
struct octeon_i2c *i2c = dev_id;

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

return IRQ_HANDLED;
@@ -284,10 +355,10 @@ static int octeon_i2c_wait(struct octeon_i2c *i2c)
{
long time_left;

- octeon_i2c_int_enable(i2c);
+ i2c->int_enable(i2c);
time_left = wait_event_timeout(i2c->queue, octeon_i2c_test_iflg(i2c),
i2c->adap.timeout);
- octeon_i2c_int_disable(i2c);
+ i2c->int_disable(i2c);
if (!time_left) {
dev_dbg(i2c->dev, "%s: timeout\n", __func__);
return -ETIMEDOUT;
@@ -385,11 +456,11 @@ static int octeon_i2c_hlc_wait(struct octeon_i2c *i2c)
{
int time_left;

- octeon_i2c_hlc_int_enable(i2c);
+ i2c->hlc_int_enable(i2c);
time_left = wait_event_timeout(i2c->queue,
octeon_i2c_hlc_test_ready(i2c),
i2c->adap.timeout);
- octeon_i2c_int_disable(i2c);
+ i2c->hlc_int_disable(i2c);
if (!time_left) {
octeon_i2c_hlc_int_clear(i2c);
return -ETIMEDOUT;
@@ -942,14 +1013,26 @@ static struct i2c_adapter octeon_i2c_ops = {
static int octeon_i2c_probe(struct platform_device *pdev)
{
struct device_node *node = pdev->dev.of_node;
+ int irq, result = 0, hlc_irq = 0;
struct resource *res_mem;
struct octeon_i2c *i2c;
- int irq, result = 0;
-
- /* 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) {
@@ -984,6 +1067,31 @@ static int octeon_i2c_probe(struct platform_device *pdev)

i2c->irq = irq;

+ if (cn78xx_style) {
+ i2c->hlc_irq = hlc_irq;
+
+ i2c->int_enable = octeon_i2c_int_enable78;
+ i2c->int_disable = octeon_i2c_int_disable78;
+ i2c->hlc_int_enable = octeon_i2c_hlc_int_enable78;
+ i2c->hlc_int_disable = 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->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_enable = octeon_i2c_int_enable;
+ i2c->int_disable = octeon_i2c_int_disable;
+ i2c->hlc_int_enable = octeon_i2c_hlc_int_enable;
+ i2c->hlc_int_disable = octeon_i2c_int_disable;
+ }
+
result = devm_request_irq(&pdev->dev, i2c->irq,
octeon_i2c_isr, 0, DRV_NAME, i2c);
if (result < 0) {
@@ -1030,6 +1138,7 @@ 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