aboutsummaryrefslogtreecommitdiff
path: root/drivers/i2c/muxes
diff options
context:
space:
mode:
authorPhil Reid2017-01-25 09:31:08 +0800
committerPeter Rosin2017-02-10 08:23:51 +0100
commitf2114795f721bd5028284ddf84b150798a9b7a73 (patch)
treefa8a69ca6f27bed885bed0005cc6a04cafe1768d /drivers/i2c/muxes
parent9aedcc61ed101b4dbb7fa7013deca4a7ed7ff418 (diff)
i2c: mux: pca954x: Add interrupt controller support
Various muxes can aggregate multiple interrupts from each i2c bus. All of the muxes with interrupt support combine the active low irq lines using an internal 'and' function and generate a combined active low output. The muxes do provide the ability to read a control register to determine which irq is active. By making the mux an irq controller isr latency can potentially be reduced by reading the status register and then only calling the registered isr on that bus segment. As there is no irq masking on the mux irq are disabled until irq_unmask is called at least once. Signed-off-by: Phil Reid <preid@electromag.com.au> Signed-off-by: Peter Rosin <peda@axentia.se>
Diffstat (limited to 'drivers/i2c/muxes')
-rw-r--r--drivers/i2c/muxes/i2c-mux-pca954x.c141
1 files changed, 139 insertions, 2 deletions
diff --git a/drivers/i2c/muxes/i2c-mux-pca954x.c b/drivers/i2c/muxes/i2c-mux-pca954x.c
index bbf088e08d73..06fd9cc85b23 100644
--- a/drivers/i2c/muxes/i2c-mux-pca954x.c
+++ b/drivers/i2c/muxes/i2c-mux-pca954x.c
@@ -41,14 +41,20 @@
#include <linux/i2c.h>
#include <linux/i2c-mux.h>
#include <linux/i2c/pca954x.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_device.h>
+#include <linux/of_irq.h>
#include <linux/pm.h>
#include <linux/slab.h>
+#include <linux/spinlock.h>
#define PCA954X_MAX_NCHANS 8
+#define PCA954X_IRQ_OFFSET 4
+
enum pca_type {
pca_9540,
pca_9542,
@@ -63,6 +69,7 @@ enum pca_type {
struct chip_desc {
u8 nchans;
u8 enable; /* used for muxes only */
+ u8 has_irq;
enum muxtype {
pca954x_ismux = 0,
pca954x_isswi
@@ -75,6 +82,10 @@ struct pca954x {
u8 last_chan; /* last register value */
u8 deselect;
struct i2c_client *client;
+
+ struct irq_domain *irq;
+ unsigned int irq_mask;
+ spinlock_t lock;
};
/* Provide specs for the PCA954x types we know about */
@@ -87,19 +98,23 @@ static const struct chip_desc chips[] = {
[pca_9542] = {
.nchans = 2,
.enable = 0x4,
+ .has_irq = 1,
.muxtype = pca954x_ismux,
},
[pca_9543] = {
.nchans = 2,
+ .has_irq = 1,
.muxtype = pca954x_isswi,
},
[pca_9544] = {
.nchans = 4,
.enable = 0x4,
+ .has_irq = 1,
.muxtype = pca954x_ismux,
},
[pca_9545] = {
.nchans = 4,
+ .has_irq = 1,
.muxtype = pca954x_isswi,
},
[pca_9547] = {
@@ -222,6 +237,114 @@ static int pca954x_deselect_mux(struct i2c_mux_core *muxc, u32 chan)
return pca954x_reg_write(muxc->parent, client, data->last_chan);
}
+static irqreturn_t pca954x_irq_handler(int irq, void *dev_id)
+{
+ struct pca954x *data = dev_id;
+ unsigned int child_irq;
+ int ret, i, handled = 0;
+
+ ret = i2c_smbus_read_byte(data->client);
+ if (ret < 0)
+ return IRQ_NONE;
+
+ for (i = 0; i < data->chip->nchans; i++) {
+ if (ret & BIT(PCA954X_IRQ_OFFSET + i)) {
+ child_irq = irq_linear_revmap(data->irq, i);
+ handle_nested_irq(child_irq);
+ handled++;
+ }
+ }
+ return handled ? IRQ_HANDLED : IRQ_NONE;
+}
+
+static void pca954x_irq_mask(struct irq_data *idata)
+{
+ struct pca954x *data = irq_data_get_irq_chip_data(idata);
+ unsigned int pos = idata->hwirq;
+ unsigned long flags;
+
+ spin_lock_irqsave(&data->lock, flags);
+
+ data->irq_mask &= ~BIT(pos);
+ if (!data->irq_mask)
+ disable_irq(data->client->irq);
+
+ spin_unlock_irqrestore(&data->lock, flags);
+}
+
+static void pca954x_irq_unmask(struct irq_data *idata)
+{
+ struct pca954x *data = irq_data_get_irq_chip_data(idata);
+ unsigned int pos = idata->hwirq;
+ unsigned long flags;
+
+ spin_lock_irqsave(&data->lock, flags);
+
+ if (!data->irq_mask)
+ enable_irq(data->client->irq);
+ data->irq_mask |= BIT(pos);
+
+ spin_unlock_irqrestore(&data->lock, flags);
+}
+
+static int pca954x_irq_set_type(struct irq_data *idata, unsigned int type)
+{
+ if ((type & IRQ_TYPE_SENSE_MASK) != IRQ_TYPE_LEVEL_LOW)
+ return -EINVAL;
+ return 0;
+}
+
+static struct irq_chip pca954x_irq_chip = {
+ .name = "i2c-mux-pca954x",
+ .irq_mask = pca954x_irq_mask,
+ .irq_unmask = pca954x_irq_unmask,
+ .irq_set_type = pca954x_irq_set_type,
+};
+
+static int pca954x_irq_setup(struct i2c_mux_core *muxc)
+{
+ struct pca954x *data = i2c_mux_priv(muxc);
+ struct i2c_client *client = data->client;
+ int c, err, irq;
+
+ if (!data->chip->has_irq || client->irq <= 0)
+ return 0;
+
+ spin_lock_init(&data->lock);
+
+ data->irq = irq_domain_add_linear(client->dev.of_node,
+ data->chip->nchans,
+ &irq_domain_simple_ops, data);
+ if (!data->irq)
+ return -ENODEV;
+
+ for (c = 0; c < data->chip->nchans; c++) {
+ irq = irq_create_mapping(data->irq, c);
+ irq_set_chip_data(irq, data);
+ irq_set_chip_and_handler(irq, &pca954x_irq_chip,
+ handle_simple_irq);
+ }
+
+ err = devm_request_threaded_irq(&client->dev, data->client->irq, NULL,
+ pca954x_irq_handler,
+ IRQF_ONESHOT | IRQF_SHARED,
+ "pca954x", data);
+ if (err)
+ goto err_req_irq;
+
+ disable_irq(data->client->irq);
+
+ return 0;
+err_req_irq:
+ for (c = 0; c < data->chip->nchans; c++) {
+ irq = irq_find_mapping(data->irq, c);
+ irq_dispose_mapping(irq);
+ }
+ irq_domain_remove(data->irq);
+
+ return err;
+}
+
/*
* I2C init/probing/exit functions
*/
@@ -286,6 +409,10 @@ static int pca954x_probe(struct i2c_client *client,
idle_disconnect_dt = of_node &&
of_property_read_bool(of_node, "i2c-mux-idle-disconnect");
+ ret = pca954x_irq_setup(muxc);
+ if (ret)
+ goto fail_del_adapters;
+
/* Now create an adapter for each channel */
for (num = 0; num < data->chip->nchans; num++) {
bool idle_disconnect_pd = false;
@@ -311,7 +438,7 @@ static int pca954x_probe(struct i2c_client *client,
dev_err(&client->dev,
"failed to register multiplexed adapter"
" %d as bus %d\n", num, force);
- goto virt_reg_failed;
+ goto fail_del_adapters;
}
}
@@ -322,7 +449,7 @@ static int pca954x_probe(struct i2c_client *client,
return 0;
-virt_reg_failed:
+fail_del_adapters:
i2c_mux_del_adapters(muxc);
return ret;
}
@@ -330,6 +457,16 @@ virt_reg_failed:
static int pca954x_remove(struct i2c_client *client)
{
struct i2c_mux_core *muxc = i2c_get_clientdata(client);
+ struct pca954x *data = i2c_mux_priv(muxc);
+ int c, irq;
+
+ if (data->irq) {
+ for (c = 0; c < data->chip->nchans; c++) {
+ irq = irq_find_mapping(data->irq, c);
+ irq_dispose_mapping(irq);
+ }
+ irq_domain_remove(data->irq);
+ }
i2c_mux_del_adapters(muxc);
return 0;