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-rw-r--r--drivers/gpio/mcp23s08.c133
-rw-r--r--include/linux/spi/mcp23s08.h25
2 files changed, 118 insertions, 40 deletions
diff --git a/drivers/gpio/mcp23s08.c b/drivers/gpio/mcp23s08.c
index 7efd7d3..8a1b405 100644
--- a/drivers/gpio/mcp23s08.c
+++ b/drivers/gpio/mcp23s08.c
@@ -40,15 +40,26 @@ struct mcp23s08 {
struct spi_device *spi;
u8 addr;
+ u8 cache[11];
/* lock protects the cached values */
struct mutex lock;
- u8 cache[11];
struct gpio_chip chip;
struct work_struct work;
};
+/* A given spi_device can represent up to four mcp23s08 chips
+ * sharing the same chipselect but using different addresses
+ * (e.g. chips #0 and #3 might be populated, but not #1 or $2).
+ * Driver data holds all the per-chip data.
+ */
+struct mcp23s08_driver_data {
+ unsigned ngpio;
+ struct mcp23s08 *mcp[4];
+ struct mcp23s08 chip[];
+};
+
static int mcp23s08_read(struct mcp23s08 *mcp, unsigned reg)
{
u8 tx[2], rx[1];
@@ -208,25 +219,18 @@ done:
/*----------------------------------------------------------------------*/
-static int mcp23s08_probe(struct spi_device *spi)
+static int mcp23s08_probe_one(struct spi_device *spi, unsigned addr,
+ unsigned base, unsigned pullups)
{
- struct mcp23s08 *mcp;
- struct mcp23s08_platform_data *pdata;
+ struct mcp23s08_driver_data *data = spi_get_drvdata(spi);
+ struct mcp23s08 *mcp = data->mcp[addr];
int status;
int do_update = 0;
- pdata = spi->dev.platform_data;
- if (!pdata || pdata->slave > 3 || !pdata->base)
- return -ENODEV;
-
- mcp = kzalloc(sizeof *mcp, GFP_KERNEL);
- if (!mcp)
- return -ENOMEM;
-
mutex_init(&mcp->lock);
mcp->spi = spi;
- mcp->addr = 0x40 | (pdata->slave << 1);
+ mcp->addr = 0x40 | (addr << 1);
mcp->chip.label = "mcp23s08",
@@ -236,27 +240,28 @@ static int mcp23s08_probe(struct spi_device *spi)
mcp->chip.set = mcp23s08_set;
mcp->chip.dbg_show = mcp23s08_dbg_show;
- mcp->chip.base = pdata->base;
+ mcp->chip.base = base;
mcp->chip.ngpio = 8;
mcp->chip.can_sleep = 1;
mcp->chip.dev = &spi->dev;
mcp->chip.owner = THIS_MODULE;
- spi_set_drvdata(spi, mcp);
-
- /* verify MCP_IOCON.SEQOP = 0, so sequential reads work */
+ /* verify MCP_IOCON.SEQOP = 0, so sequential reads work,
+ * and MCP_IOCON.HAEN = 1, so we work with all chips.
+ */
status = mcp23s08_read(mcp, MCP_IOCON);
if (status < 0)
goto fail;
- if (status & IOCON_SEQOP) {
+ if ((status & IOCON_SEQOP) || !(status & IOCON_HAEN)) {
status &= ~IOCON_SEQOP;
+ status |= IOCON_HAEN;
status = mcp23s08_write(mcp, MCP_IOCON, (u8) status);
if (status < 0)
goto fail;
}
/* configure ~100K pullups */
- status = mcp23s08_write(mcp, MCP_GPPU, pdata->pullups);
+ status = mcp23s08_write(mcp, MCP_GPPU, pullups);
if (status < 0)
goto fail;
@@ -283,11 +288,58 @@ static int mcp23s08_probe(struct spi_device *spi)
tx[1] = MCP_IPOL;
memcpy(&tx[2], &mcp->cache[MCP_IPOL], sizeof(tx) - 2);
status = spi_write_then_read(mcp->spi, tx, sizeof tx, NULL, 0);
-
- /* FIXME check status... */
+ if (status < 0)
+ goto fail;
}
status = gpiochip_add(&mcp->chip);
+fail:
+ if (status < 0)
+ dev_dbg(&spi->dev, "can't setup chip %d, --> %d\n",
+ addr, status);
+ return status;
+}
+
+static int mcp23s08_probe(struct spi_device *spi)
+{
+ struct mcp23s08_platform_data *pdata;
+ unsigned addr;
+ unsigned chips = 0;
+ struct mcp23s08_driver_data *data;
+ int status;
+ unsigned base;
+
+ pdata = spi->dev.platform_data;
+ if (!pdata || !gpio_is_valid(pdata->base))
+ return -ENODEV;
+
+ for (addr = 0; addr < 4; addr++) {
+ if (!pdata->chip[addr].is_present)
+ continue;
+ chips++;
+ }
+ if (!chips)
+ return -ENODEV;
+
+ data = kzalloc(sizeof *data + chips * sizeof(struct mcp23s08),
+ GFP_KERNEL);
+ if (!data)
+ return -ENOMEM;
+ spi_set_drvdata(spi, data);
+
+ base = pdata->base;
+ for (addr = 0; addr < 4; addr++) {
+ if (!pdata->chip[addr].is_present)
+ continue;
+ chips--;
+ data->mcp[addr] = &data->chip[chips];
+ status = mcp23s08_probe_one(spi, addr, base,
+ pdata->chip[addr].pullups);
+ if (status < 0)
+ goto fail;
+ base += 8;
+ }
+ data->ngpio = base - pdata->base;
/* NOTE: these chips have a relatively sane IRQ framework, with
* per-signal masking and level/edge triggering. It's not yet
@@ -295,8 +347,9 @@ static int mcp23s08_probe(struct spi_device *spi)
*/
if (pdata->setup) {
- status = pdata->setup(spi, mcp->chip.base,
- mcp->chip.ngpio, pdata->context);
+ status = pdata->setup(spi,
+ pdata->base, data->ngpio,
+ pdata->context);
if (status < 0)
dev_dbg(&spi->dev, "setup --> %d\n", status);
}
@@ -304,19 +357,29 @@ static int mcp23s08_probe(struct spi_device *spi)
return 0;
fail:
- kfree(mcp);
+ for (addr = 0; addr < 4; addr++) {
+ int tmp;
+
+ if (!data->mcp[addr])
+ continue;
+ tmp = gpiochip_remove(&data->mcp[addr]->chip);
+ if (tmp < 0)
+ dev_err(&spi->dev, "%s --> %d\n", "remove", tmp);
+ }
+ kfree(data);
return status;
}
static int mcp23s08_remove(struct spi_device *spi)
{
- struct mcp23s08 *mcp = spi_get_drvdata(spi);
+ struct mcp23s08_driver_data *data = spi_get_drvdata(spi);
struct mcp23s08_platform_data *pdata = spi->dev.platform_data;
+ unsigned addr;
int status = 0;
if (pdata->teardown) {
status = pdata->teardown(spi,
- mcp->chip.base, mcp->chip.ngpio,
+ pdata->base, data->ngpio,
pdata->context);
if (status < 0) {
dev_err(&spi->dev, "%s --> %d\n", "teardown", status);
@@ -324,11 +387,20 @@ static int mcp23s08_remove(struct spi_device *spi)
}
}
- status = gpiochip_remove(&mcp->chip);
+ for (addr = 0; addr < 4; addr++) {
+ int tmp;
+
+ if (!data->mcp[addr])
+ continue;
+
+ tmp = gpiochip_remove(&data->mcp[addr]->chip);
+ if (tmp < 0) {
+ dev_err(&spi->dev, "%s --> %d\n", "remove", tmp);
+ status = tmp;
+ }
+ }
if (status == 0)
- kfree(mcp);
- else
- dev_err(&spi->dev, "%s --> %d\n", "remove", status);
+ kfree(data);
return status;
}
@@ -356,4 +428,3 @@ static void __exit mcp23s08_exit(void)
module_exit(mcp23s08_exit);
MODULE_LICENSE("GPL");
-
diff --git a/include/linux/spi/mcp23s08.h b/include/linux/spi/mcp23s08.h
index 835ddf4..22ef107 100644
--- a/include/linux/spi/mcp23s08.h
+++ b/include/linux/spi/mcp23s08.h
@@ -1,18 +1,25 @@
-/* FIXME driver should be able to handle all four slaves that
- * can be hooked up to each chipselect, as well as IRQs...
- */
+/* FIXME driver should be able to handle IRQs... */
+
+struct mcp23s08_chip_info {
+ bool is_present; /* true iff populated */
+ u8 pullups; /* BIT(x) means enable pullup x */
+};
struct mcp23s08_platform_data {
- /* four slaves can share one SPI chipselect */
- u8 slave;
+ /* Four slaves (numbered 0..3) can share one SPI chipselect, and
+ * will provide 8..32 GPIOs using 1..4 gpio_chip instances.
+ */
+ struct mcp23s08_chip_info chip[4];
- /* number assigned to the first GPIO */
+ /* "base" is the number of the first GPIO. Dynamic assignment is
+ * not currently supported, and even if there are gaps in chip
+ * addressing the GPIO numbers are sequential .. so for example
+ * if only slaves 0 and 3 are present, their GPIOs range from
+ * base to base+15.
+ */
unsigned base;
- /* pins with pullups */
- u8 pullups;
-
void *context; /* param to setup/teardown */
int (*setup)(struct spi_device *spi,
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