gpio/mcp23s08: support mcp23s17 variant

mpc23s17 is very similar to the mcp23s08, except that registers are 16bit
wide, so extend the interface to work with both variants.

The s17 variant also has an additional address pin, so adjust platform
data structure to support up to 8 devices per SPI chipselect.

Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>

2 files changed, 146 insertions, 51 deletions

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index 664660e56335..9573b330f647 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -368,11 +368,11 @@ config GPIO_MAX7301
           GPIO driver for Maxim MAX7301 SPI-based GPIO expander.
 
 config GPIO_MCP23S08
-        tristate "Microchip MCP23S08 I/O expander"
+        tristate "Microchip MCP23Sxx I/O expander"
         depends on SPI_MASTER
         help
-          SPI driver for Microchip MCP23S08 I/O expander.  This provides
-          a GPIO interface supporting inputs and outputs.
+          SPI driver for Microchip MCP23S08/MPC23S17 I/O expanders.
+          This provides a GPIO interface supporting inputs and outputs.
 
 config GPIO_MC33880
         tristate "Freescale MC33880 high-side/low-side switch"
diff --git a/drivers/gpio/mcp23s08.c b/drivers/gpio/mcp23s08.c
index 69f6f1955a31..40e076083ec0 100644
--- a/drivers/gpio/mcp23s08.c
+++ b/drivers/gpio/mcp23s08.c
@@ -10,7 +10,13 @@
 #include <linux/spi/spi.h>
 #include <linux/spi/mcp23s08.h>
 #include <linux/slab.h>
+#include <asm/byteorder.h>
 
+/**
+ * MCP types supported by driver
+ */
+#define MCP_TYPE_S08    0
+#define MCP_TYPE_S17    1
 
 /* Registers are all 8 bits wide.
  *
@@ -35,27 +41,38 @@
 #define MCP_GPIO        0x09
 #define MCP_OLAT        0x0a
 
+struct mcp23s08;
+
+struct mcp23s08_ops {
+        int     (*read)(struct mcp23s08 *mcp, unsigned reg);
+        int     (*write)(struct mcp23s08 *mcp, unsigned reg, unsigned val);
+        int     (*read_regs)(struct mcp23s08 *mcp, unsigned reg,
+                             u16 *vals, unsigned n);
+};
+
 struct mcp23s08 {
         struct spi_device       *spi;
         u8                      addr;
 
-        u8                      cache[11];
+        u16                     cache[11];
         /* lock protects the cached values */
         struct mutex            lock;
 
         struct gpio_chip        chip;
 
         struct work_struct      work;
+
+        const struct mcp23s08_ops       *ops;
 };
 
-/* A given spi_device can represent up to four mcp23s08 chips
+/* A given spi_device can represent up to eight mcp23sxx 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         *mcp[8];
         struct mcp23s08         chip[];
 };
 
@@ -70,7 +87,7 @@ static int mcp23s08_read(struct mcp23s08 *mcp, unsigned reg)
         return (status < 0) ? status : rx[0];
 }
 
-static int mcp23s08_write(struct mcp23s08 *mcp, unsigned reg, u8 val)
+static int mcp23s08_write(struct mcp23s08 *mcp, unsigned reg, unsigned val)
 {
         u8      tx[3];
 
@@ -81,17 +98,81 @@ static int mcp23s08_write(struct mcp23s08 *mcp, unsigned reg, u8 val)
 }
 
 static int
-mcp23s08_read_regs(struct mcp23s08 *mcp, unsigned reg, u8 *vals, unsigned n)
+mcp23s08_read_regs(struct mcp23s08 *mcp, unsigned reg, u16 *vals, unsigned n)
 {
-        u8      tx[2];
+        u8      tx[2], *tmp;
+        int     status;
 
         if ((n + reg) > sizeof mcp->cache)
                 return -EINVAL;
         tx[0] = mcp->addr | 0x01;
         tx[1] = reg;
-        return spi_write_then_read(mcp->spi, tx, sizeof tx, vals, n);
+
+        tmp = (u8 *)vals;
+        status = spi_write_then_read(mcp->spi, tx, sizeof tx, tmp, n);
+        if (status >= 0) {
+                while (n--)
+                        vals[n] = tmp[n]; /* expand to 16bit */
+        }
+        return status;
+}
+
+static int mcp23s17_read(struct mcp23s08 *mcp, unsigned reg)
+{
+        u8      tx[2], rx[2];
+        int     status;
+
+        tx[0] = mcp->addr | 0x01;
+        tx[1] = reg << 1;
+        status = spi_write_then_read(mcp->spi, tx, sizeof tx, rx, sizeof rx);
+        return (status < 0) ? status : (rx[0] | (rx[1] << 8));
+}
+
+static int mcp23s17_write(struct mcp23s08 *mcp, unsigned reg, unsigned val)
+{
+        u8      tx[4];
+
+        tx[0] = mcp->addr;
+        tx[1] = reg << 1;
+        tx[2] = val;
+        tx[3] = val >> 8;
+        return spi_write_then_read(mcp->spi, tx, sizeof tx, NULL, 0);
+}
+
+static int
+mcp23s17_read_regs(struct mcp23s08 *mcp, unsigned reg, u16 *vals, unsigned n)
+{
+        u8      tx[2];
+        int     status;
+
+        if ((n + reg) > sizeof mcp->cache)
+                return -EINVAL;
+        tx[0] = mcp->addr | 0x01;
+        tx[1] = reg << 1;
+
+        status = spi_write_then_read(mcp->spi, tx, sizeof tx,
+                                     (u8 *)vals, n * 2);
+        if (status >= 0) {
+                while (n--)
+                        vals[n] = __le16_to_cpu((__le16)vals[n]);
+        }
+
+        return status;
 }
 
+static const struct mcp23s08_ops mcp23s08_ops = {
+        .read           = mcp23s08_read,
+        .write          = mcp23s08_write,
+        .read_regs      = mcp23s08_read_regs,
+};
+
+static const struct mcp23s08_ops mcp23s17_ops = {
+        .read           = mcp23s17_read,
+        .write          = mcp23s17_write,
+        .read_regs      = mcp23s17_read_regs,
+};
+
+
 /*----------------------------------------------------------------------*/
 
 static int mcp23s08_direction_input(struct gpio_chip *chip, unsigned offset)
@@ -101,7 +182,7 @@ static int mcp23s08_direction_input(struct gpio_chip *chip, unsigned offset)
 
         mutex_lock(&mcp->lock);
         mcp->cache[MCP_IODIR] |= (1 << offset);
-        status = mcp23s08_write(mcp, MCP_IODIR, mcp->cache[MCP_IODIR]);
+        status = mcp->ops->write(mcp, MCP_IODIR, mcp->cache[MCP_IODIR]);
         mutex_unlock(&mcp->lock);
         return status;
 }
@@ -114,7 +195,7 @@ static int mcp23s08_get(struct gpio_chip *chip, unsigned offset)
         mutex_lock(&mcp->lock);
 
         /* REVISIT reading this clears any IRQ ... */
-        status = mcp23s08_read(mcp, MCP_GPIO);
+        status = mcp->ops->read(mcp, MCP_GPIO);
         if (status < 0)
                 status = 0;
         else {
@@ -127,20 +208,20 @@ static int mcp23s08_get(struct gpio_chip *chip, unsigned offset)
 
 static int __mcp23s08_set(struct mcp23s08 *mcp, unsigned mask, int value)
 {
-        u8 olat = mcp->cache[MCP_OLAT];
+        unsigned olat = mcp->cache[MCP_OLAT];
 
         if (value)
                 olat |= mask;
         else
                 olat &= ~mask;
         mcp->cache[MCP_OLAT] = olat;
-        return mcp23s08_write(mcp, MCP_OLAT, olat);
+        return mcp->ops->write(mcp, MCP_OLAT, olat);
 }
 
 static void mcp23s08_set(struct gpio_chip *chip, unsigned offset, int value)
 {
         struct mcp23s08 *mcp = container_of(chip, struct mcp23s08, chip);
-        u8 mask = 1 << offset;
+        unsigned mask = 1 << offset;
 
         mutex_lock(&mcp->lock);
         __mcp23s08_set(mcp, mask, value);
@@ -151,14 +232,14 @@ static int
 mcp23s08_direction_output(struct gpio_chip *chip, unsigned offset, int value)
 {
         struct mcp23s08 *mcp = container_of(chip, struct mcp23s08, chip);
-        u8 mask = 1 << offset;
+        unsigned mask = 1 << offset;
         int status;
 
         mutex_lock(&mcp->lock);
         status = __mcp23s08_set(mcp, mask, value);
         if (status == 0) {
                 mcp->cache[MCP_IODIR] &= ~mask;
-                status = mcp23s08_write(mcp, MCP_IODIR, mcp->cache[MCP_IODIR]);
+                status = mcp->ops->write(mcp, MCP_IODIR, mcp->cache[MCP_IODIR]);
         }
         mutex_unlock(&mcp->lock);
         return status;
@@ -184,16 +265,16 @@ static void mcp23s08_dbg_show(struct seq_file *s, struct gpio_chip *chip)
         mcp = container_of(chip, struct mcp23s08, chip);
 
         /* NOTE: we only handle one bank for now ... */
-        bank = '0' + ((mcp->addr >> 1) & 0x3);
+        bank = '0' + ((mcp->addr >> 1) & 0x7);
 
         mutex_lock(&mcp->lock);
-        t = mcp23s08_read_regs(mcp, 0, mcp->cache, sizeof mcp->cache);
+        t = mcp->ops->read_regs(mcp, 0, mcp->cache, ARRAY_SIZE(mcp->cache));
         if (t < 0) {
                 seq_printf(s, " I/O ERROR %d\n", t);
                 goto done;
         }
 
-        for (t = 0, mask = 1; t < 8; t++, mask <<= 1) {
+        for (t = 0, mask = 1; t < chip->ngpio; t++, mask <<= 1) {
                 const char      *label;
 
                 label = gpiochip_is_requested(chip, t);
@@ -219,28 +300,33 @@ done:
 /*----------------------------------------------------------------------*/
 
 static int mcp23s08_probe_one(struct spi_device *spi, unsigned addr,
-                unsigned base, unsigned pullups)
+                              unsigned type, unsigned base, unsigned pullups)
 {
         struct mcp23s08_driver_data     *data = spi_get_drvdata(spi);
         struct mcp23s08                 *mcp = data->mcp[addr];
         int                             status;
-        int                             do_update = 0;
 
         mutex_init(&mcp->lock);
 
         mcp->spi = spi;
         mcp->addr = 0x40 | (addr << 1);
 
-        mcp->chip.label = "mcp23s08",
-
         mcp->chip.direction_input = mcp23s08_direction_input;
         mcp->chip.get = mcp23s08_get;
         mcp->chip.direction_output = mcp23s08_direction_output;
         mcp->chip.set = mcp23s08_set;
         mcp->chip.dbg_show = mcp23s08_dbg_show;
 
+        if (type == MCP_TYPE_S17) {
+                mcp->ops = &mcp23s17_ops;
+                mcp->chip.ngpio = 16;
+                mcp->chip.label = "mcp23s17";
+        } else {
+                mcp->ops = &mcp23s08_ops;
+                mcp->chip.ngpio = 8;
+                mcp->chip.label = "mcp23s08";
+        }
         mcp->chip.base = base;
-        mcp->chip.ngpio = 8;
         mcp->chip.can_sleep = 1;
         mcp->chip.dev = &spi->dev;
         mcp->chip.owner = THIS_MODULE;
@@ -248,45 +334,39 @@ static int mcp23s08_probe_one(struct spi_device *spi, unsigned addr,
         /* 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);
+        status = mcp->ops->read(mcp, MCP_IOCON);
         if (status < 0)
                 goto fail;
         if ((status & IOCON_SEQOP) || !(status & IOCON_HAEN)) {
-                status &= ~IOCON_SEQOP;
-                status |= IOCON_HAEN;
-                status = mcp23s08_write(mcp, MCP_IOCON, (u8) status);
+                /* mcp23s17 has IOCON twice, make sure they are in sync */
+                status &= ~(IOCON_SEQOP | (IOCON_SEQOP << 8));
+                status |= IOCON_HAEN | (IOCON_HAEN << 8);
+                status = mcp->ops->write(mcp, MCP_IOCON, status);
                 if (status < 0)
                         goto fail;
         }
 
         /* configure ~100K pullups */
-        status = mcp23s08_write(mcp, MCP_GPPU, pullups);
+        status = mcp->ops->write(mcp, MCP_GPPU, pullups);
         if (status < 0)
                 goto fail;
 
-        status = mcp23s08_read_regs(mcp, 0, mcp->cache, sizeof mcp->cache);
+        status = mcp->ops->read_regs(mcp, 0, mcp->cache, ARRAY_SIZE(mcp->cache));
         if (status < 0)
                 goto fail;
 
         /* disable inverter on input */
         if (mcp->cache[MCP_IPOL] != 0) {
                 mcp->cache[MCP_IPOL] = 0;
-                do_update = 1;
+                status = mcp->ops->write(mcp, MCP_IPOL, 0);
+                if (status < 0)
+                        goto fail;
         }
 
         /* disable irqs */
         if (mcp->cache[MCP_GPINTEN] != 0) {
                 mcp->cache[MCP_GPINTEN] = 0;
-                do_update = 1;
-        }
-
-        if (do_update) {
-                u8 tx[4];
-
-                tx[0] = mcp->addr;
-                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);
+                status = mcp->ops->write(mcp, MCP_GPINTEN, 0);
                 if (status < 0)
                         goto fail;
         }
@@ -305,19 +385,26 @@ static int mcp23s08_probe(struct spi_device *spi)
         unsigned                        addr;
         unsigned                        chips = 0;
         struct mcp23s08_driver_data     *data;
-        int                             status;
+        int                             status, type;
         unsigned                        base;
 
+        type = spi_get_device_id(spi)->driver_data;
+
         pdata = spi->dev.platform_data;
         if (!pdata || !gpio_is_valid(pdata->base)) {
                 dev_dbg(&spi->dev, "invalid or missing platform data\n");
                 return -EINVAL;
         }
 
-        for (addr = 0; addr < 4; addr++) {
+        for (addr = 0; addr < ARRAY_SIZE(pdata->chip); addr++) {
                 if (!pdata->chip[addr].is_present)
                         continue;
                 chips++;
+                if ((type == MCP_TYPE_S08) && (addr > 3)) {
+                        dev_err(&spi->dev,
+                                "mcp23s08 only supports address 0..3\n");
+                        return -EINVAL;
+                }
         }
         if (!chips)
                 return -ENODEV;
@@ -329,16 +416,17 @@ static int mcp23s08_probe(struct spi_device *spi)
         spi_set_drvdata(spi, data);
 
         base = pdata->base;
-        for (addr = 0; addr < 4; addr++) {
+        for (addr = 0; addr < ARRAY_SIZE(pdata->chip); 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);
+                status = mcp23s08_probe_one(spi, addr, type, base,
+                                            pdata->chip[addr].pullups);
                 if (status < 0)
                         goto fail;
-                base += 8;
+
+                base += (type == MCP_TYPE_S17) ? 16 : 8;
         }
         data->ngpio = base - pdata->base;
 
@@ -358,7 +446,7 @@ static int mcp23s08_probe(struct spi_device *spi)
         return 0;
 
 fail:
-        for (addr = 0; addr < 4; addr++) {
+        for (addr = 0; addr < ARRAY_SIZE(data->mcp); addr++) {
                 int tmp;
 
                 if (!data->mcp[addr])
@@ -388,7 +476,7 @@ static int mcp23s08_remove(struct spi_device *spi)
                 }
         }
 
-        for (addr = 0; addr < 4; addr++) {
+        for (addr = 0; addr < ARRAY_SIZE(data->mcp); addr++) {
                 int tmp;
 
                 if (!data->mcp[addr])
@@ -405,9 +493,17 @@ static int mcp23s08_remove(struct spi_device *spi)
         return status;
 }
 
+static const struct spi_device_id mcp23s08_ids[] = {
+        { "mcp23s08", MCP_TYPE_S08 },
+        { "mcp23s17", MCP_TYPE_S17 },
+        { },
+};
+MODULE_DEVICE_TABLE(spi, mcp23s08_ids);
+
 static struct spi_driver mcp23s08_driver = {
         .probe          = mcp23s08_probe,
         .remove         = mcp23s08_remove,
+        .id_table       = mcp23s08_ids,
         .driver = {
                 .name   = "mcp23s08",
                 .owner  = THIS_MODULE,
@@ -432,4 +528,3 @@ static void __exit mcp23s08_exit(void)
 module_exit(mcp23s08_exit);
 
 MODULE_LICENSE("GPL");
-MODULE_ALIAS("spi:mcp23s08");