Commit 97ddb1c8 authored by Lars Poeschel's avatar Lars Poeschel Committed by Linus Walleij
Browse files

gpio: mcp23s08: convert driver to DT 



This converts the mcp23s08 driver to be able to be used with
device tree.

There is a "spi-present-mask" device tree property, that allows to
use multiple of this spi chips on the same chipselect.

v4:
- removed the ability to specify the pullup from device tree
- updated binding doc

v3:
- removed mcp,chips device tree property in favour of a
    mcp,spi-present-mask and a flag for the pullup of every gpio
- seperated the match table. Now there is one for i2c and one for spi
- do the of reading stuff on stack of the probe function - no devm
    any more

v2:
- squashed booth patches together
- fixed build warning, when CONFIG_OF is not defined
- use of_match_ptr macro for of_match_table

Signed-off-by: default avatarLars Poeschel <poeschel@lemonage.de>
Signed-off-by: default avatarLinus Walleij <linus.walleij@linaro.org>
parent a2797bea

Documentation/devicetree/bindings/gpio/gpio-mcp23s08.txt

0 → 100644
+47 −0
Original line number Diff line number Diff line 
Microchip MCP2308/MCP23S08/MCP23017/MCP23S17 driver for

8-/16-bit I/O expander with serial interface (I2C/SPI)



Required properties:

- compatible : Should be

    - "mcp,mcp23s08" for  8 GPIO SPI version

    - "mcp,mcp23s17" for 16 GPIO SPI version

    - "mcp,mcp23008" for  8 GPIO I2C version or

    - "mcp,mcp23017" for 16 GPIO I2C version of the chip

- #gpio-cells : Should be two.

  - first cell is the pin number

  - second cell is used to specify flags. Flags are currently unused.

- gpio-controller : Marks the device node as a GPIO controller.

- reg : For an address on its bus. I2C uses this a the I2C address of the chip.

        SPI uses this to specify the chipselect line which the chip is

        connected to. The driver and the SPI variant of the chip support

        multiple chips on the same chipselect. Have a look at

        mcp,spi-present-mask below.



Required device specific properties (only for SPI chips):

- mcp,spi-present-mask : This is a present flag, that makes only sense for SPI

        chips - as the name suggests. Multiple SPI chips can share the same

        SPI chipselect. Set a bit in bit0-7 in this mask to 1 if there is a

        chip connected with the corresponding spi address set. For example if

        you have a chip with address 3 connected, you have to set bit3 to 1,

        which is 0x08. mcp23s08 chip variant only supports bits 0-3. It is not

        possible to mix mcp23s08 and mcp23s17 on the same chipselect. Set at

        least one bit to 1 for SPI chips.

- spi-max-frequency = The maximum frequency this chip is able to handle



Example I2C:

gpiom1: gpio@20 {

        compatible = "mcp,mcp23017";

        gpio-controller;

        #gpio-cells = <2>;

        reg = <0x20>;

};



Example SPI:

gpiom1: gpio@0 {

        compatible = "mcp,mcp23s17";

        gpio-controller;

        #gpio-cells = <2>;

        spi-present-mask = <0x01>;

        reg = <0>;

        spi-max-frequency = <1000000>;

};

drivers/gpio/gpio-mcp23s08.c

+106 −31
Original line number Diff line number Diff line
@@ -12,6 +12,8 @@ 
#include <linux/spi/mcp23s08.h>

#include <linux/slab.h>

#include <asm/byteorder.h>

#include <linux/of.h>

#include <linux/of_device.h>



/**

 * MCP types supported by driver
@@ -383,6 +385,10 @@ static int mcp23s08_probe_one(struct mcp23s08 *mcp, struct device *dev, 
	mcp->chip.direction_output = mcp23s08_direction_output;

	mcp->chip.set = mcp23s08_set;

	mcp->chip.dbg_show = mcp23s08_dbg_show;

#ifdef CONFIG_OF

	mcp->chip.of_gpio_n_cells = 2;

	mcp->chip.of_node = dev->of_node;

#endif



	switch (type) {

#ifdef CONFIG_SPI_MASTER
@@ -473,6 +479,35 @@ fail: 


/*----------------------------------------------------------------------*/



#ifdef CONFIG_OF

#ifdef CONFIG_SPI_MASTER

static struct of_device_id mcp23s08_spi_of_match[] = {

	{

		.compatible = "mcp,mcp23s08", .data = (void *) MCP_TYPE_S08,

	},

	{

		.compatible = "mcp,mcp23s17", .data = (void *) MCP_TYPE_S17,

	},

	{ },

};

MODULE_DEVICE_TABLE(of, mcp23s08_spi_of_match);

#endif



#if IS_ENABLED(CONFIG_I2C)

static struct of_device_id mcp23s08_i2c_of_match[] = {

	{

		.compatible = "mcp,mcp23008", .data = (void *) MCP_TYPE_008,

	},

	{

		.compatible = "mcp,mcp23017", .data = (void *) MCP_TYPE_017,

	},

	{ },

};

MODULE_DEVICE_TABLE(of, mcp23s08_i2c_of_match);

#endif

#endif /* CONFIG_OF */





#if IS_ENABLED(CONFIG_I2C)



static int mcp230xx_probe(struct i2c_client *client,
@@ -480,21 +515,31 @@ static int mcp230xx_probe(struct i2c_client *client, 
{

	struct mcp23s08_platform_data *pdata;

	struct mcp23s08 *mcp;

	int status;



	int status, base, pullups;

	const struct of_device_id *match;



	match = of_match_device(of_match_ptr(mcp23s08_i2c_of_match),

					&client->dev);

	if (match) {

		base = -1;

		pullups = 0;

	} else {

		pdata = client->dev.platform_data;

		if (!pdata || !gpio_is_valid(pdata->base)) {

		dev_dbg(&client->dev, "invalid or missing platform data\n");

			dev_dbg(&client->dev,

					"invalid or missing platform data\n");

			return -EINVAL;

		}

		base = pdata->base;

		pullups = pdata->chip[0].pullups;

	}



	mcp = kzalloc(sizeof *mcp, GFP_KERNEL);

	if (!mcp)

		return -ENOMEM;



	status = mcp23s08_probe_one(mcp, &client->dev, client, client->addr,

				    id->driver_data, pdata->base,

				    pdata->chip[0].pullups);

				    id->driver_data, base, pullups);

	if (status)

		goto fail;
@@ -531,6 +576,7 @@ static struct i2c_driver mcp230xx_driver = { 
	.driver = {

		.name	= "mcp230xx",

		.owner	= THIS_MODULE,

		.of_match_table = of_match_ptr(mcp23s08_i2c_of_match),

	},

	.probe		= mcp230xx_probe,

	.remove		= mcp230xx_remove,
@@ -565,13 +611,34 @@ static int mcp23s08_probe(struct spi_device *spi) 
	unsigned			chips = 0;

	struct mcp23s08_driver_data	*data;

	int				status, type;

	unsigned			base;

	unsigned			base = -1,

					ngpio = 0,

					pullups[ARRAY_SIZE(pdata->chip)];

	const struct			of_device_id *match;

	u32				spi_present_mask = 0;



	match = of_match_device(of_match_ptr(mcp23s08_spi_of_match), &spi->dev);

	if (match) {

		type = (int)match->data;

		status = of_property_read_u32(spi->dev.of_node,

				"mcp,spi-present-mask", &spi_present_mask);

		if (status) {

			dev_err(&spi->dev, "DT has no spi-present-mask\n");

			return -ENODEV;

		}

		if ((spi_present_mask <= 0) || (spi_present_mask >= 256)) {

			dev_err(&spi->dev, "invalid spi-present-mask\n");

			return -ENODEV;

		}



		for (addr = 0; addr < ARRAY_SIZE(pdata->chip); addr++)

			pullups[addr] = 0;

	} else {

		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");

			dev_dbg(&spi->dev,

					"invalid or missing platform data\n");

			return -EINVAL;

		}
@@ -584,31 +651,38 @@ static int mcp23s08_probe(struct spi_device *spi) 
					"mcp23s08 only supports address 0..3\n");

				return -EINVAL;

			}

			spi_present_mask |= 1 << addr;

			pullups[addr] = pdata->chip[addr].pullups;

		}



		if (!chips)

			return -ENODEV;



		base = pdata->base;

	}



	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 < ARRAY_SIZE(pdata->chip); addr++) {

		if (!pdata->chip[addr].is_present)

		if (!(spi_present_mask & (1 << addr)))

			continue;

		chips--;

		data->mcp[addr] = &data->chip[chips];

		status = mcp23s08_probe_one(data->mcp[addr], &spi->dev, spi,

					    0x40 | (addr << 1), type, base,

					    pdata->chip[addr].pullups);

					    pullups[addr]);

		if (status < 0)

			goto fail;



		if (base != -1)

			base += (type == MCP_TYPE_S17) ? 16 : 8;

		ngpio += (type == MCP_TYPE_S17) ? 16 : 8;

	}

	data->ngpio = base - pdata->base;

	data->ngpio = ngpio;



	/* NOTE:  these chips have a relatively sane IRQ framework, with

	 * per-signal masking and level/edge triggering.  It's not yet
@@ -668,6 +742,7 @@ static struct spi_driver mcp23s08_driver = { 
	.driver = {

		.name	= "mcp23s08",

		.owner	= THIS_MODULE,

		.of_match_table = of_match_ptr(mcp23s08_spi_of_match),

	},

};

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