Patchwork [U-Boot,PATCHv2] pca953x: support 16-pin devices

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Submitter Chris Packham
Date Dec. 7, 2010, 10 p.m.
Message ID <AANLkTik6U8tm44XfKZrpYYT9g2dCw-Tsx8kr7y8mjOF6@mail.gmail.com>
Download mbox | patch
Permalink /patch/74604/
State Superseded
Headers show

Comments

Chris Packham - Dec. 7, 2010, 10 p.m.
This adds support for for the PCA9535/PCA9539 family of gpio devices which
have 16 output pins.

To let the driver know which devices are 16-pin it is necessary to define
CONFIG_SYS_I2C_PCA953X_WIDTH in your board config file. This is used to
create an array of {chip, ngpio} tuples that are used to determine the
width of a particular chip. For backwards compatibility it is assumed that
any chip not defined in CONFIG_SYS_I2C_PCA953X_WIDTH has 8 pins.
---

As suggested by Peter I've implemented the 16-pin support in the existing
pca953x driver. So this is pretty much a re-write of the v1 patch. Is the commit
message sufficient to document CONFIG_SYS_I2C_PCA953X_WIDTH or is
there something under doc/ that I should be adding to.

 drivers/gpio/pca953x.c |  107 ++++++++++++++++++++++++++++++++++++++----------
 1 files changed, 85 insertions(+), 22 deletions(-)
Peter Tyser - Dec. 9, 2010, 12:08 a.m.
The patch looks good.  I had a few minor nitpicky style comments below:

> As suggested by Peter I've implemented the 16-pin support in the existing
> pca953x driver. So this is pretty much a re-write of the v1 patch. Is the commit
> message sufficient to document CONFIG_SYS_I2C_PCA953X_WIDTH or is
> there something under doc/ that I should be adding to.

You could add a brief description to the top-level README file.  There
is currently a bit of info in the "GPIO Support" section that could be
added to.

>  #include <common.h>
> @@ -38,22 +38,78 @@ enum {
>  	PCA953X_CMD_INVERT,
>  };
> 
> +#ifdef CONFIG_SYS_I2C_PCA953X_WIDTH
> +struct chip_ngpio {
> +	uint8_t chip;
> +	uint8_t ngpio;
> +};

Since this structure is 953x-specific I'd rename chip_ngpio
pca953x_chip_ngpio to clarify its a driver-specific structure and to
prevent the (unlikely) name collision down the road.

The same comment applies to ngpio()->pca953x_ngpio(),
chip_ngpios[]->pca953x_chip_ngpios[].

> +static struct chip_ngpio chip_ngpios[] = CONFIG_SYS_I2C_PCA953X_WIDTH;
> +#define NUM_CHIP_GPIOS (sizeof(chip_ngpios) / sizeof(struct chip_ngpio))
> +
> +/*
> + * Determine the number of GPIO pins supported. If we don't know we assume
> + * 8 pins.
> + */
> +static int ngpio(uint8_t chip)
> +{
> +	int i;
> +
> +	for (i = 0; i < NUM_CHIP_GPIOS; i++) {
> +		if (chip_ngpios[i].chip == chip)
> +			return chip_ngpios[i].ngpio;
> +	}

I'd remove the for loop braces above per the Linux CodingStyle
documentation that U-Boot adheres to.

There should also be an empty line above the "return 8" below.

> +	return 8;
> +}
> +#else
> +#define ngpio(chip)	8
> +#endif
> +
>  /*
>   * Modify masked bits in register
>   */
>  static int pca953x_reg_write(uint8_t chip, uint addr, uint mask, uint data)
>  {
> -	uint8_t val;
> +	uint8_t  valb;
> +	uint16_t valw;

I'd remove one of the spaces between "valb" above.  My understanding is
spaces shouldn't be used for such vertical alignment.

> 
> -	if (i2c_read(chip, addr, 1, &val, 1))
> -		return -1;
> +	if (ngpio(chip) <= 8) {
> +		if (i2c_read(chip, addr, 1, &valb, 1))
> +			return -1;
> +
> +		valb &= ~mask;
> +		valb |= data;
> +
> +		return i2c_write(chip, addr, 1, &valb, 1);
> +	} else {
> +		if (i2c_read(chip, addr << 1, 1, (u8*)&valw, 2))
> +			return -1;
> +
> +		valw &= ~mask;
> +		valw |= data;
> +
> +		return i2c_write(chip, addr << 1, 1, (u8*)&valw, 2);
> +	}
> +}
> 
> -	val &= ~mask;
> -	val |= data;
> +static int pca953x_reg_read(uint8_t chip, uint addr, uint *data)
> +{
> +	uint8_t  valb;
> +	uint16_t valw;
> 
> -	return i2c_write(chip, addr, 1, &val, 1);
> +	if (ngpio(chip) <= 8) {
> +		if (i2c_read(chip, addr, 1, &valb, 1))
> +			return -1;
> +		*data = (int) valb;

The space in "(int) valb" should be removed.  Same below.

> +	} else {
> +		if (i2c_read(chip, addr << 1, 1, (u8*)&valw, 2))
> +			return -1;
> +		*data = (int) valw;
> +	}
> +	return 0;
>  }

<snip>

> +	for (i = msb; i >= 0; i--)
> +		printf("%x",i);
> +	printf("\n");
> +	if (nr_gpio > 8)
> +		printf("--------");
>  	printf("-------------------\n");

What about changing the printing of '-'s to a for loop like
for (i = 19 + nr_gpio; i >0; i++)
	puts("-");

I'll give the next iteration of the patch a shot, it looks like it
should work just fine.

Best,
Peter
Chris Packham - Dec. 9, 2010, 4:40 a.m.
On Thu, Dec 9, 2010 at 1:08 PM, Peter Tyser <ptyser@xes-inc.com> wrote:
> The patch looks good.  I had a few minor nitpicky style comments below:
>
>> As suggested by Peter I've implemented the 16-pin support in the existing
>> pca953x driver. So this is pretty much a re-write of the v1 patch. Is the commit
>> message sufficient to document CONFIG_SYS_I2C_PCA953X_WIDTH or is
>> there something under doc/ that I should be adding to.
>
> You could add a brief description to the top-level README file.  There
> is currently a bit of info in the "GPIO Support" section that could be
> added to.
>
>>  #include <common.h>
>> @@ -38,22 +38,78 @@ enum {
>>       PCA953X_CMD_INVERT,
>>  };
>>
>> +#ifdef CONFIG_SYS_I2C_PCA953X_WIDTH
>> +struct chip_ngpio {
>> +     uint8_t chip;
>> +     uint8_t ngpio;
>> +};
>
> Since this structure is 953x-specific I'd rename chip_ngpio
> pca953x_chip_ngpio to clarify its a driver-specific structure and to
> prevent the (unlikely) name collision down the road.
>
> The same comment applies to ngpio()->pca953x_ngpio(),
> chip_ngpios[]->pca953x_chip_ngpios[].
>
>> +static struct chip_ngpio chip_ngpios[] = CONFIG_SYS_I2C_PCA953X_WIDTH;
>> +#define NUM_CHIP_GPIOS (sizeof(chip_ngpios) / sizeof(struct chip_ngpio))
>> +
>> +/*
>> + * Determine the number of GPIO pins supported. If we don't know we assume
>> + * 8 pins.
>> + */
>> +static int ngpio(uint8_t chip)
>> +{
>> +     int i;
>> +
>> +     for (i = 0; i < NUM_CHIP_GPIOS; i++) {
>> +             if (chip_ngpios[i].chip == chip)
>> +                     return chip_ngpios[i].ngpio;
>> +     }
>
> I'd remove the for loop braces above per the Linux CodingStyle
> documentation that U-Boot adheres to.
>
> There should also be an empty line above the "return 8" below.
>
>> +     return 8;
>> +}
>> +#else
>> +#define ngpio(chip)  8
>> +#endif
>> +
>>  /*
>>   * Modify masked bits in register
>>   */
>>  static int pca953x_reg_write(uint8_t chip, uint addr, uint mask, uint data)
>>  {
>> -     uint8_t val;
>> +     uint8_t  valb;
>> +     uint16_t valw;
>
> I'd remove one of the spaces between "valb" above.  My understanding is
> spaces shouldn't be used for such vertical alignment.
>
>>
>> -     if (i2c_read(chip, addr, 1, &val, 1))
>> -             return -1;
>> +     if (ngpio(chip) <= 8) {
>> +             if (i2c_read(chip, addr, 1, &valb, 1))
>> +                     return -1;
>> +
>> +             valb &= ~mask;
>> +             valb |= data;
>> +
>> +             return i2c_write(chip, addr, 1, &valb, 1);
>> +     } else {
>> +             if (i2c_read(chip, addr << 1, 1, (u8*)&valw, 2))
>> +                     return -1;
>> +
>> +             valw &= ~mask;
>> +             valw |= data;
>> +
>> +             return i2c_write(chip, addr << 1, 1, (u8*)&valw, 2);
>> +     }
>> +}
>>
>> -     val &= ~mask;
>> -     val |= data;
>> +static int pca953x_reg_read(uint8_t chip, uint addr, uint *data)
>> +{
>> +     uint8_t  valb;
>> +     uint16_t valw;
>>
>> -     return i2c_write(chip, addr, 1, &val, 1);
>> +     if (ngpio(chip) <= 8) {
>> +             if (i2c_read(chip, addr, 1, &valb, 1))
>> +                     return -1;
>> +             *data = (int) valb;
>
> The space in "(int) valb" should be removed.  Same below.
>
>> +     } else {
>> +             if (i2c_read(chip, addr << 1, 1, (u8*)&valw, 2))
>> +                     return -1;
>> +             *data = (int) valw;
>> +     }
>> +     return 0;
>>  }
>
> <snip>
>
>> +     for (i = msb; i >= 0; i--)
>> +             printf("%x",i);
>> +     printf("\n");
>> +     if (nr_gpio > 8)
>> +             printf("--------");
>>       printf("-------------------\n");
>
> What about changing the printing of '-'s to a for loop like
> for (i = 19 + nr_gpio; i >0; i++)
>        puts("-");
>
> I'll give the next iteration of the patch a shot, it looks like it
> should work just fine.
>
> Best,
> Peter
>

Hi Peter,

I'll try and get an updated patch through as soon as I can. I'm on a
training course today and tomorrow but it won't take me long to make
the changes you've suggested once I find some time.

Thanks,
Chris

Patch

diff --git a/drivers/gpio/pca953x.c b/drivers/gpio/pca953x.c
index 6e82bd6..491b79e 100644
--- a/drivers/gpio/pca953x.c
+++ b/drivers/gpio/pca953x.c
@@ -17,8 +17,8 @@ 
  */

 /*
- * Driver for NXP's 4 and 8 bit I2C gpio expanders (eg pca9537, pca9557, etc)
- * TODO: support additional devices with more than 8-bits GPIO
+ * Driver for NXP's 4, 8 and 16 bit I2C gpio expanders (eg pca9537, pca9557,
+ * pca9539, etc)
  */

 #include <common.h>
@@ -38,22 +38,78 @@  enum {
 	PCA953X_CMD_INVERT,
 };

+#ifdef CONFIG_SYS_I2C_PCA953X_WIDTH
+struct chip_ngpio {
+	uint8_t chip;
+	uint8_t ngpio;
+};
+
+static struct chip_ngpio chip_ngpios[] = CONFIG_SYS_I2C_PCA953X_WIDTH;
+#define NUM_CHIP_GPIOS (sizeof(chip_ngpios) / sizeof(struct chip_ngpio))
+
+/*
+ * Determine the number of GPIO pins supported. If we don't know we assume
+ * 8 pins.
+ */
+static int ngpio(uint8_t chip)
+{
+	int i;
+
+	for (i = 0; i < NUM_CHIP_GPIOS; i++) {
+		if (chip_ngpios[i].chip == chip)
+			return chip_ngpios[i].ngpio;
+	}
+	return 8;
+}
+#else
+#define ngpio(chip)	8
+#endif
+
 /*
  * Modify masked bits in register
  */
 static int pca953x_reg_write(uint8_t chip, uint addr, uint mask, uint data)
 {
-	uint8_t val;
+	uint8_t  valb;
+	uint16_t valw;

-	if (i2c_read(chip, addr, 1, &val, 1))
-		return -1;
+	if (ngpio(chip) <= 8) {
+		if (i2c_read(chip, addr, 1, &valb, 1))
+			return -1;
+
+		valb &= ~mask;
+		valb |= data;
+
+		return i2c_write(chip, addr, 1, &valb, 1);
+	} else {
+		if (i2c_read(chip, addr << 1, 1, (u8*)&valw, 2))
+			return -1;
+
+		valw &= ~mask;
+		valw |= data;
+
+		return i2c_write(chip, addr << 1, 1, (u8*)&valw, 2);
+	}
+}

-	val &= ~mask;
-	val |= data;
+static int pca953x_reg_read(uint8_t chip, uint addr, uint *data)
+{
+	uint8_t  valb;
+	uint16_t valw;

-	return i2c_write(chip, addr, 1, &val, 1);
+	if (ngpio(chip) <= 8) {
+		if (i2c_read(chip, addr, 1, &valb, 1))
+			return -1;
+		*data = (int) valb;
+	} else {
+		if (i2c_read(chip, addr << 1, 1, (u8*)&valw, 2))
+			return -1;
+		*data = (int) valw;
+	}
+	return 0;
 }

+
 /*
  * Set output value of IO pins in 'mask' to corresponding value in 'data'
  * 0 = low, 1 = high
@@ -86,9 +142,9 @@  int pca953x_set_dir(uint8_t chip, uint mask, uint data)
  */
 int pca953x_get_val(uint8_t chip)
 {
-	uint8_t val;
+	uint val;

-	if (i2c_read(chip, 0, 1, &val, 1))
+	if (pca953x_reg_read(chip, PCA953X_IN, &val) < 0)
 		return -1;

 	return (int)val;
@@ -102,37 +158,44 @@  int pca953x_get_val(uint8_t chip)
 static int pca953x_info(uint8_t chip)
 {
 	int i;
-	uint8_t data;
+	uint data;
+	int nr_gpio = ngpio(chip);
+	int msb     = nr_gpio - 1;

-	printf("pca953x@ 0x%x:\n\n", chip);
-	printf("gpio pins: 76543210\n");
+	printf("pca953x@ 0x%x (%d pins):\n\n", chip, nr_gpio);
+	printf("gpio pins: ");
+	for (i = msb; i >= 0; i--)
+		printf("%x",i);
+	printf("\n");
+	if (nr_gpio > 8)
+		printf("--------");
 	printf("-------------------\n");

-	if (i2c_read(chip, PCA953X_CONF, 1, &data, 1))
+	if (pca953x_reg_read(chip, PCA953X_CONF, &data) < 0)
 		return -1;
 	printf("conf:      ");
-	for (i = 7; i >= 0; i--)
+	for (i = msb; i >= 0; i--)
 		printf("%c", data & (1 << i) ? 'i' : 'o');
 	printf("\n");

-	if (i2c_read(chip, PCA953X_POL, 1, &data, 1))
+	if (pca953x_reg_read(chip, PCA953X_POL, &data) < 0)
 		return -1;
 	printf("invert:    ");
-	for (i = 7; i >= 0; i--)
+	for (i = msb; i >= 0; i--)
 		printf("%c", data & (1 << i) ? '1' : '0');
 	printf("\n");

-	if (i2c_read(chip, PCA953X_IN, 1, &data, 1))
+	if (pca953x_reg_read(chip, PCA953X_IN, &data) < 0)
 		return -1;
 	printf("input:     ");
-	for (i = 7; i >= 0; i--)
+	for (i = msb; i >= 0; i--)
 		printf("%c", data & (1 << i) ? '1' : '0');
 	printf("\n");

-	if (i2c_read(chip, PCA953X_OUT, 1, &data, 1))
+	if (pca953x_reg_read(chip, PCA953X_OUT, &data) < 0)
 		return -1;
 	printf("output:    ");
-	for (i = 7; i >= 0; i--)
+	for (i = msb; i >= 0; i--)
 		printf("%c", data & (1 << i) ? '1' : '0');
 	printf("\n");