diff mbox

Re: [PATCH] rtc-v3020: add ability to access v3020 chip with GPIOs

Message ID 49ABCEB3.6090100@compulab.co.il
State Accepted, archived
Headers show

Commit Message

Mike Rapoport March 2, 2009, 12:18 p.m. UTC
David,
Can you please review and Ack the GPIO part of the below patch?

Alessandro Zummo wrote:
> On Mon,  2 Mar 2009 13:40:57 +0200
> Mike Rapoport <mike@compulab.co.il> wrote:
> 
>> The v3020 RTC can be connected to GPIOs as well as to memory-like interface.
>> Add ability to use GPIO bit-bang for v3020 read-write access.
>>
>> Signed-off-by: Mike Rapoport <mike@compulab.co.il>
> 
>  For the rtc part you have my 
> 
>  Acked-by: Alessandro Zummo <a.zummo@towertech.it>
> 
>  please send the patch to the GPIO maintainer . Once you
>  have his Acked-by and the one of the driver's author you can
>  send it to Andrew for inclusion.
> 

Signed-off-by: Mike Rapoport <mike@compulab.co.il>
---
 drivers/rtc/rtc-v3020.c   |  190 ++++++++++++++++++++++++++++++++++++++++-----
 include/linux/rtc-v3020.h |    6 ++
 2 files changed, 176 insertions(+), 20 deletions(-)

Comments

David Brownell March 3, 2009, 9:08 p.m. UTC | #1
On Monday 02 March 2009, Mike Rapoport wrote:
> +
> +#define V3020_CS       0
> +#define V3020_WR       1
> +#define V3020_RD       2
> +#define V3020_IO       3
> +
> +struct v3020_gpio {
> +       const char *name;
> +       unsigned int gpio;
> +};
> +

> +static struct v3020_gpio v3020_gpio[] = {
> +       { "RTC CS", 0 },
> +       { "RTC WR", 0 },
> +       { "RTC RD", 0 },
> +       { "RTC IO", 0 },
> +};

After Andrew's fault path cleanup it looks OK, but I see
no point to that GPIO struct with the name.  You know the
name based on the position, if you ever need one.  Take
that away, and you can add my ack.


Also, best not to have a single static struct; there's
no need to add a driver restriction that there be only
one of these chips in a system.

- Dave




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diff mbox

Patch

diff --git a/drivers/rtc/rtc-v3020.c b/drivers/rtc/rtc-v3020.c
index 66955cc..4c330f2 100644
--- a/drivers/rtc/rtc-v3020.c
+++ b/drivers/rtc/rtc-v3020.c
@@ -27,17 +27,162 @@ 
 #include <linux/bcd.h>
 #include <linux/rtc-v3020.h>
 #include <linux/delay.h>
+#include <linux/gpio.h>

 #include <linux/io.h>

 #undef DEBUG

+struct v3020;
+
+struct v3020_chip_ops {
+	int (*map_io)(struct v3020 *chip, struct platform_device *pdev,
+		      struct v3020_platform_data *pdata);
+	void (*unmap_io)(struct v3020 *chip);
+	unsigned char (*read_bit)(struct v3020 *chip);
+	void (*write_bit)(struct v3020 *chip, unsigned char bit);
+};
+
+#define V3020_CS	0
+#define V3020_WR	1
+#define V3020_RD	2
+#define V3020_IO	3
+
+struct v3020_gpio {
+	const char *name;
+	unsigned int gpio;
+};
+
 struct v3020 {
+	/* MMIO access */
 	void __iomem *ioaddress;
 	int leftshift;
+
+	/* GPIO access */
+	struct v3020_gpio *gpio;
+
+	struct v3020_chip_ops *ops;
+
 	struct rtc_device *rtc;
 };

+
+static int v3020_mmio_map(struct v3020 *chip, struct platform_device *pdev,
+			  struct v3020_platform_data *pdata)
+{
+	if (pdev->num_resources != 1)
+		return -EBUSY;
+
+	if (pdev->resource[0].flags != IORESOURCE_MEM)
+		return -EBUSY;
+
+	chip->leftshift = pdata->leftshift;
+	chip->ioaddress = ioremap(pdev->resource[0].start, 1);
+	if (chip->ioaddress == NULL)
+		return -EBUSY;
+
+	return 0;
+}
+
+static void v3020_mmio_unmap(struct v3020 *chip)
+{
+	iounmap(chip->ioaddress);
+}
+
+static void v3020_mmio_write_bit(struct v3020 *chip, unsigned char bit)
+{
+	writel(bit << chip->leftshift, chip->ioaddress);
+}
+
+static unsigned char v3020_mmio_read_bit(struct v3020 *chip)
+{
+	return readl(chip->ioaddress) & (1 << chip->leftshift);
+}
+
+static struct v3020_chip_ops v3020_mmio_ops = {
+	.map_io		= v3020_mmio_map,
+	.unmap_io	= v3020_mmio_unmap,
+	.read_bit	= v3020_mmio_read_bit,
+	.write_bit	= v3020_mmio_write_bit,
+};
+
+static struct v3020_gpio v3020_gpio[] = {
+	{ "RTC CS", 0 },
+	{ "RTC WR", 0 },
+	{ "RTC RD", 0 },
+	{ "RTC IO", 0 },
+};
+
+static int v3020_gpio_map(struct v3020 *chip, struct platform_device *pdev,
+			  struct v3020_platform_data *pdata)
+{
+	int i, err;
+
+	v3020_gpio[V3020_CS].gpio = pdata->gpio_cs;
+	v3020_gpio[V3020_WR].gpio = pdata->gpio_wr;
+	v3020_gpio[V3020_RD].gpio = pdata->gpio_rd;
+	v3020_gpio[V3020_IO].gpio = pdata->gpio_io;
+
+	for (i = 0; i < ARRAY_SIZE(v3020_gpio); i++) {
+		err = gpio_request(v3020_gpio[i].gpio, v3020_gpio[i].name);
+		if (err)
+			goto err_request;
+
+		gpio_direction_output(v3020_gpio[i].gpio, 1);
+	}
+
+	chip->gpio = v3020_gpio;
+
+	return 0;
+
+err_request:
+	for (; i >= 0; i--)
+		gpio_free(v3020_gpio[i].gpio);
+
+	return err;
+}
+
+static void v3020_gpio_unmap(struct v3020 *chip)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(v3020_gpio); i++)
+		gpio_free(v3020_gpio[i].gpio);
+}
+
+static void v3020_gpio_write_bit(struct v3020 *chip, unsigned char bit)
+{
+	gpio_direction_output(chip->gpio[V3020_IO].gpio, bit);
+	gpio_set_value(chip->gpio[V3020_CS].gpio, 0);
+	gpio_set_value(chip->gpio[V3020_WR].gpio, 0);
+	udelay(1);
+	gpio_set_value(chip->gpio[V3020_WR].gpio, 1);
+	gpio_set_value(chip->gpio[V3020_CS].gpio, 1);
+}
+
+static unsigned char v3020_gpio_read_bit(struct v3020 *chip)
+{
+	int bit;
+
+	gpio_direction_input(chip->gpio[V3020_IO].gpio);
+	gpio_set_value(chip->gpio[V3020_CS].gpio, 0);
+	gpio_set_value(chip->gpio[V3020_RD].gpio, 0);
+	udelay(1);
+	bit = !!gpio_get_value(chip->gpio[V3020_IO].gpio);
+	udelay(1);
+	gpio_set_value(chip->gpio[V3020_RD].gpio, 1);
+	gpio_set_value(chip->gpio[V3020_CS].gpio, 1);
+
+	return bit;
+}
+
+static struct v3020_chip_ops v3020_gpio_ops = {
+	.map_io		= v3020_gpio_map,
+	.unmap_io	= v3020_gpio_unmap,
+	.read_bit	= v3020_gpio_read_bit,
+	.write_bit	= v3020_gpio_write_bit,
+};
+
 static void v3020_set_reg(struct v3020 *chip, unsigned char address,
 			unsigned char data)
 {
@@ -46,7 +191,7 @@  static void v3020_set_reg(struct v3020 *chip, unsigned char address,

 	tmp = address;
 	for (i = 0; i < 4; i++) {
-		writel((tmp & 1) << chip->leftshift, chip->ioaddress);
+		chip->ops->write_bit(chip, (tmp & 1));
 		tmp >>= 1;
 		udelay(1);
 	}
@@ -54,7 +199,7 @@  static void v3020_set_reg(struct v3020 *chip, unsigned char address,
 	/* Commands dont have data */
 	if (!V3020_IS_COMMAND(address)) {
 		for (i = 0; i < 8; i++) {
-			writel((data & 1) << chip->leftshift, chip->ioaddress);
+			chip->ops->write_bit(chip, (data & 1));
 			data >>= 1;
 			udelay(1);
 		}
@@ -67,14 +212,14 @@  static unsigned char v3020_get_reg(struct v3020 *chip, unsigned char address)
 	int i;

 	for (i = 0; i < 4; i++) {
-		writel((address & 1) << chip->leftshift, chip->ioaddress);
+		chip->ops->write_bit(chip, (address & 1));
 		address >>= 1;
 		udelay(1);
 	}

 	for (i = 0; i < 8; i++) {
 		data >>= 1;
-		if (readl(chip->ioaddress) & (1 << chip->leftshift))
+		if (chip->ops->read_bit(chip))
 			data |= 0x80;
 		udelay(1);
 	}
@@ -164,25 +309,23 @@  static int rtc_probe(struct platform_device *pdev)
 	int i;
 	int temp;

-	if (pdev->num_resources != 1)
-		return -EBUSY;
-
-	if (pdev->resource[0].flags != IORESOURCE_MEM)
-		return -EBUSY;
-
 	chip = kzalloc(sizeof *chip, GFP_KERNEL);
 	if (!chip)
 		return -ENOMEM;

-	chip->leftshift = pdata->leftshift;
-	chip->ioaddress = ioremap(pdev->resource[0].start, 1);
-	if (chip->ioaddress == NULL)
+	if (pdata->use_gpio)
+		chip->ops = &v3020_gpio_ops;
+	else
+		chip->ops = &v3020_mmio_ops;
+
+	retval = chip->ops->map_io(chip, pdev, pdata);
+	if (retval)
 		goto err_chip;

 	/* Make sure the v3020 expects a communication cycle
 	 * by reading 8 times */
 	for (i = 0; i < 8; i++)
-		temp = readl(chip->ioaddress);
+		temp = chip->ops->read_bit(chip);

 	/* Test chip by doing a write/read sequence
 	 * to the chip ram */
@@ -196,10 +339,17 @@  static int rtc_probe(struct platform_device *pdev)
 	 * are all disabled */
 	v3020_set_reg(chip, V3020_STATUS_0, 0x0);

-	dev_info(&pdev->dev, "Chip available at physical address 0x%llx,"
-		"data connected to D%d\n",
-		(unsigned long long)pdev->resource[0].start,
-		chip->leftshift);
+	if (pdata->use_gpio)
+		dev_info(&pdev->dev, "Chip available at GPIOs "
+			 "%d, %d, %d, %d\n",
+			 chip->gpio[V3020_CS].gpio, chip->gpio[V3020_WR].gpio,
+			 chip->gpio[V3020_RD].gpio, chip->gpio[V3020_IO].gpio);
+	else
+		dev_info(&pdev->dev, "Chip available at "
+			 "physical address 0x%llx,"
+			 "data connected to D%d\n",
+			 (unsigned long long)pdev->resource[0].start,
+			 chip->leftshift);

 	platform_set_drvdata(pdev, chip);

@@ -214,7 +364,7 @@  static int rtc_probe(struct platform_device *pdev)
 	return 0;

 err_io:
-	iounmap(chip->ioaddress);
+	chip->ops->unmap_io(chip);
 err_chip:
 	kfree(chip);

@@ -229,7 +379,7 @@  static int rtc_remove(struct platform_device *dev)
 	if (rtc)
 		rtc_device_unregister(rtc);

-	iounmap(chip->ioaddress);
+	chip->ops->unmap_io(chip);
 	kfree(chip);

 	return 0;
diff --git a/include/linux/rtc-v3020.h b/include/linux/rtc-v3020.h
index bf74e63..8ba646e 100644
--- a/include/linux/rtc-v3020.h
+++ b/include/linux/rtc-v3020.h
@@ -14,6 +14,12 @@ 
  * is used depends on the board. */
 struct v3020_platform_data {
 	int leftshift; /* (1<<(leftshift)) & readl() */
+
+	int use_gpio:1;
+	unsigned int gpio_cs;
+	unsigned int gpio_wr;
+	unsigned int gpio_rd;
+	unsigned int gpio_io;
 };

 #define V3020_STATUS_0	0x00