[PATCH 2/2] i2c-s3c2410: Add GPIO based bus arbitration functionality

From: Naveen Krishna Chatradhi
Date: Fri Dec 14 2012 - 00:51:12 EST


Makes use of the generic fucntions in of_i2c.c to parse arbitration
timing information and GPIOs for arbitration.

Also uses devm_gpio_request() instead of gpio_request() and
removes the gpio_free() calls

Signed-off-by: Naveen Krishna Chatradhi <ch.naveen@xxxxxxxxxxx>
---
drivers/i2c/busses/i2c-s3c2410.c | 79 +++++++++++++++++++++++---------------
1 file changed, 47 insertions(+), 32 deletions(-)

diff --git a/drivers/i2c/busses/i2c-s3c2410.c b/drivers/i2c/busses/i2c-s3c2410.c
index e93e7d6..d055cf8 100644
--- a/drivers/i2c/busses/i2c-s3c2410.c
+++ b/drivers/i2c/busses/i2c-s3c2410.c
@@ -855,54 +855,61 @@ static inline void s3c24xx_i2c_deregister_cpufreq(struct s3c24xx_i2c *i2c)
#endif

#ifdef CONFIG_OF
-static int s3c24xx_i2c_parse_dt_gpio(struct s3c24xx_i2c *i2c)
+static int of_i2c_parse_gpio(struct device *dev, const char *name,
+ int gpios[], size_t count, bool required)
{
- int idx, gpio, ret;
-
- if (i2c->quirks & QUIRK_NO_GPIO)
- return 0;
+ struct device_node *dn = dev->of_node;
+ int idx, gpio;

- for (idx = 0; idx < 2; idx++) {
- gpio = of_get_gpio(i2c->dev->of_node, idx);
+ for (idx = 0; idx < count; idx++) {
+ gpio = of_get_named_gpio(dn, name, idx);
if (!gpio_is_valid(gpio)) {
- dev_err(i2c->dev, "invalid gpio[%d]: %d\n", idx, gpio);
- goto free_gpio;
+ dev_dbg(dev, "invalid gpio[%d]: %d\n", idx, gpio);
+ if (idx || required) {
+ dev_err(dev, "invalid gpio[%d]: %d\n",
+ idx, gpio);
+ }
+ return -EINVAL;
}
- i2c->gpios[idx] = gpio;
+ gpios[idx] = gpio;

- ret = gpio_request(gpio, "i2c-bus");
- if (ret) {
- dev_err(i2c->dev, "gpio [%d] request failed\n", gpio);
- goto free_gpio;
+ if (devm_gpio_request(dev, gpio, "i2c-bus")) {
+ dev_err(dev, "gpio [%d] request failed\n", gpio);
+ return -EINVAL;
}
}
return 0;
-
-free_gpio:
- while (--idx >= 0)
- gpio_free(i2c->gpios[idx]);
- return -EINVAL;
}

-static void s3c24xx_i2c_dt_gpio_free(struct s3c24xx_i2c *i2c)
+static int s3c24xx_i2c_parse_dt_gpio(struct s3c24xx_i2c *i2c)
{
- unsigned int idx;
+ int ret = 0;

if (i2c->quirks & QUIRK_NO_GPIO)
- return;
+ goto out;
+
+ if (of_i2c_parse_gpio(i2c->dev, "gpios", i2c->gpios, 2, true)) {
+ ret = -EINVAL;
+ goto out;
+ }

- for (idx = 0; idx < 2; idx++)
- gpio_free(i2c->gpios[idx]);
+ if (i2c->adap.gpio_arbit) {
+ if (!of_i2c_parse_gpio(i2c->dev, "bus-arbitration-gpios",
+ i2c->adap.gpio_arbit->arb_gpios, I2C_ARB_GPIO_COUNT,
+ false)) {
+ dev_warn(i2c->dev, "GPIO-based arbitration enabled");
+ } else
+ ret = -EINVAL;
+ }
+
+ out:
+ return ret;
}
#else
static int s3c24xx_i2c_parse_dt_gpio(struct s3c24xx_i2c *i2c)
{
return 0;
}
-
-static void s3c24xx_i2c_dt_gpio_free(struct s3c24xx_i2c *i2c)
-{
-}
#endif

/* s3c24xx_i2c_init
@@ -981,6 +988,7 @@ static int s3c24xx_i2c_probe(struct platform_device *pdev)
{
struct s3c24xx_i2c *i2c;
struct s3c2410_platform_i2c *pdata = NULL;
+ struct i2c_gpio_arbit *arbit = NULL;
struct resource *res;
int ret;

@@ -1004,11 +1012,21 @@ static int s3c24xx_i2c_probe(struct platform_device *pdev)
goto err_noclk;
}

+ arbit = devm_kzalloc(&pdev->dev, sizeof(*arbit), GFP_KERNEL);
+ if (!arbit) {
+ ret = -ENOMEM;
+ goto err_noclk;
+ }
+
i2c->quirks = s3c24xx_get_device_quirks(pdev);
if (pdata)
memcpy(i2c->pdata, pdata, sizeof(*pdata));
- else
+ else {
s3c24xx_i2c_parse_dt(pdev->dev.of_node, i2c);
+ /* Arbitration parameters */
+ i2c->adap.gpio_arbit = of_get_arbitrator_info(
+ pdev->dev.of_node, arbit);
+ }

strlcpy(i2c->adap.name, "s3c2410-i2c", sizeof(i2c->adap.name));
i2c->adap.owner = THIS_MODULE;
@@ -1158,9 +1176,6 @@ static int s3c24xx_i2c_remove(struct platform_device *pdev)
clk_disable_unprepare(i2c->clk);
clk_put(i2c->clk);

- if (pdev->dev.of_node && IS_ERR(i2c->pctrl))
- s3c24xx_i2c_dt_gpio_free(i2c);
-
return 0;
}

--
1.7.9.5

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