On 07.02.2012 04:25, Jean-Christophe PLAGNIOL-VILLARD wrote:
On 19:38 Mon 06 Feb , Karol Lewandowski wrote:
+ - udelay: half clock cycle time in us (may depend on each platform)
Could we use "clock-frequency" as Grant have suggested during review
of previous patch to i2c-gpio?
as exaplained no as for gpio the delay is platform dependent
Following sniplet from i2c-gpio suggests that in some cases both udelay
and timeout can be calculated given presence of other parameters:
static int __devinit i2c_gpio_probe(struct platform_device *pdev)
...
if (pdata->udelay)
bit_data->udelay = pdata->udelay;
else if (pdata->scl_is_output_only)
bit_data->udelay = 50; /* 10 kHz */
else
bit_data->udelay = 5; /* 100 kHz */
if (pdata->timeout)
bit_data->timeout = pdata->timeout;
else
bit_data->timeout = HZ / 10; /* 100 ms */
However, I find it more troubling that driver manually grabs parameters
that are specific to i2c-algo-bit (timeout, udelay).
Thus, I have feeling that it should be generically addressed there. What
do you think?
https://lkml.org/lkml/2011/2/24/220
+ - timeout: timeout to get data
+
+
+Example nodes:
+
+i2c-gpio@0 {
+ compatible = "gpio-i2c";
+ gpios =<&pioA 23 0 /* sda */
+ &pioA 24 0 /* scl */
+ >;
+ gpio-i2c,sda_is_open_drain;
+ gpio-i2c,scl_is_open_drain;
+ udelay =<2>; /* ~100 kHz */
+ #address-cells =<1>;
+ #size-cells =<0>;
+
+ rv3029c2@56 {
+ compatible = "rv3029c2";
+ reg =<0x56>;
+ };
+};
diff --git a/drivers/i2c/busses/i2c-gpio.c b/drivers/i2c/busses/i2c-gpio.c
index a651779..6b5d794 100644
--- a/drivers/i2c/busses/i2c-gpio.c
+++ b/drivers/i2c/busses/i2c-gpio.c
@@ -14,6 +14,8 @@
#include<linux/module.h>
#include<linux/slab.h>
#include<linux/platform_device.h>
+#include<linux/of_gpio.h>
+#include<linux/of_i2c.h>
#include<asm/gpio.h>
@@ -78,16 +80,51 @@ static int i2c_gpio_getscl(void *data)
return gpio_get_value(pdata->scl_pin);
}
+static int of_i2c_gpio_probe(struct device_node *np,
+ struct i2c_gpio_platform_data *pdata)
+{
+ u32 reg;
+
if (of_gpio_count(np)< 2)
return -EINVAL;
ok
+ pdata->sda_pin = of_get_gpio(np, 0);
+ pdata->scl_pin = of_get_gpio(np, 1);
if (pdata->sda_pin< 0 || pdata->scl_pin< 0)
return -EINVAL;
+
+ if (of_property_read_u32(np, "udelay",®))
+ pdata->udelay = reg;
+
+ if (of_property_read_u32(np, "timeout",®))
+ pdata->timeout = reg;
One more thing missed in original review - of_property_read* rnegative
value on error, so logic has to reversed here:
if (of_property_read_u32(np, "timeout",®) == 0)
or
if (!of_property_read_u32(np, "timeout",®))
As I have been testing your driver on real hardware I've also made
changes (see below) which I have previously written about. If you would
like to see these in git-am-able format please drop me a note.
diff --git a/drivers/i2c/busses/i2c-gpio.c b/drivers/i2c/busses/i2c-gpio.c
index 6b5d794..d22c2c7 100644
--- a/drivers/i2c/busses/i2c-gpio.c
+++ b/drivers/i2c/busses/i2c-gpio.c
@@ -80,29 +80,45 @@ static int i2c_gpio_getscl(void *data)
return gpio_get_value(pdata->scl_pin);
}
+#ifdef CONFIG_OF
static int of_i2c_gpio_probe(struct device_node *np,
struct i2c_gpio_platform_data *pdata)
{
u32 reg;
+ if (!np)
+ return -EINVAL;
+
+ if (of_gpio_count(np) < 2)
+ return -EINVAL;
+
pdata->sda_pin = of_get_gpio(np, 0);
pdata->scl_pin = of_get_gpio(np, 1);
- if (of_property_read_u32(np, "udelay", ®))
+ if (pdata->sda_pin < 0 || pdata->scl_pin < 0)
+ return -EINVAL;
+
+ if (!of_property_read_u32(np, "udelay", ®))
pdata->udelay = reg;
- if (of_property_read_u32(np, "timeout", ®))
+ if (!of_property_read_u32(np, "timeout", ®))
pdata->timeout = reg;
pdata->sda_is_open_drain =
- !!of_get_property(np, "gpio-i2c,sda_is_open_drain", NULL);
+ !!of_get_property(np, "i2c-gpio,sda-open-drain", NULL);
pdata->scl_is_open_drain =
- !!of_get_property(np, "gpio-i2c,scl_is_open_drain", NULL);
+ !!of_get_property(np, "i2c-gpio,scl-open-drain", NULL);
pdata->scl_is_output_only =
- !!of_get_property(np, "gpio-i2c,scl_is_output_only", NULL);
+ !!of_get_property(np, "i2c-gpio,scl-output-only", NULL);
return 0;
}
+#else
+static int of_i2c_gpio_probe(struct device_node *np,
+ struct i2c_gpio_platform_data *pdata)
+{
+ return -EINVAL
+#endif
static int __devinit i2c_gpio_probe(struct platform_device *pdev)
{
@@ -116,15 +132,11 @@ static int __devinit i2c_gpio_probe(struct
platform_device *pdev)
if (!pdata)
return -ENOMEM;
- if (pdev->dev.of_node) {
- of_i2c_gpio_probe(pdev->dev.of_node, pdata);
- } else {
- if (!pdev->dev.platform_data) {
- ret = -ENXIO;
- goto err_alloc_adap;
- }
+ ret = -ENXIO;
+ if ((ret = of_i2c_gpio_probe(pdev->dev.of_node, pdata)) < 0 &&
!pdev->dev.platform_data)
+ goto err_alloc_adap;
+ else if (pdev->dev.platform_data)
memcpy(pdata, pdev->dev.platform_data, len);
- }
ret = -ENOMEM;
adap = kzalloc(sizeof(struct i2c_adapter), GFP_KERNEL);
@@ -235,7 +247,7 @@ static int __devexit i2c_gpio_remove(struct
platform_device *pdev)
#if defined(CONFIG_OF)
static const struct of_device_id gpio_i2c_dt_ids[] = {
- { .compatible = "gpio-i2c", },
+ { .compatible = "i2c-gpio", },
{ /* sentinel */ }
};
Regards,
--
Karol Lewandowski | Samsung Poland R&D Center | Linux/Platform
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