From: Albert Herranz <albert_herranz@xxxxxxxx> This patch is based on an earlier patch from Albert Herranz, http://git.infradead.org/users/herraa1/gc-linux-2.6.git/commit/ 9854eb78607c641ab5ae85bcbe3c9d14ac113733 The dts binding is modified as Grant suggested. The of probing is merged inline instead of a separate file. It uses the newer of gpio probe. Signed-off-by: Albert Herranz <albert_herranz@xxxxxxxx> Signed-off-by: Thomas Chou <thomas@xxxxxxxxxxxxx> --- for v2.6.39 v2 move of nodes probing to a hook, which will be optimized out when devicetree is not used. use linux/gpio.h. move binding doc to i2c/i2c-gpio.txt. Documentation/devicetree/bindings/i2c/i2c-gpio.txt | 40 +++++++++++ drivers/i2c/busses/i2c-gpio.c | 73 +++++++++++++++++++- 2 files changed, 110 insertions(+), 3 deletions(-) create mode 100644 Documentation/devicetree/bindings/i2c/i2c-gpio.txt diff --git a/Documentation/devicetree/bindings/i2c/i2c-gpio.txt b/Documentation/devicetree/bindings/i2c/i2c-gpio.txt new file mode 100644 index 0000000..541fb10 --- /dev/null +++ b/Documentation/devicetree/bindings/i2c/i2c-gpio.txt @@ -0,0 +1,40 @@ +GPIO-based I2C + +Required properties: +- compatible : should be "i2c-gpio". +- gpios : should specify GPIOs used for SDA and SCL lines, in that order. +Optional properties: +- sda-is-open-drain : present if SDA gpio is open-drain. +- scl-is-open-drain : present if SCL gpio is open-drain. +- scl-is-output-only : present if the output driver for SCL cannot be + turned off. this will prevent clock stretching from working. +- udelay : signal toggle delay. SCL frequency is (500 / udelay) kHz +- timeout : clock stretching timeout in milliseconds. + +Example: + +gpio0: starlet-gpio@0d8000c0 { + compatible = "nintendo,starlet-gpio"; + reg = <0d8000c0 4>; + gpio-controller; + #gpio-cells = <2>; +}; + +i2c-video { + #address-cells = <1>; + #size-cells = <0>; + compatible = "i2c-gpio"; + + gpios = <&gpio0 10 0 /* SDA line */ + &gpio0 11 0 /* SCL line */ + >; + sda-is-open-drain; + scl-is-open-drain; + scl-is-output-only; + udelay = <2>; + + audio-video-encoder { + compatible = "nintendo,wii-ave-rvl"; + reg = <70>; + }; +}; diff --git a/drivers/i2c/busses/i2c-gpio.c b/drivers/i2c/busses/i2c-gpio.c index d9aa9a6..dbf5b85 100644 --- a/drivers/i2c/busses/i2c-gpio.c +++ b/drivers/i2c/busses/i2c-gpio.c @@ -14,8 +14,10 @@ #include <linux/module.h> #include <linux/slab.h> #include <linux/platform_device.h> - -#include <asm/gpio.h> +#include <linux/gpio.h> +#include <linux/of_platform.h> +#include <linux/of_gpio.h> +#include <linux/of_i2c.h> /* Toggle SDA by changing the direction of the pin */ static void i2c_gpio_setsda_dir(void *data, int state) @@ -78,6 +80,53 @@ static int i2c_gpio_getscl(void *data) return gpio_get_value(pdata->scl_pin); } +/* Check if devicetree nodes exist and build platform data */ +static struct i2c_gpio_platform_data *i2c_gpio_of_probe( + struct platform_device *pdev) +{ + struct i2c_gpio_platform_data *pdata = NULL; + struct device_node *np = pdev->dev.of_node; + + if (np && of_gpio_count(np) >= 2) { + const __be32 *prop; + int sda_pin, scl_pin; + + sda_pin = of_get_gpio_flags(np, 0, NULL); + scl_pin = of_get_gpio_flags(np, 1, NULL); + if (sda_pin < 0 || scl_pin < 0) { + pr_err("%s: invalid GPIO pins, sda=%d/scl=%d\n", + np->full_name, sda_pin, scl_pin); + goto err_gpio_pin; + } + pdata = kzalloc(sizeof(*pdata), GFP_KERNEL); + if (!pdata) + goto err_alloc_pdata; + pdata->sda_pin = sda_pin; + pdata->scl_pin = scl_pin; + prop = of_get_property(np, "sda-is-open-drain", NULL); + if (prop) + pdata->sda_is_open_drain = 1; + prop = of_get_property(np, "scl-is-open-drain", NULL); + if (prop) + pdata->scl_is_open_drain = 1; + prop = of_get_property(np, "scl-is-output-only", NULL); + if (prop) + pdata->scl_is_output_only = 1; + prop = of_get_property(np, "udelay", NULL); + if (prop) + pdata->udelay = be32_to_cpup(prop); + prop = of_get_property(np, "timeout", NULL); + if (prop) { + pdata->timeout = + msecs_to_jiffies(be32_to_cpup(prop)); + } + } + +err_gpio_pin: +err_alloc_pdata: + return pdata; +} + static int __devinit i2c_gpio_probe(struct platform_device *pdev) { struct i2c_gpio_platform_data *pdata; @@ -87,6 +136,8 @@ static int __devinit i2c_gpio_probe(struct platform_device *pdev) pdata = pdev->dev.platform_data; if (!pdata) + pdata = i2c_gpio_of_probe(pdev); + if (!pdata) return -ENXIO; ret = -ENOMEM; @@ -143,6 +194,7 @@ static int __devinit i2c_gpio_probe(struct platform_device *pdev) adap->algo_data = bit_data; adap->class = I2C_CLASS_HWMON | I2C_CLASS_SPD; adap->dev.parent = &pdev->dev; + adap->dev.of_node = pdev->dev.of_node; /* * If "dev->id" is negative we consider it as zero. @@ -161,6 +213,9 @@ static int __devinit i2c_gpio_probe(struct platform_device *pdev) pdata->scl_is_output_only ? ", no clock stretching" : ""); + /* Now register all the child nodes */ + of_i2c_register_devices(adap); + return 0; err_add_bus: @@ -172,6 +227,8 @@ err_request_sda: err_alloc_bit_data: kfree(adap); err_alloc_adap: + if (!pdev->dev.platform_data) + kfree(pdata); return ret; } @@ -179,23 +236,33 @@ static int __devexit i2c_gpio_remove(struct platform_device *pdev) { struct i2c_gpio_platform_data *pdata; struct i2c_adapter *adap; + struct i2c_algo_bit_data *bit_data; adap = platform_get_drvdata(pdev); - pdata = pdev->dev.platform_data; + bit_data = adap->algo_data; + pdata = bit_data->data; i2c_del_adapter(adap); gpio_free(pdata->scl_pin); gpio_free(pdata->sda_pin); kfree(adap->algo_data); kfree(adap); + if (!pdev->dev.platform_data) + kfree(pdata); return 0; } +static const struct of_device_id i2c_gpio_match[] = { + { .compatible = "i2c-gpio", }, + {}, +}; + static struct platform_driver i2c_gpio_driver = { .driver = { .name = "i2c-gpio", .owner = THIS_MODULE, + .of_match_table = i2c_gpio_match, }, .probe = i2c_gpio_probe, .remove = __devexit_p(i2c_gpio_remove), -- 1.7.3.5 -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
