From mboxrd@z Thu Jan 1 00:00:00 1970 From: Karol Lewandowski Subject: Re: [PATCH 1/4] i2c/gpio-i2c add: add DT support Date: Mon, 06 Feb 2012 19:38:29 +0100 Message-ID: <4F301E25.5060507@samsung.com> References: <1328438337-21185-1-git-send-email-plagnioj@jcrosoft.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7BIT Return-path: In-reply-to: <1328438337-21185-1-git-send-email-plagnioj-sclMFOaUSTBWk0Htik3J/w@public.gmane.org> Sender: linux-i2c-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Jean-Christophe PLAGNIOL-VILLARD Cc: linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org, linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-i2c@vger.kernel.org On 05.02.2012 11:38, Jean-Christophe PLAGNIOL-VILLARD wrote: Hi! > +Device-Tree bindings for i2c gpio driver > + > +Required properties: > + - compatible = "gpio-i2c"; Driver name is "i2c-gpio" in file i2c-gpio.c. Previous version of patch adding DT-support (prepared by Thomas Chou[1]) used i2c-gpio - could we stick to that name? [1] https://lkml.org/lkml/2011/2/23/584 > + - gpios: sda and scl gpio > + > + > +Optional properties: > + - gpio-i2c,sda_is_open_drain: sda as open drain > + - gpio-i2c,scl_is_open_drain: scl as open drain > + - gpio-i2c,scl_is_output_only: scl as output only Most of DT-properties I've seen used hyphen, not underscore. Could we stick to that convention? (Nitpick: I think that "is" in property names is redundant too.) > + - 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? 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 > #include > #include > +#include > +#include > > #include > > @@ -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; > + 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; > + > + pdata->sda_is_open_drain = > + !!of_get_property(np, "gpio-i2c,sda_is_open_drain", NULL); > + pdata->scl_is_open_drain = > + !!of_get_property(np, "gpio-i2c,scl_is_open_drain", NULL); > + pdata->scl_is_output_only = > + !!of_get_property(np, "gpio-i2c,scl_is_output_only", NULL); > + > + return 0; > +} > + > static int __devinit i2c_gpio_probe(struct platform_device *pdev) > { > struct i2c_gpio_platform_data *pdata; > struct i2c_algo_bit_data *bit_data; > struct i2c_adapter *adap; > int ret; > + int len = sizeof(struct i2c_gpio_platform_data); > > - pdata = pdev->dev.platform_data; > + pdata = kzalloc(len, GFP_KERNEL); Could you also take into account Grant's comment about private/platform data? https://lkml.org/lkml/2011/2/3/221 > if (!pdata) > - return -ENXIO; > + return -ENOMEM; > + > + if (pdev->dev.of_node) { > + of_i2c_gpio_probe(pdev->dev.of_node, pdata); Above might fail if configuration is corrupted. > + } else { > + if (!pdev->dev.platform_data) { > + ret = -ENXIO; > + goto err_alloc_adap; > + } > + memcpy(pdata, pdev->dev.platform_data, len); > + } > > ret = -ENOMEM; > adap = kzalloc(sizeof(struct i2c_adapter), GFP_KERNEL); > @@ -143,6 +180,7 @@ 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. > @@ -154,6 +192,8 @@ static int __devinit i2c_gpio_probe(struct platform_device *pdev) > if (ret) > goto err_add_bus; > > + of_i2c_register_devices(adap); > + > platform_set_drvdata(pdev, adap); > > dev_info(&pdev->dev, "using pins %u (SDA) and %u (SCL%s)\n", > @@ -172,6 +212,7 @@ err_request_sda: > err_alloc_bit_data: > kfree(adap); > err_alloc_adap: > + kfree(pdata); > return ret; > } > > @@ -192,10 +233,20 @@ static int __devexit i2c_gpio_remove(struct platform_device *pdev) > return 0; > } > > +#if defined(CONFIG_OF) > +static const struct of_device_id gpio_i2c_dt_ids[] = { > + { .compatible = "gpio-i2c", }, There seem to be no good reason to make DT-compatible string different from driver's name that's already in use: > static struct platform_driver i2c_gpio_driver = { > .driver = { > .name = "i2c-gpio", Regards, -- Karol Lewandowski | Samsung Poland R&D Center | Linux/Platform