Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756731Ab2FONTF (ORCPT ); Fri, 15 Jun 2012 09:19:05 -0400 Received: from mail-ey0-f174.google.com ([209.85.215.174]:56597 "EHLO mail-ey0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752814Ab2FONTC (ORCPT ); Fri, 15 Jun 2012 09:19:02 -0400 Message-ID: <4FDB3642.5030804@linaro.org> Date: Fri, 15 Jun 2012 14:18:58 +0100 From: Lee Jones User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:11.0) Gecko/20120410 Thunderbird/11.0.1 MIME-Version: 1.0 To: Srinidhi Kasagar CC: Linus WALLEIJ , "arnd@arndb.de" , "linux-kernel@vger.kernel.org" , "grant.likely@secretlab.ca" , "linux-arm-kernel@lists.infradead.org" , "linux-i2c@vger.kernel.org" Subject: Re: Fwd: [PATCH 1/3] i2c: Add Device Tree support to the Nomadik I2C driver References: <1339428307-3850-1-git-send-email-lee.jones@linaro.org> <1339428307-3850-10-git-send-email-lee.jones@linaro.org> <4FD8BAD2.50703@linaro.org> <4FDAFA17.6050502@linaro.org> <20120615115042.GA27480@bnru02> <4FDB2E57.4030904@linaro.org> <20120615130544.GA28537@bnru02> In-Reply-To: <20120615130544.GA28537@bnru02> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 7590 Lines: 211 On 15/06/12 14:05, Srinidhi Kasagar wrote: > On Fri, Jun 15, 2012 at 14:45:11 +0200, Lee Jones wrote: >> On 15/06/12 12:50, Srinidhi Kasagar wrote: >>> [...] >>>> >>>> >>>> From: Lee Jones >>>> Date: Tue, 17 Apr 2012 16:04:13 +0100 >>>> Subject: [PATCH 1/1] i2c: Add Device Tree support to the Nomadik I2C driver >>>> >>>> Here we apply the bindings required for successful Device Tree >>>> probing of the i2c-nomadik driver. We also apply a fall-back >>>> configuration in case either one is not provided, or a required >>>> element is missing from the one supplied. >>>> >>>> Cc: linux-i2c@vger.kernel.org >>>> Signed-off-by: Lee Jones >>>> --- >>>> drivers/i2c/busses/i2c-nomadik.c | 82 +++++++++++++++++++++++++++++++++++++- >>>> 1 file changed, 80 insertions(+), 2 deletions(-) >>>> >>>> diff --git a/drivers/i2c/busses/i2c-nomadik.c b/drivers/i2c/busses/i2c-nomadik.c >>>> index a92440d..58e8114 100644 >>>> --- a/drivers/i2c/busses/i2c-nomadik.c >>>> +++ b/drivers/i2c/busses/i2c-nomadik.c >>>> @@ -23,6 +23,7 @@ >>>> #include >>>> #include >>>> #include >>>> +#include >>>> >>>> #include >>>> >>>> @@ -899,15 +900,86 @@ static const struct i2c_algorithm nmk_i2c_algo = { >>>> .functionality = nmk_i2c_functionality >>>> }; >>>> >>>> +static struct nmk_i2c_controller u8500_i2c = { >>>> + /* >>>> + * Slave data setup time; 250ns, 100ns, and 10ns, which >>>> + * is 14, 6 and 2 respectively for a 48Mhz i2c clock. >>>> + */ >>>> + .slsu = 0xe, >>>> + .tft = 1, /* Tx FIFO threshold */ >>>> + .rft = 8, /* Rx FIFO threshold */ >>>> + .clk_freq = 100000, /* std. mode operation */ >>>> + .timeout = 200, /* Slave response timeout(ms) */ >>>> + .sm = I2C_FREQ_MODE_FAST, >>> >>> How is this possible? you are setting clk_freq as 100kb/s and mode >>> as fast mode which is supposed to be 400kb/s. >> >> That's not how I read it: > > But it is not readable. It confuses people. I understood it. :) If you think it's unclear speak to the author, Linus. He's CC'ed. >>> enum i2c_freq_mode { >>> I2C_FREQ_MODE_STANDARD, /* up to 100 Kb/s */ >>> I2C_FREQ_MODE_FAST, /* up to 400 Kb/s */ >>> I2C_FREQ_MODE_HIGH_SPEED, /* up to 3.4 Mb/s */ >>> I2C_FREQ_MODE_FAST_PLUS, /* up to 1 Mb/s */ >>> }; >> >> The operative words here are "up to". > > I know, then none of these modes does not make sense. > >>>> +}; >>>> + >>>> +static int __devinit >>>> +nmk_i2c_of_probe(struct device_node *np, struct nmk_i2c_controller *pdata) >>>> +{ >>>> + of_property_read_u32(np, "clock-frequency", (u32*)&pdata->clk_freq); >>>> + if (!pdata->clk_freq) { >>>> + pr_warn("%s: Clock frequency not found\n", np->full_name); >>>> + return -EINVAL; >>>> + } >>>> + >>>> + of_property_read_u32(np, "stericsson,slsu", (u32*)&pdata->slsu); >>>> + if (!pdata->slsu) { >>>> + pr_warn("%s: Data line delay not found\n", np->full_name); >>>> + return -EINVAL; >>>> + } >>>> + >>>> + of_property_read_u32(np, "stericsson,tft", (u32*)&pdata->tft); >>>> + if (!pdata->tft) { >>>> + pr_warn("%s: Tx FIFO threshold not found\n", np->full_name); >>>> + return -EINVAL; >>>> + } >>>> + >>>> + of_property_read_u32(np, "stericsson,rft", (u32*)&pdata->rft); >>>> + if (!pdata->rft) { >>>> + pr_warn("%s: Rx FIFO threshold not found\n", np->full_name); >>>> + return -EINVAL; >>>> + } >>>> + >>>> + of_property_read_u32(np, "stericsson,timeout", (u32*)&pdata->timeout); >>>> + if (!pdata->timeout) { >>>> + pr_warn("%s: Timeout not found\n", np->full_name); >>>> + return -EINVAL; >>>> + } >>>> + >>>> + if (of_get_property(np, "stericsson,i2c_freq_mode_fast", NULL)) >>>> + pdata->sm = I2C_FREQ_MODE_FAST; >>>> + else >>>> + pdata->sm = I2C_FREQ_MODE_STANDARD; >>> >>> The controller has more modes like fast mode plus and high speed mode. You can't make >>> assumptions like this. >> >> These are currently unsupported. Read the comments in the file: > > I wrote this code, I remember these comments very well :) Yes, I saw. I thought that perhaps you'd forgotten. ;) >>> /* >>> * set the speed mode. Currently we support >>> * only standard and fast mode of operation >>> * TODO - support for fast mode plus (up to 1Mb/s) >>> * and high speed (up to 3.4 Mb/s) >>> */ >> >> I can add a similar comment here if it make you feel better? > > Please. No problem. >>>> + >>>> + return 0; >>>> +} >>>> + >>>> static int __devinit nmk_i2c_probe(struct platform_device *pdev) >>>> { >>>> int ret = 0; >>>> struct resource *res; >>>> - struct nmk_i2c_controller *pdata = >>>> - pdev->dev.platform_data; >>>> + struct nmk_i2c_controller *pdata = pdev->dev.platform_data; >>>> + struct device_node *np = pdev->dev.of_node; >>>> struct nmk_i2c_dev *dev; >>>> struct i2c_adapter *adap; >>>> >>>> + if (np) { >>>> + if (!pdata) { >>>> + pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL); >>>> + if (!pdata) { >>>> + ret = -ENOMEM; >>>> + goto err_no_mem; >>>> + } >>>> + } >>>> + ret = nmk_i2c_of_probe(np, pdata); >>>> + if (ret) >>>> + kfree(pdata); >>>> + } >>>> + >>>> + if (!pdata) >>>> + /* No i2c configuration found, using the default. */ >>>> + pdata =&u8500_i2c; >>> >>> There are redundant fallback configurations exists in the driver. You might need to remove >>> those, if you want to fallback here. >> >> I only see a fall-back for clk_freq. Are there others? > > No, I can see that it only exists in setup_i2c_controller(). Please fix. I can remove it, no problem. >>>> + >>>> dev = kzalloc(sizeof(struct nmk_i2c_dev), GFP_KERNEL); >>>> if (!dev) { >>>> dev_err(&pdev->dev, "cannot allocate memory\n"); >>>> @@ -1038,11 +1110,17 @@ static int __devexit nmk_i2c_remove(struct platform_device *pdev) >>>> return 0; >>>> } >>>> >>>> +static const struct of_device_id nmk_gpio_match[] = { >>>> + { .compatible = "st,nomadik-i2c", }, >>>> + {}, >>>> +}; >>>> + >>>> static struct platform_driver nmk_i2c_driver = { >>>> .driver = { >>>> .owner = THIS_MODULE, >>>> .name = DRIVER_NAME, >>>> .pm =&nmk_i2c_pm, >>>> + .of_match_table = nmk_gpio_match, >>>> }, >>>> .probe = nmk_i2c_probe, >>>> .remove = __devexit_p(nmk_i2c_remove), >>>> -- >>>> 1.7.9.5 >>>> -- Lee Jones Linaro ST-Ericsson Landing Team Lead M: +44 77 88 633 515 Linaro.org │ Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/