Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756852Ab2FOMpS (ORCPT ); Fri, 15 Jun 2012 08:45:18 -0400 Received: from mail-ey0-f174.google.com ([209.85.215.174]:60973 "EHLO mail-ey0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756725Ab2FOMpP (ORCPT ); Fri, 15 Jun 2012 08:45:15 -0400 Message-ID: <4FDB2E57.4030904@linaro.org> Date: Fri, 15 Jun 2012 13:45:11 +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@stericsson.com, 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> In-Reply-To: <20120615115042.GA27480@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: 6680 Lines: 192 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: > 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". >> +}; >> + >> +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: > /* > * 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? >> + >> + 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? >> + >> 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 >> Kind regards, Lee -- 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/