Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755343Ab3JHPZP (ORCPT ); Tue, 8 Oct 2013 11:25:15 -0400 Received: from mail.abilis.ch ([195.70.19.74]:22034 "EHLO mail.abilis.ch" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753042Ab3JHPZM (ORCPT ); Tue, 8 Oct 2013 11:25:12 -0400 X-Greylist: delayed 1379 seconds by postgrey-1.27 at vger.kernel.org; Tue, 08 Oct 2013 11:25:11 EDT From: Romain Baeriswyl To: Wolfram Sang Cc: Rob Herring , Pawel Moll , Mark Rutland , Stephen Warren , Ian Campbell , Rob Landley , Pierrick Hascoet , Vineet Gupta , Christian Ruppert , Mika Westerberg , Chiau Ee Chew , Shinya Kuribayashi , Jean Delvare , "Rafael J. Wysocki" , devicetree@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-i2c@vger.kernel.org, Romain Baeriswyl Subject: [PATCH 2/2] i2c designware add support of I2C standard mode Date: Tue, 8 Oct 2013 17:00:55 +0200 Message-Id: <1381244455-3836-2-git-send-email-romainba@abilis.com> X-Mailer: git-send-email 1.7.1 In-Reply-To: <20130828153429.GB7066@ab42.lan> References: <20130828153429.GB7066@ab42.lan> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3205 Lines: 83 Some legacy devices support ony I2C standard mode at 100kHz. This patch allows to select the standard mode through the DTS with the use of the existing clock-frequency parameter. When clock-frequency parameter is not set, the fast mode is selected. Only when the parameter is set at 100000, the standard mode is selected. Signed-off-by: Romain Baeriswyl Reviewed-by: Christian Ruppert --- .../devicetree/bindings/i2c/i2c-designware.txt | 1 + drivers/i2c/busses/i2c-designware-platdrv.c | 17 +++++++++++++++-- 2 files changed, 16 insertions(+), 2 deletions(-) diff --git a/Documentation/devicetree/bindings/i2c/i2c-designware.txt b/Documentation/devicetree/bindings/i2c/i2c-designware.txt index 5199b0c..16d0bef 100644 --- a/Documentation/devicetree/bindings/i2c/i2c-designware.txt +++ b/Documentation/devicetree/bindings/i2c/i2c-designware.txt @@ -9,6 +9,7 @@ Required properties : Recommended properties : - clock-frequency : desired I2C bus clock frequency in Hz. + Only standard mode at 100kHz and fast mode at 400kHz are supported. Optional properties : - i2c-sda-hold-time-ns : should contain the SDA hold time in nanoseconds. diff --git a/drivers/i2c/busses/i2c-designware-platdrv.c b/drivers/i2c/busses/i2c-designware-platdrv.c index 0d6fe47..5f06848 100644 --- a/drivers/i2c/busses/i2c-designware-platdrv.c +++ b/drivers/i2c/busses/i2c-designware-platdrv.c @@ -87,6 +87,7 @@ static int dw_i2c_probe(struct platform_device *pdev) struct i2c_adapter *adap; struct resource *mem; int irq, r; + u32 clk_freq; irq = platform_get_irq(pdev, 0); if (irq < 0) { @@ -122,6 +123,9 @@ static int dw_i2c_probe(struct platform_device *pdev) return PTR_ERR(dev->clk); clk_prepare_enable(dev->clk); + /* fast mode by default */ + clk_freq = 400000; + if (pdev->dev.of_node) { u32 ht = 0; u32 ic_clk = dev->get_clk_rate_khz(dev); @@ -136,6 +140,11 @@ static int dw_i2c_probe(struct platform_device *pdev) of_property_read_u32(pdev->dev.of_node, "i2c-scl-falling-time-ns", &dev->scl_falling_time); + + of_property_read_u32(pdev->dev.of_node, "clock-frequency", + &clk_freq); + if (clk_freq != 100000 && clk_freq != 400000) + return -EINVAL; } dev->functionality = @@ -145,8 +154,12 @@ static int dw_i2c_probe(struct platform_device *pdev) I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA | I2C_FUNC_SMBUS_I2C_BLOCK; - dev->master_cfg = DW_IC_CON_MASTER | DW_IC_CON_SLAVE_DISABLE | - DW_IC_CON_RESTART_EN | DW_IC_CON_SPEED_FAST; + if (clk_freq == 100000) + dev->master_cfg = DW_IC_CON_MASTER | DW_IC_CON_SLAVE_DISABLE | + DW_IC_CON_RESTART_EN | DW_IC_CON_SPEED_STD; + else + dev->master_cfg = DW_IC_CON_MASTER | DW_IC_CON_SLAVE_DISABLE | + DW_IC_CON_RESTART_EN | DW_IC_CON_SPEED_FAST; /* Try first if we can configure the device from ACPI */ r = dw_i2c_acpi_configure(pdev); -- 1.7.1 -- 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/