From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mika Westerberg Subject: Re: [PATCH v7] i2c-designware: make SDA hold time configurable Date: Tue, 14 May 2013 14:07:45 +0300 Message-ID: <20130514110745.GA10906@intel.com> References: <20130327084158.GB11010@ab42.lan> <1364373760-12469-1-git-send-email-christian.ruppert@abilis.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <1364373760-12469-1-git-send-email-christian.ruppert-ux6zf3SgZrrQT0dZR+AlfA@public.gmane.org> Sender: linux-i2c-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Wolfram Sang Cc: Christian Ruppert , "Ben Dooks (embedded platforms)" , Grant Likely , Rob Herring , Rob Landley , devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org, linux-doc-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Vineet Gupta , Pierrick Hascoet List-Id: devicetree@vger.kernel.org On Tue, Apr 09, 2013 at 12:59:54PM +0200, Christian Ruppert wrote: > This patch makes the SDA hold time configurable through device tree. > > Signed-off-by: Christian Ruppert > Signed-off-by: Pierrick Hascoet Hi Wolfram, What happened to this patch? I don't see it merged for 3.10. The reason I'm asking is that I would like to add ACPI support for the SDA hold time parameter analogous to the DT version. Thanks. > --- > .../devicetree/bindings/i2c/i2c-designware.txt | 14 ++++++++++++++ > drivers/i2c/busses/i2c-designware-core.c | 5 +++++ > drivers/i2c/busses/i2c-designware-core.h | 1 + > drivers/i2c/busses/i2c-designware-platdrv.c | 9 +++++++++ > 4 files changed, 29 insertions(+), 0 deletions(-) > > diff --git a/Documentation/devicetree/bindings/i2c/i2c-designware.txt b/Documentation/devicetree/bindings/i2c/i2c-designware.txt > index e42a2ee..21fabe7 100644 > --- a/Documentation/devicetree/bindings/i2c/i2c-designware.txt > +++ b/Documentation/devicetree/bindings/i2c/i2c-designware.txt > @@ -10,6 +10,9 @@ Recommended properties : > > - clock-frequency : desired I2C bus clock frequency in Hz. > > +Optional properties : > + - sda-hold-time : should contain the SDA hold time in nanoseconds. > + > Example : > > i2c@f0000 { > @@ -20,3 +23,14 @@ Example : > interrupts = <11>; > clock-frequency = <400000>; > }; > + > + i2c@1120000 { > + #address-cells = <1>; > + #size-cells = <0>; > + compatible = "snps,designware-i2c"; > + reg = <0x1120000 0x1000>; > + interrupt-parent = <&ictl>; > + interrupts = <12 1>; > + clock-frequency = <400000>; > + sda-hold-time = <300>; > + }; > diff --git a/drivers/i2c/busses/i2c-designware-core.c b/drivers/i2c/busses/i2c-designware-core.c > index 94fd818..ba40e14 100644 > --- a/drivers/i2c/busses/i2c-designware-core.c > +++ b/drivers/i2c/busses/i2c-designware-core.c > @@ -67,6 +67,7 @@ > #define DW_IC_STATUS 0x70 > #define DW_IC_TXFLR 0x74 > #define DW_IC_RXFLR 0x78 > +#define DW_IC_SDA_HOLD 0x7c > #define DW_IC_TX_ABRT_SOURCE 0x80 > #define DW_IC_COMP_PARAM_1 0xf4 > #define DW_IC_COMP_TYPE 0xfc > @@ -310,6 +311,10 @@ int i2c_dw_init(struct dw_i2c_dev *dev) > dw_writel(dev, lcnt, DW_IC_FS_SCL_LCNT); > dev_dbg(dev->dev, "Fast-mode HCNT:LCNT = %d:%d\n", hcnt, lcnt); > > + /* Configure SDA Hold Time if required */ > + if (dev->sda_hold_time) > + dw_writel(dev, dev->sda_hold_time, DW_IC_SDA_HOLD); > + > /* Configure Tx/Rx FIFO threshold levels */ > dw_writel(dev, dev->tx_fifo_depth - 1, DW_IC_TX_TL); > dw_writel(dev, 0, DW_IC_RX_TL); > diff --git a/drivers/i2c/busses/i2c-designware-core.h b/drivers/i2c/busses/i2c-designware-core.h > index 9c1840e..33dfec3 100644 > --- a/drivers/i2c/busses/i2c-designware-core.h > +++ b/drivers/i2c/busses/i2c-designware-core.h > @@ -88,6 +88,7 @@ struct dw_i2c_dev { > u32 master_cfg; > unsigned int tx_fifo_depth; > unsigned int rx_fifo_depth; > + u32 sda_hold_time; > }; > > #define ACCESS_SWAP 0x00000001 > diff --git a/drivers/i2c/busses/i2c-designware-platdrv.c b/drivers/i2c/busses/i2c-designware-platdrv.c > index 0ceb6e1..0a6e29b 100644 > --- a/drivers/i2c/busses/i2c-designware-platdrv.c > +++ b/drivers/i2c/busses/i2c-designware-platdrv.c > @@ -34,6 +34,7 @@ > #include > #include > #include > +#include > #include > #include > #include > @@ -136,6 +137,14 @@ static int dw_i2c_probe(struct platform_device *pdev) > } > clk_prepare_enable(dev->clk); > > + if (pdev->dev.of_node) { > + u32 ht; > + u32 ic_clk = dev->get_clk_rate_khz(dev); > + > + of_property_read_u32(pdev->dev.of_node, "sda-hold-time", &ht); > + dev->sda_hold_time = ((u64)ic_clk * ht + 500000) / 1000000; > + } > + > dev->functionality = > I2C_FUNC_I2C | > I2C_FUNC_10BIT_ADDR | > -- > 1.7.1 >