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Message-ID: <20110302132833.GA2207@pengutronix.de>
Date: Wed, 2 Mar 2011 14:28:33 +0100
From: Wolfram Sang <w.sang@...gutronix.de>
To: Fabien Marteau <fabien.marteau@...adeus.com>
Cc: "Jean Delvare (PC drivers, core)" <khali@...ux-fr.org>,
"Ben Dooks (embedded platforms)" <ben-linux@...ff.org>,
"Uwe Kleine-König"
<u.kleine-koenig@...gutronix.de>,
Arnaud Patard <apatard@...driva.com>,
Tejun Heo <tj@...nel.org>, linux-i2c@...r.kernel.org,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH] i2c: Adding mangling capability to i2c imx bus
controller.
Hi Fabien,
thanks for your patch. Nice addition.
On Mon, Jan 31, 2011 at 04:29:53PM +0100, Fabien Marteau wrote:
> Adding Mangling capability to i2c imx bus controller.
Can you give a rough description how you tested it?
> Signed-off-by: Fabien Marteau <fabien.marteau@...adeus.com>
> ---
> Index: linux-2.6.36/drivers/i2c/busses/i2c-imx.c
> ===================================================================
> --- linux-2.6.36.orig/drivers/i2c/busses/i2c-imx.c 2010-10-20 22:30:22.000000000 +0200
> +++ linux-2.6.36/drivers/i2c/busses/i2c-imx.c 2011-01-31 16:23:34.000000000 +0100
> @@ -300,17 +300,28 @@
Please use "--show-c-function" for diff/quilt. This makes reviewing a
tad easier.
> {
> int i, result;
>
> - dev_dbg(&i2c_imx->adapter.dev, "<%s> write slave address: addr=0x%x\n",
> - __func__, msgs->addr << 1);
> + if ((msgs->flags & I2C_M_NOSTART) == 0) {
Please use !flag instead of == 0 as it is done in the rest of the
driver.
> + /* write slave address */
> + if (msgs->flags & I2C_M_REV_DIR_ADDR) {
> + dev_dbg(&i2c_imx->adapter.dev,
> + "<%s> write slave address: addr=0x%x\n",
> + __func__, msgs->addr << 1 | 0x01);
> + writeb((msgs->addr << 1) | 0x01,
> + i2c_imx->base + IMX_I2C_I2DR);
> + } else {
> + dev_dbg(&i2c_imx->adapter.dev,
> + "<%s> write slave address: addr=0x%x\n",
> + __func__, msgs->addr << 1);
> + writeb((msgs->addr << 1), i2c_imx->base + IMX_I2C_I2DR);
> + }
What about:
dev_dbg();
writeb(msgs->addr << 1 | !!(msg->flags & I2C_M_REV_DIR_ADDR));
Hmm, probably more readable would be
write_flag = (msg->flags & I2C_M_REV_DIR_ADDR) ? I2C_SMBUS_READ : I2C_SMBUS_WRITE
and use that? Also, not sure about the additional dev_dbg.
> + result = i2c_imx_trx_complete(i2c_imx);
> + if (result)
> + return result;
> + result = i2c_imx_acked(i2c_imx);
> + if (result != 0)
if (result)
> + return result;
> + }
>
> - /* write slave address */
> - writeb(msgs->addr << 1, i2c_imx->base + IMX_I2C_I2DR);
> - result = i2c_imx_trx_complete(i2c_imx);
> - if (result)
> - return result;
> - result = i2c_imx_acked(i2c_imx);
> - if (result)
> - return result;
> dev_dbg(&i2c_imx->adapter.dev, "<%s> write data\n", __func__);
>
> /* write data */
> @@ -323,7 +334,7 @@
> if (result)
> return result;
> result = i2c_imx_acked(i2c_imx);
> - if (result)
> + if ((result != 0) && ((msgs[0].flags & I2C_M_IGNORE_NAK) == 0))
if (result && !(msgs[0].flags & I2C_M_IGNORE_NAK))
> return result;
> }
> return 0;
> @@ -334,18 +345,27 @@
> int i, result;
> unsigned int temp;
>
> - dev_dbg(&i2c_imx->adapter.dev,
> - "<%s> write slave address: addr=0x%x\n",
> - __func__, (msgs->addr << 1) | 0x01);
> -
> - /* write slave address */
> - writeb((msgs->addr << 1) | 0x01, i2c_imx->base + IMX_I2C_I2DR);
> - result = i2c_imx_trx_complete(i2c_imx);
> - if (result)
> - return result;
> - result = i2c_imx_acked(i2c_imx);
> - if (result)
> - return result;
> + if ((msgs->flags & I2C_M_NOSTART) == 0) {
!flag
> + /* write slave address */
> + if (msgs->flags & I2C_M_REV_DIR_ADDR) {
> + dev_dbg(&i2c_imx->adapter.dev,
> + "<%s> write slave address: addr=0x%x\n",
> + __func__, (msgs->addr << 1));
> + writeb((msgs->addr << 1), i2c_imx->base + IMX_I2C_I2DR);
> + } else {
> + dev_dbg(&i2c_imx->adapter.dev,
> + "<%s> write slave address: addr=0x%x\n",
> + __func__, (msgs->addr << 1) | 0x01);
> + writeb((msgs->addr << 1) | 0x01,
> + i2c_imx->base + IMX_I2C_I2DR);
> + }
Please fix similar to above.
> + result = i2c_imx_trx_complete(i2c_imx);
> + if (result)
> + return result;
> + result = i2c_imx_acked(i2c_imx);
> + if (result != 0)
if (result)
> + return result;
> + }
>
> dev_dbg(&i2c_imx->adapter.dev, "<%s> setup bus\n", __func__);
>
> @@ -405,7 +425,7 @@
>
> /* read/write data */
> for (i = 0; i < num; i++) {
> - if (i) {
> + if (i && ((msgs[i].flags & I2C_M_NOSTART) == 0)) {
if (i && !(flag))
(Please check for other occasions, I might have missed one)
> dev_dbg(&i2c_imx->adapter.dev,
> "<%s> repeated start\n", __func__);
> temp = readb(i2c_imx->base + IMX_I2C_I2CR);
> @@ -454,7 +474,7 @@
>
> static u32 i2c_imx_func(struct i2c_adapter *adapter)
> {
> - return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
> + return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_PROTOCOL_MANGLING;
> }
>
> static struct i2c_algorithm i2c_imx_algo = {
> --
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Regards,
Wolfram
--
Pengutronix e.K. | Wolfram Sang |
Industrial Linux Solutions | http://www.pengutronix.de/ |
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