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i2c: i2c-mxs: move to use generic DMA helper 

With the generic DMA device tree helper supported by mxs-dma driver,
client devices only need to call dma_request_slave_channel() for
requesting a DMA channel from dmaengine.

Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Wolfram Sang <wsa@the-dreams.de>
This commit is contained in:
Shawn Guo 2013-02-26 11:20:22 +08:00
parent 26aafa77df
commit e5aba13da0
2 changed files with 11 additions and 41 deletions
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12
Documentation/devicetree/bindings/i2c/i2c-mxs.txt
View File

@ -3,10 +3,13 @@
Required properties:
- compatible: Should be "fsl,<chip>-i2c"
- reg: Should contain registers location and length
- interrupts: Should contain ERROR and DMA interrupts
- interrupts: Should contain ERROR interrupt number
- clock-frequency: Desired I2C bus clock frequency in Hz.
Only 100000Hz and 400000Hz modes are supported.
- fsl,i2c-dma-channel: APBX DMA channel for the I2C
- dmas: DMA specifier, consisting of a phandle to DMA controller node
and I2C DMA channel ID.
Refer to dma.txt and fsl-mxs-dma.txt for details.
- dma-names: Must be "rx-tx".
Examples:
@ -15,7 +18,8 @@ i2c0: i2c@80058000 {
#size-cells = <0>;
compatible = "fsl,imx28-i2c";
reg = <0x80058000 2000>;
interrupts = <111 68>;
interrupts = <111>;
clock-frequency = <100000>;
fsl,i2c-dma-channel = <6>;
dmas = <&dma_apbx 6>;
dma-names = "rx-tx";
};

40
drivers/i2c/busses/i2c-mxs.c
View File

@ -31,7 +31,6 @@
#include <linux/of_i2c.h>
#include <linux/dma-mapping.h>
#include <linux/dmaengine.h>
#include <linux/fsl/mxs-dma.h>
#define DRIVER_NAME "mxs-i2c"
@ -113,9 +112,7 @@ struct mxs_i2c_dev {
uint32_t timing1;
/* DMA support components */
int dma_channel;
struct dma_chan *dmach;
struct mxs_dma_data dma_data;
uint32_t pio_data[2];
uint32_t addr_data;
struct scatterlist sg_io[2];
@ -518,21 +515,6 @@ static const struct i2c_algorithm mxs_i2c_algo = {
.functionality = mxs_i2c_func,
};
static bool mxs_i2c_dma_filter(struct dma_chan *chan, void *param)
{
struct mxs_i2c_dev *i2c = param;
if (!mxs_dma_is_apbx(chan))
return false;
if (chan->chan_id != i2c->dma_channel)
return false;
chan->private = &i2c->dma_data;
return true;
}
static void mxs_i2c_derive_timing(struct mxs_i2c_dev *i2c, int speed)
{
/* The I2C block clock run at 24MHz */
@ -577,17 +559,6 @@ static int mxs_i2c_get_ofdata(struct mxs_i2c_dev *i2c)
struct device_node *node = dev->of_node;
int ret;
/*
* TODO: This is a temporary solution and should be changed
* to use generic DMA binding later when the helpers get in.
*/
ret = of_property_read_u32(node, "fsl,i2c-dma-channel",
&i2c->dma_channel);
if (ret) {
dev_err(dev, "Failed to get DMA channel!\n");
return -ENODEV;
}
ret = of_property_read_u32(node, "clock-frequency", &speed);
if (ret) {
dev_warn(dev, "No I2C speed selected, using 100kHz\n");
@ -607,8 +578,7 @@ static int mxs_i2c_probe(struct platform_device *pdev)
struct pinctrl *pinctrl;
struct resource *res;
resource_size_t res_size;
int err, irq, dmairq;
dma_cap_mask_t mask;
int err, irq;
pinctrl = devm_pinctrl_get_select_default(dev);
if (IS_ERR(pinctrl))
@ -620,9 +590,8 @@ static int mxs_i2c_probe(struct platform_device *pdev)
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
irq = platform_get_irq(pdev, 0);
dmairq = platform_get_irq(pdev, 1);
if (!res || irq < 0 || dmairq < 0)
if (!res || irq < 0)
return -ENOENT;
res_size = resource_size(res);
@ -648,10 +617,7 @@ static int mxs_i2c_probe(struct platform_device *pdev)
}
/* Setup the DMA */
dma_cap_zero(mask);
dma_cap_set(DMA_SLAVE, mask);
i2c->dma_data.chan_irq = dmairq;
i2c->dmach = dma_request_channel(mask, mxs_i2c_dma_filter, i2c);
i2c->dmach = dma_request_slave_channel(dev, "rx-tx");
if (!i2c->dmach) {
dev_err(dev, "Failed to request dma\n");
return -ENODEV;