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Commit e5aba13d authored by Shawn Guo's avatar Shawn Guo
Browse files

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: default avatarShawn Guo <shawn.guo@linaro.org>
Reviewed-by: default avatarArnd Bergmann <arnd@arndb.de>
Acked-by: default avatarWolfram Sang <wsa@the-dreams.de>
parent 26aafa77

Documentation/devicetree/bindings/i2c/i2c-mxs.txt

+8 −4
Original line number Original line Diff line number Diff line
@@ -3,10 +3,13 @@ 
Required properties:

Required properties:

- compatible: Should be "fsl,<chip>-i2c"

- compatible: Should be "fsl,<chip>-i2c"

- reg: Should contain registers location and length

- 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.

- clock-frequency: Desired I2C bus clock frequency in Hz.

                   Only 100000Hz and 400000Hz modes are supported.

                   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:

Examples:
@@ -15,7 +18,8 @@ i2c0: i2c@80058000 { 
	#size-cells = <0>;

	#size-cells = <0>;

	compatible = "fsl,imx28-i2c";

	compatible = "fsl,imx28-i2c";

	reg = <0x80058000 2000>;

	reg = <0x80058000 2000>;

	interrupts = <111 68>;

	interrupts = <111>;

	clock-frequency = <100000>;

	clock-frequency = <100000>;

	fsl,i2c-dma-channel = <6>;

	dmas = <&dma_apbx 6>;

	dma-names = "rx-tx";

};
 
};

drivers/i2c/busses/i2c-mxs.c

+3 −37
Original line number Original line Diff line number Diff line
@@ -31,7 +31,6 @@ 
#include <linux/of_i2c.h>

#include <linux/of_i2c.h>

#include <linux/dma-mapping.h>

#include <linux/dma-mapping.h>

#include <linux/dmaengine.h>

#include <linux/dmaengine.h>

#include <linux/fsl/mxs-dma.h>





#define DRIVER_NAME "mxs-i2c"

#define DRIVER_NAME "mxs-i2c"
@@ -113,9 +112,7 @@ struct mxs_i2c_dev { 
	uint32_t timing1;

	uint32_t timing1;





	/* DMA support components */

	/* DMA support components */

	int				dma_channel;

	struct dma_chan         	*dmach;

	struct dma_chan         	*dmach;

	struct mxs_dma_data		dma_data;

	uint32_t			pio_data[2];

	uint32_t			pio_data[2];

	uint32_t			addr_data;

	uint32_t			addr_data;

	struct scatterlist		sg_io[2];

	struct scatterlist		sg_io[2];
@@ -518,21 +515,6 @@ static const struct i2c_algorithm mxs_i2c_algo = { 
	.functionality = mxs_i2c_func,

	.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)

static void mxs_i2c_derive_timing(struct mxs_i2c_dev *i2c, int speed)

{

{

	/* The I2C block clock run at 24MHz */

	/* 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;

	struct device_node *node = dev->of_node;

	int ret;

	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);

	ret = of_property_read_u32(node, "clock-frequency", &speed);

	if (ret) {

	if (ret) {

		dev_warn(dev, "No I2C speed selected, using 100kHz\n");

		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 pinctrl *pinctrl;

	struct resource *res;

	struct resource *res;

	resource_size_t res_size;

	resource_size_t res_size;

	int err, irq, dmairq;

	int err, irq;

	dma_cap_mask_t mask;





	pinctrl = devm_pinctrl_get_select_default(dev);

	pinctrl = devm_pinctrl_get_select_default(dev);

	if (IS_ERR(pinctrl))

	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);

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);

	irq = platform_get_irq(pdev, 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;

		return -ENOENT;





	res_size = resource_size(res);

	res_size = resource_size(res);
@@ -648,10 +617,7 @@ static int mxs_i2c_probe(struct platform_device *pdev) 
	}

	}





	/* Setup the DMA */

	/* Setup the DMA */

	dma_cap_zero(mask);

	i2c->dmach = dma_request_slave_channel(dev, "rx-tx");

	dma_cap_set(DMA_SLAVE, mask);

	i2c->dma_data.chan_irq = dmairq;

	i2c->dmach = dma_request_channel(mask, mxs_i2c_dma_filter, i2c);

	if (!i2c->dmach) {

	if (!i2c->dmach) {

		dev_err(dev, "Failed to request dma\n");

		dev_err(dev, "Failed to request dma\n");

		return -ENODEV;

		return -ENODEV;