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Commit 75d31c23 authored by Måns Rullgård's avatar Måns Rullgård Committed by Wolfram Sang
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i2c: xlr: add support for Sigma Designs controller variant 



Sigma Designs chips use a variant of this controller with the following
differences:

- The BUSY bit in the STATUS register is inverted
- Bit 8 of the CONFIG register must be set
- The controller can generate interrupts

This patch adds support for the first two of these.  It also calculates
and sets the correct clock divisor if a clk is provided.  The bus
frequency is optionally speficied in the device tree node.

Signed-off-by: default avatarMans Rullgard <mans@mansr.com>
Signed-off-by: default avatarWolfram Sang <wsa@the-dreams.de>
parent 51549c08

drivers/i2c/busses/Kconfig

+3 −3
Original line number Diff line number Diff line
@@ -963,11 +963,11 @@ config I2C_XILINX 
	  will be called xilinx_i2c.



config I2C_XLR

	tristate "XLR I2C support"

	depends on CPU_XLR

	tristate "Netlogic XLR and Sigma Designs I2C support"

	depends on CPU_XLR || ARCH_TANGOX

	help

	  This driver enables support for the on-chip I2C interface of

	  the Netlogic XLR/XLS MIPS processors.

	  the Netlogic XLR/XLS MIPS processors and Sigma Designs SOCs.



	  This driver can also be built as a module.  If so, the module

	  will be called i2c-xlr.

drivers/i2c/busses/i2c-xlr.c

+77 −4
Original line number Diff line number Diff line
@@ -17,6 +17,8 @@ 
#include <linux/i2c.h>

#include <linux/io.h>

#include <linux/platform_device.h>

#include <linux/of_device.h>

#include <linux/clk.h>



/* XLR I2C REGISTERS */

#define XLR_I2C_CFG		0x00
@@ -63,11 +65,23 @@ static inline u32 xlr_i2c_rdreg(u32 __iomem *base, unsigned int reg) 
	return __raw_readl(base + reg);

}



struct xlr_i2c_config {

	u32 status_busy;	/* value of STATUS[0] when busy */

	u32 cfg_extra;		/* extra CFG bits to set */

};



struct xlr_i2c_private {

	struct i2c_adapter adap;

	u32 __iomem *iobase;

	const struct xlr_i2c_config *cfg;

	struct clk *clk;

};



static int xlr_i2c_busy(struct xlr_i2c_private *priv, u32 status)

{

	return (status & XLR_I2C_BUS_BUSY) == priv->cfg->status_busy;

}



static int xlr_i2c_tx(struct xlr_i2c_private *priv,  u16 len,

	u8 *buf, u16 addr)

{
@@ -80,7 +94,8 @@ static int xlr_i2c_tx(struct xlr_i2c_private *priv, u16 len, 
	offset = buf[0];

	xlr_i2c_wreg(priv->iobase, XLR_I2C_ADDR, offset);

	xlr_i2c_wreg(priv->iobase, XLR_I2C_DEVADDR, addr);

	xlr_i2c_wreg(priv->iobase, XLR_I2C_CFG, XLR_I2C_CFG_ADDR);

	xlr_i2c_wreg(priv->iobase, XLR_I2C_CFG,

			XLR_I2C_CFG_ADDR | priv->cfg->cfg_extra);

	xlr_i2c_wreg(priv->iobase, XLR_I2C_BYTECNT, len - 1);



	timeout = msecs_to_jiffies(XLR_I2C_TIMEOUT);
@@ -121,7 +136,7 @@ static int xlr_i2c_tx(struct xlr_i2c_private *priv, u16 len, 
		if (i2c_status & XLR_I2C_ACK_ERR)

			return -EIO;



		if ((i2c_status & XLR_I2C_BUS_BUSY) == 0 && pos >= len)

		if (!xlr_i2c_busy(priv, i2c_status) && pos >= len)

			return 0;

	}

	dev_err(&adap->dev, "I2C transmit timeout\n");
@@ -136,7 +151,8 @@ static int xlr_i2c_rx(struct xlr_i2c_private *priv, u16 len, u8 *buf, u16 addr) 
	int nbytes, timedout;

	u8 byte;



	xlr_i2c_wreg(priv->iobase, XLR_I2C_CFG, XLR_I2C_CFG_NOADDR);

	xlr_i2c_wreg(priv->iobase, XLR_I2C_CFG,

			XLR_I2C_CFG_NOADDR | priv->cfg->cfg_extra);

	xlr_i2c_wreg(priv->iobase, XLR_I2C_BYTECNT, len);

	xlr_i2c_wreg(priv->iobase, XLR_I2C_DEVADDR, addr);
@@ -174,7 +190,7 @@ static int xlr_i2c_rx(struct xlr_i2c_private *priv, u16 len, u8 *buf, u16 addr) 
		if (i2c_status & XLR_I2C_ACK_ERR)

			return -EIO;



		if ((i2c_status & XLR_I2C_BUS_BUSY) == 0)

		if (!xlr_i2c_busy(priv, i2c_status))

			return 0;

	}
@@ -190,6 +206,10 @@ static int xlr_i2c_xfer(struct i2c_adapter *adap, 
	int ret = 0;

	struct xlr_i2c_private *priv = i2c_get_adapdata(adap);



	ret = clk_enable(priv->clk);

	if (ret)

		return ret;



	for (i = 0; ret == 0 && i < num; i++) {

		msg = &msgs[i];

		if (msg->flags & I2C_M_RD)
@@ -200,6 +220,8 @@ static int xlr_i2c_xfer(struct i2c_adapter *adap, 
					msg->addr);

	}



	clk_disable(priv->clk);



	return (ret != 0) ? ret : num;

}
@@ -214,22 +236,70 @@ static struct i2c_algorithm xlr_i2c_algo = { 
	.functionality	= xlr_func,

};



static const struct xlr_i2c_config xlr_i2c_config_default = {

	.status_busy	= XLR_I2C_BUS_BUSY,

	.cfg_extra	= 0,

};



static const struct xlr_i2c_config xlr_i2c_config_tangox = {

	.status_busy	= 0,

	.cfg_extra	= 1 << 8,

};



static const struct of_device_id xlr_i2c_dt_ids[] = {

	{

		.compatible	= "sigma,smp8642-i2c",

		.data		= &xlr_i2c_config_tangox,

	},

	{ }

};



static int xlr_i2c_probe(struct platform_device *pdev)

{

	const struct of_device_id *match;

	struct xlr_i2c_private  *priv;

	struct resource *res;

	struct clk *clk;

	unsigned long clk_rate;

	unsigned long clk_div;

	u32 busfreq;

	int ret;



	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);

	if (!priv)

		return -ENOMEM;



	match = of_match_device(xlr_i2c_dt_ids, &pdev->dev);

	if (match)

		priv->cfg = match->data;

	else

		priv->cfg = &xlr_i2c_config_default;



	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);

	priv->iobase = devm_ioremap_resource(&pdev->dev, res);

	if (IS_ERR(priv->iobase))

		return PTR_ERR(priv->iobase);



	if (of_property_read_u32(pdev->dev.of_node, "clock-frequency",

				 &busfreq))

		busfreq = 100000;



	clk = devm_clk_get(&pdev->dev, NULL);

	if (!IS_ERR(clk)) {

		ret = clk_prepare_enable(clk);

		if (ret)

			return ret;



		clk_rate = clk_get_rate(clk);

		clk_div = DIV_ROUND_UP(clk_rate, 2 * busfreq);

		xlr_i2c_wreg(priv->iobase, XLR_I2C_CLKDIV, clk_div);



		clk_disable(clk);

		priv->clk = clk;

	}



	priv->adap.dev.parent = &pdev->dev;

	priv->adap.dev.of_node	= pdev->dev.of_node;

	priv->adap.owner	= THIS_MODULE;

	priv->adap.algo_data	= priv;

	priv->adap.algo		= &xlr_i2c_algo;
@@ -255,6 +325,8 @@ static int xlr_i2c_remove(struct platform_device *pdev) 


	priv = platform_get_drvdata(pdev);

	i2c_del_adapter(&priv->adap);

	clk_unprepare(priv->clk);



	return 0;

}
@@ -263,6 +335,7 @@ static struct platform_driver xlr_i2c_driver = { 
	.remove = xlr_i2c_remove,

	.driver = {

		.name   = "xlr-i2cbus",

		.of_match_table	= xlr_i2c_dt_ids,

	},

};