Patchwork [5/7] i2c: Add device tree support to i2c-pnx.c

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Submitter stigge@antcom.de
Date April 2, 2012, 12:56 p.m.
Message ID <1333371364-21347-6-git-send-email-stigge@antcom.de>
Download mbox | patch
Permalink /patch/150141/
State New
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Comments

stigge@antcom.de - April 2, 2012, 12:56 p.m.
This patch adds device tree support to the pnx-i2c driver by using platform
resources for memory region and irq and removing dependency on mach includes.

The following platforms are affected:

* PNX
* LPC31xx (WIP)
* LPC32xx

The patch is based on a patch by Jon Smirl, working on lpc31xx integration

Signed-off-by: Roland Stigge <stigge@antcom.de>

---

 Applies to v3.4-rc1

 Updates:
 * Introducing slave-addr for I2C controller (this convention already exists in
   the kernel)
 * Bugfix: of_i2c_register_devices() was missing

 Documentation/devicetree/bindings/i2c/pnx.txt |   36 +++++
 drivers/i2c/busses/i2c-pnx.c                  |  160 +++++++++++++++++++-------
 include/linux/i2c-pnx.h                       |   10 -
 3 files changed, 158 insertions(+), 48 deletions(-)
Arnd Bergmann - April 2, 2012, 1:17 p.m.
On Monday 02 April 2012, Roland Stigge wrote:

> --- /dev/null
> +++ linux-2.6/Documentation/devicetree/bindings/i2c/pnx.txt
> @@ -0,0 +1,36 @@
> +* NXP PNX I2C Controller
> +
> +Required properties:
> +
> + - reg: Offset and length of the register set for the device
> + - compatible: should be "nxp,pnx-i2c"
> + - interrupts: <a b> where a is the interrupt number and b is a
> +   field that represents an encoding of the sense and level
> +   information for the interrupt

The encoding of the interrupt is specific to the controller and does
not belong here. Just write that there is one interrupt line to be
configure.

> + - interrupt-parent: the phandle for the interrupt controller that
> +   services interrupts for this device.

interrupt-parent should be optional, it can be set in the (grand-)parent
device on systems where all devices use the same controller.

You should also require

#address-cells = <1>;
#size-cells = <0>;

To create an address space for i2c slave device numbers.
> +Examples:
> +
> +	i2c1: i2c@400A0000 {
> +		compatible = "nxp,pnx-i2c";
> +		reg = <0x400A0000 0x100>;
> +		interrupt-parent = <&mic>;
> +		interrupts = <51 0>;
> +	};
> +
> +	i2c2: i2c@400A8000 {
> +		compatible = "nxp,pnx-i2c";
> +		reg = <0x400A8000 0x100>;

Best use all lowercase letters in the addresses.

> +		interrupt-parent = <&mic>;
> +		interrupts = <50 0>;
> +		clock-frequency = <0x186a0>;
> +		pnx,timeout = <0x64>;
> +		slave-addr = <0x11>;
> +	};

>  static struct platform_driver i2c_pnx_driver = {
>  	.driver = {
>  		.name = "pnx-i2c",
>  		.owner = THIS_MODULE,
> +#ifdef CONFIG_OF
> +		.of_match_table = i2c_pnx_of_match,
> +#endif
>  	},
>  	.probe = i2c_pnx_probe,
>  	.remove = __devexit_p(i2c_pnx_remove),

of_match_ptr() instead of this #ifdef, please.

	Arnd

Patch

--- /dev/null
+++ linux-2.6/Documentation/devicetree/bindings/i2c/pnx.txt
@@ -0,0 +1,36 @@ 
+* NXP PNX I2C Controller
+
+Required properties:
+
+ - reg: Offset and length of the register set for the device
+ - compatible: should be "nxp,pnx-i2c"
+ - interrupts: <a b> where a is the interrupt number and b is a
+   field that represents an encoding of the sense and level
+   information for the interrupt
+ - interrupt-parent: the phandle for the interrupt controller that
+   services interrupts for this device.
+
+Optional properties:
+
+ - clock-frequency: desired I2C bus clock frequency in Hz, Default: 100000 Hz
+ - pnx,timeout: I2C bus timeout in milliseconds, Default: 10 ms
+ - slave-addr: Address used by the controller, Hardware default: 110
+
+Examples:
+
+	i2c1: i2c@400A0000 {
+		compatible = "nxp,pnx-i2c";
+		reg = <0x400A0000 0x100>;
+		interrupt-parent = <&mic>;
+		interrupts = <51 0>;
+	};
+
+	i2c2: i2c@400A8000 {
+		compatible = "nxp,pnx-i2c";
+		reg = <0x400A8000 0x100>;
+		interrupt-parent = <&mic>;
+		interrupts = <50 0>;
+		clock-frequency = <0x186a0>;
+		pnx,timeout = <0x64>;
+		slave-addr = <0x11>;
+	};
--- linux-2.6.orig/drivers/i2c/busses/i2c-pnx.c
+++ linux-2.6/drivers/i2c/busses/i2c-pnx.c
@@ -23,16 +23,61 @@ 
 #include <linux/err.h>
 #include <linux/clk.h>
 #include <linux/slab.h>
+#include <linux/of_i2c.h>
 
-#include <mach/hardware.h>
-#include <mach/i2c.h>
+#define I2C_PNX_TIMEOUT_DEFAULT		10 /* msec */
+#define I2C_PNX_SPEED_KHZ_DEFAULT	100
+#define I2C_PNX_REGION_SIZE		0x100
+
+enum {
+	mstatus_tdi = 0x00000001,
+	mstatus_afi = 0x00000002,
+	mstatus_nai = 0x00000004,
+	mstatus_drmi = 0x00000008,
+	mstatus_active = 0x00000020,
+	mstatus_scl = 0x00000040,
+	mstatus_sda = 0x00000080,
+	mstatus_rff = 0x00000100,
+	mstatus_rfe = 0x00000200,
+	mstatus_tff = 0x00000400,
+	mstatus_tfe = 0x00000800,
+};
+
+enum {
+	mcntrl_tdie = 0x00000001,
+	mcntrl_afie = 0x00000002,
+	mcntrl_naie = 0x00000004,
+	mcntrl_drmie = 0x00000008,
+	mcntrl_daie = 0x00000020,
+	mcntrl_rffie = 0x00000040,
+	mcntrl_tffie = 0x00000080,
+	mcntrl_reset = 0x00000100,
+	mcntrl_cdbmode = 0x00000400,
+};
 
-#define I2C_PNX_TIMEOUT		10 /* msec */
-#define I2C_PNX_SPEED_KHZ	100
-#define I2C_PNX_REGION_SIZE	0x100
+enum {
+	rw_bit = 1 << 0,
+	start_bit = 1 << 8,
+	stop_bit = 1 << 9,
+};
+
+#define I2C_REG_RX(a)	((a)->ioaddr)		/* Rx FIFO reg (RO) */
+#define I2C_REG_TX(a)	((a)->ioaddr)		/* Tx FIFO reg (WO) */
+#define I2C_REG_STS(a)	((a)->ioaddr + 0x04)	/* Status reg (RO) */
+#define I2C_REG_CTL(a)	((a)->ioaddr + 0x08)	/* Ctl reg */
+#define I2C_REG_CKL(a)	((a)->ioaddr + 0x0c)	/* Clock divider low */
+#define I2C_REG_CKH(a)	((a)->ioaddr + 0x10)	/* Clock divider high */
+#define I2C_REG_ADR(a)	((a)->ioaddr + 0x14)	/* I2C address */
+#define I2C_REG_RFL(a)	((a)->ioaddr + 0x18)	/* Rx FIFO level (RO) */
+#define I2C_REG_TFL(a)	((a)->ioaddr + 0x1c)	/* Tx FIFO level (RO) */
+#define I2C_REG_RXB(a)	((a)->ioaddr + 0x20)	/* Num of bytes Rx-ed (RO) */
+#define I2C_REG_TXB(a)	((a)->ioaddr + 0x24)	/* Num of bytes Tx-ed (RO) */
+#define I2C_REG_TXS(a)	((a)->ioaddr + 0x28)	/* Tx slave FIFO (RO) */
+#define I2C_REG_STFL(a)	((a)->ioaddr + 0x2c)	/* Tx slave FIFO level (RO) */
 
-static inline int wait_timeout(long timeout, struct i2c_pnx_algo_data *data)
+static inline int wait_timeout(struct i2c_pnx_algo_data *data)
 {
+	long timeout = data->timeout;
 	while (timeout > 0 &&
 			(ioread32(I2C_REG_STS(data)) & mstatus_active)) {
 		mdelay(1);
@@ -41,8 +86,9 @@  static inline int wait_timeout(long time
 	return (timeout <= 0);
 }
 
-static inline int wait_reset(long timeout, struct i2c_pnx_algo_data *data)
+static inline int wait_reset(struct i2c_pnx_algo_data *data)
 {
+	long timeout = data->timeout;
 	while (timeout > 0 &&
 			(ioread32(I2C_REG_CTL(data)) & mcntrl_reset)) {
 		mdelay(1);
@@ -54,7 +100,7 @@  static inline int wait_reset(long timeou
 static inline void i2c_pnx_arm_timer(struct i2c_pnx_algo_data *alg_data)
 {
 	struct timer_list *timer = &alg_data->mif.timer;
-	unsigned long expires = msecs_to_jiffies(I2C_PNX_TIMEOUT);
+	unsigned long expires = msecs_to_jiffies(alg_data->timeout);
 
 	if (expires <= 1)
 		expires = 2;
@@ -92,7 +138,7 @@  static int i2c_pnx_start(unsigned char s
 	}
 
 	/* First, make sure bus is idle */
-	if (wait_timeout(I2C_PNX_TIMEOUT, alg_data)) {
+	if (wait_timeout(alg_data)) {
 		/* Somebody else is monopolizing the bus */
 		dev_err(&alg_data->adapter.dev,
 			"%s: Bus busy. Slave addr = %02x, cntrl = %x, stat = %x\n",
@@ -185,7 +231,7 @@  static int i2c_pnx_master_xmit(struct i2
 		if (alg_data->mif.len == 0) {
 			if (alg_data->last) {
 				/* Wait until the STOP is seen. */
-				if (wait_timeout(I2C_PNX_TIMEOUT, alg_data))
+				if (wait_timeout(alg_data))
 					dev_err(&alg_data->adapter.dev,
 						"The bus is still active after timeout\n");
 			}
@@ -283,7 +329,7 @@  static int i2c_pnx_master_rcv(struct i2c
 		if (alg_data->mif.len == 0) {
 			if (alg_data->last)
 				/* Wait until the STOP is seen. */
-				if (wait_timeout(I2C_PNX_TIMEOUT, alg_data))
+				if (wait_timeout(alg_data))
 					dev_err(&alg_data->adapter.dev,
 						"The bus is still active after timeout\n");
 
@@ -399,7 +445,7 @@  static void i2c_pnx_timeout(unsigned lon
 
 	ctl |= mcntrl_reset;
 	iowrite32(ctl, I2C_REG_CTL(alg_data));
-	wait_reset(I2C_PNX_TIMEOUT, alg_data);
+	wait_reset(alg_data);
 	alg_data->mif.ret = -EIO;
 	complete(&alg_data->mif.complete);
 }
@@ -414,18 +460,18 @@  static inline void bus_reset_if_active(s
 			alg_data->adapter.name);
 		iowrite32(ioread32(I2C_REG_CTL(alg_data)) | mcntrl_reset,
 			  I2C_REG_CTL(alg_data));
-		wait_reset(I2C_PNX_TIMEOUT, alg_data);
+		wait_reset(alg_data);
 	} else if (!(stat & mstatus_rfe) || !(stat & mstatus_tfe)) {
 		/* If there is data in the fifo's after transfer,
 		 * flush fifo's by reset.
 		 */
 		iowrite32(ioread32(I2C_REG_CTL(alg_data)) | mcntrl_reset,
 			  I2C_REG_CTL(alg_data));
-		wait_reset(I2C_PNX_TIMEOUT, alg_data);
+		wait_reset(alg_data);
 	} else if (stat & mstatus_nai) {
 		iowrite32(ioread32(I2C_REG_CTL(alg_data)) | mcntrl_reset,
 			  I2C_REG_CTL(alg_data));
-		wait_reset(I2C_PNX_TIMEOUT, alg_data);
+		wait_reset(alg_data);
 	}
 }
 
@@ -569,14 +615,9 @@  static int __devinit i2c_pnx_probe(struc
 	int ret = 0;
 	struct i2c_pnx_algo_data *alg_data;
 	unsigned long freq;
-	struct i2c_pnx_data *i2c_pnx = pdev->dev.platform_data;
-
-	if (!i2c_pnx || !i2c_pnx->name) {
-		dev_err(&pdev->dev, "%s: no platform data supplied\n",
-		       __func__);
-		ret = -EINVAL;
-		goto out;
-	}
+	struct resource *res;
+	u32 speed = I2C_PNX_SPEED_KHZ_DEFAULT * 1000;
+	u32 slave_addr = ~0;
 
 	alg_data = kzalloc(sizeof(*alg_data), GFP_KERNEL);
 	if (!alg_data) {
@@ -586,14 +627,22 @@  static int __devinit i2c_pnx_probe(struc
 
 	platform_set_drvdata(pdev, alg_data);
 
-	strlcpy(alg_data->adapter.name, i2c_pnx->name,
-		sizeof(alg_data->adapter.name));
 	alg_data->adapter.dev.parent = &pdev->dev;
 	alg_data->adapter.algo = &pnx_algorithm;
 	alg_data->adapter.algo_data = alg_data;
 	alg_data->adapter.nr = pdev->id;
-	alg_data->i2c_pnx = i2c_pnx;
-
+	alg_data->timeout = I2C_PNX_TIMEOUT_DEFAULT;
+#ifdef CONFIG_OF
+	alg_data->adapter.dev.of_node = of_node_get(pdev->dev.of_node);
+	if (pdev->dev.of_node) {
+		of_property_read_u32(pdev->dev.of_node, "pnx,timeout",
+				     &alg_data->timeout);
+		of_property_read_u32(pdev->dev.of_node, "clock-frequency",
+				     &speed);
+		of_property_read_u32(pdev->dev.of_node, "slave-addr",
+				     &slave_addr);
+	}
+#endif
 	alg_data->clk = clk_get(&pdev->dev, NULL);
 	if (IS_ERR(alg_data->clk)) {
 		ret = PTR_ERR(alg_data->clk);
@@ -604,17 +653,27 @@  static int __devinit i2c_pnx_probe(struc
 	alg_data->mif.timer.function = i2c_pnx_timeout;
 	alg_data->mif.timer.data = (unsigned long)alg_data;
 
+	snprintf(alg_data->adapter.name, sizeof(alg_data->adapter.name),
+		 "%s", pdev->name);
+
 	/* Register I/O resource */
-	if (!request_mem_region(i2c_pnx->base, I2C_PNX_REGION_SIZE,
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res) {
+		dev_err(&pdev->dev, "Unable to get mem resource.\n");
+		ret = -EBUSY;
+		goto out_clkget;
+	}
+	if (!request_mem_region(res->start, I2C_PNX_REGION_SIZE,
 				pdev->name)) {
 		dev_err(&pdev->dev,
 		       "I/O region 0x%08x for I2C already in use.\n",
-		       i2c_pnx->base);
-		ret = -ENODEV;
+		       res->start);
+		ret = -ENOMEM;
 		goto out_clkget;
 	}
 
-	alg_data->ioaddr = ioremap(i2c_pnx->base, I2C_PNX_REGION_SIZE);
+	alg_data->base = res->start;
+	alg_data->ioaddr = ioremap(res->start, I2C_PNX_REGION_SIZE);
 	if (!alg_data->ioaddr) {
 		dev_err(&pdev->dev, "Couldn't ioremap I2C I/O region\n");
 		ret = -ENOMEM;
@@ -625,6 +684,9 @@  static int __devinit i2c_pnx_probe(struc
 	if (ret)
 		goto out_unmap;
 
+	if (slave_addr != ~0)
+		iowrite32(slave_addr, I2C_REG_ADR(alg_data));
+
 	freq = clk_get_rate(alg_data->clk);
 
 	/*
@@ -638,20 +700,25 @@  static int __devinit i2c_pnx_probe(struc
 	 * the deglitching filter length.
 	 */
 
-	tmp = ((freq / 1000) / I2C_PNX_SPEED_KHZ) / 2 - 2;
+	tmp = (freq / speed) / 2 - 2;
 	if (tmp > 0x3FF)
 		tmp = 0x3FF;
 	iowrite32(tmp, I2C_REG_CKH(alg_data));
 	iowrite32(tmp, I2C_REG_CKL(alg_data));
 
 	iowrite32(mcntrl_reset, I2C_REG_CTL(alg_data));
-	if (wait_reset(I2C_PNX_TIMEOUT, alg_data)) {
+	if (wait_reset(alg_data)) {
 		ret = -ENODEV;
 		goto out_clock;
 	}
 	init_completion(&alg_data->mif.complete);
 
-	ret = request_irq(i2c_pnx->irq, i2c_pnx_interrupt,
+	alg_data->irq = platform_get_irq(pdev, 0);
+	if (alg_data->irq < 0) {
+		dev_err(&pdev->dev, "Failed to get IRQ from platform resource\n");
+		goto out_irq;
+	}
+	ret = request_irq(alg_data->irq, i2c_pnx_interrupt,
 			0, pdev->name, alg_data);
 	if (ret)
 		goto out_clock;
@@ -663,39 +730,39 @@  static int __devinit i2c_pnx_probe(struc
 		goto out_irq;
 	}
 
+	of_i2c_register_devices(&alg_data->adapter);
+
 	dev_dbg(&pdev->dev, "%s: Master at %#8x, irq %d.\n",
-	       alg_data->adapter.name, i2c_pnx->base, i2c_pnx->irq);
+	       alg_data->adapter.name, res->start, alg_data->irq);
 
 	return 0;
 
 out_irq:
-	free_irq(i2c_pnx->irq, alg_data);
+	free_irq(alg_data->irq, alg_data);
 out_clock:
 	clk_disable(alg_data->clk);
 out_unmap:
 	iounmap(alg_data->ioaddr);
 out_release:
-	release_mem_region(i2c_pnx->base, I2C_PNX_REGION_SIZE);
+	release_mem_region(res->start, I2C_PNX_REGION_SIZE);
 out_clkget:
 	clk_put(alg_data->clk);
 out_drvdata:
 	kfree(alg_data);
 err_kzalloc:
 	platform_set_drvdata(pdev, NULL);
-out:
 	return ret;
 }
 
 static int __devexit i2c_pnx_remove(struct platform_device *pdev)
 {
 	struct i2c_pnx_algo_data *alg_data = platform_get_drvdata(pdev);
-	struct i2c_pnx_data *i2c_pnx = alg_data->i2c_pnx;
 
-	free_irq(i2c_pnx->irq, alg_data);
+	free_irq(alg_data->irq, alg_data);
 	i2c_del_adapter(&alg_data->adapter);
 	clk_disable(alg_data->clk);
 	iounmap(alg_data->ioaddr);
-	release_mem_region(i2c_pnx->base, I2C_PNX_REGION_SIZE);
+	release_mem_region(alg_data->base, I2C_PNX_REGION_SIZE);
 	clk_put(alg_data->clk);
 	kfree(alg_data);
 	platform_set_drvdata(pdev, NULL);
@@ -703,10 +770,21 @@  static int __devexit i2c_pnx_remove(stru
 	return 0;
 }
 
+#ifdef CONFIG_OF
+static const struct of_device_id i2c_pnx_of_match[] = {
+	{ .compatible = "nxp,pnx-i2c" },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, i2c_pnx_of_match);
+#endif
+
 static struct platform_driver i2c_pnx_driver = {
 	.driver = {
 		.name = "pnx-i2c",
 		.owner = THIS_MODULE,
+#ifdef CONFIG_OF
+		.of_match_table = i2c_pnx_of_match,
+#endif
 	},
 	.probe = i2c_pnx_probe,
 	.remove = __devexit_p(i2c_pnx_remove),
--- linux-2.6.orig/include/linux/i2c-pnx.h
+++ linux-2.6/include/linux/i2c-pnx.h
@@ -29,14 +29,10 @@  struct i2c_pnx_algo_data {
 	struct i2c_pnx_mif	mif;
 	int			last;
 	struct clk		*clk;
-	struct i2c_pnx_data	*i2c_pnx;
 	struct i2c_adapter	adapter;
-};
-
-struct i2c_pnx_data {
-	const char *name;
-	u32 base;
-	int irq;
+	phys_addr_t		base;
+	int			irq;
+	u32			timeout;
 };
 
 #endif /* __I2C_PNX_H__ */