[PATCH 1/5] i2c: at91: add new fixes for some TWI ip versions

[ludovic.desroches at atmel.com]

From: Ludovic Desroches <ludovic.desroches at atmel.com>

The at91sam9261 TWI ip version requires also some fixes. The id_entry
field from the platform device structure has been replaced by the use
of cpu_is_xxx function to determine when to use these fixes.

Signed-off-by: Ludovic Desroches <ludovic.desroches at atmel.com>
---
 arch/arm/mach-at91/at91rm9200_devices.c |  9 -------
 drivers/i2c/busses/i2c-at91.c           | 42 +++++++++++++++++++--------------
 2 files changed, 24 insertions(+), 27 deletions(-)

diff --git a/arch/arm/mach-at91/at91rm9200_devices.c b/arch/arm/mach-at91/at91rm9200_devices.c
index 2b9b493..e6b7d05 100644
--- a/arch/arm/mach-at91/at91rm9200_devices.c
+++ b/arch/arm/mach-at91/at91rm9200_devices.c
@@ -494,18 +494,9 @@ static struct resource twi_resources[] = {
 	},
 };
 
-static const struct platform_device_id twi_id = {
-	/*
-	 * driver_data is "1" for hardware with ckdiv upper limit == 5
-	 * (AT91RM9200 erratum 22), "0" for twi modules without this bug
-	 */
-	.driver_data	= 1,
-};
-
 static struct platform_device at91rm9200_twi_device = {
 	.name		= "at91_i2c",
 	.id		= -1,
-	.id_entry	= &twi_id,
 	.resource	= twi_resources,
 	.num_resources	= ARRAY_SIZE(twi_resources),
 };
diff --git a/drivers/i2c/busses/i2c-at91.c b/drivers/i2c/busses/i2c-at91.c
index b1cb780..4599522 100644
--- a/drivers/i2c/busses/i2c-at91.c
+++ b/drivers/i2c/busses/i2c-at91.c
@@ -27,6 +27,8 @@
 #include <linux/platform_device.h>
 #include <linux/slab.h>
 
+#include <mach/cpu.h>
+
 #define TWI_CLK_HZ		100000			/* max 400 Kbits/s */
 #define AT91_I2C_TIMEOUT	msecs_to_jiffies(100)	/* transfer timeout */
 
@@ -72,7 +74,6 @@ struct at91_twi_dev {
 	int			irq;
 	unsigned		transfer_status;
 	struct i2c_adapter	adapter;
-	bool			is_rm9200;
 	unsigned		twi_cwgr_reg;
 };
 
@@ -111,20 +112,28 @@ static void at91_init_twi_bus(struct at91_twi_dev *dev)
  */
 static void __devinit at91_calc_twi_clock(struct at91_twi_dev *dev, int twi_clk)
 {
-	const int offset = dev->is_rm9200 ? 3 : 4;
-	const int div = max(0, (int)DIV_ROUND_UP(clk_get_rate(dev->clk),
-						 2 * twi_clk) - offset);
-	int ckdiv = fls(div >> 8);
-	int cdiv = div >> ckdiv;
-
-	if (dev->is_rm9200 && (ckdiv > 5)) {
-		dev_warn(dev->dev, "AT91RM9200 erratum 22: using ckdiv = 5.\n");
-		ckdiv = 5;
-		cdiv = 255;
-	} else if (ckdiv > 7) {
-		dev_warn(dev->dev, "%d exceeds 3 bits for ckdiv, limiting.\n",
-			 ckdiv);
-		ckdiv = 7;
+	int offset, div, max_ckdiv, ckdiv, cdiv;
+
+	if (cpu_is_at91rm9200()) {
+		offset = 3;
+		max_ckdiv = 5;
+	} else if (cpu_is_at91sam9261()) {
+		offset = 4;
+		max_ckdiv = 5;
+	} else {
+		offset = 4;
+		max_ckdiv = 7;
+	}
+
+	div = max(0, (int)DIV_ROUND_UP(clk_get_rate(dev->clk),
+				       2 * twi_clk) - offset);
+	ckdiv = fls(div >> 8);
+	cdiv = div >> ckdiv;
+
+	if (ckdiv > max_ckdiv) {
+		dev_warn(dev->dev, "%d exceeds ckdiv max value which is %d.\n",
+			 ckdiv, max_ckdiv);
+		ckdiv = max_ckdiv;
 		cdiv = 255;
 	}
 
@@ -331,9 +340,6 @@ static int __devinit at91_twi_probe(struct platform_device *pdev)
 		goto err_release_region;
 	}
 
-	if (pdev->id_entry && pdev->id_entry->driver_data == 1)
-		dev->is_rm9200 = 1;
-
 	init_completion(&dev->cmd_complete);
 
 	dev->dev = &pdev->dev;
-- 
1.7.11.3