[U-Boot] [PATCH 6/8 V6] I2C: Modify the I2C driver for EXYNOS5

Joonyoung Shim jy0922.shim at samsung.com
Mon Jul 23 06:37:01 CEST 2012


Hi, Rajeshwari.

On 07/19/2012 08:39 PM, Rajeshwari Shinde wrote:
> This patch modifies the S3C I2C driver to suppport EXYNOS5.
> The cahnges made to driver are as follows:
>          - I2C base address is passed as a parameter to many
>          functions to avoid multiple #ifdef
>          - Channel initialisation is moved to a commom funation
>          as it is required by i2c_init.
>          - Hardcoding for I2CCON_ACKGEN removed.
>          - Replaced printf with debug.
>          - Checkpatch issues resolved.
>          - Pinmux setting will be done in board/samsung/smdk5250/smdk5250.c
>          to avoid repeated setting of gpio lines, as it have multi bus support.
>
> Signed-off-by: Alim Akhtar <alim.akhtar at samsung.com>
> Signed-off-by: Doug Anderson <dianders at chromium.org>
> Signed-off-by: Rajeshwari Shinde <rajeshwari.s at samsung.com>
> Acked-by: Simon Glass <sjg at chromium.org>
> ---
> Changes in V2:
>          - Removed #define for I2C cahnnels from hearder file except for I2C0.
>          - Incorporated review comments from Simon Glass.
> Changes in V3:
>          - Incorporated review comments from Joonyoung Shim.
>          - Reduced the number of #ifdef by modifying get_i2c_base function.
>          - Removed duplicate code.
> Changes in V4:
>          - Resolved build error for s3c2410.
> Changes in V5:
>          - Pinmux setting will be done in board/samsung/smdk5250/smdk5250.c
>            to avoid repeated setting of gpio lines, as it have multi bus support.
>          - I2C bus offset calulation done based on EXYNOS_I2C_SPACING
>          - Peripharal related code removed.
> Changes in V6:
> 	- g_current_bus made common to all platforms.
>   drivers/i2c/s3c24x0_i2c.c |  193 +++++++++++++++++++++++++++-----------------
>   1 files changed, 118 insertions(+), 75 deletions(-)
>
> diff --git a/drivers/i2c/s3c24x0_i2c.c b/drivers/i2c/s3c24x0_i2c.c
> index ba6f39b..421c7dd 100644
> --- a/drivers/i2c/s3c24x0_i2c.c
> +++ b/drivers/i2c/s3c24x0_i2c.c
> @@ -27,10 +27,15 @@
>    */
>   
>   #include <common.h>
> +#ifdef CONFIG_EXYNOS5
> +#include <asm/arch/clk.h>
> +#include <asm/arch/cpu.h>
> +#else
>   #include <asm/arch/s3c24x0_cpu.h>
> -
> +#endif
>   #include <asm/io.h>
>   #include <i2c.h>
> +#include "s3c24x0_i2c.h"
>   
>   #ifdef CONFIG_HARD_I2C
>   
> @@ -45,6 +50,7 @@
>   
>   #define I2CSTAT_BSY	0x20	/* Busy bit */
>   #define I2CSTAT_NACK	0x01	/* Nack bit */
> +#define I2CCON_ACKGEN	0x80	/* Acknowledge generation */
>   #define I2CCON_IRPND	0x10	/* Interrupt pending bit */
>   #define I2C_MODE_MT	0xC0	/* Master Transmit Mode */
>   #define I2C_MODE_MR	0x80	/* Master Receive Mode */
> @@ -53,6 +59,10 @@
>   
>   #define I2C_TIMEOUT 1		/* 1 second */
>   
> +
> +static unsigned int g_current_bus;	/* Stores Current I2C Bus */
> +
> +#ifndef CONFIG_EXYNOS5
>   static int GetI2CSDA(void)
>   {
>   	struct s3c24x0_gpio *gpio = s3c24x0_get_base_gpio();
> @@ -77,16 +87,17 @@ static void SetI2CSCL(int x)
>   	struct s3c24x0_gpio *gpio = s3c24x0_get_base_gpio();
>   
>   #ifdef CONFIG_S3C2410
> -	writel((readl(&gpio->gpedat) & ~0x4000) | (x & 1) << 14, &gpio->gpedat);
> +	writel((readl(&gpio->gpedat) & ~0x4000) |
> +					(x & 1) << 14, &gpio->gpedat);
>   #endif
>   #ifdef CONFIG_S3C2400
>   	writel((readl(&gpio->pgdat) & ~0x0040) | (x & 1) << 6, &gpio->pgdat);
>   #endif
>   }
> +#endif
>   
> -static int WaitForXfer(void)
> +static int WaitForXfer(struct s3c24x0_i2c *i2c)
>   {
> -	struct s3c24x0_i2c *i2c = s3c24x0_get_base_i2c();
>   	int i;
>   
>   	i = I2C_TIMEOUT * 10000;
> @@ -98,35 +109,77 @@ static int WaitForXfer(void)
>   	return (readl(&i2c->iiccon) & I2CCON_IRPND) ? I2C_OK : I2C_NOK_TOUT;
>   }
>   
> -static int IsACK(void)
> +static int IsACK(struct s3c24x0_i2c *i2c)
>   {
> -	struct s3c24x0_i2c *i2c = s3c24x0_get_base_i2c();
> -
>   	return !(readl(&i2c->iicstat) & I2CSTAT_NACK);
>   }
>   
> -static void ReadWriteByte(void)
> +static void ReadWriteByte(struct s3c24x0_i2c *i2c)
>   {
> -	struct s3c24x0_i2c *i2c = s3c24x0_get_base_i2c();
> -
>   	writel(readl(&i2c->iiccon) & ~I2CCON_IRPND, &i2c->iiccon);
>   }
>   
> +static struct s3c24x0_i2c *get_base_i2c(void)
> +{
> +#ifdef CONFIG_EXYNOS5
> +	struct s3c24x0_i2c *i2c = (struct s3c24x0_i2c *)(samsung_get_base_i2c()
> +							+ (EXYNOS5_I2C_SPACING
> +							* g_current_bus));
> +	return i2c;
> +#else
> +	return s3c24x0_get_base_i2c();
> +#endif
> +}
> +
> +static void i2c_ch_init(struct s3c24x0_i2c *i2c, int speed, int slaveadd)
> +{
> +	ulong freq, pres = 16, div;
> +#ifdef CONFIG_EXYNOS5
> +	freq = get_i2c_clk();
> +#else
> +	freq = get_PCLK();
> +#endif
> +	/* calculate prescaler and divisor values */
> +	if ((freq / pres / (16 + 1)) > speed)
> +		/* set prescaler to 512 */
> +		pres = 512;
> +
> +	div = 0;
> +	while ((freq / pres / (div + 1)) > speed)
> +		div++;
> +
> +	/* set prescaler, divisor according to freq, also set ACKGEN, IRQ */
> +	writel((div & 0x0F) | 0xA0 | ((pres == 512) ? 0x40 : 0), &i2c->iiccon);
> +
> +	/* init to SLAVE REVEIVE and set slaveaddr */
> +	writel(0, &i2c->iicstat);
> +	writel(slaveadd, &i2c->iicadd);
> +	/* program Master Transmit (and implicit STOP) */
> +	writel(I2C_MODE_MT | I2C_TXRX_ENA, &i2c->iicstat);
> +}
> +
>   void i2c_init(int speed, int slaveadd)
>   {
> -	struct s3c24x0_i2c *i2c = s3c24x0_get_base_i2c();
> +	struct s3c24x0_i2c *i2c = get_base_i2c();

This will refer g_current_bus before g_current_bus is initialized to 0.

> +#ifndef CONFIG_EXYNOS5
>   	struct s3c24x0_gpio *gpio = s3c24x0_get_base_gpio();
> -	ulong freq, pres = 16, div;
> +#endif
>   	int i;
>   
> -	/* wait for some time to give previous transfer a chance to finish */
> +	/* By default i2c channel 0 is the current bus */
> +	g_current_bus = 0;

Let's initialize i2c at here.

i2c = get_base_i2c();

>   
> +#ifdef CONFIG_EXYNOS5
> +	i2c_ch_init(i2c, CONFIG_SYS_I2C_SPEED, CONFIG_SYS_I2C_SLAVE);
> +#endif

I think it doesn't need to do this at here.

> +	/* wait for some time to give previous transfer a chance to finish */
>   	i = I2C_TIMEOUT * 1000;
>   	while ((readl(&i2c->iicstat) && I2CSTAT_BSY) && (i > 0)) {

I think this is bug, should use & instead of &&.

while ((readl(&i2c->iicstat) & I2CSTAT_BSY) && (i > 0)) {

>   		udelay(1000);
>   		i--;
>   	}
>   
> +#ifndef CONFIG_EXYNOS5
>   	if ((readl(&i2c->iicstat) & I2CSTAT_BSY) || GetI2CSDA() == 0) {
>   #ifdef CONFIG_S3C2410
>   		ulong old_gpecon = readl(&gpio->gpecon);
> @@ -171,26 +224,8 @@ void i2c_init(int speed, int slaveadd)
>   #endif
>   	}
>   
> -	/* calculate prescaler and divisor values */
> -	freq = get_PCLK();
> -	if ((freq / pres / (16 + 1)) > speed)
> -		/* set prescaler to 512 */
> -		pres = 512;
> -
> -	div = 0;
> -	while ((freq / pres / (div + 1)) > speed)
> -		div++;
> -
> -	/* set prescaler, divisor according to freq, also set
> -	 * ACKGEN, IRQ */
> -	writel((div & 0x0F) | 0xA0 | ((pres == 512) ? 0x40 : 0), &i2c->iiccon);
> -
> -	/* init to SLAVE REVEIVE and set slaveaddr */
> -	writel(0, &i2c->iicstat);
> -	writel(slaveadd, &i2c->iicadd);
> -	/* program Master Transmit (and implicit STOP) */
> -	writel(I2C_MODE_MT | I2C_TXRX_ENA, &i2c->iicstat);
> -
> +	i2c_ch_init(i2c, speed, slaveadd);

Also EXYNOS5, let's do i2c_ch_init() using speed and slaveadd arguments 
at here.

> +#endif /* #ifndef CONFIG_EXYNOS5 */
>   }
>   
>   /*
> @@ -200,19 +235,19 @@ void i2c_init(int speed, int slaveadd)
>    * by the char, we could make it larger if needed. If it is
>    * 0 we skip the address write cycle.
>    */
> -static
> -int i2c_transfer(unsigned char cmd_type,
> -		 unsigned char chip,
> -		 unsigned char addr[],
> -		 unsigned char addr_len,
> -		 unsigned char data[], unsigned short data_len)
> +static int i2c_transfer(struct s3c24x0_i2c *i2c,
> +			unsigned char cmd_type,
> +			unsigned char chip,
> +			unsigned char addr[],
> +			unsigned char addr_len,
> +			unsigned char data[],
> +			unsigned short data_len)
>   {
> -	struct s3c24x0_i2c *i2c = s3c24x0_get_base_i2c();
>   	int i, result;
>   
>   	if (data == 0 || data_len == 0) {
>   		/*Don't support data transfer of no length or to address 0 */
> -		printf("i2c_transfer: bad call\n");
> +		debug("i2c_transfer: bad call\n");
>   		return I2C_NOK;
>   	}
>   
> @@ -226,7 +261,7 @@ int i2c_transfer(unsigned char cmd_type,
>   	if (readl(&i2c->iicstat) & I2CSTAT_BSY)
>   		return I2C_NOK_TOUT;
>   
> -	writel(readl(&i2c->iiccon) | 0x80, &i2c->iiccon);
> +	writel(readl(&i2c->iiccon) | I2CCON_ACKGEN, &i2c->iiccon);
>   	result = I2C_OK;
>   
>   	switch (cmd_type) {
> @@ -238,16 +273,16 @@ int i2c_transfer(unsigned char cmd_type,
>   			       &i2c->iicstat);
>   			i = 0;
>   			while ((i < addr_len) && (result == I2C_OK)) {
> -				result = WaitForXfer();
> +				result = WaitForXfer(i2c);
>   				writel(addr[i], &i2c->iicds);
> -				ReadWriteByte();
> +				ReadWriteByte(i2c);
>   				i++;
>   			}
>   			i = 0;
>   			while ((i < data_len) && (result == I2C_OK)) {
> -				result = WaitForXfer();
> +				result = WaitForXfer(i2c);
>   				writel(data[i], &i2c->iicds);
> -				ReadWriteByte();
> +				ReadWriteByte(i2c);
>   				i++;
>   			}
>   		} else {
> @@ -257,19 +292,19 @@ int i2c_transfer(unsigned char cmd_type,
>   			       &i2c->iicstat);
>   			i = 0;
>   			while ((i < data_len) && (result = I2C_OK)) {
> -				result = WaitForXfer();
> +				result = WaitForXfer(i2c);
>   				writel(data[i], &i2c->iicds);
> -				ReadWriteByte();
> +				ReadWriteByte(i2c);
>   				i++;
>   			}
>   		}
>   
>   		if (result == I2C_OK)
> -			result = WaitForXfer();
> +			result = WaitForXfer(i2c);
>   
>   		/* send STOP */
>   		writel(I2C_MODE_MR | I2C_TXRX_ENA, &i2c->iicstat);
> -		ReadWriteByte();
> +		ReadWriteByte(i2c);
>   		break;
>   
>   	case I2C_READ:
> @@ -279,13 +314,13 @@ int i2c_transfer(unsigned char cmd_type,
>   			/* send START */
>   			writel(readl(&i2c->iicstat) | I2C_START_STOP,
>   			       &i2c->iicstat);
> -			result = WaitForXfer();
> -			if (IsACK()) {
> +			result = WaitForXfer(i2c);
> +			if (IsACK(i2c)) {
>   				i = 0;
>   				while ((i < addr_len) && (result == I2C_OK)) {
>   					writel(addr[i], &i2c->iicds);
> -					ReadWriteByte();
> -					result = WaitForXfer();
> +					ReadWriteByte(i2c);
> +					result = WaitForXfer(i2c);
>   					i++;
>   				}
>   
> @@ -293,16 +328,17 @@ int i2c_transfer(unsigned char cmd_type,
>   				/* resend START */
>   				writel(I2C_MODE_MR | I2C_TXRX_ENA |
>   				       I2C_START_STOP, &i2c->iicstat);
> -				ReadWriteByte();
> -				result = WaitForXfer();
> +			ReadWriteByte(i2c);
> +			result = WaitForXfer(i2c);
>   				i = 0;
>   				while ((i < data_len) && (result == I2C_OK)) {
>   					/* disable ACK for final READ */
>   					if (i == data_len - 1)
>   						writel(readl(&i2c->iiccon)
> -						       & ~0x80, &i2c->iiccon);
> -					ReadWriteByte();
> -					result = WaitForXfer();
> +							& ~I2CCON_ACKGEN,
> +							&i2c->iiccon);
> +				ReadWriteByte(i2c);
> +				result = WaitForXfer(i2c);
>   					data[i] = readl(&i2c->iicds);
>   					i++;
>   				}
> @@ -316,17 +352,18 @@ int i2c_transfer(unsigned char cmd_type,
>   			/* send START */
>   			writel(readl(&i2c->iicstat) | I2C_START_STOP,
>   			       &i2c->iicstat);
> -			result = WaitForXfer();
> +			result = WaitForXfer(i2c);
>   
> -			if (IsACK()) {
> +			if (IsACK(i2c)) {
>   				i = 0;
>   				while ((i < data_len) && (result == I2C_OK)) {
>   					/* disable ACK for final READ */
>   					if (i == data_len - 1)
>   						writel(readl(&i2c->iiccon) &
> -						       ~0x80, &i2c->iiccon);
> -					ReadWriteByte();
> -					result = WaitForXfer();
> +							~I2CCON_ACKGEN,
> +							&i2c->iiccon);
> +					ReadWriteByte(i2c);
> +					result = WaitForXfer(i2c);
>   					data[i] = readl(&i2c->iicds);
>   					i++;
>   				}
> @@ -337,22 +374,24 @@ int i2c_transfer(unsigned char cmd_type,
>   
>   		/* send STOP */
>   		writel(I2C_MODE_MR | I2C_TXRX_ENA, &i2c->iicstat);
> -		ReadWriteByte();
> +		ReadWriteByte(i2c);
>   		break;
>   
>   	default:
> -		printf("i2c_transfer: bad call\n");
> +		debug("i2c_transfer: bad call\n");
>   		result = I2C_NOK;
>   		break;
>   	}
>   
> -	return (result);
> +	return result;
>   }
>   
>   int i2c_probe(uchar chip)
>   {
> +	struct s3c24x0_i2c *i2c;
>   	uchar buf[1];
>   
> +	i2c = get_base_i2c();
>   	buf[0] = 0;
>   
>   	/*
> @@ -360,16 +399,17 @@ int i2c_probe(uchar chip)
>   	 * address was <ACK>ed (i.e. there was a chip at that address which
>   	 * drove the data line low).
>   	 */
> -	return i2c_transfer(I2C_READ, chip << 1, 0, 0, buf, 1) != I2C_OK;
> +	return i2c_transfer(i2c, I2C_READ, chip << 1, 0, 0, buf, 1) != I2C_OK;
>   }
>   
>   int i2c_read(uchar chip, uint addr, int alen, uchar *buffer, int len)
>   {
> +	struct s3c24x0_i2c *i2c;
>   	uchar xaddr[4];
>   	int ret;
>   
>   	if (alen > 4) {
> -		printf("I2C read: addr len %d not supported\n", alen);
> +		debug("I2C read: addr len %d not supported\n", alen);
>   		return 1;
>   	}
>   
> @@ -396,10 +436,11 @@ int i2c_read(uchar chip, uint addr, int alen, uchar *buffer, int len)
>   		chip |= ((addr >> (alen * 8)) &
>   			 CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW);
>   #endif
> -	if ((ret =
> -	     i2c_transfer(I2C_READ, chip << 1, &xaddr[4 - alen], alen,
> -			  buffer, len)) != 0) {
> -		printf("I2c read: failed %d\n", ret);
> +	i2c = get_base_i2c();
> +	ret = i2c_transfer(i2c, I2C_READ, chip << 1, &xaddr[4 - alen], alen,
> +			buffer, len);
> +	if (ret != 0) {
> +		debug("I2c read: failed %d\n", ret);
>   		return 1;
>   	}
>   	return 0;
> @@ -407,10 +448,11 @@ int i2c_read(uchar chip, uint addr, int alen, uchar *buffer, int len)
>   
>   int i2c_write(uchar chip, uint addr, int alen, uchar *buffer, int len)
>   {
> +	struct s3c24x0_i2c *i2c;
>   	uchar xaddr[4];
>   
>   	if (alen > 4) {
> -		printf("I2C write: addr len %d not supported\n", alen);
> +		debug("I2C write: addr len %d not supported\n", alen);
>   		return 1;
>   	}
>   
> @@ -436,8 +478,9 @@ int i2c_write(uchar chip, uint addr, int alen, uchar *buffer, int len)
>   		chip |= ((addr >> (alen * 8)) &
>   			 CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW);
>   #endif
> +	i2c = get_base_i2c();
>   	return (i2c_transfer
> -		(I2C_WRITE, chip << 1, &xaddr[4 - alen], alen, buffer,
> +		(i2c, I2C_WRITE, chip << 1, &xaddr[4 - alen], alen, buffer,
>   		 len) != 0);
>   }
>   #endif /* CONFIG_HARD_I2C */

Thanks.


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