[U-Boot] [PATCH 5/7 V5] I2C: Modify the I2C driver for EXYNOS5

Simon Glass sjg at chromium.org
Wed Jul 18 22:06:03 CEST 2012


Hi,

On Thu, Jul 5, 2012 at 12:59 PM, Rajeshwari Shinde
<rajeshwari.s at samsung.com> 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>
> ---

One more comment on this if not too late. I wonder if the
g_current_bus variable could exist for all variants, but always be
zero, so you can get rid of some of the #ifdef EXYNOS5 stuff? It seems
like it might be a harmless change?

Regards,
Simon

> 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.
>  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..bbd2ef8 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 */
>
> +
> +#ifdef CONFIG_EXYNOS5
> +static unsigned int g_current_bus;     /* Stores Current I2C Bus */
> +#else
>  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()
> +                                                       + (EXYNOS_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();
> +#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 */
> +#ifdef CONFIG_EXYNOS5
> +       /* By default i2c channel 0 is the current bus */
> +       g_current_bus = 0;
>
> +       i2c_ch_init(i2c, CONFIG_SYS_I2C_SPEED, CONFIG_SYS_I2C_SLAVE);
> +#endif
> +       /* wait for some time to give previous transfer a chance to finish */
>         i = I2C_TIMEOUT * 1000;
>         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);
> +#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 */
> --
> 1.7.4.4
>


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