[U-Boot] [PATCH 6/8 V2] I2C: Modify the I2C driver for EXYNOS5

Simon Glass sjg at chromium.org
Tue Jun 12 07:52:49 CEST 2012


On Wed, Jun 6, 2012 at 11:09 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
>        - I2C init for Exynos5 is made as different function.
>        - Channel initialisation is moved to a commom funation
>        as it is required by both the i2c_init.
>        - Separate functions written to get I2C base address,
>        peripheral id for pinmux support.
>        - Hardcoding for I2CCON_ACKGEN removed.
>        - Replaced printf with debug.
>        - Checkpatch issues resolved.
>
> 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.
>

Acked-by: Simon Glass <sjg at chromium.org>

(Looking forward to getting the transfer loop simplified one day!)


>  drivers/i2c/s3c24x0_i2c.c |  254
> ++++++++++++++++++++++++++++++++-------------
>  drivers/i2c/s3c24x0_i2c.h |    3 +
>  2 files changed, 184 insertions(+), 73 deletions(-)
>
> diff --git a/drivers/i2c/s3c24x0_i2c.c b/drivers/i2c/s3c24x0_i2c.c
> index ba6f39b..a71f147 100644
> --- a/drivers/i2c/s3c24x0_i2c.c
> +++ b/drivers/i2c/s3c24x0_i2c.c
> @@ -27,10 +27,17 @@
>  */
>
>  #include <common.h>
> +#ifdef CONFIG_EXYNOS5
> +#include <asm/arch/clk.h>
> +#include <asm/arch/cpu.h>
> +#include <asm/arch/gpio.h>
> +#include <asm/arch/pinmux.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 +52,7 @@
>
>  #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 +61,44 @@
>
>  #define I2C_TIMEOUT 1          /* 1 second */
>
> +#ifdef CONFIG_EXYNOS5
> +static unsigned int g_current_bus;     /* Stores Current I2C Bus */
> +
> +/* We should not rely on any particular ordering of these IDs */
> +static enum periph_id periph_for_dev[] = {
> +       PERIPH_ID_I2C0,
> +       PERIPH_ID_I2C1,
> +       PERIPH_ID_I2C2,
> +       PERIPH_ID_I2C3,
> +       PERIPH_ID_I2C4,
> +       PERIPH_ID_I2C5,
> +       PERIPH_ID_I2C6,
> +       PERIPH_ID_I2C7,
> +};
> +
> +static enum periph_id i2c_get_periph_id(unsigned dev_index)
> +{
> +       if (dev_index < ARRAY_SIZE(periph_for_dev))
> +               return periph_for_dev[dev_index];
> +
> +       debug("%s: invalid bus %d", __func__, dev_index);
> +
> +       return PERIPH_ID_NONE;
> +}
> +
> +static struct s3c24x0_i2c *get_base_i2c(int bus_idx)
> +{
> +       struct s3c24x0_i2c *i2c = (struct s3c24x0_i2c
> *)samsung_get_base_i2c();
> +
> +       return &i2c[bus_idx];
> +}
> +
> +static inline struct exynos5_gpio_part1 *exynos_get_base_gpio1(void)
> +{
> +       return (struct exynos5_gpio_part1 *)(EXYNOS5_GPIO_PART1_BASE);
> +}
> +
> +#else
>  static int GetI2CSDA(void)
>  {
>        struct s3c24x0_gpio *gpio = s3c24x0_get_base_gpio();
> @@ -77,16 +123,17 @@ 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;
> @@ -98,25 +145,84 @@ 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 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);
> +}
> +
> +static void i2c_bus_init(struct s3c24x0_i2c *i2c, unsigned int bus)
> +{
> +       int periph_id = i2c_get_periph_id(bus);
> +
> +       exynos_pinmux_config(periph_id, 0);
> +
> +       i2c_ch_init(i2c, CONFIG_SYS_I2C_SPEED, CONFIG_SYS_I2C_SLAVE);
> +}
> +
> +#ifdef CONFIG_EXYNOS5
> +void i2c_init(int speed, int slaveadd)
> +{
> +       struct s3c24x0_i2c *i2c;
> +       struct exynos5_gpio_part1 *gpio;
> +       int i;
> +
> +       /* By default i2c channel 0 is the current bus */
> +       g_current_bus = I2C0;
> +
> +       i2c = get_base_i2c(g_current_bus);
> +
> +       i2c_bus_init(i2c, g_current_bus);
> +
> +       /* 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--;
> +       }
> +
> +       gpio = exynos_get_base_gpio1();
> +       writel((readl(&gpio->b3.con) & ~0x00FF) | 0x0022, &gpio->b3.con);
> +
> +       i2c_ch_init(i2c, speed, slaveadd);
> +}
> +
> +#else
>  void i2c_init(int speed, int slaveadd)
>  {
>        struct s3c24x0_i2c *i2c = s3c24x0_get_base_i2c();
>        struct s3c24x0_gpio *gpio = s3c24x0_get_base_gpio();
> -       ulong freq, pres = 16, div;
>        int i;
>
>        /* wait for some time to give previous transfer a chance to finish
> */
> @@ -171,27 +277,9 @@ 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
>
>  /*
>  * cmd_type is 0 for write, 1 for read.
> @@ -200,19 +288,19 @@ 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 +314,7 @@ 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 +326,16 @@ 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 +345,19 @@ 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 +367,13 @@ 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 +381,17 @@ 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 +405,18 @@ 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 +427,28 @@ 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];
>
> +#ifdef CONFIG_EXYNOS5
> +       i2c = get_base_i2c(g_current_bus);
> +#else
> +       i2c = s3c24x0_get_base_i2c();
> +#endif
>        buf[0] = 0;
>
>        /*
> @@ -360,16 +456,17 @@ 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 +493,15 @@ 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);
> +#ifdef CONFIG_EXYNOS5
> +       i2c = get_base_i2c(g_current_bus);
> +#else
> +       i2c = s3c24x0_get_base_i2c();
> +#endif
> +       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 +509,11 @@ 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 +539,13 @@ int i2c_write(uchar chip, uint addr, int alen, uchar
> *buffer, int len)
>                chip |= ((addr >> (alen * 8)) &
>                         CONFIG_SYS_I2C_EEPROM_ADDR_OVERFLOW);
>  #endif
> +#ifdef CONFIG_EXYNOS5
> +       i2c = get_base_i2c(g_current_bus);
> +#else
> +       i2c = s3c24x0_get_base_i2c();
> +#endif
>        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 */
> diff --git a/drivers/i2c/s3c24x0_i2c.h b/drivers/i2c/s3c24x0_i2c.h
> index d357a0a..57aafb1 100644
> --- a/drivers/i2c/s3c24x0_i2c.h
> +++ b/drivers/i2c/s3c24x0_i2c.h
> @@ -23,6 +23,9 @@
>  #ifndef _S3C24X0_I2C_H
>  #define _S3C24X0_I2C_H
>
> +/* I2C channels exynos5 has 8 i2c channel */
> +#define I2C0           0
> +
>  struct s3c24x0_i2c {
>        u32     iiccon;
>        u32     iicstat;
> --
> 1.7.4.4
>
>


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