[U-Boot] [PATCH 6/8 V4] I2C: Modify the I2C driver for EXYNOS5

Rajeshwari Birje rajeshwari.birje at gmail.com
Tue Jun 19 12:57:59 CEST 2012


Hi Joonyoung Shim,

On Tue, Jun 19, 2012 at 1:20 PM, Joonyoung Shim <dofmind at gmail.com> wrote:
> Hi,
>
> I add some comments at the below.
>
-- ok
> And current SMDK5250 uses Exynos5250 EVT0 base codes,
> but i know the kernel supports only Exynos5250 EVT1.
>
> So, let's remove Exynos5250 EVT0 codes and add EVT1 codes at the u-boot also.
> Could you follow up it?
>
-- Yes currently we are working on that
> Thanks.
>
> 2012/6/19 Rajeshwari Shinde <rajeshwari.s at samsung.com>:
>> 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.
>> 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.
>>  drivers/i2c/s3c24x0_i2c.c |  239 +++++++++++++++++++++++++++++++--------------
>>  drivers/i2c/s3c24x0_i2c.h |    3 +
>>  2 files changed, 168 insertions(+), 74 deletions(-)
>>
>> diff --git a/drivers/i2c/s3c24x0_i2c.c b/drivers/i2c/s3c24x0_i2c.c
>> index ba6f39b..0b31cd1 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 +61,32 @@
>>
>>  #define I2C_TIMEOUT 1          /* 1 second */
>>
>> +static unsigned int g_current_bus;     /* Stores Current I2C Bus */
>> +
>> +#ifdef CONFIG_EXYNOS5
>> +/* 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;
>> +}
>> +
>> +#else
>>  static int GetI2CSDA(void)
>>  {
>>        struct s3c?--24x0_gpio *gpio = s3c24x0_get_base_gpio();
>> @@ -77,16 +111,17 @@ 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;
>> @@ -98,27 +133,93 @@ 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(int bus_idx)
>> +{
>> +#ifdef CONFIG_EXYNOS5
>> +       struct s3c24x0_i2c *i2c = (struct s3c24x0_i2c *)samsung_get_base_i2c();
>> +       return &i2c[bus_idx];
>> +#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);
>> +}
>> +
>> +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);
>
> This will cause compile errors at the s3c24xx.
> Also the i2c_bus_init() doesn't be used at the s3c24xx.
>
-- yes will correct this.

>> +
>> +       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 = s3c24x0_get_base_i2c();
>> +       struct s3c24x0_i2c *i2c;
>> +       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--;
>> +       }
>> +}
>
> I think you can make i2c_init() to one function using #ifdef in function.
-- Will do this
>
>> +
>> +#else
>> +void i2c_init(int speed, int slaveadd)
>> +{
>> +       struct s3c24x0_i2c *i2c = get_base_i2c();
>
> Without parameter?
-- Will correct this.
>
>>        struct s3c24x0_gpio *gpio = s3c24x0_get_base_gpio();
>> -       ulong freq, pres = 16, div;
>>        int i;
>>
>> +       /* By default i2c channel 0 is the current bus */
>> +       g_current_bus = I2C0;
>> +
>>        /* wait for some time to give previous transfer a chance to finish */
>>
>>        i = I2C_TIMEOUT * 1000;
>> @@ -171,27 +272,9 @@ 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 +283,19 @@ 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 +309,7 @@ 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 +321,16 @@ 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 +340,19 @@ 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 +362,13 @@ 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 +376,17 @@ 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 +400,18 @@ 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 +422,24 @@ 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(g_current_bus);
>>        buf[0] = 0;
>>
>>        /*
>> @@ -360,16 +447,17 @@ 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 +484,11 @@ 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(g_current_bus);
>> +       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 +496,11 @@ 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 +526,9 @@ 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(g_current_bus);
>>        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
>>
>
> --
> - Joonyoung Shim
> _______________________________________________
> U-Boot mailing list
> U-Boot at lists.denx.de
> http://lists.denx.de/mailman/listinfo/u-boot

Regards,
Rajeshwari Shinde.


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