[5/6] I2C: Driver changes for FDT support

Functions added to get the I2C bus number and reset I2C bus using
FDT node.

Signed-off-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Rajeshwari Shinde <rajeshwari.s@samsung.com>
---
 drivers/i2c/s3c24x0_i2c.c |   89 ++++++++++++++++++++++++++++++++++++++++++++-
 drivers/i2c/s3c24x0_i2c.h |    7 ++++
 include/i2c.h             |   28 ++++++++++++++
 3 files changed, 123 insertions(+), 1 deletions(-)

Hi Rajeshwari,

On Wed, Nov 7, 2012 at 9:30 PM, Rajeshwari Shinde
<rajeshwari.s@samsung.com> wrote:
> Functions added to get the I2C bus number and reset I2C bus using
> FDT node.
>
> Signed-off-by: Simon Glass <sjg@chromium.org>
> Signed-off-by: Rajeshwari Shinde <rajeshwari.s@samsung.com>
> ---
>  drivers/i2c/s3c24x0_i2c.c |   89 ++++++++++++++++++++++++++++++++++++++++++++-
>  drivers/i2c/s3c24x0_i2c.h |    7 ++++
>  include/i2c.h             |   28 ++++++++++++++
>  3 files changed, 123 insertions(+), 1 deletions(-)
>
> diff --git a/drivers/i2c/s3c24x0_i2c.c b/drivers/i2c/s3c24x0_i2c.c
> index 9bc4c7f..952f76c 100644
> --- a/drivers/i2c/s3c24x0_i2c.c
> +++ b/drivers/i2c/s3c24x0_i2c.c
> @@ -27,6 +27,7 @@
>   */
>
>  #include <common.h>
> +#include <fdtdec.h>
>  #ifdef CONFIG_EXYNOS5
>  #include <asm/arch/clk.h>
>  #include <asm/arch/cpu.h>
> @@ -60,7 +61,14 @@
>  #define I2C_TIMEOUT 1          /* 1 second */
>
>
> -static unsigned int g_current_bus;     /* Stores Current I2C Bus */
> +/*
> + * For SPL boot some boards need i2c before SDRAM is initialised so force
> + * variables to live in SRAM
> + */
> +static unsigned int g_current_bus __attribute__((section(".data")));
> +static struct s3c24x0_i2c_bus i2c_bus[CONFIG_MAX_I2C_NUM]
> +                       __attribute__((section(".data")));
> +static int i2c_busses __attribute__((section(".data")));
>
>  #ifndef CONFIG_EXYNOS5
>  static int GetI2CSDA(void)
> @@ -507,4 +515,83 @@ int i2c_write(uchar chip, uint addr, int alen, uchar *buffer, int len)
>                 (i2c, I2C_WRITE, chip << 1, &xaddr[4 - alen], alen, buffer,
>                  len) != 0);
>  }
> +
> +#ifdef CONFIG_OF_CONTROL
> +unsigned int i2c_fdt_bus_values(const void *blob)
> +{
> +
> +       int node_list[CONFIG_MAX_I2C_NUM];
> +       int count, i;
> +
> +       count = fdtdec_find_aliases_for_id(blob, "i2c",
> +               COMPAT_SAMSUNG_S3C2440_I2C, node_list,
> +               CONFIG_MAX_I2C_NUM);
> +       for (i = 0; i < count; i++) {
> +               struct s3c24x0_i2c_bus *bus;
> +               int node = node_list[i];
> +
> +               if (node < 0)
> +                       continue;
> +               bus = &i2c_bus[i];
> +               bus->regs = (struct s3c24x0_i2c *)
> +                       fdtdec_get_addr(blob, node, "reg");
> +               bus->node = node;
> +               bus->bus_num = i2c_busses++;
> +       }
> +
> +       return count;
> +}
> +

This seems to be the init function for i2c, so how about calling it
board_i2c_init() or similar. I don't think you need to return the
count of i2c ports - you can just use CONFIG_MAX_I2C_NUM anywhere that
it is needed.

> +static struct s3c24x0_i2c_bus *get_bus(int bus_idx)

should probably be unsigned so that you don't need to check < 0

> +{
> +       if (bus_idx < i2c_busses)
> +               return &i2c_bus[bus_idx];
> +       debug("Undefined bus: %d\n", bus_idx);
> +       return NULL;
> +}
> +
> +int i2c_get_bus_num_fdt(const void *blob, int node)
> +{
> +       enum fdt_compat_id compat;
> +       fdt_addr_t reg;
> +       int i;
> +
> +       compat = fdtdec_lookup(blob, node);
> +       if (compat != COMPAT_SAMSUNG_S3C2440_I2C) {
> +               debug("%s: Not a supported I2C node\n", __func__);
> +               return -1;
> +       }
> +       reg = fdtdec_get_addr(blob, node, "reg");
> +       for (i = 0; i < i2c_busses; i++) {
> +               if (reg == (fdt_addr_t)(uintptr_t)i2c_bus[i].regs)
> +                       return i;
> +       }

This seems painful. You already have a table of node versus bus
number, created in the function above, so why not just look in that?

> +
> +       debug("%s: Can't find any matched I2C bus\n", __func__);
> +       return -1;
> +}
> +
> +int i2c_reset_port_fdt(const void *blob, int node)
> +{
> +       struct s3c24x0_i2c_bus *i2c;
> +
> +       int bus;
> +
> +       bus = i2c_get_bus_num_fdt(blob, node);
> +       if (bus < 0) {
> +               debug("could not get bus for node %d\n", node);
> +               return -1;
> +       }
> +       i2c = get_bus(bus);
> +       if (!i2c) {
> +               debug("get_bus() failed for node node %d\n", node);
> +               return -1;
> +       }
> +
> +       i2c_ch_init(i2c->regs, CONFIG_SYS_I2C_SPEED, CONFIG_SYS_I2C_SLAVE);
> +
> +       return 0;
> +}
> +#endif
> +
>  #endif /* CONFIG_HARD_I2C */
> diff --git a/drivers/i2c/s3c24x0_i2c.h b/drivers/i2c/s3c24x0_i2c.h
> index 2dd4b06..bdd5514 100644
> --- a/drivers/i2c/s3c24x0_i2c.h
> +++ b/drivers/i2c/s3c24x0_i2c.h
> @@ -30,4 +30,11 @@ struct s3c24x0_i2c {
>         u32     iicds;
>         u32     iiclc;
>  };
> +
> +struct s3c24x0_i2c_bus {
> +       int node;       /* device tree node */
> +       int bus_num;    /* i2c bus number */
> +       struct s3c24x0_i2c *regs;
> +};
> +
>  #endif /* _S3C24X0_I2C_H */
> diff --git a/include/i2c.h b/include/i2c.h
> index 16f099d..52be093 100644
> --- a/include/i2c.h
> +++ b/include/i2c.h
> @@ -262,4 +262,32 @@ extern int get_multi_scl_pin(void);
>  extern int get_multi_sda_pin(void);
>  extern int multi_i2c_init(void);
>  #endif
> +
> +#ifdef CONFIG_OF_CONTROL

I think you can omit this line - it doesn't hurt to have unused
prototypes. We will get a link error if someone does something silly.

> +/**
> + * Get FDT values for i2c bus.
> + *
> + * @param blob  Device tree blbo
> + * @return the number of I2C bus
> + */
> +unsigned int i2c_fdt_bus_values(const void *blob);
> +
> +/**
> + * Find the I2C bus number by given a FDT I2C node.
> + *
> + * @param blob  Device tree blbo
> + * @param node  FDT I2C node to find
> + * @return the number of I2C bus (zero based), or -1 on error
> + */
> +int i2c_get_bus_num_fdt(const void *blob, int node);
> +
> +/**
> + * Reset the I2C bus represented by the given a FDT I2C node.
> + *
> + * @param blob  Device tree blbo
> + * @param node  FDT I2C node to find
> + * @return 0 if port was reset, -1 if not found
> + */
> +int i2c_reset_port_fdt(const void *blob, int node);
> +#endif
>  #endif /* _I2C_H_ */
> --
> 1.7.4.4
>

Regards,
Simon