Re: [U-Boot] [PATCH v2] dm:gpio:mxc add DT support

21 Jan 2015

Hi, Igor
On 1/20/2015 10:39 PM, Igor Grinberg wrote:
...
On 01/20/15 09:15, Peng Fan wrote:
...
This patch add DT support for mxc gpio driver.
Include a bank_index entry in platdata. This can avoid using
`plat - mxc_plat` to calculate bank number. Also this can simplify code.
Although, I don't insist, but I would recommend to split the patch into 2:
the bank_index rework and the DT support addition.
Ok. I can split this in v3 patch.
...
...
There are two places still using CONFIG_OF_CONTROL macro, just to
shrink code size if only support DM but not support DT.

The U_BOOT_DEVICES and mxc_plat array are complied out. To DT,
 platdata is alloced using calloc, so there is no need to use mxc_plat.
add a function mxc_get_gpio_addr to get "reg" property if DT support.
 If no DT, this function just returns NULL.

I have some comments on this one, please see below...
Reply below.
...
...
The following situations are tested:

with DM, without DT
with DM and DT
without DM

Since device tree has not been upstreamed, if want to test this patch.
The followings need to be done.

pieces of code does not gpio_request when using gpio_direction_xxx and
etc, need to request gpio.
move the gpio settings from board_early_init_f to board_init
define CONFIG_DM ,CONFIG_DM_GPIO and CONFIG_OF_CONTROL
Add device tree file and do related configuration in
`make ARCH=arm menuconfig`

These will be done in future patches by step.
Signed-off-by: Peng Fan Peng.Fan@freescale.com
Changes v2:

remove uneccessary #ifdef
add more stuff in commit log
include a new function mxc_get_gpio_addr to get register base.
This function is different for DT and not DT, by `#ifdef`.
If using one implementation for DT and not DT, final image will be big.
include a new entry in platdata, named bank_index. it can simplify DT
support. To no DT, bank_index is static initilized; to DT, bank_index
is get from device's req_seq.

drivers/gpio/mxc_gpio.c | 89 +++++++++++++++++++++++++++++++++++++++----------
  1 file changed, 71 insertions(+), 18 deletions(-)

diff --git a/drivers/gpio/mxc_gpio.c b/drivers/gpio/mxc_gpio.c
index 8bb9e39..5826620 100644
--- a/drivers/gpio/mxc_gpio.c
+++ b/drivers/gpio/mxc_gpio.c
@@ -23,6 +23,7 @@ enum mxc_gpio_direction {
  #define GPIO_PER_BANK			32
struct mxc_gpio_plat {

int bank_index;
struct gpio_regs *regs;
};

@@ -150,6 +151,9 @@ int gpio_direction_output(unsigned gpio, int value)
  #endif
#ifdef CONFIG_DM_GPIO
+#include <fdtdec.h>
+DECLARE_GLOBAL_DATA_PTR;

static int mxc_gpio_is_output(struct gpio_regs *regs, int offset)
{
 u32 val;

@@ -258,23 +262,6 @@ static const struct dm_gpio_ops gpio_mxc_ops = {
   .get_function		= mxc_gpio_get_function,
  };
-static const struct mxc_gpio_plat mxc_plat[] = {

{ (struct gpio_regs *)GPIO1_BASE_ADDR },
{ (struct gpio_regs *)GPIO2_BASE_ADDR },
{ (struct gpio_regs *)GPIO3_BASE_ADDR },

-#if defined(CONFIG_MX25) || defined(CONFIG_MX27) || defined(CONFIG_MX51) || \

defined(CONFIG_MX53) || defined(CONFIG_MX6)


{ (struct gpio_regs *)GPIO4_BASE_ADDR },

-#endif
-#if defined(CONFIG_MX27) || defined(CONFIG_MX53) || defined(CONFIG_MX6)

{ (struct gpio_regs *)GPIO5_BASE_ADDR },
{ (struct gpio_regs *)GPIO6_BASE_ADDR },

-#endif
-#if defined(CONFIG_MX53) || defined(CONFIG_MX6)

{ (struct gpio_regs *)GPIO7_BASE_ADDR },

-#endif
-};

static int mxc_gpio_probe(struct udevice *dev)
{
 struct mxc_bank_info *bank = dev_get_priv(dev);

@@ -283,7 +270,7 @@ static int mxc_gpio_probe(struct udevice *dev)
   int banknum;
   char name[18], *str;

banknum = plat - mxc_plat;


banknum = plat->bank_index;
sprintf(name, "GPIO%d_", banknum + 1);
str = strdup(name);
if (!str)

@@ -295,12 +282,77 @@ static int mxc_gpio_probe(struct udevice *dev)
   return 0;
  }
+#ifdef CONFIG_OF_CONTROL
+static struct gpio_regs *mxc_get_gpio_addr(struct udevice *device)
+{

fdt_addr_t addr;
addr = fdtdec_get_addr(gd->fdt_blob, device->of_offset, "reg");
if (addr == FDT_ADDR_T_NONE)
return NULL;


else
return (struct gpio_regs *)addr;



+}
+#else
+static struct gpio_regs *mxc_get_gpio_addr(struct udevice *device)
+{

return NULL;

+}
+#endif
In general, I'm fine with this concept, but I believe we should implement
a stub for fdtdec_get_addr() function in the fdtdec.h (say just returning
FDT_ADDR_T_NONE), as otherwise we might end up with multiple drivers
implementing the same noop callback just to work around a poor fdtdec_*()
interface.
I tried to implement a stub function in fdtdec.h like this:
__weak fdt_addr_t fdtdec_get_addr_wrap(xxxx)
{
     return FDT_ADDR_T_NONE;
}
And in driver code, implement non weak version as following:
#ifdef CONFIG_OF_CONTROL
fdt_addr_t fdtdec_get_addr_wrap(xxxx)
{
     ..........
}
#endif
But gcc complains about conficting types, since we have a weak 
implementation in header file and a strong implementation in c file. If 
the weak one is in fdtxx c file, no error, but i thinke this is not a 
good idea to put this in fdtxx c file. If we do not want DT, but only 
DM, DT code should not be compiled into the final image.
I tried another way, add the following piece code in 
driver/core/device.c and function prototype in device.h,
"
#ifdef CONFIG_OF_CONTROL
void *dev_reg_addr(struct udevice *dev)
{
     fdt_addr_t addr;
addr = fdtdev_get_addr(gd->fdt_blob, dev->of_offset, "reg");
     if (addr == FDT_ADDR_T_NONE)
         return NULL;
     else
         return (void *)addr
}
#else
void *dev_reg_addr(struct udevice *dev)
{
     return NULL;
}
#endif
"
I think `#ifdef` is needed here. I think this way is better that put 
stub function in fdtdec.h. Using this way, the driver code can just `add 
= dev_reg_addr(device)` to get reg address.
Maybe the upper piece code should be put in a new file named 
device-util.c in directory device/core but not device.c?
Comments?
...
...



+static int mxc_gpio_bind(struct udevice *device)
+{

struct mxc_gpio_plat *plat = device->platdata;
struct gpio_regs *regs;

if (plat)
return 0;



regs = mxc_get_gpio_addr(device);
if (!regs)
return -ENXIO;



plat = calloc(1, sizeof(*plat));
if (!plat)
return -ENOMEM;



plat->regs = regs;
plat->bank_index = device->req_seq;
device->platdata = plat;

return 0;

+}



+static const struct udevice_id mxc_gpio_ids[] = {

{ .compatible = "fsl,imx35-gpio" },
{ }

+};

U_BOOT_DRIVER(gpio_mxc) = {
 .name	= "gpio_mxc",
 .id	= UCLASS_GPIO,
 .ops	= &gpio_mxc_ops,
 .probe	= mxc_gpio_probe,
 .priv_auto_alloc_size = sizeof(struct mxc_bank_info),
.of_match = mxc_gpio_ids,
.bind	= mxc_gpio_bind,

+};



+#ifndef CONFIG_OF_CONTROL
+static const struct mxc_gpio_plat mxc_plat[] = {

{ 0, (struct gpio_regs *)GPIO1_BASE_ADDR },
{ 1, (struct gpio_regs *)GPIO2_BASE_ADDR },
{ 2, (struct gpio_regs *)GPIO3_BASE_ADDR },

+#if defined(CONFIG_MX25) || defined(CONFIG_MX27) || defined(CONFIG_MX51) || \

defined(CONFIG_MX53) || defined(CONFIG_MX6)


{ 3, (struct gpio_regs *)GPIO4_BASE_ADDR },

+#endif
+#if defined(CONFIG_MX27) || defined(CONFIG_MX53) || defined(CONFIG_MX6)

{ 4, (struct gpio_regs *)GPIO5_BASE_ADDR },
{ 5, (struct gpio_regs *)GPIO6_BASE_ADDR },

+#endif
+#if defined(CONFIG_MX53) || defined(CONFIG_MX6)

{ 6, (struct gpio_regs *)GPIO7_BASE_ADDR },

+#endif
  };
U_BOOT_DEVICES(mxc_gpios) = {
@@ -320,3 +372,4 @@ U_BOOT_DEVICES(mxc_gpios) = {
  #endif
  };
  #endif
+#endif
Regards,
Peng.

    