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SubjectRe: [PATCH v2 6/6] ARM: davinci: da850: configure system configuration chip(CFGCHIP3) for emac
Sekhar ,

On Sun, Feb 3, 2013 at 6:15 PM, Sekhar Nori <nsekhar@ti.com> wrote:
> On 1/28/2013 7:17 PM, Prabhakar Lad wrote:
>> From: Lad, Prabhakar <prabhakar.lad@ti.com>
>>
>> The system configuration chip CFGCHIP3, controls the emac module.
>> This patch appropriately configures this register for emac and
>> sets DA850_MII_MDIO_CLKEN_PIN GPIO pin appropriately.
>>
>> Signed-off-by: Lad, Prabhakar <prabhakar.lad@ti.com>
>> Cc: linux-arm-kernel@lists.infradead.org
>> Cc: linux-kernel@vger.kernel.org
>> Cc: davinci-linux-open-source@linux.davincidsp.com
>> Cc: netdev@vger.kernel.org
>> Cc: devicetree-discuss@lists.ozlabs.org
>> Cc: Sekhar Nori <nsekhar@ti.com>
>> Cc: Heiko Schocher <hs@denx.de>
>> ---
>> arch/arm/mach-davinci/da8xx-dt.c | 28 ++++++++++++++++++++++++++++
>> 1 files changed, 28 insertions(+), 0 deletions(-)
>>
>> diff --git a/arch/arm/mach-davinci/da8xx-dt.c b/arch/arm/mach-davinci/da8xx-dt.c
>> index e533a0a..4a096e3 100644
>> --- a/arch/arm/mach-davinci/da8xx-dt.c
>> +++ b/arch/arm/mach-davinci/da8xx-dt.c
>> @@ -8,6 +8,7 @@
>> * published by the Free Software Foundation.
>> */
>> #include <linux/io.h>
>> +#include <linux/gpio.h>
>> #include <linux/of_irq.h>
>> #include <linux/of_platform.h>
>> #include <linux/irqdomain.h>
>> @@ -39,6 +40,32 @@ static void __init da8xx_init_irq(void)
>>
>> #ifdef CONFIG_ARCH_DAVINCI_DA850
>>
>> +static void __init da8xx_config_emac(void)
>> +{
>> +#define DA850_MII_MDIO_CLKEN_PIN GPIO_TO_PIN(2, 6)
>> +#define DA850_EMAC_MODE_SELECT BIT(8)
>> + void __iomem *cfg_chip3_base;
>> + int ret;
>> + u32 val;
>> +
>> + cfg_chip3_base = DA8XX_SYSCFG0_VIRT(DA8XX_CFGCHIP3_REG);
>> +
>> + val = __raw_readl(cfg_chip3_base);
>> + val &= ~DA850_EMAC_MODE_SELECT;
>> + /* configure the CFGCHIP3 register for MII */
>> + __raw_writel(val, cfg_chip3_base);
>
> Use readl/writel instead.
>
Ok.

>> + pr_info("EMAC: MII PHY configured\n");
>> +
>> + ret = gpio_request(DA850_MII_MDIO_CLKEN_PIN, "mdio_clk_en");
>> + if (ret) {
>> + pr_warn("Cannot open GPIO %d\n",
>> + DA850_MII_MDIO_CLKEN_PIN);
>> + return;
>> + }
>> + /* Enable/Disable MII MDIO clock */
>> + gpio_direction_output(DA850_MII_MDIO_CLKEN_PIN, 0);
>> +}
>> +
>> struct of_dev_auxdata da8xx_auxdata[] __initdata = {
>> OF_DEV_AUXDATA("ti,davinci_mdio", 0x01e24000, "davinci_mdio.0", NULL),
>> OF_DEV_AUXDATA("ti,davinci-dm6467-emac", 0x01e20000, "davinci_emac.1",
>> @@ -52,6 +79,7 @@ static void __init da850_init_machine(void)
>> da8xx_auxdata, NULL);
>>
>> da8xx_uart_clk_enable();
>> + da8xx_config_emac();
>
> There are couple of issues with this implementation.
>
> 1) da8xx_config_emac() is specific to DA850 EVM, but masquerades as
> generic for da8xx. Looks like you need two functions, one for soc
> specific configuration and one board specific.
Ok.

> 2) da8xx_config_emac() goes through all the time, whether the
> particular board has emac module or not. Shouldn't
> da8xx_config_emac() check if emac is actually enabled in the passed
> dtb and only the do the configuration?

Ok. Can you give some pointers how we can access the dtb in board files.

> 3) The function assumes mii is used always, you can use the rmii_en dt
> property to check if rmii/mii is enabled and configure the soc/board
> accordingly.

Ok.

> 4) If the same function can work both for da850 and da830, then it can
> be implemented outside of CONFIG_ARCH_DAVINCI_DA850.
>
Ok.

Regards,
--Prabhakar

> Thanks,
> Sekhar


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