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

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

Thanks,
Sekhar


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