Re: [alsa-devel] [RFC/PATCH] pxa2xx_ac97 and gpio reset line

On 19 Feb 2009, at 20:44, Robert Jarzmik robert.jarzmik@free.fr wrote:

Hi Mark,

I can't find out if somebody had submitted that kind of patch before. This is a starting point of discussion. I'm not fully convinced by my own code, and so I post it here for advice.

What I'd really like is to be able to choose the PXA AC97 gpio reset (GPIO95 or GPIO113) through platform_data, but I couldn't find a way of doing it. I hope you'll have some kind of idea.

This is a sensible idea in principle but should be done via platform data for the AC97 driver rather than via Kconfig - it'll need an update to use the platform in ASoC but I'll need to do those anyway.

Cheers.

-- Robert

From 8d4a0c602b85528af2a35fd3f1f1bd8ddca22985 Mon Sep 17 00:00:00 2001 From: Robert Jarzmik robert.jarzmik@free.fr Date: Thu, 19 Feb 2009 21:35:42 +0100 Subject: [PATCH] Allow choice in ac97 gpio reset line

As the PXA series allow 2 gpios to reset the ac97 bus, allow through configuration the definition of the correct gpio which will reset the AC97 bus.

This comes from a silicon defect on the PXA series, where the gpio must be manually controlled in warm reset cases.

Signed-off-by: Robert Jarzmik rjarzmik@free.fr

sound/arm/Kconfig | 17 +++++++++++ sound/arm/pxa2xx-ac97-lib.c | 68 ++++++++++++++++++++++++++++++++++ +++++--- 2 files changed, 80 insertions(+), 5 deletions(-)

diff --git a/sound/arm/Kconfig b/sound/arm/Kconfig index f8e6de4..2749274 100644 --- a/sound/arm/Kconfig +++ b/sound/arm/Kconfig @@ -39,6 +39,23 @@ config SND_PXA2XX_LIB config SND_PXA2XX_LIB_AC97 bool

+choice

• prompt "PXA GPIO line used to reset AC97 bus"
• depends on SND_PXA2XX_LIB_AC97
• help

•  Choose which GPIO is assigned the AC97 reset function.
  

•  Usually board designers use GPIO 113, but GPIO 95 can be used
  

•  as well.
  

+config SND_PXA2XX_LIB_AC97_RESET113

• bool "GPIO113"

+config SND_PXA2XX_LIB_AC97_RESET95

• bool "GPIO95"

+endchoice

config SND_PXA2XX_AC97 tristate "AC97 driver for the Intel PXA2xx chip" depends on ARCH_PXA diff --git a/sound/arm/pxa2xx-ac97-lib.c b/sound/arm/pxa2xx-ac97-lib.c index 35afd0c..aa522d2 100644 --- a/sound/arm/pxa2xx-ac97-lib.c +++ b/sound/arm/pxa2xx-ac97-lib.c @@ -31,6 +31,8 @@ static DECLARE_WAIT_QUEUE_HEAD(gsr_wq); static volatile long gsr_bits; static struct clk *ac97_clk; static struct clk *ac97conf_clk; +static int is_ac97_resetgpio_95; +static int is_ac97_resetgpio_113;

/*

• Beware PXA27x bugs:

@@ -42,6 +44,55 @@ static struct clk *ac97conf_clk;

• 1 jiffy timeout if interrupt never comes).

*/

+enum {

• RESETGPIO_FORCE_HIGH,
• RESETGPIO_FORCE_LOW,
• RESETGPIO_NORMAL_ALTFUNC

+};

+/**

• • set_resetgpio_mode - computes and sets the AC97_RESET gpio mode

on PXA

• • @mode: chosen action
• • As the PXA CPUs suffer from a AC97 bug, a manual control of the

reset

• • line must be done to insure proper work of AC97 reset line.
• • This function computes the correct gpio_mode for further use by

reset

• • functions, and applied the change through pxa_gpio_mode.
• */

+static void set_resetgpio_mode(int resetgpio_action) +{

• int mode = 0;
• if (is_ac97_resetgpio_113)

•    switch (resetgpio_action) {
  

•    case RESETGPIO_FORCE_LOW:
  

•        mode = 113 | GPIO_OUT | GPIO_DFLT_LOW;
  

•        break;
  

•    case RESETGPIO_FORCE_HIGH:
  

•        mode = 113 | GPIO_OUT | GPIO_DFLT_HIGH;
  

•        break;
  

•    case RESETGPIO_NORMAL_ALTFUNC:
  

•        mode = 113 | GPIO_ALT_FN_2_OUT;
  

•        break;
  

•    };
  

• if (is_ac97_resetgpio_95)

•    switch (resetgpio_action) {
  

•    case RESETGPIO_FORCE_LOW:
  

•        mode = 95 | GPIO_OUT | GPIO_DFLT_LOW;
  

•        break;
  

•    case RESETGPIO_FORCE_HIGH:
  

•        mode = 95 | GPIO_OUT | GPIO_DFLT_HIGH;
  

•        break;
  

•    case RESETGPIO_NORMAL_ALTFUNC:
  

•        mode = 95 | GPIO_ALT_FN_1_OUT;
  

•        break;
  

•    };
  

• if (mode)

•    pxa_gpio_mode(mode);
  

+}

unsigned short pxa2xx_ac97_read(struct snd_ac97 *ac97, unsigned short reg) { unsigned short val = -1; @@ -137,10 +188,10 @@ static inline void pxa_ac97_warm_pxa27x(void)

/* warm reset broken on Bulverde, so manually keep AC97 reset high */

• pxa_gpio_mode(113 | GPIO_OUT | GPIO_DFLT_HIGH);

• set_resetgpio_mode(RESETGPIO_FORCE_HIGH); udelay(10); GCR |= GCR_WARM_RST;

• pxa_gpio_mode(113 | GPIO_ALT_FN_2_OUT);

• set_resetgpio_mode(RESETGPIO_NORMAL_ALTFUNC); udelay(500);

}

@@ -308,8 +359,8 @@ int pxa2xx_ac97_hw_resume(void) pxa_gpio_mode(GPIO29_SDATA_IN_AC97_MD); } if (cpu_is_pxa27x()) {

•    /* Use GPIO 113 as AC97 Reset on Bulverde */
  

•    pxa_gpio_mode(113 | GPIO_ALT_FN_2_OUT);
  

•    /* Use GPIO 113 or 95 as AC97 Reset on Bulverde */
  

•    set_resetgpio_mode(RESETGPIO_NORMAL_ALTFUNC);
  

  } clk_enable(ac97_clk); return 0;

@@ -321,6 +372,13 @@ int __devinit pxa2xx_ac97_hw_probe(struct platform_device *dev) { int ret;

+#ifdef CONFIG_SND_PXA2XX_LIB_AC97_RESET113

• is_ac97_resetgpio_113 = 1;

+#endif +#ifdef CONFIG_SND_PXA2XX_LIB_AC97_RESET95

• is_ac97_resetgpio_95 = 1;

+#endif

• if (cpu_is_pxa25x() || cpu_is_pxa27x()) { pxa_gpio_mode(GPIO31_SYNC_AC97_MD); pxa_gpio_mode(GPIO30_SDATA_OUT_AC97_MD);

@@ -330,7 +388,7 @@ int __devinit pxa2xx_ac97_hw_probe(struct platform_device *dev)

if (cpu_is_pxa27x()) { /* Use GPIO 113 as AC97 Reset on Bulverde */

•    pxa_gpio_mode(113 | GPIO_ALT_FN_2_OUT);
  

•    set_resetgpio_mode(RESETGPIO_NORMAL_ALTFUNC);
   ac97conf_clk = clk_get(&dev->dev, "AC97CONFCLK");
   if (IS_ERR(ac97conf_clk)) {
       ret = PTR_ERR(ac97conf_clk);
  

-- 1.5.6.5