Re: is there any generic GPIO chip framework like IRQ chips?

From: David Brownell
Date: Sun Apr 15 2007 - 16:56:30 EST

To merge, this would be split apart ... what's interesting here is
the way the new leds-gpio driver can be made to talk to leds that
sit across an I2C link.


========== CUT HERE
This presumes various patches updating:

- LED framework to support generic GPIOs (in MM and LED queue)

- LED framework's generic GPIO support to understand that some GPIOs
can't be directly accessed in timer callbacks (patch submitted)

- I2C to support "new style" drivers (driver model conformance, in MM
and i2c queues);

- Kernel.org to match current OMAP trees (in the works, huge)

- OMAP to use the "struct gpio_chip" infrastructure for its GPIOs (a
previous patch in this series)

- TPS65010 to be such a "new style" I2C driver (blocked waiting for OMAP
and I2C patches to merge);

Given those prerequisites, this patch:

* Exposes tps65010 GPIOs and LEDs through the GPIO framework (gaining an
activity light for CF access)

* Converts the OSK board to use that framework (not quite everywhere; at
least the ads7846 driver and serial line wakeup still need updating)

* Removes "old style" OSK led support, except with the Mistral board
whose red-or-green LED isn't really supported by the new framework

Note that this is the first example of the "I2C GPIO expander" case,
where the GPIOs can't be accessed in non-sleeping contexts.

---
arch/arm/mach-omap1/board-osk.c | 66 +++++++++++++++++-------
arch/arm/mach-omap1/leds-osk.c | 92 ----------------------------------
arch/arm/mach-omap1/leds.c | 15 ++---
drivers/i2c/chips/tps65010.c | 59 +++++++++++++++++++++
include/asm-arm/arch-omap/board-osk.h | 11 ++++
include/asm-arm/arch-omap/tps65010.h | 17 ++++++
6 files changed, 141 insertions(+), 119 deletions(-)

--- osk2.orig/include/asm-arm/arch-omap/tps65010.h 2007-04-15 11:09:12.000000000 -0700
+++ osk2/include/asm-arm/arch-omap/tps65010.h 2007-04-15 11:09:15.000000000 -0700
@@ -152,5 +152,22 @@ extern int tps65010_config_vregs1(unsign
*/
extern int tps65013_set_low_pwr(unsigned mode);

+
+/**
+ * struct tps65010_board - packages GPIO and LED lines
+ * @base: the GPIO number to assign to GPIO-1
+ * @outmask: bit (N-1) is set to allow GPIO-N to be used
+ * as an (open drain) output
+ *
+ * Board data may be used to package the GPIO (and LED) lines
+ * for use in by the generic GPIO and LED frameworks. The first
+ * four GPIOs starting at gpio_base are GPIO1..GPIO4; the next
+ * two are LED1..LED2.
+ */
+struct tps65010_board {
+ int base;
+ unsigned outmask;
+};
+
#endif /* __ASM_ARCH_TPS65010_H */

--- osk2.orig/drivers/i2c/chips/tps65010.c 2007-04-15 11:09:12.000000000 -0700
+++ osk2/drivers/i2c/chips/tps65010.c 2007-04-15 11:09:15.000000000 -0700
@@ -34,9 +34,9 @@
#include <linux/mutex.h>

#include <asm/irq.h>
+#include <asm/gpio.h>
#include <asm/mach-types.h>

-#include <asm/arch/gpio.h>
#include <asm/arch/mux.h>
#include <asm/arch/tps65010.h>

@@ -91,7 +91,8 @@ struct tps65010 {
u8 chgstatus, regstatus, chgconf;
u8 nmask1, nmask2;

- /* not currently tracking GPIO state */
+ u8 outmask;
+ struct gpio_chip chip;
};

#define POWER_POLL_DELAY msecs_to_jiffies(5000)
@@ -454,6 +455,38 @@ static irqreturn_t tps65010_irq(int irq,

/*-------------------------------------------------------------------------*/

+/* offsets 0..3 == GPIO1..GPIO4
+ * offsets 4..5 == LED1..LED2 (we set one of the non-BLINK modes)
+ */
+static void
+tps65010_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
+{
+ if (offset < 4)
+ tps65010_set_gpio_out_value(offset + 1, value);
+ else
+ tps65010_set_led(offset - 3, value ? ON : OFF);
+}
+
+static int
+tps65010_output(struct gpio_chip *chip, unsigned offset, int value)
+{
+ /* GPIOs may be input-only */
+ if (offset < 4) {
+ struct tps65010 *tps;
+
+ tps = container_of(chip, struct tps65010, chip);
+ if (!(tps->outmask & (1 << offset)))
+ return -EINVAL;
+ tps65010_set_gpio_out_value(offset + 1, value);
+ } else
+ tps65010_set_led(offset - 3, value ? ON : OFF);
+
+ return 0;
+}
+
+
+/*-------------------------------------------------------------------------*/
+
static struct tps65010 *the_tps;

static int __exit tps65010_remove(struct i2c_client *client)
@@ -475,6 +508,7 @@ static int tps65010_probe(struct i2c_cli
struct tps65010 *tps;
int status;
unsigned long irqflags;
+ struct tps65010_board *board = client->dev.platform_data;

if (the_tps) {
dev_dbg(&client->dev, "only one %s for now\n", DRIVER_NAME);
@@ -585,6 +619,27 @@ static int tps65010_probe(struct i2c_cli

tps->file = debugfs_create_file(DRIVER_NAME, S_IRUGO, NULL,
tps, DEBUG_FOPS);
+
+ /* optionally register GPIOs (and leds) */
+ if (board && board->base > 0) {
+ tps->outmask = board->outmask;
+
+ /* tps->chip.get = tps65010_gpio_get; */
+ tps->chip.set = tps65010_gpio_set;
+ /* tps->chip.direction_input = tps65010_input; */
+ tps->chip.direction_output = tps65010_output;
+ tps->chip.base = board->base;
+ tps->chip.name = client->name;
+ /* we don't handle GPIO input irqs (yet?) ... */
+ tps->chip.ngpio = 6;
+ tps->chip.can_sleep = 1;
+
+ status = gpio_chip_declare(&tps->chip);
+ if (status < 0)
+ dev_dbg(&client->dev, "can't declare GPIOs, err %d\n",
+ status);
+ }
+
return 0;
fail1:
kfree(tps);
--- osk2.orig/include/asm-arm/arch-omap/board-osk.h 2007-04-15 11:09:12.000000000 -0700
+++ osk2/include/asm-arm/arch-omap/board-osk.h 2007-04-15 11:09:15.000000000 -0700
@@ -32,5 +32,16 @@
/* At OMAP5912 OSK the Ethernet is directly connected to CS1 */
#define OMAP_OSK_ETHR_START 0x04800300

+/* TPS65010 has four GPIOs. nPG and LED2 can be treated like GPIOs with
+ * alternate pin configurations for hardware-controlled blinking.
+ */
+#define OSK_TPS_GPIO_BASE (OMAP_MAX_GPIO_LINES + 16 /* MPUIO */)
+# define OSK_TPS_GPIO_USB_PWR_EN (OSK_TPS_GPIO_BASE + 0)
+# define OSK_TPS_GPIO_LED_D3 (OSK_TPS_GPIO_BASE + 1)
+# define OSK_TPS_GPIO_LAN_RESET (OSK_TPS_GPIO_BASE + 2)
+# define OSK_TPS_GPIO_DSP_PWR_EN (OSK_TPS_GPIO_BASE + 3)
+# define OSK_TPS_GPIO_LED_D9 (OSK_TPS_GPIO_BASE + 4)
+# define OSK_TPS_GPIO_LED_D2 (OSK_TPS_GPIO_BASE + 5)
+
#endif /* __ASM_ARCH_OMAP_OSK_H */

--- osk2.orig/arch/arm/mach-omap1/board-osk.c 2007-04-15 11:09:12.000000000 -0700
+++ osk2/arch/arm/mach-omap1/board-osk.c 2007-04-15 11:09:15.000000000 -0700
@@ -33,6 +33,7 @@
#include <linux/irq.h>
#include <linux/interrupt.h>
#include <linux/i2c.h>
+#include <linux/leds.h>

#include <linux/mtd/mtd.h>
#include <linux/mtd/partitions.h>
@@ -182,11 +183,17 @@ static struct platform_device *osk5912_d
&osk5912_mcbsp1_device,
};

+static struct tps65010_board tps_board = {
+ .base = OSK_TPS_GPIO_BASE,
+ .outmask = 0x0f,
+};
+
static struct i2c_board_info __initdata osk_i2c_board_info[] = {
{
I2C_BOARD_INFO("tps65010", 0x48),
.type = "tps65010",
.irq = OMAP_GPIO_IRQ(OMAP_MPUIO(1)),
+ .platform_data = &tps_board,
},
#ifdef CONFIG_OMAP_OSK_MISTRAL
{
@@ -202,7 +209,7 @@ static struct i2c_board_info __initdata

static void __init osk_init_smc91x(void)
{
- if ((omap_request_gpio(0)) < 0) {
+ if ((gpio_request(0, "smc_irq")) < 0) {
printk("Error requesting gpio 0 for smc91x irq\n");
return;
}
@@ -214,7 +221,7 @@ static void __init osk_init_smc91x(void)
static void __init osk_init_cf(void)
{
omap_cfg_reg(M7_1610_GPIO62);
- if ((omap_request_gpio(62)) < 0) {
+ if ((gpio_request(62, "cf_irq")) < 0) {
printk("Error requesting gpio 62 for CF irq\n");
return;
}
@@ -338,7 +345,7 @@ static struct platform_device *mistral_d

static int mistral_get_pendown_state(void)
{
- return !omap_get_gpio_datain(4);
+ return !gpio_get_value(4);
}

static const struct ads7846_platform_data mistral_ts_info = {
@@ -400,10 +407,9 @@ static void __init osk_mistral_init(void
omap_cfg_reg(W14_1610_CCP_DATAP);

/* CAM_PWDN */
- if (omap_request_gpio(11) == 0) {
+ if (gpio_request(11, "cam_pwdn") == 0) {
omap_cfg_reg(N20_1610_GPIO11);
- omap_set_gpio_direction(11, 0 /* out */);
- omap_set_gpio_dataout(11, 0 /* off */);
+ gpio_direction_output(11, 0 /* off */);
} else
pr_debug("OSK+Mistral: CAM_PWDN is awol\n");

@@ -416,9 +422,9 @@ static void __init osk_mistral_init(void

/* the sideways button (SW1) is for use as a "wakeup" button */
omap_cfg_reg(N15_1610_MPUIO2);
- if (omap_request_gpio(OMAP_MPUIO(2)) == 0) {
+ if (gpio_request(OMAP_MPUIO(2), "wakeup") == 0) {
int ret = 0;
- omap_set_gpio_direction(OMAP_MPUIO(2), 1);
+ gpio_direction_input(OMAP_MPUIO(2));
set_irq_type(OMAP_GPIO_IRQ(OMAP_MPUIO(2)), IRQT_RISING);
#ifdef CONFIG_PM
/* share the IRQ in case someone wants to use the
@@ -429,7 +435,7 @@ static void __init osk_mistral_init(void
IRQF_SHARED, "mistral_wakeup",
&osk_mistral_wake_interrupt);
if (ret != 0) {
- omap_free_gpio(OMAP_MPUIO(2));
+ gpio_free(OMAP_MPUIO(2));
printk(KERN_ERR "OSK+Mistral: no wakeup irq, %d?\n",
ret);
} else
@@ -442,10 +448,8 @@ static void __init osk_mistral_init(void
* board, like the touchscreen, EEPROM, and wakeup (!) switch.
*/
omap_cfg_reg(PWL);
- if (omap_request_gpio(2) == 0) {
- omap_set_gpio_direction(2, 0 /* out */);
- omap_set_gpio_dataout(2, 1 /* on */);
- }
+ if (gpio_request(2, "lcd_pwdn") == 0)
+ gpio_direction_output(2, 1 /* on */);

platform_add_devices(mistral_devices, ARRAY_SIZE(mistral_devices));
}
@@ -474,8 +478,8 @@ static void __init osk_init(void)

/* irq for tps65010 chip */
// omap_cfg_reg(U19_1610_MPUIO1);
- omap_request_gpio(OMAP_MPUIO(1));
- omap_set_gpio_direction(OMAP_MPUIO(1), 1);
+ if (gpio_request(OMAP_MPUIO(1), "tps65010"))
+ gpio_direction_input(OMAP_MPUIO(1));

i2c_register_board_info(1, osk_i2c_board_info,
ARRAY_SIZE(osk_i2c_board_info));
@@ -490,6 +494,26 @@ static void __init osk_map_io(void)
}

#ifdef CONFIG_TPS65010
+
+static struct gpio_led tps_leds[] = {
+ { .gpio = OSK_TPS_GPIO_LED_D9, .name = "d9:green",
+ .default_trigger = "ide-disk", /* CF */ },
+ { .gpio = OSK_TPS_GPIO_LED_D2, .name = "d2:green", },
+ { .gpio = OSK_TPS_GPIO_LED_D3, .name = "d3:green", .active_low = 1,
+ .default_trigger = "heartbeat", },
+};
+
+static struct gpio_led_platform_data tps_led_data = {
+ .num_leds = ARRAY_SIZE(tps_leds),
+ .leds = tps_leds,
+};
+
+static struct platform_device tps_led_dev = {
+ .name = "leds-gpio",
+ .id = -1,
+ .dev.platform_data = &tps_led_data,
+};
+
static int __init osk_tps_init(void)
{
if (!machine_is_omap_osk())
@@ -504,16 +528,20 @@ static int __init osk_tps_init(void)
/* Set GPIO 1 HIGH to disable VBUS power supply;
* OHCI driver powers it up/down as needed.
*/
- tps65010_set_gpio_out_value(GPIO1, HIGH);
+ if (gpio_request(OSK_TPS_GPIO_USB_PWR_EN, "vbus_dis") == 0)
+ gpio_direction_output(OSK_TPS_GPIO_USB_PWR_EN, 1);

/* Set GPIO 2 low to turn on LED D3 */
tps65010_set_gpio_out_value(GPIO2, HIGH);

/* Set GPIO 3 low to take ethernet out of reset */
- tps65010_set_gpio_out_value(GPIO3, LOW);
+ if (gpio_request(OSK_TPS_GPIO_LAN_RESET, "lan_reset") == 0)
+ gpio_direction_output(OSK_TPS_GPIO_LAN_RESET, 0);

/* gpio4 for VDD_DSP */
- // FIXME power DSP iff it's configured
+ /* FIXME power DSP iff it's configured */
+ if (gpio_request(OSK_TPS_GPIO_DSP_PWR_EN, "dsp_pwr_en") == 0)
+ gpio_direction_output(OSK_TPS_GPIO_DSP_PWR_EN, 1);

/* Enable LOW_PWR */
tps65010_set_low_pwr(ON);
@@ -522,7 +550,7 @@ static int __init osk_tps_init(void)
tps65010_config_vregs1(TPS_LDO2_ENABLE | TPS_VLDO2_3_0V
| TPS_LDO1_ENABLE);

- return 0;
+ return platform_device_register(&tps_led_dev);
}
fs_initcall(osk_tps_init);
#endif
--- osk2.orig/arch/arm/mach-omap1/leds-osk.c 2007-04-15 11:09:12.000000000 -0700
+++ osk2/arch/arm/mach-omap1/leds-osk.c 2007-04-15 11:09:15.000000000 -0700
@@ -1,7 +1,7 @@
/*
* linux/arch/arm/mach-omap1/leds-osk.c
*
- * LED driver for OSK, and optionally Mistral QVGA, boards
+ * LED driver for OSK's optional Mistral QVGA board
*/
#include <linux/init.h>
#include <linux/workqueue.h>
@@ -11,7 +11,6 @@
#include <asm/system.h>

#include <asm/arch/gpio.h>
-#include <asm/arch/tps65010.h>

#include "leds.h"

@@ -20,51 +19,11 @@
#define LED_STATE_CLAIMED (1 << 1)
static u8 led_state;

-#define GREEN_LED (1 << 0) /* TPS65010 LED1 */
-#define AMBER_LED (1 << 1) /* TPS65010 LED2 */
-#define RED_LED (1 << 2) /* TPS65010 GPIO2 */
#define TIMER_LED (1 << 3) /* Mistral board */
#define IDLE_LED (1 << 4) /* Mistral board */
static u8 hw_led_state;


-/* TPS65010 leds are changed using i2c -- from a task context.
- * Using one of these for the "idle" LED would be impractical...
- */
-#define TPS_LEDS (GREEN_LED | RED_LED | AMBER_LED)
-
-static u8 tps_leds_change;
-
-static void tps_work(struct work_struct *unused)
-{
- for (;;) {
- u8 leds;
-
- local_irq_disable();
- leds = tps_leds_change;
- tps_leds_change = 0;
- local_irq_enable();
-
- if (!leds)
- break;
-
- /* careful: the set_led() value is on/off/blink */
- if (leds & GREEN_LED)
- tps65010_set_led(LED1, !!(hw_led_state & GREEN_LED));
- if (leds & AMBER_LED)
- tps65010_set_led(LED2, !!(hw_led_state & AMBER_LED));
-
- /* the gpio led doesn't have that issue */
- if (leds & RED_LED)
- tps65010_set_gpio_out_value(GPIO2,
- !(hw_led_state & RED_LED));
- }
-}
-
-static DECLARE_WORK(work, tps_work);
-
-#ifdef CONFIG_OMAP_OSK_MISTRAL
-
/* For now, all system indicators require the Mistral board, since that
* LED can be manipulated without a task context. This LED is either red,
* or green, but not both; it can't give the full "disco led" effect.
@@ -88,24 +47,19 @@ static void mistral_setled(void)
omap_set_gpio_dataout(GPIO_LED_RED, red);
}

-#endif
-
void osk_leds_event(led_event_t evt)
{
unsigned long flags;
- u16 leds;

local_irq_save(flags);

if (!(led_state & LED_STATE_ENABLED) && evt != led_start)
goto done;

- leds = hw_led_state;
switch (evt) {
case led_start:
led_state |= LED_STATE_ENABLED;
hw_led_state = 0;
- leds = ~0;
break;

case led_halted:
@@ -118,7 +72,6 @@ void osk_leds_event(led_event_t evt)
case led_claim:
led_state |= LED_STATE_CLAIMED;
hw_led_state = 0;
- leds = ~0;
break;

case led_release:
@@ -126,8 +79,6 @@ void osk_leds_event(led_event_t evt)
hw_led_state = 0;
break;

-#ifdef CONFIG_OMAP_OSK_MISTRAL
-
case led_timer:
hw_led_state ^= TIMER_LED;
mistral_setled();
@@ -143,51 +94,10 @@ void osk_leds_event(led_event_t evt)
mistral_setled();
break;

-#endif /* CONFIG_OMAP_OSK_MISTRAL */
-
- /* "green" == tps LED1 (leftmost, normally power-good)
- * works only with DC adapter, not on battery power!
- */
- case led_green_on:
- if (led_state & LED_STATE_CLAIMED)
- hw_led_state |= GREEN_LED;
- break;
- case led_green_off:
- if (led_state & LED_STATE_CLAIMED)
- hw_led_state &= ~GREEN_LED;
- break;
-
- /* "amber" == tps LED2 (middle) */
- case led_amber_on:
- if (led_state & LED_STATE_CLAIMED)
- hw_led_state |= AMBER_LED;
- break;
- case led_amber_off:
- if (led_state & LED_STATE_CLAIMED)
- hw_led_state &= ~AMBER_LED;
- break;
-
- /* "red" == LED on tps gpio3 (rightmost) */
- case led_red_on:
- if (led_state & LED_STATE_CLAIMED)
- hw_led_state |= RED_LED;
- break;
- case led_red_off:
- if (led_state & LED_STATE_CLAIMED)
- hw_led_state &= ~RED_LED;
- break;
-
default:
break;
}

- leds ^= hw_led_state;
- leds &= TPS_LEDS;
- if (leds && (led_state & LED_STATE_CLAIMED)) {
- tps_leds_change |= leds;
- schedule_work(&work);
- }
-
done:
local_irq_restore(flags);
}
--- osk2.orig/arch/arm/mach-omap1/leds.c 2007-04-15 11:09:12.000000000 -0700
+++ osk2/arch/arm/mach-omap1/leds.c 2007-04-15 11:09:15.000000000 -0700
@@ -5,11 +5,12 @@
*/
#include <linux/kernel.h>
#include <linux/init.h>
+#include <linux/list.h>

#include <asm/leds.h>
+#include <asm/gpio.h>
#include <asm/mach-types.h>

-#include <asm/arch/gpio.h>
#include <asm/arch/mux.h>

#include "leds.h"
@@ -25,17 +26,17 @@ omap_leds_init(void)
|| machine_is_omap_perseus2())
leds_event = h2p2_dbg_leds_event;

+#ifdef CONFIG_OMAP_OSK_MISTRAL
else if (machine_is_omap_osk())
leds_event = osk_leds_event;
+#endif

else
return -1;

if (machine_is_omap_h2()
|| machine_is_omap_h3()
-#ifdef CONFIG_OMAP_OSK_MISTRAL
|| machine_is_omap_osk()
-#endif
) {

/* LED1/LED2 pins can be used as GPIO (as done here), or by
@@ -47,14 +48,14 @@ omap_leds_init(void)
* that's a different kind of LED (just one color at a time).
*/
omap_cfg_reg(P18_1610_GPIO3);
- if (omap_request_gpio(3) == 0)
- omap_set_gpio_direction(3, 0);
+ if (gpio_request(3, "timer_led") == 0)
+ gpio_direction_output(3, 0);
else
printk(KERN_WARNING "LED: can't get GPIO3/red?\n");

omap_cfg_reg(MPUIO4);
- if (omap_request_gpio(OMAP_MPUIO(4)) == 0)
- omap_set_gpio_direction(OMAP_MPUIO(4), 0);
+ if (gpio_request(OMAP_MPUIO(4), "idle_led") == 0)
+ gpio_direction_output(OMAP_MPUIO(4), 0);
else
printk(KERN_WARNING "LED: can't get MPUIO4/green?\n");
}
-
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