Re: [PATCH] misc/pca9552: Add qom set and get

["Philippe Mathieu-Daudé" <philmd@redhat.com>]

Odd... I only received Cédric answer, not Joel patch.

On 11/18/19 11:00 AM, Cédric Le Goater wrote:
> On 18/11/2019 07:17, Joel Stanley wrote:
>> Following the pattern of the work recently done with the ASPEED GPIO
>> model, this adds support for inspecting and modifying the PCA9552 LEDs
>> from the monitor.
>>
>>   (qemu) qom-set  /machine/unattached/device[17] led0 on
>>   (qemu) qom-get  /machine/unattached/device[17] led0
>>   "on"
>>
>>   (qemu) qom-set  /machine/unattached/device[17] led0 off
>>   (qemu) qom-get  /machine/unattached/device[17] led0
>>   "off"
>>
>>   (qemu) qom-set  /machine/unattached/device[17] led0 pwm0
>>   (qemu) qom-get  /machine/unattached/device[17] led0
>>   "pwm0"
>>
>>   (qemu) qom-set  /machine/unattached/device[17] led0 pwm1
>>   (qemu) qom-get  /machine/unattached/device[17] led0
>>   "pwm1"
> 
> It would be nice to revive the QOM get patchset from David.
> 
> 	http://patchwork.ozlabs.org/patch/666458/
> 
> Did we reach some consensus ?
> 
>> Signed-off-by: Joel Stanley <joel@jms.id.au>
> 
> Some comments below.
> 
>> ---
>> The qom device in mainline qemu is a different path. Using the monitor
>> examine `info qom-tree /machine/unattached/` to discover it.
>>
>> This can be tested with a Witherspoon image.
>>
>> $ wget https://openpower.xyz/job/openbmc-build/distro=ubuntu,label=builder,target=witherspoon/lastSuccessfulBuild/artifact/deploy/images/witherspoon/obmc-phosphor-image-witherspoon.ubi.mtd
>>
>> $ qemu-system-arm -M witherspoon-bmc -serial pty -monitor pty -nographic \
>>   -drive file=obmc-phosphor-image-witherspoon.ubi.mtd,format=raw,if=mtd
>> char device redirected to /dev/pts/5 (label compat_monitor0)
>> char device redirected to /dev/pts/10 (label serial0)
>>
>> $ screen /dev/pts/5
>> QEMU 4.1.91 monitor - type 'help' for more information
>> (qemu) qom-get  /machine/unattached/device[17] led0
>> "off"
>>
>> $ screen /dev/pts/19
>> root@witherspoon:~# cd /sys/class/gpio/
>> root@witherspoon:/sys/class/gpio# echo 248 > export
>> root@witherspoon:/sys/class/gpio# cat gpio248/value
>> 0
>>
>> (qemu) qom-set  /machine/unattached/device[17] led0 on
>>
>> root@witherspoon:/sys/class/gpio# echo out > gpio248/direction
>> root@witherspoon:/sys/class/gpio# cat gpio248/value
>> 1
>>
>> (qemu) qom-get  /machine/unattached/device[17] led0
>> "on"
>>
>> (qemu) qom-set  /machine/unattached/device[17] led0 off
>> (qemu) qom-get  /machine/unattached/device[17] led0
>> "off"
>>
>> root@witherspoon:/sys/class/gpio# cat gpio248/value
>> 0

I am assuming this is 5.0 material.

This is a good starting point, and is useful.

However this would be useful for other boards/devices too.

What about defining a InterfaceInfo[] for external GPIOs?

Shouldn't we use the qemu_irq type for that then?

>>
>> Signed-off-by: Joel Stanley <joel@jms.id.au>
>> ---
>>   hw/misc/pca9552.c | 91 +++++++++++++++++++++++++++++++++++++++++++++++
>>   1 file changed, 91 insertions(+)
>>
>> diff --git a/hw/misc/pca9552.c b/hw/misc/pca9552.c
>> index 73be28d9369c..0362aac8c862 100644
>> --- a/hw/misc/pca9552.c
>> +++ b/hw/misc/pca9552.c
>> @@ -15,12 +15,16 @@
>>   #include "hw/misc/pca9552.h"
>>   #include "hw/misc/pca9552_regs.h"
>>   #include "migration/vmstate.h"
>> +#include "qapi/error.h"
>> +#include "qapi/visitor.h"
>>   
>>   #define PCA9552_LED_ON   0x0
>>   #define PCA9552_LED_OFF  0x1
>>   #define PCA9552_LED_PWM0 0x2
>>   #define PCA9552_LED_PWM1 0x3
>>   
>> +static const char *led_state[] = {"on", "off", "pwm0", "pwm1"};

BTW "pwm0/pwm1" as "state" is confuse, but I understand this is how the 
PCA9552 datasheet describes it.

>> +
>>   static uint8_t pca9552_pin_get_config(PCA9552State *s, int pin)
>>   {
>>       uint8_t reg   = PCA9552_LS0 + (pin / 4);
>> @@ -169,6 +173,84 @@ static int pca9552_event(I2CSlave *i2c, enum i2c_event event)
>>       return 0;
>>   }
>>   
>> +static void pca9552_get_led(Object *obj, Visitor *v, const char *name,
>> +                            void *opaque, Error **errp)
>> +{
>> +    PCA9552State *s = PCA9552(obj);
>> +    int led, rc, reg;
>> +    char *str;
>> +    uint8_t state;
>> +
>> +    rc = sscanf(name, "led%2d", &led);
>> +    if (rc != 1) {
>> +        error_setg(errp, "%s: error reading %s", __func__, name);
>> +        return;
>> +    }
>> +    if (led < 0 || led > s->nr_leds) {
>> +        error_setg(errp, "%s invalid led %s", __func__, name);
>> +        return;
>> +    }
>> +    /*
>> +     * Get the LSx register as the qom interface should expose the device
>> +     * state, not the modeled 'input line' behaviour which would come from
>> +     * reading the INPUTx reg
>> +     */
>> +    reg = PCA9552_LS0 + led / 4;
>> +    state = (pca9552_read(s, reg) >> (led % 8)) & 0x3;
> 
> Could we add accessors to extract the register fields and to clarify
> the layout ?
> 
>> +    str = g_strdup(led_state[state]);
>> +    visit_type_str(v, name, &str, errp);
>> +}
>> +
>> +/*
>> + * Return an LED selector register value based on an existing one, with
>> + * the appropriate 2-bit state value set for the given LED number (0-3).
>> + */
>> +static inline uint8_t pca955x_ledsel(uint8_t oldval, int led_num, int state)
>> +{
>> +        return (oldval & (~(0x3 << (led_num << 1)))) |
>> +                ((state & 0x3) << (led_num << 1));
>> +}
>> +
>> +static void pca9552_set_led(Object *obj, Visitor *v, const char *name,
>> +                            void *opaque, Error **errp)
>> +{
>> +    PCA9552State *s = PCA9552(obj);
>> +    Error *local_err = NULL;
>> +    int led, rc, reg, val;
>> +    uint8_t state;
>> +    char *state_str;
>> +
>> +    visit_type_str(v, name, &state_str, &local_err);
>> +    if (local_err) {
>> +        error_propagate(errp, local_err);
>> +        return;
>> +    }
>> +    rc = sscanf(name, "led%2d", &led);
>> +    if (rc != 1) {
>> +        error_setg(errp, "%s: error reading %s", __func__, name);
>> +        return;
>> +    }
>> +    if (led < 0 || led > s->nr_leds) {
>> +        error_setg(errp, "%s invalid led %s", __func__, name);
>> +        return;
>> +    }
>> +
>> +    for (state = 0; state < ARRAY_SIZE(led_state); state++) {
>> +        if (!strcmp(state_str, led_state[state])) {
>> +            break;
>> +        }
>> +    }
>> +    if (state >= ARRAY_SIZE(led_state)) {
>> +        error_setg(errp, "%s invalid led state %s", __func__, state_str);
>> +        return;
>> +    }
>> +
>> +    reg = PCA9552_LS0 + led / 4;
>> +    val = pca9552_read(s, reg);
>> +    val = pca955x_ledsel(val, led % 4, state);
>> +    pca9552_write(s, reg, val);
>> +}
>> +
>>   static const VMStateDescription pca9552_vmstate = {
>>       .name = "PCA9552",
>>       .version_id = 0,
>> @@ -204,6 +286,7 @@ static void pca9552_reset(DeviceState *dev)
>>   static void pca9552_initfn(Object *obj)
>>   {
>>       PCA9552State *s = PCA9552(obj);
>> +    int led;
>>   
>>       /* If support for the other PCA955X devices are implemented, these
>>        * constant values might be part of class structure describing the
>> @@ -211,6 +294,14 @@ static void pca9552_initfn(Object *obj)
>>        */
>>       s->max_reg = PCA9552_LS3;
>>       s->nr_leds = 16;
>> +
>> +    for (led = 0; led < s->nr_leds; led++) {
>> +        char *name;
>> +
>> +        name = g_strdup_printf("led%d", led);
>> +        object_property_add(obj, name, "bool", pca9552_get_led, pca9552_set_led,
>> +                            NULL, NULL, NULL);
> 
> It misses a :
> 
>     g_free(name)
> 
> C.
> 
>> +    }
>>   }
>>   
>>   static void pca9552_class_init(ObjectClass *klass, void *data)
>>
> 
>