From mboxrd@z Thu Jan 1 00:00:00 1970 From: Javier Martinez Canillas Subject: Re: [PATCH v6 08/23] mfd: max77686: Add Dynamic Voltage Scaling (DVS) support Date: Fri, 04 Jul 2014 13:32:57 +0200 Message-ID: <53B690E9.4000003@collabora.co.uk> References: <1404467722-26687-1-git-send-email-javier.martinez@collabora.co.uk> <1404467722-26687-9-git-send-email-javier.martinez@collabora.co.uk> <1404472510.14069.6.camel@AMDC1943> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <1404472510.14069.6.camel@AMDC1943> Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Krzysztof Kozlowski Cc: Lee Jones , Mark Brown , Mike Turquette , Liam Girdwood , Alessandro Zummo , Kukjin Kim , Doug Anderson , Olof Johansson , Tomeu Vizoso , Yadwinder Singh Brar , Tushar Behera , Andreas Farber , linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-samsung-soc-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-samsung-soc@vger.kernel.org Hello Krzysztof, Again, thanks a lot for taking the time to review the series. On 07/04/2014 01:15 PM, Krzysztof Kozlowski wrote: > On pi=C4=85, 2014-07-04 at 11:55 +0200, Javier Martinez Canillas wrot= e: >> Some regulators on the MAX77686 PMIC have Dynamic Voltage Scaling >> (DVS) support that allows output voltage to change dynamically. >>=20 >> For MAX77686, these regulators are Buck regulators 2, 3 and 4. >>=20 >> Each Buck output voltage is selected using a set of external >> inputs: DVS1-3 and SELB2-4. >>=20 >> DVS registers can be used to configure the output voltages for each >> Buck regulator and which one is active is controled by DVSx lines. >>=20 >> SELBx lines are used to control if individual Buck lines are ON or O= =46F. >>=20 >> This patch adds support to configure the DVSx and SELBx lines >> from DT and to setup and read the GPIO lines connected to them. >>=20 >> Signed-off-by: Javier Martinez Canillas >> --- >> drivers/mfd/max77686.c | 115 ++++++++++++++++++++++++++++++++= +++++++++++ >> include/linux/mfd/max77686.h | 18 ++++--- >> 2 files changed, 125 insertions(+), 8 deletions(-) >=20 > One minor comment below, but overall looks good to me: > Reviewed-by: Krzysztof Kozlowski >=20 >=20 >> diff --git a/drivers/mfd/max77686.c b/drivers/mfd/max77686.c >> index 8650832..648d564 100644 >> --- a/drivers/mfd/max77686.c >> +++ b/drivers/mfd/max77686.c >> @@ -32,8 +32,10 @@ >> #include >> #include >> #include >> +#include >> #include >> #include >> +#include >> =20 >> #define I2C_ADDR_RTC (0x0C >> 1) >> =20 >> @@ -101,9 +103,115 @@ static const struct of_device_id max77686_pmic= _dt_match[] =3D { >> {}, >> }; >> =20 >> +static void max77686_dt_parse_dvs_gpio(struct device *dev) >> +{ >> + struct max77686_platform_data *pd =3D dev_get_platdata(dev); >> + int i; >> + >> + /* >> + * NOTE: we don't consider GPIO errors fatal; board may have some = lines >> + * directly pulled high or low and thus doesn't specify them. >> + */ >> + for (i =3D 0; i < ARRAY_SIZE(pd->buck_gpio_dvs); i++) >> + pd->buck_gpio_dvs[i] =3D >> + devm_gpiod_get_index(dev, "max77686,pmic-buck-dvs", i); >> + >> + for (i =3D 0; i < ARRAY_SIZE(pd->buck_gpio_selb); i++) >> + pd->buck_gpio_selb[i] =3D >> + devm_gpiod_get_index(dev, "max77686,pmic-buck-selb", i); >> +} >> + >> +/** >> + * max77686_setup_gpios - init DVS-related GPIOs >> + * >> + * This function claims / initalizations GPIOs related to DVS if th= ey are >> + * defined. This may have the effect of switching voltages if the >> + * pdata->buck_default_idx does not match the boot time state of pi= ns. >> + */ >> +int max77686_setup_gpios(struct device *dev) >> +{ >> + struct max77686_platform_data *pd =3D dev_get_platdata(dev); >> + int buck_default_idx =3D pd->buck_default_idx; >> + int ret; >> + int i; >> + >> + /* Set all SELB high to avoid glitching while DVS is changing */ >> + for (i =3D 0; i < ARRAY_SIZE(pd->buck_gpio_selb); i++) { >> + struct gpio_desc *gpio =3D pd->buck_gpio_selb[i]; >> + >> + /* OK if some GPIOs aren't defined */ >> + if (IS_ERR(gpio)) >> + continue; >> + >> + ret =3D gpiod_direction_output_raw(gpio, 1); >> + if (ret) { >> + dev_err(dev, "can't set gpio[%d] dir: %d\n", i, ret); >> + return ret; >> + } >> + } >> + >> + /* Set our initial setting */ >> + for (i =3D 0; i < ARRAY_SIZE(pd->buck_gpio_dvs); i++) { >> + struct gpio_desc *gpio =3D pd->buck_gpio_dvs[i]; >> + >> + /* OK if some GPIOs aren't defined */ >> + if (IS_ERR(gpio)) >> + continue; >> + >> + /* If a GPIO is valid, set it */ >> + gpiod_direction_output(gpio, (buck_default_idx >> i) & 1); >> + if (ret) { >> + dev_err(dev, "can't set gpio[%d]: dir %d\n", i, ret); >> + return ret; >> + } >> + } >> + >> + /* Now set SELB low to take effect */ >> + for (i =3D 0; i < ARRAY_SIZE(pd->buck_gpio_selb); i++) { >> + struct gpio_desc *gpio =3D pd->buck_gpio_selb[i]; >> + >> + if (!IS_ERR(gpio)) >> + gpiod_set_value(gpio, 0); >> + } >> + >> + return 0; >> +} >> +EXPORT_SYMBOL_GPL(max77686_setup_gpios); >> + >> +/** >> + * max77686_read_gpios - read the current state of the dvs GPIOs >> + * >> + * We call this function at bootup to detect what slot the firmware= was >> + * using for the DVS GPIOs. That way we can properly preserve the = firmware's >> + * voltage settings >> + */ >> +int max77686_read_gpios(struct max77686_platform_data *pdata) >> +{ >=20 > Can you document that this function can sleep? It is quite obvious bu= t > the function is exported so maybe it is worth noting. >=20 Sure, I'll add that to the comment. > Best regards, > Krzysztof >=20 Best regards, Javier -- To unsubscribe from this list: send the line "unsubscribe devicetree" i= n the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html