Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758125AbaGDLdM (ORCPT ); Fri, 4 Jul 2014 07:33:12 -0400 Received: from bhuna.collabora.co.uk ([93.93.135.160]:38281 "EHLO bhuna.collabora.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751989AbaGDLdK (ORCPT ); Fri, 4 Jul 2014 07:33:10 -0400 Message-ID: <53B690E9.4000003@collabora.co.uk> Date: Fri, 04 Jul 2014 13:32:57 +0200 From: Javier Martinez Canillas User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Icedove/24.5.0 MIME-Version: 1.0 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@lists.infradead.org, devicetree@vger.kernel.org, linux-samsung-soc@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v6 08/23] mfd: max77686: Add Dynamic Voltage Scaling (DVS) support 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> In-Reply-To: <1404472510.14069.6.camel@AMDC1943> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@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 pią, 2014-07-04 at 11:55 +0200, Javier Martinez Canillas wrote: >> Some regulators on the MAX77686 PMIC have Dynamic Voltage Scaling >> (DVS) support that allows output voltage to change dynamically. >> >> For MAX77686, these regulators are Buck regulators 2, 3 and 4. >> >> Each Buck output voltage is selected using a set of external >> inputs: DVS1-3 and SELB2-4. >> >> DVS registers can be used to configure the output voltages for each >> Buck regulator and which one is active is controled by DVSx lines. >> >> SELBx lines are used to control if individual Buck lines are ON or OFF. >> >> This patch adds support to configure the DVSx and SELBx lines >> from DT and to setup and read the GPIO lines connected to them. >> >> Signed-off-by: Javier Martinez Canillas >> --- >> drivers/mfd/max77686.c | 115 +++++++++++++++++++++++++++++++++++++++++++ >> include/linux/mfd/max77686.h | 18 ++++--- >> 2 files changed, 125 insertions(+), 8 deletions(-) > > One minor comment below, but overall looks good to me: > Reviewed-by: Krzysztof Kozlowski > > >> 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 >> >> #define I2C_ADDR_RTC (0x0C >> 1) >> >> @@ -101,9 +103,115 @@ static const struct of_device_id max77686_pmic_dt_match[] = { >> {}, >> }; >> >> +static void max77686_dt_parse_dvs_gpio(struct device *dev) >> +{ >> + struct max77686_platform_data *pd = 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 = 0; i < ARRAY_SIZE(pd->buck_gpio_dvs); i++) >> + pd->buck_gpio_dvs[i] = >> + devm_gpiod_get_index(dev, "max77686,pmic-buck-dvs", i); >> + >> + for (i = 0; i < ARRAY_SIZE(pd->buck_gpio_selb); i++) >> + pd->buck_gpio_selb[i] = >> + 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 they are >> + * defined. This may have the effect of switching voltages if the >> + * pdata->buck_default_idx does not match the boot time state of pins. >> + */ >> +int max77686_setup_gpios(struct device *dev) >> +{ >> + struct max77686_platform_data *pd = dev_get_platdata(dev); >> + int buck_default_idx = pd->buck_default_idx; >> + int ret; >> + int i; >> + >> + /* Set all SELB high to avoid glitching while DVS is changing */ >> + for (i = 0; i < ARRAY_SIZE(pd->buck_gpio_selb); i++) { >> + struct gpio_desc *gpio = pd->buck_gpio_selb[i]; >> + >> + /* OK if some GPIOs aren't defined */ >> + if (IS_ERR(gpio)) >> + continue; >> + >> + ret = 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 = 0; i < ARRAY_SIZE(pd->buck_gpio_dvs); i++) { >> + struct gpio_desc *gpio = 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 = 0; i < ARRAY_SIZE(pd->buck_gpio_selb); i++) { >> + struct gpio_desc *gpio = 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) >> +{ > > Can you document that this function can sleep? It is quite obvious but > the function is exported so maybe it is worth noting. > Sure, I'll add that to the comment. > Best regards, > Krzysztof > Best regards, Javier -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/