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s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=9I+jvIuGkrYC7w12Jy77CUvwauedMrIdRwXtD/swi0U=; b=rmI5l+HNJsRUcorIvhSFLiM1PhCGGf0ASH7TxN5/Q63Dlr3jilJWkswUVRKMq2LNtK J2D7ngSKjfjWSJWPeprLPeJ2ZOTg5zuQ7F/naHs5nKmIXGB5UXn6ojNsFHsQe5RLF3j3 gkwGQ6bBd7dCACid2ktyZP5lmYRGg9aUU/N8URIWxthX0qLJzba605gP3fqYVlNNEKlm 3Ajpczg7SriaF9OcI3VIlRQhmfFTEsIF0UV1ZoE4ZpDTHknJXONK2eUNOUtTijp+WSZd j+5sjoxcBug4XcUt6iudb8+zpm45nrtgK8XEi+dReD1unxHVOVTeSMF1ToO7eFKlgI16 Pcxw== X-Gm-Message-State: AOAM533bEfysa7pSUiLGI0vtKj86D7PjkQJLw5Kyz/bg+MWOH0IdsUhg xuhPptrWzhaz6L2fuyUl9fmHEFsw/aZQnt9GAaC08w== X-Google-Smtp-Source: ABdhPJykJY1zWrWHmNv1qhh0XGc9mZHysTgRPPx0BaMujb9Mx9dYhMjPxl8GGwLIWVx58MUoIp0bAc7SpECJwSg9rjk= X-Received: by 2002:aa7:c894:: with SMTP id p20mr34410895eds.42.1629680715488; Sun, 22 Aug 2021 18:05:15 -0700 (PDT) MIME-Version: 1.0 References: <20210304034141.7062-1-brad@pensando.io> <20210304034141.7062-2-brad@pensando.io> In-Reply-To: From: Brad Larson Date: Sun, 22 Aug 2021 18:05:04 -0700 Message-ID: Subject: Re: [PATCH 1/8] gpio: Add Elba SoC gpio driver for spi cs control To: Linus Walleij Cc: Linux ARM , Arnd Bergmann , Bartosz Golaszewski , Mark Brown , Serge Semin , Adrian Hunter , Ulf Hansson , Olof Johansson , "open list:GPIO SUBSYSTEM" , linux-spi , linux-mmc , "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" , "linux-kernel@vger.kernel.org" X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210822_180517_325244_16AD530A X-CRM114-Status: GOOD ( 23.00 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi Linus, On Thu, Mar 4, 2021 at 12:29 AM Linus Walleij wrote: > On Thu, Mar 4, 2021 at 4:42 AM Brad Larson wrote: > > > This GPIO driver is for the Pensando Elba SoC which > > provides control of four chip selects on two SPI busses. [...] > > +#include > > Use this in new drivers: > #include The updated patchset will use linux/gpio/driver.h > > + * pin: 3 2 | 1 0 > > + * bit: 7------6------5------4----|---3------2------1------0 > > + * cs1 cs1_ovr cs0 cs0_ovr | cs1 cs1_ovr cs0 cs0_ovr > > + * ssi1 | ssi0 > > + */ > > +#define SPICS_PIN_SHIFT(pin) (2 * (pin)) > > +#define SPICS_MASK(pin) (0x3 << SPICS_PIN_SHIFT(pin)) > > +#define SPICS_SET(pin, val) ((((val) << 1) | 0x1) << SPICS_PIN_SHIFT(pin)) > > So 2 bits per GPIO line in one register? (Nice doc!) > > > +struct elba_spics_priv { > > + void __iomem *base; > > + spinlock_t lock; > > + struct gpio_chip chip; > > +}; > > + > > +static int elba_spics_get_value(struct gpio_chip *chip, unsigned int pin) > > +{ > > + return -ENXIO; > > +} > > Write a comment that the chip only supports output mode, > because it repurposes SPI CS pins as generic GPIO out, > maybe at the top of the file? The top of the file will look like this in the updated patchset. * Pensando Elba ASIC SPI chip select driver. The SoC supports output * direction only as it uses a generic GPIO pin for SPI CS. > I suppose these systems also actually (ab)use the SPI cs > for things that are not really SPI CS? Because otherwise > this could just be part of the SPI driver (native chip select). The SPI cs are not used for any other purpose, we needed four chip selects and native DW supports two. > > +static const struct of_device_id ebla_spics_of_match[] = { > > + { .compatible = "pensando,elba-spics" }, > > Have you documented this? Yes as part of patchset v2: [PATCH v2 11/13] dt-bindings: gpio: Add Pensando Elba SoC support which documents "pensando,elba-spics" in new file bindings/gpio/pensando,elba-spics.yaml. Regards, Brad _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel