From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6B6607E9; Thu, 4 Jul 2024 13:06:29 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720098389; cv=none; b=Zn0n3fzRrf44BvIh1fgG4/VcFMx+j1RFG/HutXe9kWCL2T5Z4F5/QBZwnQKZkBluIvDwpjVveqh3GVmP54+dpWdpAaaOIrKarJQ+XL0798cyOblMCTggrfc4qQN8TyzrhZatSJsn44f+URk5HlQmRvuFghnDj3Ay5aaoGPCCVcw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720098389; c=relaxed/simple; bh=fr9VTxP3EMKYu6iAweQ5TeL5jGzD+I3zD4zVkfgV38c=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=JXYH+nvx4AnyrG+5VyGLcWf6D+FsTaXaiMiuvswztvKdhUh5ZrSdNVeFP3u83egioD1EwC/+VQT+CYOWwZuY3sKRNdoPb/4DuZbM3Y7jhkZQCYV4e2+lTOI4IdtkE9u2JQ4WIBW8n0IvJHOsyuQgN6Ddjzq2vjeF+kQlS5Xrlwc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=2fy9YDEE; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="2fy9YDEE" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6943DC3277B; Thu, 4 Jul 2024 13:06:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1720098389; bh=fr9VTxP3EMKYu6iAweQ5TeL5jGzD+I3zD4zVkfgV38c=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=2fy9YDEEsW9nE2YfxGCxk+dtvffq5AyxiFcmz6J/4XAJwDWRUl1pr2vGKCAZNQ9xg sgNY3p9bv/VKTZ0oLxLsyKh1I3N0saBb1RiAQPvRuTYjksw/b4QYUpXxHRHcKvnTPQ mU8AtmT7iEj6tUhDgIi0FwE6QXiwMLl4AeMiRtQo= Date: Thu, 4 Jul 2024 15:06:26 +0200 From: Greg Kroah-Hartman To: Ayush Singh Cc: Mark Brown , Vaishnav M A , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Derek Kiernan , Dragan Cvetic , Arnd Bergmann , Nishanth Menon , Vignesh Raghavendra , Tero Kristo , Michael Walle , Andrew Lunn , jkridner@beagleboard.org, robertcnelson@beagleboard.org, linux-spi@vger.kernel.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH v5 6/7] mikrobus: Add mikroBUS driver Message-ID: <2024070400-grievance-unmolded-fa66@gregkh> References: <20240627-mikrobus-scratch-spi-v5-0-9e6c148bf5f0@beagleboard.org> <20240627-mikrobus-scratch-spi-v5-6-9e6c148bf5f0@beagleboard.org> Precedence: bulk X-Mailing-List: linux-spi@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240627-mikrobus-scratch-spi-v5-6-9e6c148bf5f0@beagleboard.org> On Thu, Jun 27, 2024 at 09:56:16PM +0530, Ayush Singh wrote: > Adds support for SPI mikroBUS addon boards with configuration based on > device tree. The goal is to get a minimal version in mainline to sort > out the device tree structure that should be used. > > A mikroBUS board can use any combination of the following based protocols: > I2C, SPI, UART, PWM, Analog, GPIO with possibility of all pins being used > as GPIO instead of their original purpose. This requires the driver to be > flexible and identify the type of board based on the compatible string. So this has nothing to do with greybus? Or am I thinking of something else? > +menuconfig MIKROBUS > + tristate "Module for instantiating devices on mikroBUS ports" > + depends on GPIOLIB > + help > + This option enables the mikroBUS driver. mikroBUS is an add-on > + board socket standard that offers maximum expandability with > + the smallest number of pins. The mikroBUS driver instantiates > + devices on a mikroBUS port described mikroBUS manifest which is > + passed using a sysfs interface. > + > + Remove extra blank line. > + Say Y here to enable support for this driver. This isn't needed. > + > + To compile this code as a module, chose M here: the module > + will be called mikrobus.ko > + > source "drivers/misc/c2port/Kconfig" > source "drivers/misc/eeprom/Kconfig" > source "drivers/misc/cb710/Kconfig" > diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile > index 153a3f4837e8..f10f1414270b 100644 > --- a/drivers/misc/Makefile > +++ b/drivers/misc/Makefile > @@ -69,3 +69,4 @@ obj-$(CONFIG_TMR_INJECT) += xilinx_tmr_inject.o > obj-$(CONFIG_TPS6594_ESM) += tps6594-esm.o > obj-$(CONFIG_TPS6594_PFSM) += tps6594-pfsm.o > obj-$(CONFIG_NSM) += nsm.o > +obj-$(CONFIG_MIKROBUS) += mikrobus.o > diff --git a/drivers/misc/mikrobus.c b/drivers/misc/mikrobus.c > new file mode 100644 > index 000000000000..bf160a0e8903 > --- /dev/null > +++ b/drivers/misc/mikrobus.c > @@ -0,0 +1,361 @@ > +// SPDX-License-Identifier: GPL-2.0: > +/* > + * Copyright 2024 Ayush Singh > + */ > + > +#define pr_fmt(fmt) "mikrobus:%s: " fmt, __func__ KBUILD_MODNAME? Also, why is this needed at all, as you are a bus/subsystem you should never need a pr_*() call, but instead just use dev_*() ones instead. > + > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > + > +struct mikrobus_spi_cs_item { > + const char *cs_name; > + u32 cs; Documentation? What is "cs"? More vowels please... > +}; > + > +/** > + * struct mikrobus_port - MikroBUS Driver > + * > + * @dev: underlying platform_device Why must this be a platform device? What requires that? > + * @board_ocs: board device tree changeset > + * @pinctrl: mikroBUS pinctrl > + * @mikrobus_spi_cs: list of supported chipselect address and name > + * @mikrobus_spi_cs_count: length of mikrobus_spi_cs > + * @spi_ctrl: spi controller of mikroBUS connector > + * @spi_dev: spi mikroBUS board > + */ > +struct mikrobus_port { > + struct platform_device *dev; > + struct of_changeset board_ocs; > + struct pinctrl *pctrl; > + > + struct mikrobus_spi_cs_item *spi_cs; > + int spi_cs_count; > + struct spi_controller *spi_ctrl; > + struct spi_device *spi_dev; What controls the lifespan of this object? You have multiple devices pointed to here with different lifecycles, what controls this one? > +}; > + > +/* > + * mikrobus_pinctrl_select: Select pinctrl state for mikrobus pin Either use kerneldoc or not, should be /** right? > + * > + * @port: mikrobus port > + * @pinctrl_selected: pinctrl state to be selected > + */ > +static int mikrobus_pinctrl_select(struct device *dev, > + const char *pinctrl_selected) > +{ > + int ret; > + struct pinctrl_state *state; > + struct mikrobus_port *mb = dev_get_drvdata(dev); > + > + state = pinctrl_lookup_state(mb->pctrl, pinctrl_selected); > + if (IS_ERR(state)) > + return dev_err_probe(dev, PTR_ERR(state), > + "failed to find state %s", > + pinctrl_selected); > + > + ret = pinctrl_select_state(mb->pctrl, state); > + if (ret) > + return dev_err_probe(dev, ret, "failed to select state %s", > + pinctrl_selected); > + > + dev_dbg_ratelimited(dev, "setting pinctrl %s", pinctrl_selected); Why rate limited? What is going to cause this to spam the log? > + > + return 0; > +} > + > +/* > + * mikrobus_lookup_cs - lookup mikroBUS SPI chipselect by name > + * > + * @mb: mikroBUS port > + * @cs_name: chipselect name Use "chipselect" instead of "cs" everywhere please. > + */ > +static int mikrobus_lookup_cs(const struct mikrobus_port *mb, > + const char *cs_name) > +{ > + for (int i = 0; i < mb->spi_cs_count; ++i) { > + if (strcmp(cs_name, mb->spi_cs[i].cs_name) == 0) > + return mb->spi_cs[i].cs; > + } > + > + return -1; what does -1 mean? Use real error numbers please. > +} > + > +static int mikrobus_spi_set_cs(struct device *dev, struct device_node *np) > +{ > + struct mikrobus_port *mb = dev_get_drvdata(dev); > + const char *temp_str; > + int reg_len; > + int ret, i; > + u32 *reg = NULL; > + > + reg_len = of_property_count_strings(np, "spi-cs"); > + /* Use default cs if spi-cs property not present */ > + if (reg_len <= 0) { > + reg_len = 1; > + reg = devm_kmalloc_array(dev, reg_len, sizeof(*reg), > + GFP_KERNEL); > + if (!reg) > + return -ENOMEM; > + > + ret = mikrobus_lookup_cs(mb, "default"); > + if (ret < 0) > + goto free_reg; > + > + reg[0] = ret; > + } else { > + reg = devm_kmalloc_array(dev, reg_len, sizeof(*reg), > + GFP_KERNEL); > + if (!reg) > + return -ENOMEM; > + > + for (i = 0; i < reg_len; ++i) { > + ret = of_property_read_string_index(np, "spi-cs", i, > + &temp_str); > + if (ret < 0) > + goto free_reg; > + > + ret = mikrobus_lookup_cs(mb, temp_str); > + if (ret < 0) > + goto free_reg; > + > + reg[i] = ret; > + } > + } > + > + ret = of_changeset_add_prop_u32_array(&mb->board_ocs, np, "reg", reg, > + reg_len); > + if (ret < 0) > + goto free_reg; > + > + ret = of_changeset_apply(&mb->board_ocs); > + if (ret < 0) > + goto free_reg; > + > + devm_kfree(dev, reg); > + return 0; > + > +free_reg: > + devm_kfree(dev, reg); > + return ret; > +} > + > +static int of_register_mikrobus_device(struct mikrobus_port *mb, > + struct device_node *np) > +{ > + const char *temp_str; > + int i, pinctrl_count, ret; > + struct spi_device *spi_dev; > + struct device *dev = &mb->dev->dev; That's some pointer dereferencing without checking anything, what could go wrong... Why don't you have your own real device? Why are you relying on a platform device without actually showing your device anywhere in the kernel's device topology? Are you sure that is ok? > + > + pinctrl_count = of_property_count_strings(np, "pinctrl-apply"); > + if (pinctrl_count < 0) > + return dev_err_probe(dev, pinctrl_count, > + "Missing required property pinctrl-apply"); > + > + for (i = 0; i < pinctrl_count; ++i) { > + ret = of_property_read_string_index(np, "pinctrl-apply", i, > + &temp_str); > + if (ret < 0) > + return ret; > + > + ret = mikrobus_pinctrl_select(dev, temp_str); > + if (ret < 0) > + return dev_err_probe(dev, ret, "Failed to set pinctrl"); > + } > + > + if (mb->spi_ctrl && !mb->spi_dev && > + of_device_is_compatible(np, "mikrobus-spi")) { > + ret = mikrobus_spi_set_cs(dev, np); > + if (ret < 0) > + return dev_err_probe(dev, ret, > + "Failed to set SPI chipselect"); > + > + spi_dev = of_register_spi_device(mb->spi_ctrl, np); > + if (IS_ERR(spi_dev)) > + return dev_err_probe(dev, PTR_ERR(spi_dev), > + "Failed to register SPI device"); > + mb->spi_dev = spi_dev; > + } > + > + return 0; > +} > + > +static int of_register_mikrobus_board(struct mikrobus_port *mb) > +{ > + struct device *dev = &mb->dev->dev; > + int board_len, i, ret; > + struct device_node *np; > + > + board_len = of_count_phandle_with_args(dev->of_node, "board", NULL); > + for (i = 0; i < board_len; ++i) { > + np = of_parse_phandle(dev->of_node, "board", i); > + if (!np) { > + ret = dev_err_probe(dev, -ENODEV, "Board not found"); > + goto free_np; > + } > + > + ret = of_register_mikrobus_device(mb, np); > + if (ret < 0) > + goto free_np; > + > + of_node_put(np); > + } > + > + return 0; > +free_np: > + of_node_put(np); > + return ret; > +} > + > +static int mikrobus_port_probe(struct platform_device *pdev) > +{ > + int ret, i; > + struct mikrobus_port *mb; > + struct device_node *np; > + struct device *dev = &pdev->dev; > + > + mb = devm_kmalloc(dev, sizeof(*mb), GFP_KERNEL); > + if (!mb) > + return -ENOMEM; > + > + dev_set_drvdata(dev, mb); > + > + of_changeset_init(&mb->board_ocs); > + mb->dev = pdev; > + mb->pctrl = NULL; > + mb->spi_ctrl = NULL; > + mb->spi_dev = NULL; > + mb->spi_cs = NULL; > + mb->spi_cs_count = 0; > + > + mb->pctrl = devm_pinctrl_get(dev); > + if (IS_ERR(mb->pctrl)) > + return dev_err_probe(dev, PTR_ERR(mb->pctrl), > + "failed to get pinctrl [%ld]", > + PTR_ERR(mb->pctrl)); > + > + np = of_parse_phandle(dev->of_node, "spi-controller", 0); > + if (np) { > + mb->spi_ctrl = of_find_spi_controller_by_node(np); > + if (mb->spi_ctrl) { > + ret = of_property_count_u32_elems(dev->of_node, > + "spi-cs"); > + if (ret < 0) { > + dev_err(dev, "Missing property spi-cs"); > + goto free_np; > + } > + > + mb->spi_cs_count = ret; > + > + ret = of_property_count_strings(dev->of_node, > + "spi-cs-names"); > + if (ret < 0) { > + dev_err(dev, "Missing property spi-cs-names"); > + goto free_np; > + } > + > + if (mb->spi_cs_count != ret) { > + ret = dev_err_probe( > + dev, -EINVAL, > + "spi-cs and spi-cs-names out of sync"); > + goto free_np; > + } > + > + mb->spi_cs = devm_kmalloc_array(dev, mb->spi_cs_count, > + sizeof(*mb->spi_cs), > + GFP_KERNEL); > + if (!mb->spi_cs) { > + ret = -ENOMEM; > + goto free_np; > + } > + > + for (i = 0; i < mb->spi_cs_count; ++i) { > + of_property_read_u32_index(dev->of_node, > + "spi-cs", i, > + &mb->spi_cs->cs); > + of_property_read_string_index( > + dev->of_node, "spi-cs-names", i, > + &mb->spi_cs->cs_name); > + } > + } > + } > + of_node_put(np); > + > + ret = of_register_mikrobus_board(mb); > + if (ret < 0) > + return dev_err_probe(dev, -EINVAL, > + "Failed to register mikrobus board"); > + > + return 0; > + > +free_np: > + of_node_put(np); > + return ret; > +} > + > +static void mikrobus_port_remove(struct platform_device *pdev) > +{ > + struct mikrobus_port *mb = dev_get_drvdata(&pdev->dev); > + > + spi_unregister_device(mb->spi_dev); > + > + of_changeset_revert(&mb->board_ocs); > +} > + > +static const struct of_device_id mikrobus_port_of_match[] = { > + { .compatible = "mikrobus-connector" }, > + {}, > +}; > +MODULE_DEVICE_TABLE(of, mikrobus_port_of_match); > + > +static struct platform_driver mikrobus_port_driver = { > + .probe = mikrobus_port_probe, > + .remove = mikrobus_port_remove, Again, why is this a platform driver? Why is a platform device used at all here? > + .driver = { > + .name = "mikrobus", > + .of_match_table = mikrobus_port_of_match, > + }, > +}; > + > +static const struct bus_type mikrobus_bus_type = { > + .name = "mikrobus", > +}; > + > +static int mikrobus_init(void) > +{ > + int ret; > + > + ret = bus_register(&mikrobus_bus_type); > + if (ret) { > + pr_err("bus_register failed (%d)", ret); > + return ret; > + } > + > + ret = platform_driver_register(&mikrobus_port_driver); > + if (ret) > + pr_err("driver register failed [%d]", ret); It fails yet you leave your bus around? Not good :( thanks, greg k-h