Re: [PATCH v14 1/5] mfd: mxs-lradc: Add support for mxs-lradc MFD
From: Stefan Wahren
Date: Wed Mar 01 2017 - 15:15:09 EST
> Ksenija Stanojevic <ksenija.stanojevic@xxxxxxxxx> hat am 1. MÃrz 2017 um 19:02 geschrieben:
>
>
> Add core files for low resolution analog-to-digital converter (mxs-lradc)
> MFD driver.
>
> Signed-off-by: Ksenija Stanojevic <ksenija.stanojevic@xxxxxxxxx>
> Acked-by: Lee Jones <lee.jones@xxxxxxxxxx>
> ---
> Changes in v14:
> - none
>
> Changes in v13:
> - none
>
> Changes in v12:
> - use BIT macro
>
> Changes in v11:
> - create static struct mfd_cells
> - don't set platform data in mfd cells, set driver data instead
> - remove mxs_lradc_reg_* functions, use writel function instead
>
> Changes in v10:
> - fetch base address from DT
> - add a NULL check for of_match_device
>
> Changes in v9:
> - improve commit message.
>
> Changes in v8:
> - rebase onto 4.9-rc1
>
> Changes in v7:
> - define macros ADC_CELL and TSC_CELL
> - remove one cell and dynamically set them in the switch()
> - fail in the touchscreen driver instead of mfd driver if
> hardware doesn't contain a touchscreen
>
> Changes in v6:
> - update copyright
> - add kernel-doc header for struct mxs-lradc
> - add error message
> - change EINVAL to ENODEV
> - use PLATFORM_DEVID_NONE instead -1
> - cosmetic fixes
>
> Changes in v5:
> - use DEFINE_RES_MEM
> - don't pass ioreammaped adress to platform cells
> - move comment outside of struct mxs_lradc
> - change type of argument in mxs_lradc_reg_set, mxs_lradc_reg_clear,
> mxs_lradc_reg_wrt (struct mxs_lradc * -> void __iomem *)
>
> Changes in v4:
> - update copyright
> - use DEFINE_RES_IRQ_NAMED
> - remove mxs_lradc_add_device function
> - use struct mfd_cell in static form
> - improve spacing
> - remove unnecessary comment
> - remove platform_get_irq
> - remove touch_ret and use ret instead
> - rename use_touchscreen to touchscreen_wire
> - use goto statements
> - remove irq[13], irq_count and irq_name from struct mxs_lradc
> - remove all defines from inside the struct definition
>
> Changes in v3:
> - add note to commit message
> - move switch statement into if(touch_ret == 0) branch
> - add MODULE_AUTHOR
>
> Changes in v2:
> - do not change spacing in Kconfig
> - make struct mfd_cell part of struct mxs_lradc
> - use switch instead of if in mxs_lradc_irq_mask
> - use only necessary header files in mxs_lradc.h
> - use devm_mfd_add_device
> - use separate function to register mfd device
> - change licence to GPL
> - add copyright
>
> drivers/mfd/Kconfig | 17 +++
> drivers/mfd/Makefile | 1 +
> drivers/mfd/mxs-lradc.c | 264 ++++++++++++++++++++++++++++++++++++++++++
> include/linux/mfd/mxs-lradc.h | 187 ++++++++++++++++++++++++++++++
> 4 files changed, 469 insertions(+)
> create mode 100644 drivers/mfd/mxs-lradc.c
> create mode 100644 include/linux/mfd/mxs-lradc.h
>
> diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
> index 55ecdfb..8bbc91b 100644
> --- a/drivers/mfd/Kconfig
> +++ b/drivers/mfd/Kconfig
> @@ -344,6 +344,23 @@ config MFD_MC13XXX_I2C
> help
> Select this if your MC13xxx is connected via an I2C bus.
>
> +config MFD_MXS_LRADC
> + tristate "Freescale i.MX23/i.MX28 LRADC"
> + depends on ARCH_MXS || COMPILE_TEST
> + select MFD_CORE
> + select STMP_DEVICE
> + help
> + Say yes here to build support for the Low Resolution
> + Analog-to-Digital Converter (LRADC) found on the i.MX23 and i.MX28
> + processors. This driver provides common support for accessing the
> + device, additional drivers must be enabled in order to use the
> + functionality of the device:
> + mxs-lradc-adc for ADC readings
> + mxs-lradc-ts for touchscreen support
> +
> + This driver can also be built as a module. If so, the module will be
> + called mxs-lradc.
> +
> config MFD_MX25_TSADC
> tristate "Freescale i.MX25 integrated Touchscreen and ADC unit"
> select REGMAP_MMIO
> diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
> index 31ce076..790698a 100644
> --- a/drivers/mfd/Makefile
> +++ b/drivers/mfd/Makefile
> @@ -215,3 +215,4 @@ obj-$(CONFIG_MFD_ALTERA_A10SR) += altera-a10sr.o
> obj-$(CONFIG_MFD_SUN4I_GPADC) += sun4i-gpadc.o
>
> obj-$(CONFIG_MFD_STM32_TIMERS) += stm32-timers.o
> +obj-$(CONFIG_MFD_MXS_LRADC) += mxs-lradc.o
> diff --git a/drivers/mfd/mxs-lradc.c b/drivers/mfd/mxs-lradc.c
> new file mode 100644
> index 0000000..2ae8487
> --- /dev/null
> +++ b/drivers/mfd/mxs-lradc.c
> @@ -0,0 +1,264 @@
> +/*
> + * Freescale MXS Low Resolution Analog-to-Digital Converter driver
> + *
> + * Copyright (c) 2012 DENX Software Engineering, GmbH.
> + * Copyright (c) 2017 Ksenija Stanojevic <ksenija.stanojevic@xxxxxxxxx>
> + *
> + * Authors:
> + * Marek Vasut <marex@xxxxxxx>
> + * Ksenija Stanojevic <ksenija.stanojevic@xxxxxxxxx>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
> + * GNU General Public License for more details.
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/device.h>
> +#include <linux/mfd/core.h>
> +#include <linux/mfd/mxs-lradc.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/of_device.h>
> +#include <linux/platform_device.h>
> +#include <linux/slab.h>
> +
> +#define ADC_CELL 0
> +#define TSC_CELL 1
> +#define RES_MEM 0
> +
> +enum mx23_lradc_irqs {
> + MX23_LRADC_TS_IRQ = 0,
> + MX23_LRADC_CH0_IRQ,
> + MX23_LRADC_CH1_IRQ,
> + MX23_LRADC_CH2_IRQ,
> + MX23_LRADC_CH3_IRQ,
> + MX23_LRADC_CH4_IRQ,
> + MX23_LRADC_CH5_IRQ,
> + MX23_LRADC_CH6_IRQ,
> + MX23_LRADC_CH7_IRQ,
> +};
> +
> +enum mx28_lradc_irqs {
> + MX28_LRADC_TS_IRQ = 0,
> + MX28_LRADC_TRESH0_IRQ,
> + MX28_LRADC_TRESH1_IRQ,
> + MX28_LRADC_CH0_IRQ,
> + MX28_LRADC_CH1_IRQ,
> + MX28_LRADC_CH2_IRQ,
> + MX28_LRADC_CH3_IRQ,
> + MX28_LRADC_CH4_IRQ,
> + MX28_LRADC_CH5_IRQ,
> + MX28_LRADC_CH6_IRQ,
> + MX28_LRADC_CH7_IRQ,
> + MX28_LRADC_BUTTON0_IRQ,
> + MX28_LRADC_BUTTON1_IRQ,
> +};
> +
> +static struct resource mx23_adc_resources[] = {
> + DEFINE_RES_MEM(0x0, 0x0),
> + DEFINE_RES_IRQ_NAMED(MX23_LRADC_CH0_IRQ, "mxs-lradc-channel0"),
> + DEFINE_RES_IRQ_NAMED(MX23_LRADC_CH1_IRQ, "mxs-lradc-channel1"),
> + DEFINE_RES_IRQ_NAMED(MX23_LRADC_CH2_IRQ, "mxs-lradc-channel2"),
> + DEFINE_RES_IRQ_NAMED(MX23_LRADC_CH3_IRQ, "mxs-lradc-channel3"),
> + DEFINE_RES_IRQ_NAMED(MX23_LRADC_CH4_IRQ, "mxs-lradc-channel4"),
> + DEFINE_RES_IRQ_NAMED(MX23_LRADC_CH5_IRQ, "mxs-lradc-channel5"),
> +};
> +
> +static struct resource mx23_touchscreen_resources[] = {
> + DEFINE_RES_MEM(0x0, 0x0),
> + DEFINE_RES_IRQ_NAMED(MX23_LRADC_TS_IRQ, "mxs-lradc-touchscreen"),
> + DEFINE_RES_IRQ_NAMED(MX23_LRADC_CH6_IRQ, "mxs-lradc-channel6"),
> + DEFINE_RES_IRQ_NAMED(MX23_LRADC_CH7_IRQ, "mxs-lradc-channel7"),
> +};
> +
> +static struct resource mx28_adc_resources[] = {
> + DEFINE_RES_MEM(0x0, 0x0),
> + DEFINE_RES_IRQ_NAMED(MX28_LRADC_TRESH0_IRQ, "mxs-lradc-thresh0"),
> + DEFINE_RES_IRQ_NAMED(MX28_LRADC_TRESH1_IRQ, "mxs-lradc-thresh1"),
> + DEFINE_RES_IRQ_NAMED(MX28_LRADC_CH0_IRQ, "mxs-lradc-channel0"),
> + DEFINE_RES_IRQ_NAMED(MX28_LRADC_CH1_IRQ, "mxs-lradc-channel1"),
> + DEFINE_RES_IRQ_NAMED(MX28_LRADC_CH2_IRQ, "mxs-lradc-channel2"),
> + DEFINE_RES_IRQ_NAMED(MX28_LRADC_CH3_IRQ, "mxs-lradc-channel3"),
> + DEFINE_RES_IRQ_NAMED(MX28_LRADC_CH4_IRQ, "mxs-lradc-channel4"),
> + DEFINE_RES_IRQ_NAMED(MX28_LRADC_CH5_IRQ, "mxs-lradc-channel5"),
> + DEFINE_RES_IRQ_NAMED(MX28_LRADC_BUTTON0_IRQ, "mxs-lradc-button0"),
> + DEFINE_RES_IRQ_NAMED(MX28_LRADC_BUTTON1_IRQ, "mxs-lradc-button1"),
> +};
> +
> +static struct resource mx28_touchscreen_resources[] = {
> + DEFINE_RES_MEM(0x0, 0x0),
> + DEFINE_RES_IRQ_NAMED(MX28_LRADC_TS_IRQ, "mxs-lradc-touchscreen"),
> + DEFINE_RES_IRQ_NAMED(MX28_LRADC_CH6_IRQ, "mxs-lradc-channel6"),
> + DEFINE_RES_IRQ_NAMED(MX28_LRADC_CH7_IRQ, "mxs-lradc-channel7"),
> +};
> +
> +static struct mfd_cell mx23_cells[] = {
> + {
> + .name = "mxs-lradc-adc",
> + .resources = mx23_adc_resources,
> + .num_resources = ARRAY_SIZE(mx23_adc_resources),
> + },
> + {
> + .name = "mxs-lradc-ts",
> + .resources = mx23_touchscreen_resources,
> + .num_resources = ARRAY_SIZE(mx23_touchscreen_resources),
> + },
> +};
> +
> +static struct mfd_cell mx28_cells[] = {
> + {
> + .name = "mxs-lradc-adc",
> + .resources = mx28_adc_resources,
> + .num_resources = ARRAY_SIZE(mx28_adc_resources),
> + },
> + {
> + .name = "mxs-lradc-ts",
> + .resources = mx28_touchscreen_resources,
> + .num_resources = ARRAY_SIZE(mx28_touchscreen_resources),
> + }
> +};
> +
> +static const struct of_device_id mxs_lradc_dt_ids[] = {
> + { .compatible = "fsl,imx23-lradc", .data = (void *)IMX23_LRADC, },
> + { .compatible = "fsl,imx28-lradc", .data = (void *)IMX28_LRADC, },
> + { /* sentinel */ }
> +};
> +MODULE_DEVICE_TABLE(of, mxs_lradc_dt_ids);
> +
> +static int mxs_lradc_probe(struct platform_device *pdev)
> +{
> + const struct of_device_id *of_id;
> + struct device *dev = &pdev->dev;
> + struct device_node *node = dev->of_node;
> + struct mxs_lradc *lradc;
> + struct mfd_cell *cells = NULL;
> + struct resource *res;
> + int ret = 0;
> + u32 ts_wires = 0;
> +
> + lradc = devm_kzalloc(&pdev->dev, sizeof(*lradc), GFP_KERNEL);
> + if (!lradc)
> + return -ENOMEM;
> +
> + of_id = of_match_device(mxs_lradc_dt_ids, &pdev->dev);
> + if (!of_id)
> + return -EINVAL;
> +
> + lradc->soc = (enum mxs_lradc_id)of_id->data;
> +
> + lradc->clk = devm_clk_get(&pdev->dev, NULL);
> + if (IS_ERR(lradc->clk)) {
> + dev_err(dev, "Failed to get the delay unit clock\n");
> + return PTR_ERR(lradc->clk);
> + }
> +
> + ret = clk_prepare_enable(lradc->clk);
> + if (ret) {
> + dev_err(dev, "Failed to enable the delay unit clock\n");
> + return ret;
> + }
> +
> + ret = of_property_read_u32(node, "fsl,lradc-touchscreen-wires",
> + &ts_wires);
> +
> + if (!ret) {
> + lradc->buffer_vchans = BUFFER_VCHANS_LIMITED;
> +
> + switch (ts_wires) {
> + case 4:
> + lradc->touchscreen_wire = MXS_LRADC_TOUCHSCREEN_4WIRE;
> + break;
> + case 5:
> + if (lradc->soc == IMX28_LRADC) {
> + lradc->touchscreen_wire =
> + MXS_LRADC_TOUCHSCREEN_5WIRE;
> + break;
> + }
> + /* fall through to an error message for i.MX23 */
> + default:
> + dev_err(&pdev->dev,
> + "Unsupported number of touchscreen wires (%d)\n"
> + , ts_wires);
> + ret = -EINVAL;
> + goto err_clk;
> + }
> + } else {
> + lradc->buffer_vchans = BUFFER_VCHANS_ALL;
> + }
> +
> + platform_set_drvdata(pdev, lradc);
> +
> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + if (!res)
> + return -ENOMEM;
> +
> + switch (lradc->soc) {
> + case IMX23_LRADC:
> + mx23_adc_resources[RES_MEM] = *res;
> + mx23_touchscreen_resources[RES_MEM] = *res;
> + cells = mx23_cells;
> + break;
> + case IMX28_LRADC:
> + mx28_adc_resources[RES_MEM] = *res;
> + mx28_touchscreen_resources[RES_MEM] = *res;
> + cells = mx28_cells;
> + break;
> + default:
> + dev_err(dev, "Unsupported SoC\n");
> + ret = -ENODEV;
> + goto err_clk;
> + }
> +
> + ret = devm_mfd_add_devices(&pdev->dev, PLATFORM_DEVID_NONE,
> + &cells[ADC_CELL], 1, NULL, 0, NULL);
> + if (ret) {
> + dev_err(&pdev->dev, "Failed to add the ADC subdevice\n");
> + goto err_clk;
> + }
> +
> + ret = devm_mfd_add_devices(&pdev->dev, PLATFORM_DEVID_NONE,
> + &cells[TSC_CELL], 1, NULL, 0, NULL);
> + if (ret) {
> + dev_err(&pdev->dev,
> + "Failed to add the touchscreen subdevice\n");
> + goto err_clk;
> + }
Since touchscreen is optional it doesn't make to try to register it, notice in the touchscreen driver there is no touchscreen, give the user a confusing error and finally disable the clock.
Here are my suggestions:
1) Use the solution from Patch V6 but with an explaining comment that touchscreen is optional
if (!lradc->touchscreen_wire)
return 0;
2) Return a special error from touchscreen registration so mfd knowns this result is expected.
I'm open for better solutions.
@Lee: What's your opinion?