On Tue, 2025-04-29 at 20:51 +0100, Srinivas Kandagatla wrote:
> On Tue, Apr 29, 2025 at 09:21:42AM +0100, André Draszik wrote:
> > The Maxim MAX77759 is a companion PMIC for USB Type-C applications and
> > includes Battery Charger, Fuel Gauge, temperature sensors, USB Type-C
> > Port Controller (TCPC), NVMEM, and a GPIO expander.
> >
> > This driver exposes the non volatile memory using the platform device
> > registered by the core MFD driver.
> >
> > Signed-off-by: André Draszik <andre.dras...@linaro.org>
> > ---
> > v8:
> > * replace MODULE_ALIAS() with .id_table (Krzysztof)
> > * drop previous tags
> >
> > v5:
> > * follow API updates of max77759 core driver
> >
> > v2:
> > * align sentinel in max77759_nvmem_of_id[] with other max77759 drivers
> > (Christophe)
> > ---
> > MAINTAINERS | 1 +
> > drivers/nvmem/Kconfig | 12 +++
> > drivers/nvmem/Makefile | 2 +
> > drivers/nvmem/max77759-nvmem.c | 162
> > +++++++++++++++++++++++++++++++++++++++++
> > 4 files changed, 177 insertions(+)
> >
> > diff --git a/MAINTAINERS b/MAINTAINERS
> > index
> > 0db5e1fe64930e85265913e6a7dd2669c645cf42..b821502afc48f95d48fb8c6ac6941d1dd8e63582
> > 100644
> > --- a/MAINTAINERS
> > +++ b/MAINTAINERS
> > @@ -14670,6 +14670,7 @@ S: Maintained
> > F: Documentation/devicetree/bindings/*/maxim,max77759*.yaml
> > F: drivers/gpio/gpio-max77759.c
> > F: drivers/mfd/max77759.c
> > +F: drivers/nvmem/max77759-nvmem.c
> > F: include/linux/mfd/max77759.h
> >
> > MAXIM MAX77802 PMIC REGULATOR DEVICE DRIVER
> > diff --git a/drivers/nvmem/Kconfig b/drivers/nvmem/Kconfig
> > index
> > 8671b7c974b933e147154bb40b5d41b5730518d2..3de07ef524906ad24a89e58abdfe93529a83c80f
> > 100644
> > --- a/drivers/nvmem/Kconfig
> > +++ b/drivers/nvmem/Kconfig
> > @@ -154,6 +154,18 @@ config NVMEM_LPC18XX_OTP
> > To compile this driver as a module, choose M here: the module
> > will be called nvmem_lpc18xx_otp.
> >
> > +config NVMEM_MAX77759
> > + tristate "Maxim Integrated MAX77759 NVMEM Support"
> > + depends on MFD_MAX77759
> > + default MFD_MAX77759
> > + help
> > + Say Y here to include support for the user-accessible storage found
> > + in Maxim Integrated MAX77759 PMICs. This IC provides space for 30
> > + bytes of storage.
> > +
> > + This driver can also be built as a module. If so, the module
> > + will be called nvmem-max77759.
> > +
> > config NVMEM_MESON_EFUSE
> > tristate "Amlogic Meson GX eFuse Support"
> > depends on (ARCH_MESON || COMPILE_TEST) && MESON_SM
> > diff --git a/drivers/nvmem/Makefile b/drivers/nvmem/Makefile
> > index
> > 5b77bbb6488bf89bfb305750a1cbf4a6731a0a58..a9d03cfbbd27e68d40f8c330e72e20378b12a481
> > 100644
> > --- a/drivers/nvmem/Makefile
> > +++ b/drivers/nvmem/Makefile
> > @@ -34,6 +34,8 @@ obj-$(CONFIG_NVMEM_LPC18XX_EEPROM) +=
> > nvmem_lpc18xx_eeprom.o
> > nvmem_lpc18xx_eeprom-y := lpc18xx_eeprom.o
> > obj-$(CONFIG_NVMEM_LPC18XX_OTP) += nvmem_lpc18xx_otp.o
> > nvmem_lpc18xx_otp-y := lpc18xx_otp.o
> > +obj-$(CONFIG_NVMEM_MAX77759) += nvmem-max77759.o
> > +nvmem-max77759-y := max77759-nvmem.o
> > obj-$(CONFIG_NVMEM_MESON_EFUSE) += nvmem_meson_efuse.o
> > nvmem_meson_efuse-y := meson-efuse.o
> > obj-$(CONFIG_NVMEM_MESON_MX_EFUSE) += nvmem_meson_mx_efuse.o
> > diff --git a/drivers/nvmem/max77759-nvmem.c b/drivers/nvmem/max77759-nvmem.c
> > new file mode 100644
> > index
> > 0000000000000000000000000000000000000000..df7d1998fa2f116450d2fd50eba70d9b61a24574
> > --- /dev/null
> > +++ b/drivers/nvmem/max77759-nvmem.c
> > @@ -0,0 +1,162 @@
> > +// SPDX-License-Identifier: GPL-2.0-only
> > +//
> > +// Copyright 2020 Google Inc
> > +// Copyright 2025 Linaro Ltd.
> > +//
> > +// NVMEM driver for Maxim MAX77759
> > +
> > +#include <linux/dev_printk.h>
> > +#include <linux/device.h>
> > +#include <linux/device/driver.h>
> > +#include <linux/err.h>
> > +#include <linux/mfd/max77759.h>
> > +#include <linux/mod_devicetable.h>
> > +#include <linux/module.h>
> > +#include <linux/nvmem-provider.h>
> > +#include <linux/overflow.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/string.h>
> > +
> > +#define MAX77759_NVMEM_OPCODE_HEADER_LEN 3
> > +/*
> > + * NVMEM commands have a three byte header (which becomes part of the
> > command),
> > + * so we need to subtract that.
> > + */
> > +#define MAX77759_NVMEM_SIZE (MAX77759_MAXQ_OPCODE_MAXLENGTH \
> > + - MAX77759_NVMEM_OPCODE_HEADER_LEN)
> > +
> > +struct max77759_nvmem {
> > + struct device *dev;
> > + struct max77759 *max77759;
> > +};
> > +
> > +static bool max77759_nvmem_is_valid(unsigned int offset, size_t bytes)
> > +{
> > + return (offset + bytes - 1 <= MAX77759_NVMEM_SIZE);
> > +}
> Do you really need this check?
> nvmem core should take care of this boundary checks.
I think I went by what qcom-spmi-sdam is doing, but I now realise it's
doing a little bit more. Will drop.
Thanks Srini!
A.
