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Message-id: <53970994.8010400@samsung.com>
Date: Tue, 10 Jun 2014 15:35:16 +0200
From: Tomasz Figa <t.figa@...sung.com>
To: Pankaj Dubey <pankaj.dubey@...sung.com>,
linux-samsung-soc@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-arm-kernel@...ts.infradead.org
Cc: kgene.kim@...sung.com, arnd@...db.de,
Rob Herring <robh+dt@...nel.org>,
Randy Dunlap <rdunlap@...radead.org>,
Wolfram Sang <wsa@...-dreams.de>,
Russell King <linux@....linux.org.uk>,
devicetree@...r.kernel.org, linux-doc@...r.kernel.org,
linux-i2c@...r.kernel.org
Subject: Re: [PATCH v3 1/6] i2c: s3c2410: Handle i2c sys_cfg register in i2c
driver
Hi Pankaj,
On 10.05.2014 09:20, Pankaj Dubey wrote:
> Let's handle i2c interrupt re-configuration in i2c driver. This will
> help us in removing some soc specific checks from machine files.
> Since only Exynos5250, and Exynos5420 need to do this, added syscon
> based phandle to i2c device nodes of respective SoC DT files.
> Also handle saving and restoring of SYS_I2C_CFG register during
> suspend and resume of i2c driver. This will help in removing soc
> specific check from mach-exynos/pm.c.
>
> CC: Rob Herring <robh+dt@...nel.org>
> CC: Randy Dunlap <rdunlap@...radead.org>
> CC: Wolfram Sang <wsa@...-dreams.de>
> CC: Russell King <linux@....linux.org.uk>
> CC: devicetree@...r.kernel.org
> CC: linux-doc@...r.kernel.org
> CC: linux-i2c@...r.kernel.org
> Signed-off-by: Pankaj Dubey <pankaj.dubey@...sung.com>
> ---
> .../devicetree/bindings/arm/samsung/sysreg.txt | 1 +
> arch/arm/boot/dts/exynos5.dtsi | 5 +++
> arch/arm/boot/dts/exynos5250.dtsi | 4 +++
> arch/arm/boot/dts/exynos5420.dtsi | 4 +++
What about Exynos5410 and Exynos5800?
> drivers/i2c/busses/i2c-s3c2410.c | 32 ++++++++++++++++++++
> 5 files changed, 46 insertions(+)
[snip]
> diff --git a/drivers/i2c/busses/i2c-s3c2410.c b/drivers/i2c/busses/i2c-s3c2410.c
> index ae44910..e707062 100644
> --- a/drivers/i2c/busses/i2c-s3c2410.c
> +++ b/drivers/i2c/busses/i2c-s3c2410.c
> @@ -39,6 +39,8 @@
> #include <linux/of.h>
> #include <linux/of_gpio.h>
> #include <linux/pinctrl/consumer.h>
> +#include <linux/mfd/syscon.h>
> +#include <linux/regmap.h>
>
> #include <asm/irq.h>
>
> @@ -91,6 +93,9 @@
> /* Max time to wait for bus to become idle after a xfer (in us) */
> #define S3C2410_IDLE_TIMEOUT 5000
>
> +/* Exynos5 Sysreg offset */
> +#define EXYNOS5_SYS_I2C_CFG 0x0234
> +
> /* i2c controller state */
> enum s3c24xx_i2c_state {
> STATE_IDLE,
> @@ -127,6 +132,8 @@ struct s3c24xx_i2c {
> #if defined(CONFIG_ARM_S3C24XX_CPUFREQ)
> struct notifier_block freq_transition;
> #endif
> + struct regmap *sysreg;
> + unsigned int sys_i2s_cfg;
typo: s/i2s/i2c/
> };
>
> static struct platform_device_id s3c24xx_driver_ids[] = {
> @@ -1075,6 +1082,8 @@ static void
> s3c24xx_i2c_parse_dt(struct device_node *np, struct s3c24xx_i2c *i2c)
> {
> struct s3c2410_platform_i2c *pdata = i2c->pdata;
> + u32 val = 0;
> + int id;
>
> if (!np)
> return;
> @@ -1084,6 +1093,23 @@ s3c24xx_i2c_parse_dt(struct device_node *np, struct s3c24xx_i2c *i2c)
> of_property_read_u32(np, "samsung,i2c-slave-addr", &pdata->slave_addr);
> of_property_read_u32(np, "samsung,i2c-max-bus-freq",
> (u32 *)&pdata->frequency);
> + /*
> + * Exynos5's legacy i2c controller and new high speed i2c
> + * controller have muxed interrupt sources. By default the
What do you mean by "by default"? Is it a setting from the bootloader or
reset value?
Probably to ensure that the mux is set correctly, same thing should be
also added to hsi2c driver.
> + * interrupts for 4-channel HS-I2C controller are enabled.
> + * If node for first four channels of legacy i2c controller
> + * are available then re-configure the interrupts via the
> + * system register.
> + */
> + id = of_alias_get_id(np, "i2c");
> + i2c->sysreg = syscon_regmap_lookup_by_phandle(np,
> + "samsung,syscon-phandle");
> + if (IS_ERR(i2c->sysreg)) {
> + /* As this is not compulsory do not return error */
> + pr_info("i2c-%d skipping re-configuration of interrutps\n", id);
> + return;
> + }
> + regmap_update_bits(i2c->sysreg, EXYNOS5_SYS_I2C_CFG, BIT(id), val);
As Wolfram pointed, val can be replaced with immediate 0 here.
> }
> #else
> static void
> @@ -1268,6 +1294,9 @@ static int s3c24xx_i2c_suspend_noirq(struct device *dev)
>
> i2c->suspended = 1;
>
> + if (!IS_ERR(i2c->sysreg))
> + regmap_read(i2c->sysreg, EXYNOS5_SYS_I2C_CFG, &i2c->sys_i2s_cfg);
> +
> return 0;
> }
>
> @@ -1276,6 +1305,9 @@ static int s3c24xx_i2c_resume(struct device *dev)
> struct platform_device *pdev = to_platform_device(dev);
> struct s3c24xx_i2c *i2c = platform_get_drvdata(pdev);
>
> + if (!IS_ERR(i2c->sysreg))
> + regmap_write(i2c->sysreg, i2c->sys_i2s_cfg, EXYNOS5_SYS_I2C_CFG);
According to include/linux/regmap.h:
int regmap_write(struct regmap *map, unsigned int reg, unsigned int val);
So in your code reg is swapped with val.
Best regards,
Tomasz
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