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Thu, 02 Apr 2026 07:19:40 -0700 (PDT) From: Anand Moon To: Heiko Stuebner , Andi Shyti , linux-arm-kernel@lists.infradead.org (moderated list:ARM/Rockchip SoC support), linux-rockchip@lists.infradead.org (open list:ARM/Rockchip SoC support), linux-i2c@vger.kernel.org (open list:I2C SUBSYSTEM HOST DRIVERS), linux-kernel@vger.kernel.org (open list) Cc: Anand Moon Subject: [PATCH v3 2/2] i2c: rk3x: Fix deadlock by splitting rk3x_i2c_adapt_div into locked/unlocked variants Date: Thu, 2 Apr 2026 19:49:23 +0530 Message-ID: <20260402141927.7216-2-linux.amoon@gmail.com> X-Mailer: git-send-email 2.50.1 In-Reply-To: <20260402141927.7216-1-linux.amoon@gmail.com> References: <20260402141927.7216-1-linux.amoon@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Introduce __rk3x_i2c_adapt_div() function as a locked-only helper to handle core timing calculations and register updates. This restructuring allows these operations to be safely called from contexts where i2c->lock is already held—such as during error recovery in rk3x_i2c_xfer_common avoiding recursive locking or deadlocks. Signed-off-by: Anand Moon --- v3: new patch to avoid deadlock. --- drivers/i2c/busses/i2c-rk3x.c | 25 +++++++++++++++---------- 1 file changed, 15 insertions(+), 10 deletions(-) diff --git a/drivers/i2c/busses/i2c-rk3x.c b/drivers/i2c/busses/i2c-rk3x.c index 06a77780cf82..2556a3d8b2a1 100644 --- a/drivers/i2c/busses/i2c-rk3x.c +++ b/drivers/i2c/busses/i2c-rk3x.c @@ -880,22 +880,18 @@ static int rk3x_i2c_v1_calc_timings(unsigned long clk_rate, return ret; } -static void rk3x_i2c_adapt_div(struct rk3x_i2c *i2c, unsigned long clk_rate) +static void __rk3x_i2c_adapt_div(struct rk3x_i2c *i2c, unsigned long clk_rate) { struct i2c_timings *t = &i2c->t; struct rk3x_i2c_calced_timings calc; unsigned long period, time_hold = (WAIT_TIMEOUT / 2) * 1000000; u64 t_low_ns, t_high_ns; - unsigned long flags; u32 val; int ret; ret = i2c->soc_data->calc_timings(clk_rate, t, &calc); WARN_ONCE(ret != 0, "Could not reach SCL freq %u", t->bus_freq_hz); - clk_enable(i2c->pclk); - - spin_lock_irqsave(&i2c->lock, flags); val = i2c_readl(i2c, REG_CON); val &= ~REG_CON_TUNING_MASK; val |= calc.tuning; @@ -909,10 +905,6 @@ static void rk3x_i2c_adapt_div(struct rk3x_i2c *i2c, unsigned long clk_rate) i2c_writel(i2c, val, REG_SCL_OE_DB); } - spin_unlock_irqrestore(&i2c->lock, flags); - - clk_disable(i2c->pclk); - t_low_ns = div_u64(8ULL * HZ_PER_GHZ * (calc.div_low + 1), clk_rate); t_high_ns = div_u64(8ULL * HZ_PER_GHZ * (calc.div_high + 1), clk_rate); dev_dbg(i2c->dev, @@ -922,6 +914,19 @@ static void rk3x_i2c_adapt_div(struct rk3x_i2c *i2c, unsigned long clk_rate) t_low_ns, t_high_ns); } +static void rk3x_i2c_adapt_div(struct rk3x_i2c *i2c, unsigned long clk_rate) +{ + unsigned long flags; + + clk_enable(i2c->pclk); + + spin_lock_irqsave(&i2c->lock, flags); + __rk3x_i2c_adapt_div(i2c, clk_rate); + spin_unlock_irqrestore(&i2c->lock, flags); + + clk_disable(i2c->pclk); +} + /** * rk3x_i2c_clk_notifier_cb - Clock rate change callback * @nb: Pointer to notifier block @@ -1152,7 +1157,7 @@ static int rk3x_i2c_xfer_common(struct i2c_adapter *adap, if (ret == -ETIMEDOUT && i2c->soc_data->has_scl_oe_debounce) { if (ipd & REG_INT_SLV_HDSCL) { dev_err(i2c->dev, "SCL hold by slave detected, resetting timings.\n"); - rk3x_i2c_adapt_div(i2c, clk_get_rate(i2c->clk)); + __rk3x_i2c_adapt_div(i2c, clk_get_rate(i2c->clk)); } } -- 2.50.1