From: Heiner Kallweit <hkallweit1@gmail.com> To: Wolfram Sang <wsa@the-dreams.de>, Jerome Brunet <jbrunet@baylibre.com> Cc: "linux-i2c@vger.kernel.org" <linux-i2c@vger.kernel.org>, linux-amlogic@lists.infradead.org Subject: [PATCH v2 04/10] i2c: meson: use full 12 bits for clock divider Date: Thu, 9 Mar 2017 07:40:46 +0100 [thread overview] Message-ID: <a61a6f48-a157-81ec-7f1b-09cb27b22613@gmail.com> (raw) In-Reply-To: <f39c9314-4314-3d98-aef2-3bc3c815e63b@gmail.com> The clock divider has 12 bits, splitted into a 10 bit field and a 2 bit field. The extra 2 bits aren't used currently. Change this to use the full 12 bits and warn if the requested frequency is too low. Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com> Acked-by: Jerome Brunet <jbrunet@baylibre.com> --- v2: - added Acked-by --- drivers/i2c/busses/i2c-meson.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) diff --git a/drivers/i2c/busses/i2c-meson.c b/drivers/i2c/busses/i2c-meson.c index 5e243efa..a5764be5 100644 --- a/drivers/i2c/busses/i2c-meson.c +++ b/drivers/i2c/busses/i2c-meson.c @@ -35,7 +35,9 @@ #define REG_CTRL_STATUS BIT(2) #define REG_CTRL_ERROR BIT(3) #define REG_CTRL_CLKDIV_SHIFT 12 -#define REG_CTRL_CLKDIV_MASK ((BIT(10) - 1) << REG_CTRL_CLKDIV_SHIFT) +#define REG_CTRL_CLKDIV_MASK GENMASK(21, 12) +#define REG_CTRL_CLKDIVEXT_SHIFT 28 +#define REG_CTRL_CLKDIVEXT_MASK GENMASK(29, 28) #define I2C_TIMEOUT_MS 500 @@ -136,8 +138,15 @@ static void meson_i2c_set_clk_div(struct meson_i2c *i2c) unsigned int div; div = DIV_ROUND_UP(clk_rate, i2c->timings.bus_freq_hz * 4); + + /* clock divider has 12 bits */ + WARN_ON(div >= (1 << 12)); + meson_i2c_set_mask(i2c, REG_CTRL, REG_CTRL_CLKDIV_MASK, - div << REG_CTRL_CLKDIV_SHIFT); + (div & GENMASK(9, 0)) << REG_CTRL_CLKDIV_SHIFT); + + meson_i2c_set_mask(i2c, REG_CTRL, REG_CTRL_CLKDIVEXT_MASK, + (div >> 10) << REG_CTRL_CLKDIVEXT_SHIFT); dev_dbg(i2c->dev, "%s: clk %lu, freq %u, div %u\n", __func__, clk_rate, i2c->timings.bus_freq_hz, div); -- 2.12.0
WARNING: multiple messages have this Message-ID (diff)
From: hkallweit1@gmail.com (Heiner Kallweit) To: linus-amlogic@lists.infradead.org Subject: [PATCH v2 04/10] i2c: meson: use full 12 bits for clock divider Date: Thu, 9 Mar 2017 07:40:46 +0100 [thread overview] Message-ID: <a61a6f48-a157-81ec-7f1b-09cb27b22613@gmail.com> (raw) In-Reply-To: <f39c9314-4314-3d98-aef2-3bc3c815e63b@gmail.com> The clock divider has 12 bits, splitted into a 10 bit field and a 2 bit field. The extra 2 bits aren't used currently. Change this to use the full 12 bits and warn if the requested frequency is too low. Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com> Acked-by: Jerome Brunet <jbrunet@baylibre.com> --- v2: - added Acked-by --- drivers/i2c/busses/i2c-meson.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) diff --git a/drivers/i2c/busses/i2c-meson.c b/drivers/i2c/busses/i2c-meson.c index 5e243efa..a5764be5 100644 --- a/drivers/i2c/busses/i2c-meson.c +++ b/drivers/i2c/busses/i2c-meson.c @@ -35,7 +35,9 @@ #define REG_CTRL_STATUS BIT(2) #define REG_CTRL_ERROR BIT(3) #define REG_CTRL_CLKDIV_SHIFT 12 -#define REG_CTRL_CLKDIV_MASK ((BIT(10) - 1) << REG_CTRL_CLKDIV_SHIFT) +#define REG_CTRL_CLKDIV_MASK GENMASK(21, 12) +#define REG_CTRL_CLKDIVEXT_SHIFT 28 +#define REG_CTRL_CLKDIVEXT_MASK GENMASK(29, 28) #define I2C_TIMEOUT_MS 500 @@ -136,8 +138,15 @@ static void meson_i2c_set_clk_div(struct meson_i2c *i2c) unsigned int div; div = DIV_ROUND_UP(clk_rate, i2c->timings.bus_freq_hz * 4); + + /* clock divider has 12 bits */ + WARN_ON(div >= (1 << 12)); + meson_i2c_set_mask(i2c, REG_CTRL, REG_CTRL_CLKDIV_MASK, - div << REG_CTRL_CLKDIV_SHIFT); + (div & GENMASK(9, 0)) << REG_CTRL_CLKDIV_SHIFT); + + meson_i2c_set_mask(i2c, REG_CTRL, REG_CTRL_CLKDIVEXT_MASK, + (div >> 10) << REG_CTRL_CLKDIVEXT_SHIFT); dev_dbg(i2c->dev, "%s: clk %lu, freq %u, div %u\n", __func__, clk_rate, i2c->timings.bus_freq_hz, div); -- 2.12.0
next prev parent reply other threads:[~2017-03-09 7:10 UTC|newest] Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top 2017-03-09 6:33 [PATCH v2 00/10] i2c: meson: series with improvements Heiner Kallweit 2017-03-09 6:33 ` Heiner Kallweit 2017-03-09 6:35 ` [PATCH v2 01/10] i2c: meson: i2c: meson: use min instead of min_t where min_t isn't needed Heiner Kallweit 2017-03-09 6:35 ` Heiner Kallweit 2017-03-09 6:37 ` [PATCH v2 02/10] i2c: meson: remove member irq from struct meson_i2c Heiner Kallweit 2017-03-09 6:37 ` Heiner Kallweit 2017-03-09 6:39 ` [PATCH v2 03/10] i2c: meson: use i2c core for DT clock-frequency parsing Heiner Kallweit 2017-03-09 6:39 ` Heiner Kallweit 2017-03-09 8:26 ` Neil Armstrong 2017-03-09 8:26 ` Neil Armstrong 2017-03-09 20:13 ` Heiner Kallweit 2017-03-09 20:13 ` Heiner Kallweit 2017-03-09 6:40 ` Heiner Kallweit [this message] 2017-03-09 6:40 ` [PATCH v2 04/10] i2c: meson: use full 12 bits for clock divider Heiner Kallweit 2017-03-09 6:42 ` [PATCH v2 05/10] i2c: meson: set clock divider in probe instead of setting it for each transfer Heiner Kallweit 2017-03-09 6:42 ` Heiner Kallweit 2017-03-10 23:17 ` Kevin Hilman 2017-03-10 23:17 ` Kevin Hilman 2017-03-10 23:36 ` Heiner Kallweit 2017-03-10 23:36 ` Heiner Kallweit 2017-03-09 6:43 ` [PATCH v2 06/10] i2c: meson: remove variable count from meson_i2c_xfer Heiner Kallweit 2017-03-09 6:43 ` Heiner Kallweit 2017-03-09 6:53 ` [PATCH v2 07/10] i2c: meson: improve interrupt handler and detect spurious interrupts Heiner Kallweit 2017-03-09 6:53 ` Heiner Kallweit 2017-03-09 6:56 ` [PATCH v2 08/10] i2c: meson: don't create separate token chain just for the stop command Heiner Kallweit 2017-03-09 6:56 ` Heiner Kallweit 2017-03-09 6:58 ` [PATCH v2 09/10] i2c: meson: remove meson_i2c_write_tokens Heiner Kallweit 2017-03-09 6:58 ` Heiner Kallweit 2017-03-09 7:01 ` [PATCH v2 10/10] i2c: meson: improve and simplify interrupt handler Heiner Kallweit 2017-03-09 7:01 ` Heiner Kallweit
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